faastjs/dist/faastjs.d.ts

/**
 * Faast.js transforms ordinary JavaScript modules into serverless cloud
 * functions that can run on AWS Lambda.
 *
 * The main entry point to faast.js is the {@link faast} function, which returns
 * an object that implements the {@link FaastModule} interface. The most common
 * options are {@link CommonOptions}. Using faast.js requires writing two
 * modules, one containing the functions to upload to the cloud, and the other
 * that invokes faast.js and calls the resulting cloud functions.
 * @packageDocumentation
 */

/// <reference types="node" />

import childProcess from 'child_process';
import { CloudWatchLogs } from '@aws-sdk/client-cloudwatch-logs';
import { CreateFunctionRequest } from '@aws-sdk/client-lambda';
import { default as debug_2 } from 'debug';
import { IAM } from '@aws-sdk/client-iam';
import { Lambda } from '@aws-sdk/client-lambda';
import { Pricing } from '@aws-sdk/client-pricing';
import { S3 } from '@aws-sdk/client-s3';
import { SNS } from '@aws-sdk/client-sns';
import { SQS } from '@aws-sdk/client-sqs';
import { STS } from '@aws-sdk/client-sts';
import { VError } from 'verror';
import webpack from 'webpack';
import { Writable } from 'stream';

declare type AnyFunction = (...args: any[]) => any;

/**
 * `Async<T>` maps regular values to Promises and Iterators to AsyncIterators,
 * If `T` is already a Promise or an AsyncIterator, it remains the same. This
 * type is used to infer the return value of cloud functions from the types of
 * the functions in the user's input module.
 * @public
 */
export declare type Async<T> = T extends AsyncGenerator<infer R> ? AsyncGenerator<R> : T extends Generator<infer R> ? AsyncGenerator<R> : T extends Promise<infer R> ? Promise<R> : Promise<T>;

/**
 * `AsyncDetail<T>` is similar to {@link Async} except it maps retun values R to
 * `Detail<R>`, which is the return value with additional information about each
 * cloud function invocation.
 * @public
 */
export declare type AsyncDetail<T> = T extends AsyncGenerator<infer R> ? AsyncGenerator<Detail<R>> : T extends Generator<infer R> ? AsyncGenerator<Detail<R>> : T extends Promise<infer R> ? Promise<Detail<R>> : Promise<Detail<T>>;

declare class AsyncIterableQueue<T> extends AsyncQueue<IteratorResult<T>> {
    push(value: T | Promise<T>): void;
    done(): void;
    [Symbol.asyncIterator](): this;
}

declare class AsyncQueue<T> {
    protected deferred: Array<Deferred<T>>;
    protected enqueued: Promise<T>[];
    enqueue(value: T | Promise<T>): void;
    next(): Promise<T>;
    clear(): void;
}

/**
 * Factory for AWS service clients, which allows for custom construction and configuration.
 * {@link https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/index.html#configuration | AWS Configuration}.
 * @public
 * @remarks
 * This is an advanced option. This provides a way for a faast.js client to
 * instantiate AWS service objects for itself to provide custom options.
 * Note that if you create a service object yourself, it won't have the
 * default options that faast.js would use, which are:
 *
 * - maxAttempts (faast.js default: 6)
 * - region (faast.js default: "us-west-2")
 * - logger (faast.js default: log.awssdk)
 */
export declare interface AwsClientFactory {
    createCloudWatchLogs?: () => CloudWatchLogs;
    createIAM?: () => IAM;
    createLambda?: () => Lambda;
    /**
     * A special AWS Lambda factory for creating lambda functions that are
     * used for faast.js invocations. These special clients have the following
     * options set by default in faast.js:
     *
     *  // Retries are handled by faast.js, not the sdk.
     *  maxAttempts: 0,
     */
    createLambdaForInvocations?: () => Lambda;
    createPricing?: () => Pricing;
    createS3?: () => S3;
    createSNS?: () => SNS;
    createSQS?: () => SQS;
    createSts?: () => STS;
}

/**
 * The return type of {@link faastAws}. See {@link FaastModuleProxy}.
 * @public
 */
export declare type AwsFaastModule<M extends object = object> = FaastModuleProxy<M, AwsOptions, AwsState>;

declare type AwsGcWork = {
    type: "SetLogRetention";
    logGroupName: string;
    retentionInDays: number;
} | {
    type: "DeleteResources";
    resources: AwsResources;
} | {
    type: "DeleteLayerVersion";
    LayerName: string;
    VersionNumber: number;
};

declare interface AwsLayerInfo {
    Version: number;
    LayerVersionArn: string;
    LayerName: string;
}

declare class AwsMetrics {
    outboundBytes: number;
    sns64kRequests: number;
    sqs64kRequests: number;
}

/**
 * AWS-specific options for {@link faastAws}.
 * @public
 */
export declare interface AwsOptions extends CommonOptions {
    /**
     * The region to create resources in. Garbage collection is also limited to
     * this region. Default: `"us-west-2"`.
     */
    region?: AwsRegion;
    /**
     * The role that the lambda function will assume when executing user code.
     * Default: `"faast-cached-lambda-role"`. Rarely used.
     * @remarks
     * When a lambda executes, it first assumes an
     * {@link https://docs.aws.amazon.com/lambda/latest/dg/lambda-intro-execution-role.html | execution role}
     * to grant access to resources.
     *
     * By default, faast.js creates this execution role for you and leaves it
     * permanently in your account (the role is shared across all lambda
     * functions created by faast.js). By default, faast.js grants administrator
     * privileges to this role so your code can perform any AWS operation it
     * requires.
     *
     * You can
     * {@link https://console.aws.amazon.com/iam/home#/roles | create a custom role}
     * that specifies more limited permissions if you prefer not to grant
     * administrator privileges. Any role you assign for faast.js modules needs
     * at least the following permissions:
     *
     * - Execution Role:
     * ```json
     *   {
     *       "Version": "2012-10-17",
     *       "Statement": [
     *           {
     *               "Effect": "Allow",
     *               "Action": ["logs:*"],
     *               "Resource": "arn:aws:logs:*:*:log-group:faast-*"
     *           },
     *           {
     *               "Effect": "Allow",
     *               "Action": ["sqs:*"],
     *               "Resource": "arn:aws:sqs:*:*:faast-*"
     *           }
     *       ]
     *   }
     * ```
     *
     * - Trust relationship (also known as `AssumeRolePolicyDocument` in the AWS
     *   SDK):
     * ```json
     *   {
     *     "Version": "2012-10-17",
     *     "Statement": [
     *       {
     *         "Effect": "Allow",
     *         "Principal": {
     *           "Service": "lambda.amazonaws.com"
     *         },
     *         "Action": "sts:AssumeRole"
     *       }
     *     ]
     *   }
     * ```
     *
     */
    RoleName?: string;
    /**
     * Additional options to pass to AWS Lambda creation. See
     * {@link https://docs.aws.amazon.com/lambda/latest/dg/API_CreateFunction.html | CreateFunction}.
     * @remarks
     * If you need specialized options, you can pass them to the AWS Lambda SDK
     * directly. Note that if you override any settings set by faast.js, you may
     * cause faast.js to not work:
     *
     * ```typescript
     *   const request: aws.Lambda.CreateFunctionRequest = {
     *       FunctionName,
     *       Role,
     *       Runtime: "nodejs18.x",
     *       Handler: "index.trampoline",
     *       Code,
     *       Description: "faast trampoline function",
     *       Timeout,
     *       MemorySize,
     *       ...awsLambdaOptions
     *   };
     * ```
     */
    awsLambdaOptions?: Partial<CreateFunctionRequest>;
    /**
     * AWS service factories. See {@link AwsClientFactory}.
     */
    awsClientFactory?: AwsClientFactory;
    /** @internal */
    _gcWorker?: (work: AwsGcWork, services: AwsServices) => Promise<void>;
}

/**
 * Valid AWS
 * {@link https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html | regions}.
 * Not all of these regions have Lambda support.
 * @public
 */
export declare type AwsRegion = "us-east-1" | "us-east-2" | "us-west-1" | "us-west-2" | "ca-central-1" | "eu-central-1" | "eu-west-1" | "eu-west-2" | "eu-west-3" | "ap-northeast-1" | "ap-northeast-2" | "ap-northeast-3" | "ap-southeast-1" | "ap-southeast-2" | "ap-south-1" | "sa-east-1";

declare interface AwsResources {
    FunctionName: string;
    RoleName: string;
    region: AwsRegion;
    ResponseQueueUrl?: string;
    ResponseQueueArn?: string;
    RequestTopicArn?: string;
    SNSLambdaSubscriptionArn?: string;
    logGroupName: string;
    layer?: AwsLayerInfo;
    Bucket?: string;
}

declare interface AwsServices {
    readonly lambda: Lambda;
    readonly lambda2: Lambda;
    readonly cloudwatch: CloudWatchLogs;
    readonly iam: IAM;
    readonly sqs: SQS;
    readonly sns: SNS;
    readonly pricing: Pricing;
    readonly sts: STS;
    readonly s3: S3;
}

/**
 * @public
 */
declare interface AwsState {
    /** @internal */
    resources: AwsResources;
    /** @internal */
    services: AwsServices;
    /** @internal */
    options: Required<AwsOptions>;
    /** @internal */
    metrics: AwsMetrics;
    /** @internal */
    gcPromise?: Promise<"done" | "skipped">;
}

declare interface CallId {
    callId: string;
}

declare type CallId_2 = string;

declare interface CallingContext {
    call: FunctionCall;
    startTime: number;
    logUrl?: string;
    executionId?: string;
    instanceId?: string;
}

/**
 * Options that apply to the {@link FaastModule.cleanup} method.
 * @public
 */
export declare interface CleanupOptions {
    /**
     * If true, delete provider cloud resources. Default: true.
     * @remarks
     * The cleanup operation has two functions: stopping the faast.js runtime
     * and deleting cloud resources that were instantiated. If `deleteResources`
     * is false, then only the runtime is stopped and no cloud resources are
     * deleted. This can be useful for debugging and examining the state of
     * resources created by faast.js.
     *
     * It is supported to call {@link FaastModule.cleanup} twice: once with
     * `deleteResources` set to `false`, which only stops the runtime, and then
     * again set to `true` to delete resources. This can be useful for testing.
     */
    deleteResources?: boolean;
    /**
     * If true, delete cached resources. Default: false.
     * @remarks
     * Some resources are cached persistently between calls for performance
     * reasons. If this option is set to true, these cached resources are
     * deleted when cleanup occurs, instead of being left behind for future use.
     * For example, on AWS this includes the Lambda Layers that are created for
     * {@link CommonOptions.packageJson} dependencies. Note that only the cached
     * resources created by this instance of FaastModule are deleted, not cached
     * resources from other FaastModules. This is similar to setting
     * `useCachedDependencies` to `false` during function construction, except
     * `deleteCaches` can be set at function cleanup time, and any other
     * FaastModules created before cleanup may use the cached Layers.
     */
    deleteCaches?: boolean;
    /**
     * Number of seconds to wait for garbage collection. Default: 10.
     * @remarks
     * Garbage collection can still be operating when cleanup is called; this
     * option limits the amount of time faast waits for the garbage collector.
     * If set to 0, the wait is unlimited.
     */
    gcTimeout?: number;
}

/**
 * Options common across all faast.js providers. Used as argument to {@link faast}.
 * @remarks
 * There are also more specific options for each provider. See
 * {@link AwsOptions} and {@link LocalOptions}.
 * @public
 */
export declare interface CommonOptions {
    /**
     * If true, create a child process to isolate user code from faast
     * scaffolding. Default: true.
     * @remarks
     * If a child process is not created, faast runs in the same node instance
     * as the user code and may not execute in a timely fashion because user
     * code may
     * {@link https://nodejs.org/en/docs/guides/dont-block-the-event-loop/ | block the event loop}.
     * Creating a child process for user code allows faast.js to continue
     * executing even if user code never yields. This provides better
     * reliability and functionality:
     *
     * - Detect timeout errors more reliably, even if the function doesn't
     *   relinquish the CPU. Not applicable to AWS, which sends separate failure
     *   messages in case of timeout. See {@link CommonOptions.timeout}.
     *
     * - CPU metrics used for detecting invocations with high latency, which can
     *   be used for automatically retrying calls to reduce tail latency.
     *
     * The cost of creating a child process is mainly in the memory overhead of
     * creating another node process.
     */
    childProcess?: boolean;
    /**
     * When childProcess is true, the child process will be spawned with the
     * value of this property as the setting for --max-old-space-size.
     * @remarks
     * This is useful if a function requires the node process to limit its
     * memory so that another spawned process (e.g. a browser instance) can use
     * the rest.
     * @public
     */
    childProcessMemoryMb?: number;
    /**
     * The maximum number of concurrent invocations to allow. Default: 100,
     * except for the `local` provider, where the default is 10.
     * @remarks
     * The concurrency limit applies to all invocations of all of the faast
     * functions summed together. It is not a per-function limit. To apply a
     * per-function limit, use {@link throttle}. A value of 0 is equivalent to
     * Infinity. A value of 1 ensures mutually exclusive invocations.
     */
    concurrency?: number;
    /**
     * A user-supplied description for this function, which may make it easier
     * to track different functions when multiple functions are created.
     */
    description?: string;
    /**
     * Exclude a subset of files included by {@link CommonOptions.include}.
     * @remarks
     * The exclusion can be a directory or glob. Exclusions apply to all included
     * entries.
     */
    exclude?: string[];
    /**
     * Rate limit invocations (invocations/sec). Default: no rate limit.
     * @remarks
     * Some services cannot handle more than a certain number of requests per
     * second, and it is easy to overwhelm them with a large number of cloud
     * functions. Specify a rate limit in invocation/second to restrict how
     * faast.js issues requests.
     */
    rate?: number;
    /**
     * Environment variables available during serverless function execution.
     * Default: \{\}.
     */
    env?: {
        [key: string]: string;
    };
    /**
     * Garbage collector mode. Default: `"auto"`.
     * @remarks
     * Garbage collection deletes resources that were created by previous
     * instantiations of faast that were not cleaned up by
     * {@link FaastModule.cleanup}, either because it was not called or because
     * the process terminated and did not execute this cleanup step. In `"auto"`
     * mode, garbage collection may be throttled to run up to once per hour no
     * matter how many faast.js instances are created. In `"force"` mode,
     * garbage collection is run without regard to whether another gc has
     * already been performed recently. In `"off"` mode, garbage collection is
     * skipped entirely. This can be useful for performance-sensitive tests, or
     * for more control over when gc is performed.
     *
     * Garbage collection is cloud-specific, but in general garbage collection
     * should not interfere with the behavior or performance of faast cloud
     * functions. When {@link FaastModule.cleanup} runs, it waits for garbage
     * collection to complete. Therefore the cleanup step can in some
     * circumstances take a significant amount of time even after all
     * invocations have returned.
     *
     * It is generally recommended to leave garbage collection in `"auto"` mode,
     * otherwise garbage resources may accumulate over time and you will
     * eventually hit resource limits on your account.
     *
     * Also see {@link CommonOptions.retentionInDays}.
     */
    gc?: "auto" | "force" | "off";
    /**
     * Include files to make available in the remote function. See
     * {@link IncludeOption}.
     * @remarks
     * Each include entry is a directory or glob pattern. Paths can be specified
     * as relative or absolute paths. Relative paths are resolved relative to
     * the current working directory, or relative to the `cwd` option.
     *
     * If the include entry is a directory `"foo/bar"`, the directory
     * `"./foo/bar"` will be available in the cloud function. Directories are
     * recursively added.
     *
     * Glob patterns use the syntax of
     * {@link https://github.com/isaacs/node-glob | node glob}.
     *
     * Also see {@link CommonOptions.exclude} for file exclusions.
     */
    include?: (string | IncludeOption)[];
    /**
     * Maximum number of times that faast will retry each invocation. Default: 2
     * (invocations can therefore be attemped 3 times in total).
     * @remarks
     * Retries are automatically attempted for transient infrastructure-level
     * failures such as rate limits or netowrk failures. User-level exceptions
     * are not retried automatically. In addition to retries performed by faast,
     * some providers automatically attempt retries. These are not controllable
     * by faast. But as a result, your function may be retried many more times
     * than this setting suggests.
     */
    maxRetries?: number;
    /**
     * Memory limit for each function in MB. This setting has an effect on
     * pricing. Default varies by provider.
     * @remarks
     * Each provider has different settings for memory size, and performance
     * varies depending on the setting. By default faast picks a likely optimal
     * value for each provider.
     *
     * - aws: 1728MB
     *
     * - local: 512MB (however, memory size limits aren't reliable in local mode.)
     */
    memorySize?: number;
    /**
     * Specify invocation mode. Default: `"auto"`.
     * @remarks
     * Modes specify how invocations are triggered. In https mode, the functions
     * are invoked through an https request or the provider's API. In queue
     * mode, a provider-specific queue is used to invoke functions. Queue mode
     * adds additional latency and (usually negligible) cost, but may scale
     * better for some providers. In auto mode the best default is chosen for
     * each provider depending on its particular performance characteristics.
     *
     * The defaults are:
     *
     * - aws: `"auto"` is `"https"`. In https mode, the AWS SDK api
     *   is used to invoke functions. In queue mode, an AWS SNS topic is created
     *   and triggers invocations. The AWS API Gateway service is never used by
     *   faast, as it incurs a higher cost and is not needed to trigger
     *   invocations.
     *
     * - local: The local provider ignores the mode setting and always uses an
     *   internal asynchronous queue to schedule calls.
     *
     * Size limits are affected by the choice of mode. On AWS the limit is 256kb
     * for arguments and return values in `"queue"` mode, and 6MB for `"https"`
     * mode.
     *
     * Note that no matter which mode is selected, faast.js always creates a
     * queue for sending back intermediate results for bookeeping and
     * performance monitoring.
     */
    mode?: "https" | "queue" | "auto";
    /**
     * Specify a package.json file to include with the code package.
     * @remarks
     * By default, faast.js will use webpack to bundle dependencies your remote
     * module imports. In normal usage there is no need to specify a separate
     * package.json, as webpack will statically analyze your imports and
     * determine which files to bundle.
     *
     * However, there are some use cases where this is not enough. For example,
     * some dependencies contain native code compiled during installation, and
     * webpack cannot bundle these native modules. such as dependencies with
     * native code.  or are specifically not designed to work with webpack. In
     * these cases, you can create a separate `package.json` for these
     * dependencies and pass the filename as the `packageJson` option. If
     * `packageJson` is an `object`, it is assumed to be a parsed JSON object
     * with the same structure as a package.json file (useful for specifying a
     * synthetic `package.json` directly in code).
     *
     * The way the `packageJson` is handled varies by provider:
     *
     * - local: Runs `npm install` in a temporary directory it prepares for the
     *   function.
     *
     * - aws: Recursively calls faast.js to run `npm install` inside a separate
     *   lambda function specifically created for this purpose. Faast.js uses
     *   lambda to install dependencies to ensure that native dependencies are
     *   compiled in an environment that can produce binaries linked against
     *   lambda's
     *   {@link https://aws.amazon.com/blogs/compute/running-executables-in-aws-lambda/ | execution environment}.
     *   Packages are saved in a Lambda Layer.
     *
     * For AWS, if {@link CommonOptions.useDependencyCaching} is `true` (which
     * is the default), then the Lambda Layer created will be reused in future
     * function creation requests if the contents of `packageJson` are the same.
     *
     * The `FAAST_PACKAGE_DIR` environment variable can be useful for debugging
     * `packageJson` issues.
     */
    packageJson?: string | object;
    /**
     * Cache installed dependencies from {@link CommonOptions.packageJson}. Only
     * applies to AWS. Default: true.
     * @remarks
     * If `useDependencyCaching` is `true`, The resulting `node_modules` folder
     * is cached in a Lambda Layer with the name `faast-${key}`, where `key` is
     * the SHA1 hash of the `packageJson` contents. These cache entries are
     * removed by garbage collection, by default after 24h. Using caching
     * reduces the need to install and upload dependencies every time a function
     * is created. This is important for AWS because it creates an entirely
     * separate lambda function to install dependencies remotely, which can
     * substantially increase function deployment time.
     *
     * If `useDependencyCaching` is false, the lambda layer is created with the
     * same name as the lambda function, and then is deleted when cleanup is
     * run.
     */
    useDependencyCaching?: boolean;
    /**
     * Specify how many days to wait before reclaiming cloud garbage. Default:
     * 1.
     * @remarks
     * Garbage collection only deletes resources after they age beyond a certain
     * number of days. This option specifies how many days old a resource needs
     * to be before being considered garbage by the collector. Note that this
     * setting is not recorded when the resources are created. For example,
     * suppose this is the sequence of events:
     *
     * - Day 0: `faast()` is called with `retentionInDays` set to 5. Then, the
     *   function crashes (or omits the call to {@link FaastModule.cleanup}).
     *
     * - Day 1: `faast()` is called with `retentionInDays` set to 1.
     *
     * In this sequence of events, on Day 0 the garbage collector runs and
     * removes resources with age older than 5 days. Then the function leaves
     * new garbage behind because it crashed or did not complete cleanup. On Day
     * 1, the garbage collector runs and deletes resources at least 1 day old,
     * which includes garbage left behind from Day 0 (based on the creation
     * timestamp of the resources). This deletion occurs even though retention
     * was set to 5 days when resources were created on Day 0.
     *
     * Note that if `retentionInDays` is set to 0, garbage collection will
     * remove all resources, even ones that may be in use by other running faast
     * instances. Not recommended.
     *
     * See {@link CommonOptions.gc}.
     */
    retentionInDays?: number;
    /**
     * Reduce tail latency by retrying invocations that take substantially
     * longer than other invocations of the same function. Default: 3.
     * @remarks
     * faast.js automatically measures the mean and standard deviation (σ) of
     * the time taken by invocations of each function. Retries are attempted
     * when the time for an invocation exceeds the mean time by a certain
     * threshold. `speculativeRetryThreshold` specifies how many multiples of σ
     * an invocation needs to exceed the mean for a given function before retry
     * is attempted.
     *
     * The default value of σ is 3. This means a call to a function is retried
     * when the time to execute exceeds three standard deviations from the mean
     * of all prior executions of the same function.
     *
     * This feature is experimental.
     * @beta
     */
    speculativeRetryThreshold?: number;
    /**
     * Execution time limit for each invocation, in seconds. Default: 60.
     * @remarks
     * Each provider has a maximum time limit for how long invocations can run
     * before being automatically terminated (or frozen). The following are the
     * maximum time limits as of February 2019:
     *
     * - aws:
     *   {@link https://docs.aws.amazon.com/lambda/latest/dg/limits.html | 15 minutes}
     *
     * - local: unlimited
     *
     * Faast.js has a proactive timeout detection feature. It automatically
     * attempts to detect when the time limit is about to be reached and
     * proactively sends a timeout exception. Faast does this because not all
     * providers reliably send timely feedback when timeouts occur, leaving
     * developers to look through cloud logs. In general faast.js' timeout will
     * be up to 5s earlier than the timeout specified, in order to give time to
     * allow faast.js to send a timeout message. Proactive timeout detection
     * only works with {@link CommonOptions.childProcess} set to `true` (the
     * default).
     */
    timeout?: number;
    /**
     * Extra webpack options to use to bundle the code package.
     * @remarks
     * By default, faast.js uses webpack to bundle the code package. Webpack
     * automatically handles finding and bundling dependencies, adding source
     * mappings, etc. If you need specialized bundling, use this option to add
     * or override the default webpack configuration. The library
     * {@link https://github.com/survivejs/webpack-merge | webpack-merge} is
     * used to combine configurations.
     *
     * ```typescript
     * const config: webpack.Configuration = merge({
     *     entry,
     *     mode: "development",
     *     output: {
     *         path: "/",
     *         filename: outputFilename,
     *         libraryTarget: "commonjs2"
     *     },
     *     target: "node",
     *     resolveLoader: { modules: [__dirname, `${__dirname}/dist`] },
     *     node: { global: true, __dirname: false, __filename: false }
     *   },
     *   webpackOptions);
     * ```
     *
     * Take care when setting the values of `entry`, `output`, or
     * `resolveLoader`. If these options are overwritten, faast.js may fail to
     * bundle your code. In particular, setting `entry` to an array value will
     * help `webpack-merge` to concatenate its value instead of replacing the
     * value that faast.js inserts for you.
     *
     * Default:
     *
     * - aws: `{ externals: [new RegExp("^aws-sdk/?")] }`. In the lambda
     *   environment `"aws-sdk"` is available in the ambient environment and
     *   does not need to be bundled.
     *
     * - other providers: `{}`
     *
     * The `FAAST_PACKAGE_DIR` environment variable can be useful for debugging
     * webpack issues.
     */
    webpackOptions?: webpack.Configuration;
    /**
     * Check arguments and return values from cloud functions are serializable
     * without losing information. Default: true.
     * @remarks
     * Arguments to cloud functions are automatically serialized with
     * `JSON.stringify` with a custom replacer that handles built-in JavaScript
     * types such as `Date` and `Buffer`. Return values go through the same
     * process. Some JavaScript objects cannot be serialized. By default
     * `validateSerialization` will verify that every argument and return value
     * can be serialized and deserialized without losing information. A
     * `FaastError` will be thrown if faast.js detects a problem according to
     * the following procedure:
     *
     * 1. Serialize arguments and return values with `JSON.stringify` using a
     *    special `replacer` function.
     *
     * 2. Deserialize the values with `JSON.parse` with a special `reviver`
     *    function.
     *
     * 3. Use
     *    {@link https://nodejs.org/api/assert.html#assert_assert_deepstrictequal_actual_expected_message | assert.deepStringEqual}
     *    to compare the original object with the deserialized object from step
     *    2.
     *
     * There is some overhead to this process because each argument is
     * serialized and deserialized, which can be costly if arguments or return
     * values are large.
     */
    validateSerialization?: boolean;
    /**
     * Debugging output options.
     * @internal
     */
    debugOptions?: {
        [key: string]: boolean;
    };
}

/**
 * Analyze the cost of a workload across many provider configurations.
 * @public
 */
export declare namespace CostAnalyzer {
    /**
     * An input to {@link CostAnalyzer.analyze}, specifying one
     * configuration of faast.js to run against a workload. See
     * {@link AwsOptions}.
     * @public
     */
    export type Configuration = {
        provider: "aws";
        options: AwsOptions;
    };
    /**
     * Default AWS cost analyzer configurations include all memory sizes for AWS
     * Lambda.
     * @remarks
     * The default AWS cost analyzer configurations include every memory size
     * from 128MB to 3008MB in 64MB increments. Each configuration has the
     * following settings:
     *
     * ```typescript
     * {
     *     provider: "aws",
     *     options: {
     *         mode: "https",
     *         memorySize,
     *         timeout: 300,
     *         gc: "off",
     *         childProcess: true
     *     }
     * }
     * ```
     *
     * Use `Array.map` to change or `Array.filter` to remove some of these
     * configurations. For example:
     *
     * ```typescript
     * const configsWithAtLeast1GB = awsConfigurations.filter(c => c.memorySize > 1024)
     * const shorterTimeout = awsConfigurations.map(c => ({...c, timeout: 60 }));
     * ```
     * @public
     */
    const awsConfigurations: Configuration[];
    /**
     * User-defined custom metrics for a workload. These are automatically
     * summarized in the output; see {@link CostAnalyzer.Workload}.
     * @public
     */
    export type WorkloadAttribute<A extends string> = {
        [attr in A]: number;
    };
    /**
     * A user-defined cost analyzer workload for {@link CostAnalyzer.analyze}.
     * @public
     * Example:
     */
    export interface Workload<T extends object, A extends string> {
        /**
         * The imported module that contains the cloud functions to test.
         */
        funcs: T;
        /**
         * A function that executes cloud functions on
         * `faastModule.functions.*`. The work function should return `void` if
         * there are no custom workload attributes. Otherwise, it should return
         * a {@link CostAnalyzer.WorkloadAttribute} object which maps
         * user-defined attribute names to numerical values for the workload.
         * For example, this might measure bandwidth or some other metric not
         * tracked by faast.js, but are relevant for evaluating the
         * cost-performance tradeoff of the configurations analyzed by the cost
         * analyzer.
         */
        work: (faastModule: FaastModule<T>) => Promise<WorkloadAttribute<A> | void>;
        /**
         * An array of configurations to run the work function against (see
         * {@link CostAnalyzer.Configuration}). For example, each entry in the
         * array may specify a provider, memory size, and other options.
         * Default: {@link CostAnalyzer.awsConfigurations}.
         */
        configurations?: Configuration[];
        /**
         * Combine {@link CostAnalyzer.WorkloadAttribute} instances returned
         * from multiple workload executions (caused by value of
         * {@link CostAnalyzer.Workload.repetitions}). The default is a function
         * that takes the average of each attribute.
         */
        summarize?: (summaries: WorkloadAttribute<A>[]) => WorkloadAttribute<A>;
        /**
         * Format an attribute value for console output. This is displayed by
         * the cost analyzer when all of the repetitions for a configuration
         * have completed. The default returns
         * `${attribute}:${value.toFixed(1)}`.
         */
        format?: (attr: A, value: number) => string;
        /**
         * Format an attribute value for CSV. The default returns
         * `value.toFixed(1)`.
         */
        formatCSV?: (attr: A, value: number) => string;
        /**
         * If true, do not output live results to the console. Can be useful for
         * running the cost analyzer as part of automated tests. Default: false.
         */
        silent?: boolean;
        /**
         * The number of repetitions to run the workload for each cost analyzer
         * configuration. Higher repetitions help reduce the jitter in the
         * results. Repetitions execute in the same FaastModule instance.
         * Default: 10.
         */
        repetitions?: number;
        /**
         * The amount of concurrency to allow. Concurrency can arise from
         * multiple repetitions of the same configuration, or concurrenct
         * executions of different configurations. This concurrency limit
         * throttles the total number of concurrent workload executions across
         * both of these sources of concurrency. Default: 64.
         */
        concurrency?: number;
    }
    /**
     * A cost estimate result for a specific cost analyzer configuration.
     * @public
     */
    export interface Estimate<A extends string> {
        /**
         * The cost snapshot for the cost analysis of the specific (workload,
         * configuration) combination. See {@link CostSnapshot}.
         */
        costSnapshot: CostSnapshot;
        /**
         * The worload configuration that was analyzed. See
         * {@link CostAnalyzer.Configuration}.
         */
        config: Configuration;
        /**
         * Additional workload metrics returned from the work function. See
         * {@link CostAnalyzer.WorkloadAttribute}.
         */
        extraMetrics: WorkloadAttribute<A>;
    }
    /**
     * Estimate the cost of a workload using multiple configurations and
     * providers.
     * @param userWorkload - a {@link CostAnalyzer.Workload} object specifying
     * the workload to run and additional parameters.
     * @returns A promise for a {@link CostAnalyzer.Result}
     * @public
     * @remarks
     * It can be deceptively difficult to set optimal parameters for AWS Lambda
     * and similar services. On the surface there appears to be only one
     * parameter: memory size. Choosing more memory also gives more CPU
     * performance, but it's unclear how much. It's also unclear where single
     * core performance stops getting better. The workload cost analyzer solves
     * these problems by making it easy to run cost experiments.
     * ```text
     *                                                      (AWS)
     *                                                    ┌───────┐
     *                                              ┌────▶│ 128MB │
     *                                              │     └───────┘
     *                                              │     ┌───────┐
     *                      ┌─────────────────┐     ├────▶│ 256MB │
     *  ┌──────────────┐    │                 │     │     └───────┘
     *  │   workload   │───▶│                 │     │        ...
     *  └──────────────┘    │                 │     │     ┌───────┐
     *                      │  cost analyzer  │─────┼────▶│3008MB │
     *  ┌──────────────┐    │                 │           └───────┘
     *  │configurations│───▶│                 │
     *  └──────────────┘    │                 │
     *                      └─────────────────┘
     *
     * ```
     * `costAnalyzer` is the entry point. It automatically runs this workload
     * against multiple configurations in parallel. Then it uses faast.js' cost
     * snapshot mechanism to automatically determine the price of running the
     * workload with each configuration.
     *
     * Example:
     *
     * ```typescript
     * // functions.ts
     * export function randomNumbers(n: number) {
     *     let sum = 0;
     *     for (let i = 0; i < n; i++) {
     *         sum += Math.random();
     *     }
     *     return sum;
     * }
     *
     * // cost-analyzer-example.ts
     * import { writeFileSync } from "fs";
     * import { CostAnalyzer, FaastModule } from "faastjs";
     * import * as funcs from "./functions";
     *
     * async function work(faastModule: FaastModule<typeof funcs>) {
     *     await faastModule.functions.randomNumbers(100000000);
     * }
     *
     * async function main() {
     *     const results = await CostAnalyzer.analyze({ funcs, work });
     *     writeFileSync("cost.csv", results.csv());
     * }
     *
     * main();
     * ```
     *
     * Example output (this is printed to `console.log` unless the
     * {@link CostAnalyzer.Workload.silent} is `true`):
     * ```text
     *   ✔ aws 128MB queue 15.385s 0.274σ $0.00003921
     *   ✔ aws 192MB queue 10.024s 0.230σ $0.00003576
     *   ✔ aws 256MB queue 8.077s 0.204σ $0.00003779
     *      ▲    ▲     ▲     ▲       ▲        ▲
     *      │    │     │     │       │        │
     *  provider │    mode   │     stdev     average
     *           │           │   execution  estimated
     *         memory        │     time       cost
     *          size         │
     *                 average cloud
     *                 execution time
     * ```
     *
     * The output lists the provider, memory size, ({@link CommonOptions.mode}),
     * average time of a single execution of the workload, the standard
     * deviation (in seconds) of the execution time, and average estimated cost
     * for a single run of the workload.
     *
     * The "execution time" referenced here is not wall clock time, but rather
     * execution time in the cloud function. The execution time does not include
     * any time the workload spends waiting locally. If the workload invokes
     * multiple cloud functions, their execution times will be summed even if
     * they happen concurrently. This ensures the execution time and cost are
     * aligned.
     */
    export function analyze<T extends object, A extends string>(userWorkload: Workload<T, A>): Promise<Result<T, A>>;
    /**
     * Cost analyzer results for each workload and configuration.
     * @remarks
     * The `estimates` property has the cost estimates for each configuration.
     * See {@link CostAnalyzer.Estimate}.
     * @public
     */
    export class Result<T extends object, A extends string> {
        /** The workload analyzed. */
        readonly workload: Required<Workload<T, A>>;
        /**
         * Cost estimates for each configuration of the workload. See
         * {@link CostAnalyzer.Estimate}.
         */
        readonly estimates: Estimate<A>[];
        /** @internal */
        constructor(
        /** The workload analyzed. */
        workload: Required<Workload<T, A>>, 
        /**
         * Cost estimates for each configuration of the workload. See
         * {@link CostAnalyzer.Estimate}.
         */
        estimates: Estimate<A>[]);
        /**
         * Comma-separated output of cost analyzer. One line per cost analyzer
         * configuration.
         * @remarks
         * The columns are:
         *
         * - `memory`: The memory size allocated.
         *
         * - `cloud`: The cloud provider.
         *
         * - `mode`: See {@link CommonOptions.mode}.
         *
         * - `options`: A string summarizing other faast.js options applied to the
         *   `workload`. See {@link CommonOptions}.
         *
         * - `completed`: Number of repetitions that successfully completed.
         *
         * - `errors`: Number of invocations that failed.
         *
         * - `retries`: Number of retries that were attempted.
         *
         * - `cost`: The average cost of executing the workload once.
         *
         * - `executionTime`: the aggregate time spent executing on the provider for
         *   all cloud function invocations in the workload. This is averaged across
         *   repetitions.
         *
         * - `executionTimeStdev`: The standard deviation of `executionTime`.
         *
         * - `billedTime`: the same as `exectionTime`, except rounded up to the next
         *   100ms for each invocation. Usually very close to `executionTime`.
         */
        csv(): string;
    }
}

/**
 * A line item in the cost estimate, including the resource usage metric
 * measured and its pricing.
 * @public
 */
export declare class CostMetric {
    /** The name of the cost metric, e.g. `functionCallDuration` */
    readonly name: string;
    /** The price in USD per unit measured. */
    readonly pricing: number;
    /** The name of the units that pricing is measured in for this metric. */
    readonly unit: string;
    /** The measured value of the cost metric, in units. */
    readonly measured: number;
    /**
     * The plural form of the unit name. By default the plural form will be the
     * name of the unit with "s" appended at the end, unless the last letter is
     * capitalized, in which case there is no plural form (e.g. "GB").
     */
    readonly unitPlural?: string;
    /**
     * An optional comment, usually providing a link to the provider's pricing
     * page and other data.
     */
    readonly comment?: string;
    /**
     * True if this cost metric is only for informational purposes (e.g. AWS's
     * `logIngestion`) and does not contribute cost.
     */
    readonly informationalOnly?: boolean;
    /** @internal */
    constructor(arg: PropertiesExcept<CostMetric, AnyFunction>);
    /**
     * The cost contribution of this cost metric. Equal to
     * {@link CostMetric.pricing} * {@link CostMetric.measured}.
     */
    cost(): number;
    /**
     * Return a string with the cost estimate for this metric, omitting
     * comments.
     */
    describeCostOnly(): string;
    /** Describe this cost metric, including comments. */
    toString(): string;
}

/**
 * A summary of the costs incurred by a faast.js module at a point in time.
 * Output of {@link FaastModule.costSnapshot}.
 * @remarks
 * Cost information provided by faast.js is an estimate. It is derived from
 * internal faast.js measurements and not by consulting data provided by your
 * cloud provider.
 *
 * **Faast.js does not guarantee the accuracy of cost estimates.**
 *
 * **Use at your own risk.**
 *
 * Example using AWS:
 * ```typescript
 * const faastModule = await faast("aws", m);
 * try {
 *     // Invoke faastModule.functions.*
 * } finally {
 *     await faastModule.cleanup();
 *     console.log(`Cost estimate:`);
 *     console.log(`${await faastModule.costSnapshot()}`);
 * }
 * ```
 *
 * AWS example output:
 * ```text
 * Cost estimate:
 * functionCallDuration  $0.00002813/second            0.6 second     $0.00001688    68.4%  [1]
 * sqs                   $0.00000040/request             9 requests   $0.00000360    14.6%  [2]
 * sns                   $0.00000050/request             5 requests   $0.00000250    10.1%  [3]
 * functionCallRequests  $0.00000020/request             5 requests   $0.00000100     4.1%  [4]
 * outboundDataTransfer  $0.09000000/GB         0.00000769 GB         $0.00000069     2.8%  [5]
 * logIngestion          $0.50000000/GB                  0 GB         $0              0.0%  [6]
 * ---------------------------------------------------------------------------------------
 *                                                                    $0.00002467 (USD)
 *
 *   * Estimated using highest pricing tier for each service. Limitations apply.
 *  ** Does not account for free tier.
 * [1]: https://aws.amazon.com/lambda/pricing (rate = 0.00001667/(GB*second) * 1.6875 GB = 0.00002813/second)
 * [2]: https://aws.amazon.com/sqs/pricing
 * [3]: https://aws.amazon.com/sns/pricing
 * [4]: https://aws.amazon.com/lambda/pricing
 * [5]: https://aws.amazon.com/ec2/pricing/on-demand/#Data_Transfer
 * [6]: https://aws.amazon.com/cloudwatch/pricing/ - Log ingestion costs not currently included.
 * ```
 *
 * A cost snapshot contains several {@link CostMetric} values. Each `CostMetric`
 * summarizes one component of the overall cost of executing the functions so
 * far. Some cost metrics are common to all faast providers, and other metrics
 * are provider-specific. The common metrics are:
 *
 * - `functionCallDuration`: the estimated billed CPU time (rounded to the next
 *   100ms) consumed by completed cloud function calls. This is the metric that
 *   usually dominates cost.
 *
 * - `functionCallRequests`: the number of invocation requests made. Most
 *   providers charge for each invocation.
 *
 * Provider-specific metrics vary. For example, AWS has the following additional
 * metrics:
 *
 * - `sqs`: AWS Simple Queueing Service. This metric captures the number of
 *   queue requests made to insert and retrieve queued results (each 64kb chunk
 *   is counted as an additional request). SQS is used even if
 *   {@link CommonOptions.mode} is not set to `"queue"`, because it is necessary
 *   for monitoring cloud function invocations.
 *
 * - `sns`: AWS Simple Notification Service. SNS is used to invoke Lambda
 *   functions when {@link CommonOptions.mode} is `"queue"`.
 *
 * - `outboundDataTransfer`: an estimate of the network data transferred out
 *   from the cloud provider for this faast.js module. This estimate only counts
 *   data returned from cloud function invocations and infrastructure that
 *   faast.js sets up. It does not count any outbound data sent by your cloud
 *   functions that are not known to faast.js. Note that if you run faast.js on
 *   EC2 in the same region (see {@link AwsOptions.region}), then the data
 *   transfer costs will be zero (however, the cost snapshot will not include
 *   EC2 costs). Also note that if your cloud function transfers data from/to S3
 *   buckets in the same region, there is no cost as long as that data is not
 *   returned from the function.
 *
 * - `logIngestion`: this cost metric is always zero for AWS. It is present to
 *   remind the user that AWS charges for log data ingested by CloudWatch Logs
 *   that are not measured by faast.js. Log entries may arrive significantly
 *   after function execution completes, and there is no way for faast.js to
 *   know exactly how long to wait, therefore it does not attempt to measure
 *   this cost. In practice, if your cloud functions do not perform extensive
 *   logging on all invocations, log ingestion costs from faast.js are likely to
 *   be low or fall within the free tier.
 *
 * The Local provider has no extra metrics.
 *
 * Prices are retrieved dynamically from AWS and cached locally.
 * Cached prices expire after 24h. For each cost metric, faast.js uses the
 * highest price tier to compute estimated pricing.
 *
 * Cost estimates do not take free tiers into account.
 * @public
 */
export declare class CostSnapshot {
    /** The {@link Provider}, e.g. "aws" */
    readonly provider: string;
    /**
     * The options used to initialize the faast.js module where this cost
     * snapshot was generated.
     */
    readonly options: CommonOptions | AwsOptions;
    /** The function statistics that were used to compute prices. */
    readonly stats: FunctionStats;
    /**
     * The cost metric components for this cost snapshot. See
     * {@link CostMetric}.
     */
    readonly costMetrics: CostMetric[];
    /** @internal */
    constructor(
    /** The {@link Provider}, e.g. "aws" */
    provider: string, 
    /**
     * The options used to initialize the faast.js module where this cost
     * snapshot was generated.
     */
    options: CommonOptions | AwsOptions, stats: FunctionStats, costMetrics?: CostMetric[]);
    /** Sum of cost metrics. */
    total(): number;
    /** A summary of all cost metrics and prices in this cost snapshot. */
    toString(): string;
    /**
     * Comma separated value output for a cost snapshot.
     * @remarks
     * The format is "metric,unit,pricing,measured,cost,percentage,comment".
     *
     * Example output:
     * ```text
     * metric,unit,pricing,measured,cost,percentage,comment
     * functionCallDuration,second,0.00002813,0.60000000,0.00001688,64.1% ,"https://aws.amazon.com/lambda/pricing (rate = 0.00001667/(GB*second) * 1.6875 GB = 0.00002813/second)"
     * functionCallRequests,request,0.00000020,5,0.00000100,3.8% ,"https://aws.amazon.com/lambda/pricing"
     * outboundDataTransfer,GB,0.09000000,0.00000844,0.00000076,2.9% ,"https://aws.amazon.com/ec2/pricing/on-demand/#Data_Transfer"
     * sqs,request,0.00000040,13,0.00000520,19.7% ,"https://aws.amazon.com/sqs/pricing"
     * sns,request,0.00000050,5,0.00000250,9.5% ,"https://aws.amazon.com/sns/pricing"
     * logIngestion,GB,0.50000000,0,0,0.0% ,"https://aws.amazon.com/cloudwatch/pricing/ - Log ingestion costs not currently included."
     * ```
     */
    csv(): string;
    /** @internal */
    push(metric: CostMetric): void;
    /**
     * Find a specific cost metric by name.
     * @returns a {@link CostMetric} if found, otherwise `undefined`.
     */
    find(name: string): CostMetric | undefined;
}

declare interface CpuMeasurement {
    stime: number;
    utime: number;
    elapsed: number;
}

declare interface CpuMetricsMessage {
    kind: "cpumetrics";
    callId: CallId_2;
    metrics: CpuMeasurement;
}

declare class Deferred<T = void> {
    promise: Promise<T>;
    resolve: (arg: T | PromiseLike<T>) => void;
    reject: (err?: any) => void;
    constructor();
}

/**
 * A function return value with additional detailed information.
 * @public
 */
export declare interface Detail<R> {
    /**
     * A Promise for the function's return value.
     */
    value: R;
    /**
     * The URL of the logs for the specific execution of this function call.
     * @remarks
     * This is different from the general logUrl from
     * {@link FaastModule.logUrl}, which provides a link to the logs for all
     * invocations of all functions within that module. Whereas this logUrl is
     * only for this specific invocation.
     */
    logUrl?: string;
    /**
     * If available, the provider-specific execution identifier for this
     * invocation.
     * @remarks
     * This ID may be added to the log entries for this invocation by the cloud
     * provider.
     */
    executionId?: string;
    /**
     * If available, the provider-specific instance identifier for this
     * invocation.
     * @remarks
     * This ID refers to the specific container or VM used to execute this
     * function invocation. The instance may be reused across multiple
     * invocations.
     */
    instanceId?: string;
}

declare type ErrorCallback = (err: Error) => Error;

declare interface Executor {
    wrapper: Wrapper;
    logUrl: string;
    logStream?: Writable;
}

declare type ExtractPropertyNamesExceptType<T, U> = {
    [K in keyof T]: T[K] extends U ? never : K;
}[keyof T];

/**
 * The main entry point for faast with any provider and only common options.
 * @param provider - One of `"aws"` or `"local"`. See
 * {@link Provider}.
 * @param fmodule - A module imported with `import * as X from "Y";`. Using
 * `require` also works but loses type information.
 * @param options - See {@link CommonOptions}.
 * @returns See {@link FaastModule}.
 * @remarks
 * Example of usage:
 * ```typescript
 * import { faast } from "faastjs";
 * import * as mod from "./path/to/module";
 * (async () => {
 *     const faastModule = await faast("aws", mod);
 *     try {
 *         const result = await faastModule.functions.func("arg");
 *     } finally {
 *         await faastModule.cleanup();
 *     }
 * })();
 * ```
 * @public
 */
export declare function faast<M extends object>(provider: Provider, fmodule: M, options?: CommonOptions): Promise<FaastModule<M>>;

/**
 * The main entry point for faast with AWS provider.
 * @param fmodule - A module imported with `import * as X from "Y";`. Using
 * `require` also works but loses type information.
 * @param options - Most common options are in {@link CommonOptions}.
 * Additional AWS-specific options are in {@link AwsOptions}.
 * @public
 */
export declare function faastAws<M extends object>(fmodule: M, options?: AwsOptions): Promise<AwsFaastModule<M>>;

/**
 * FaastError is a subclass of VError (https://github.com/joyent/node-verror).
 * that is thrown by faast.js APIs and cloud function invocations.
 * @remarks
 * `FaastError` is a subclass of
 * {@link https://github.com/joyent/node-verror | VError}, which provides an API
 * for nested error handling. The main API is the same as the standard Error
 * class, namely the err.message, err.name, and err.stack properties.
 *
 * Several static methods on {@link FaastError} are inherited from VError:
 *
 * FaastError.fullStack(err) - property provides a more detailed stack trace
 * that include stack traces of causes in the causal chain.
 *
 * FaastError.info(err) - returns an object with fields `functionName`, `args`,
 * and `logUrl`. The `logUrl` property is a URL pointing to the logs for a
 * specific invocation that caused the error.`logUrl` will be surrounded by
 * whitespace on both sides to ease parsing as a URL by IDEs.
 *
 * FaastError.hasCauseWithName(err, cause) - returns true if the FaastError or
 * any of its causes includes an error with the given name, otherwise false. All
 * of the available names are in the enum {@link FaastErrorNames}. For example,
 * to detect if a FaastError was caused by a cloud function timeout:
 *
 * ```typescript
 *   FaastError.hasCauseWithName(err, FaastErrorNames.ETIMEOUT)
 * ```
 *
 * FaastError.findCauseByName(err, cause) - like FaastError.hasCauseWithName()
 * except it returns the Error in the causal chain with the given name instead
 * of a boolean, otherwise null.
 *
 * @public
 */
export declare class FaastError extends VError {
}

/**
 * Possible FaastError names. See {@link FaastError}. To test for errors
 * matching these names, use the static method
 * {@link FaastError}.hasCauseWithName().
 * @public
 */
export declare enum FaastErrorNames {
    /** Generic error. See {@link FaastError}. */
    EGENERIC = "VError",
    /** The arguments passed to the cloud function could not be serialized without losing information.  */
    ESERIALIZE = "FaastSerializationError",
    /** The remote cloud function timed out. */
    ETIMEOUT = "FaastTimeoutError",
    /** The remote cloud function exceeded memory limits. */
    EMEMORY = "FaastOutOfMemoryError",
    /** The function invocation was cancelled by user request. */
    ECANCEL = "FaastCancelError",
    /** The exception was thrown by user's remote code, not by faast.js or the cloud provider. */
    EEXCEPTION = "UserException",
    /** Could not create the remote cloud function or supporting infrastructure. */
    ECREATE = "FaastCreateFunctionError",
    /** The remote cloud function failed to execute because of limited concurrency. */
    ECONCURRENCY = "FaastConcurrencyError"
}

/**
 * The main entry point for faast with Local provider.
 * @param fmodule - A module imported with `import * as X from "Y";`. Using
 * `require` also works but loses type information.
 * @param options - Most common options are in {@link CommonOptions}.
 * Additional Local-specific options are in {@link LocalOptions}.
 * @returns a Promise for {@link LocalFaastModule}.
 * @public
 */
export declare function faastLocal<M extends object>(fmodule: M, options?: LocalOptions): Promise<LocalFaastModule<M>>;

/**
 * The main interface for invoking, cleaning up, and managing faast.js cloud
 * functions. Returned by {@link faast}.
 * @public
 */
export declare interface FaastModule<M extends object> {
    /** See {@link Provider}.  */
    provider: Provider;
    /**
     * Each call of a cloud function creates a separate remote invocation.
     * @remarks
     * The module passed into {@link faast} or its provider-specific variants
     * ({@link faastAws} and {@link faastLocal}) is mapped
     * to a {@link ProxyModule} version of the module, which performs the
     * following mapping:
     *
     * - All function exports that are generators are mapped to async
     *   generators.
     *
     * - All function exports that return async generators are preserved as-is.
     *
     * - All function exports that return promises have their type signatures
     *   preserved as-is.
     *
     * - All function exports that return type T, where T is not a Promise,
     *   Generator, or AsyncGenerator, are mapped to functions that return
     *   Promise<T>. Argument types are preserved as-is.
     *
     * - All non-function exports are omitted in the remote module.
     *
     * Arguments and return values are serialized with `JSON.stringify` when
     * cloud functions are called, therefore what is received on the remote side
     * might not match what was sent. Faast.js attempts to detect nonsupported
     * arguments on a best effort basis.
     *
     * If the cloud function throws an exception or rejects its promise with an
     * instance of `Error`, then the function will reject with
     * {@link FaastError} on the local side. If the exception or rejection
     * resolves to any value that is not an instance of `Error`, the remote
     * function proxy will reject with the value of
     * `JSON.parse(JSON.stringify(err))`.
     *
     * Arguments and return values have size limitations that vary by provider
     * and mode:
     *
     * - AWS: 256KB in queue mode, 6MB arguments and 256KB return values in https mode. See
     *   {@link https://docs.aws.amazon.com/lambda/latest/dg/limits.html | AWS Lambda Limits}.
     *
     * - Local: limited only by available memory and the limits of
     *   {@link https://nodejs.org/api/child_process.html#child_process_subprocess_send_message_sendhandle_options_callback | childprocess.send}.
     *
     * Note that payloads may be base64 encoded for some providers and therefore
     * different in size than the original payload. Also, some bookkeeping data
     * are passed along with arguments and contribute to the size limit.
     */
    functions: ProxyModule<M>;
    /**
     * Similar to {@link FaastModule.functions} except each function returns a
     * {@link Detail} object
     * @remarks
     * Advanced users of faast.js may want more information about each function
     * invocation than simply the result of the function call. For example, the
     * specific logUrl for each invocation, to help with detailed debugging.
     * This interface provides a way to get this detailed information.
     */
    functionsDetail: ProxyModuleDetail<M>;
    /**
     * Stop the faast.js runtime for this cloud function and clean up ephemeral
     * cloud resources.
     * @returns a Promise that resolves when the `FaastModule` runtime stops and
     * ephemeral resources have been deleted.
     * @remarks
     * It is best practice to always call `cleanup` when done with a cloud
     * function. A typical way to ensure this in normal execution is to use the
     * `finally` construct:
     *
     * ```typescript
     * const faastModule = await faast("aws", m);
     * try {
     *     // Call faastModule.functions.*
     * } finally {
     *     // Note the `await`
     *     await faastModule.cleanup();
     * }
     * ```
     *
     * After the cleanup promise resolves, the cloud function instance can no
     * longer invoke new calls on {@link FaastModule.functions}. However, other
     * methods on {@link FaastModule} are safe to call, such as
     * {@link FaastModule.costSnapshot}.
     *
     * Cleanup also stops statistics events (See {@link FaastModule.off}).
     *
     * By default, cleanup will delete all ephemeral cloud resources but leave
     * behind cached resources for use by future cloud functions. Deleted
     * resources typically include cloud functions, queues, and queue
     * subscriptions. Logs are not deleted by cleanup.
     *
     * Note that `cleanup` leaves behind some provider-specific resources:
     *
     * - AWS: Cloudwatch logs are preserved until the garbage collector in a
     *   future cloud function instance deletes them. The default log expiration
     *   time is 24h (or the value of {@link CommonOptions.retentionInDays}). In
     *   addition, the AWS Lambda IAM role is not deleted by cleanup. This role
     *   is shared across cloud function instances. Lambda layers are also not
     *   cleaned up immediately on AWS when {@link CommonOptions.packageJson} is
     *   used and {@link CommonOptions.useDependencyCaching} is true. Cached
     *   layers are cleaned up by garbage collection. Also see
     *   {@link CleanupOptions.deleteCaches}.
     *
     * - Local: Logs are preserved in a temporary directory on local disk.
     *   Garbage collection in a future cloud function instance will delete logs
     *   older than 24h.
     */
    cleanup(options?: CleanupOptions): Promise<void>;
    /**
     * The URL of logs generated by this cloud function.
     * @remarks
     * Logs are not automatically downloaded because they cause outbound data
     * transfer, which can be expensive. Also, logs may arrive at the logging
     * service well after the cloud functions have completed. This log URL
     * specifically filters the logs for this cloud function instance.
     * Authentication is required to view cloud provider logs.
     *
     * The local provider returns a `file://` url pointing to a file for logs.
     */
    logUrl(): string;
    /**
     * Register a callback for statistics events.
     * @remarks
     * The callback is invoked once for each cloud function that was invoked
     * within the last 1s interval, with a {@link FunctionStatsEvent}
     * summarizing the statistics for each function. Typical usage:
     *
     * ```typescript
     * faastModule.on("stats", console.log);
     * ```
     */
    on(name: "stats", listener: (statsEvent: FunctionStatsEvent) => void): void;
    /**
     * Deregister a callback for statistics events.
     * @remarks
     * Stops the callback listener from receiving future function statistics
     * events. Calling {@link FaastModule.cleanup} also turns off statistics
     * events.
     */
    off(name: "stats", listener: (statsEvent: FunctionStatsEvent) => void): void;
    /**
     * Get a near real-time cost estimate of cloud function invocations.
     * @returns a Promise for a {@link CostSnapshot}.
     * @remarks
     * A cost snapshot provides a near real-time estimate of the costs of the
     * cloud functions invoked. The cost estimate only includes the cost of
     * successfully completed calls. Unsuccessful calls may lack the data
     * required to provide cost information. Calls that are still in flight are
     * not included in the cost snapshot. For this reason, it is typically a
     * good idea to get a cost snapshot after awaiting the result of
     * {@link FaastModule.cleanup}.
     *
     * Code example:
     *
     * ```typescript
     * const faastModule = await faast("aws", m);
     * try {
     *     // invoke cloud functions on faastModule.functions.*
     * } finally {
     *      await faastModule.cleanup();
     *      const costSnapshot = await faastModule.costSnapshot();
     *      console.log(costSnapshot);
     * }
     * ```
     */
    costSnapshot(): Promise<CostSnapshot>;
    /**
     * Statistics for a specific function or the entire faast.js module.
     *
     * @param functionName - The name of the function to retrieve statistics
     * for. If the function does not exist or has not been invoked, a new
     * instance of {@link FunctionStats} is returned with zero values. If
     * `functionName` omitted (undefined), then aggregate statistics are
     * returned that summarize all cloud functions within this faast.js module.
     * @returns an snapshot of {@link FunctionStats} at a point in time.
     */
    stats(functionName?: string): FunctionStats;
}

/**
 * Implementation of {@link FaastModule}.
 * @remarks
 * `FaastModuleProxy` provides a unified developer experience for faast.js
 * modules on top of provider-specific runtime APIs. Most users will not create
 * `FaastModuleProxy` instances themselves; instead use {@link faast}, or
 * {@link faastAws} or {@link faastLocal}.
 * `FaastModuleProxy` implements the {@link FaastModule} interface, which is the
 * preferred public interface for faast modules. `FaastModuleProxy` can be used
 * to access provider-specific details and state, and is useful for deeper
 * testing.
 * @public
 */
export declare class FaastModuleProxy<M extends object, O extends CommonOptions, S> implements FaastModule<M> {
    private impl;
    /** @internal */
    readonly state: S;
    private fmodule;
    private modulePath;
    /** The options set for this instance, which includes default values. */
    readonly options: Required<CommonOptions>;
    /** The {@link Provider}, e.g. "aws". */
    provider: Provider;
    /** {@inheritdoc FaastModule.functions} */
    functions: ProxyModule<M>;
    /** {@inheritdoc FaastModule.functionsDetail} */
    functionsDetail: ProxyModuleDetail<M>;
    /** @internal */
    private _stats;
    private _cpuUsage;
    private _memoryLeakDetector;
    private _funnel;
    private _rateLimiter?;
    private _skew;
    private _statsTimer?;
    private _cleanupHooks;
    private _initialInvocationTime;
    private _callResultsPending;
    private _collectorPump;
    private _emitter;
    /**
     * Constructor
     * @internal
     */
    constructor(impl: ProviderImpl<O, S>, 
    /** @internal */
    state: S, fmodule: M, modulePath: string, 
    /** The options set for this instance, which includes default values. */
    options: Required<CommonOptions>);
    /** {@inheritdoc FaastModule.cleanup} */
    cleanup(userCleanupOptions?: CleanupOptions): Promise<void>;
    /** {@inheritdoc FaastModule.logUrl} */
    logUrl(): string;
    private startStats;
    private stopStats;
    /** {@inheritdoc FaastModule.on} */
    on(name: "stats", listener: (statsEvent: FunctionStatsEvent) => void): void;
    /** {@inheritdoc FaastModule.off} */
    off(name: "stats", listener: (statsEvent: FunctionStatsEvent) => void): void;
    private withCancellation;
    private processResponse;
    private invoke;
    private lookupFname;
    private createCallId;
    private wrapGenerator;
    private clearPending;
    private wrapFunction;
    /** {@inheritdoc FaastModule.costSnapshot} */
    costSnapshot(): Promise<CostSnapshot>;
    /** {@inheritdoc FaastModule.stats} */
    stats(functionName?: string): FunctionStats;
    private resultCollector;
    private adjustCollectorConcurrencyLevel;
}

declare interface FunctionCall extends CallId {
    args: string;
    modulePath: string;
    name: string;
    ResponseQueueId: string;
}

declare interface FunctionStartedMessage {
    kind: "functionstarted";
    callId: CallId_2;
}

/**
 * Summary statistics for function invocations.
 * @remarks
 * ```
 *               localStartLatency      remoteStartLatency      executionTime
 *             ◀──────────────────▶◁ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ▷◀──────────▶
 *
 * ┌───────────────────────────────────┬──────────────────────────────────────┐
 * │                                   │                                      │
 * │               Local               │            Cloud Provider            │
 * │                                   │                                      │
 * │                    ┌─────────┐    │   ┌──────────┐         ┌──────────┐  │
 * │                    │         │    │   │          │         │          │  │
 * │                    │  local  │    │   │ request  │         │          │  │
 * │   invoke  ────────▶│  queue  │────┼──▶│  queue   ├────────▶│          │  │
 * │                    │         │    │   │          │         │          │  │
 * │                    └─────────┘    │   └──────────┘         │  cloud   │  │
 * │                                   │                        │ function │  │
 * │                    ┌─────────┐    │   ┌──────────┐         │          │  │
 * │                    │         │    │   │          │         │          │  │
 * │   result  ◀────────│  local  │◀───┼───│ response │◀────────│          │  │
 * │                    │ polling │    │   │  queue   │         │          │  │
 * │                    │         │    │   │          │         │          │  │
 * │                    └─────────┘    │   └──────────┘         └──────────┘  │
 * │                                   │                                      │
 * └───────────────────────────────────┴──────────────────────────────────────┘
 *
 *             ◁ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ▷
 *                      returnLatency                  ◀───────▶
 *                                                     sendResponseLatency
 * ```
 *
 * `localStartLatency` and `executionTime` are measured on one machine and are
 * free of clock skew. `remoteStartLatency` and `returnLatency` are measured as
 * time differences between machines and are subject to much more uncertainty,
 * and effects like clock skew.
 *
 * All times are in milliseconds.
 *
 * @public
 */
export declare class FunctionStats {
    /**
     * Statistics for how long invocations stay in the local queue before being
     * sent to the cloud provider.
     */
    localStartLatency: Statistics;
    /**
     * Statistics for how long requests take to start execution after being sent
     * to the cloud provider. This typically includes remote queueing and cold
     * start times. Because this measurement requires comparing timestamps from
     * different machines, it is subject to clock skew and other effects, and
     * should not be considered highly accurate. It can be useful for detecting
     * excessively high latency problems. Faast.js attempt to correct for clock
     * skew heuristically.
     */
    remoteStartLatency: Statistics;
    /**
     * Statistics for function execution time in milliseconds.  This is measured
     * as wall clock time inside the cloud function, and does not include the
     * time taken to send the response to the response queue. Note that most
     * cloud providers round up to the next 100ms for pricing.
     */
    executionTime: Statistics;
    /**
     * Statistics for how long it takes to send the response to the response
     * queue.
     */
    sendResponseLatency: Statistics;
    /**
     * Statistics for how long it takes to return a response from the end of
     * execution time to the receipt of the response locally. This measurement
     * requires comparing timestamps from different machines, and is subject to
     * clock skew and other effects. It should not be considered highly
     * accurate. It can be useful for detecting excessively high latency
     * problems. Faast.js attempts to correct for clock skew heuristically.
     */
    returnLatency: Statistics;
    /**
     * Statistics for amount of time billed. This is similar to
     * {@link FunctionStats.executionTime} except each sampled time is rounded
     * up to the next 100ms.
     */
    estimatedBilledTime: Statistics;
    /**
     * The number of invocations attempted. If an invocation is retried, this
     * only counts the invocation once.
     */
    invocations: number;
    /**
     * The number of invocations that were successfully completed.
     */
    completed: number;
    /**
     * The number of invocation retries attempted. This counts retries
     * attempted by faast.js to recover from transient errors, but does not
     * count retries by the cloud provider.
     */
    retries: number;
    /**
     * The number of invocations that resulted in an error. If an invocation is
     * retried, an error is only counted once, no matter how many retries were
     * attempted.
     */
    errors: number;
    /**
     * Summarize the function stats as a string.
     * @returns a string showing the value of completed, retries, errors, and
     * mean execution time. This string excludes invocations by default because
     * it is often fixed.
     */
    toString(): string;
    /** @internal */
    clone(): FunctionStats;
}

/**
 * Summarize statistics about cloud function invocations.
 * @public
 */
export declare class FunctionStatsEvent {
    /** The name of the cloud function the statistics are about. */
    readonly fn: string;
    /** See {@link FunctionStats}. */
    readonly stats: FunctionStats;
    /**
     * @internal
     */
    constructor(
    /** The name of the cloud function the statistics are about. */
    fn: string, 
    /** See {@link FunctionStats}. */
    stats: FunctionStats);
    /**
     * Returns a string summarizing the statistics event.
     * @remarks
     * The string includes number of completed calls, errors, and retries, and
     * the mean execution time for the calls that completed within the last time
     * interval (1s).
     */
    toString(): string;
}

/**
 * Options for the {@link CommonOptions.include} option.
 * @public
 */
export declare interface IncludeOption {
    /**
     * The path to the directory or glob to add to the cloud function.
     */
    path: string;
    /**
     * The working directory if `path` is relative. Defaults to `process.cwd()`.
     * For example, if `cwd` is `"foo"` and `path` is `"bar"`, then the
     * contents of the directory `foo/bar/` will be added to the remote
     * function under the path `bar/`.
     */
    cwd?: string;
}

declare interface IteratorResponseMessage extends ResponseContext {
    kind: "iterator";
    sequence: number;
}

/**
 * Specify {@link throttle} limits. These limits shape the way throttle invokes
 * the underlying function.
 * @public
 */
export declare interface Limits {
    /**
     * The maximum number of concurrent executions of the underlying function to
     * allow. Must be supplied, there is no default. Specifying `0` or
     * `Infinity` is allowed and means there is no concurrency limit.
     */
    concurrency: number;
    /**
     * The maximum number of calls per second to allow to the underlying
     * function. Default: no rate limit.
     */
    rate?: number;
    /**
     * The maximum number of calls to the underlying function to "burst" -- e.g.
     * the number that can be issued immediately as long as the rate limit is
     * not exceeded. For example, if rate is 5 and burst is 5, and 10 calls are
     * made to the throttled function, 5 calls are made immediately and then
     * after 1 second, another 5 calls are made immediately. Setting burst to 1
     * means calls are issued uniformly every `1/rate` seconds. If `rate` is not
     * specified, then `burst` does not apply. Default: 1.
     */
    burst?: number;
    /**
     * Retry if the throttled function returns a rejected promise. `retry` can
     * be a number or a function. If it is a number `N`, then up to `N`
     * additional attempts are made in addition to the initial call. If retry is
     * a function, it should return `true` if another retry attempt should be
     * made, otherwise `false`. The first argument will be the value of the
     * rejected promise from the previous call attempt, and the second argument
     * will be the number of previous retry attempts (e.g. the first call will
     * have value 0). Default: 0 (no retry attempts).
     */
    retry?: number | ((err: any, retries: number) => boolean);
    /**
     * If `memoize` is `true`, then every call to the throttled function will be
     * saved as an entry in a map from arguments to return value. If same
     * arguments are seen again in a future call, the return value is retrieved
     * from the Map rather than calling the function again. This can be useful
     * for avoiding redundant calls that are expected to return the same results
     * given the same arguments.
     *
     * The arguments will be captured with `JSON.stringify`, therefore types
     * that do not stringify uniquely won't be distinguished from each other.
     * Care must be taken when specifying `memoize` to ensure avoid incorrect
     * results.
     */
    memoize?: boolean;
    /**
     * Similar to `memoize` except the map from function arguments to results is
     * stored in a persistent cache on disk. This is useful to prevent redundant
     * calls to APIs which are expected to return the same results for the same
     * arguments, and which are likely to be called across many faast.js module
     * instantiations. This is used internally by faast.js for caching cloud
     * prices for AWS, and for saving the last garbage collection
     * date for AWS. Persistent cache entries expire after a period of time. See
     * {@link PersistentCache}.
     */
    cache?: PersistentCache;
    /**
     * A promise that, if resolved, causes cancellation of pending throttled
     * invocations. This is typically created using `Deferred`. The idea is to
     * use the resolving of the promise as an asynchronous signal that any
     * pending invocations in this throttled function should be cleared.
     * @internal
     */
    cancel?: Promise<void>;
}

/**
 * The return type of {@link faastLocal}. See {@link FaastModuleProxy}.
 * @public
 */
export declare type LocalFaastModule<M extends object = object> = FaastModuleProxy<M, LocalOptions, LocalState>;

/**
 * Local provider options for {@link faastLocal}.
 *
 * @public
 */
export declare interface LocalOptions extends CommonOptions {
    /** @internal */
    _gcWorker?: (tempdir: string) => Promise<void>;
}

/**
 * @public
 */
declare interface LocalState {
    /** @internal */
    executors: Executor[];
    /** @internal */
    getExecutor: () => Promise<Executor>;
    /** The temporary directory where the local function is deployed. */
    tempDir: string;
    /** The file:// URL for the local function log file directory.  */
    logUrl: string;
    /** @internal */
    gcPromise?: Promise<void>;
    /** @internal */
    queue: AsyncQueue<Message>;
    /** Options used to initialize the local function. */
    options: Required<LocalOptions>;
}

/**
 * Faast.js loggers.
 * @remarks
 * Unless otherwise specified, each log is disabled by default unless the value
 * of the DEBUG environment variable is set to the corresponding value. For
 * example:
 *
 * ```
 *   $ DEBUG=faast:info,faast:provider <cmd>
 *   $ DEBUG=faast:* <cmd>
 * ```
 *
 * Logs can also be enabled or disabled programmatically:
 * ```typescript
 * import { log } from "faastjs"
 * log.info.enabled = true;
 * log.provider.enabled = true;
 * ```
 *
 * Each log outputs specific information:
 *
 * `info` - General informational logging.
 *
 * `minimal` - Outputs only basic information like the function name created in
 * the cloud.
 *
 * `warn` - Warnings. Enabled by default.
 *
 * `gc` - Garbage collection verbose logging.
 *
 * `leaks` - Memory leak detector warnings for the cloud function. Enabled by
 * default.
 *
 * `calls` - Verbose logging of each faast.js enabled function invocation.
 *
 * `webpack` - Verbose logging from webpack and packaging details.
 *
 * `provider` - Verbose logging of each interaction between faast.js runtime and
 * the provider-specific implementation.
 *
 * `awssdk` - Verbose logging of AWS SDK. This can be useful for identifying
 * which API calls are failing, retrying, or encountering rate limits.
 *
 * @public
 */
export declare const log: {
    info: debug_2.Debugger;
    minimal: debug_2.Debugger;
    warn: debug_2.Debugger;
    gc: debug_2.Debugger;
    leaks: debug_2.Debugger;
    calls: debug_2.Debugger;
    webpack: debug_2.Debugger;
    provider: debug_2.Debugger;
    awssdk: debug_2.Debugger;
};

declare type Message = PromiseResponseMessage | IteratorResponseMessage | FunctionStartedMessage | CpuMetricsMessage;

declare type MessageCallback = (msg: Message) => Promise<void>;

declare interface ModuleType {
    [name: string]: any;
}

/**
 * A simple persistent key-value store. Used to implement {@link Limits.cache}
 * for {@link throttle}.
 * @remarks
 * Entries can be expired, but are not actually deleted individually. The entire
 * cache can be deleted at once. Hence this cache is useful for storing results
 * that are expensive to compute but do not change too often (e.g. the
 * node_modules folder from an 'npm install' where 'package.json' is not
 * expected to change too often).
 *
 * By default faast.js will use the directory `~/.faastjs` as a local cache to
 * store data such as pricing retrieved from cloud APIs, and garbage collection
 * information. This directory can be safely deleted if no faast.js instances
 * are running.
 * @public
 */
export declare class PersistentCache {
    /**
     * The directory under the user's home directory that will be used to
     * store cached values. The directory will be created if it doesn't
     * exist.
     */
    readonly dirRelativeToHomeDir: string;
    /**
     * The age (in ms) after which a cached entry is invalid. Default:
     * `24*3600*1000` (1 day).
     */
    readonly expiration: number;
    private initialized;
    private initialize;
    /**
     * The directory on disk where cached values are stored.
     */
    readonly dir: string;
    /**
     * Construct a new persistent cache, typically used with {@link Limits} as
     * part of the arguments to {@link throttle}.
     * @param dirRelativeToHomeDir - The directory under the user's home
     * directory that will be used to store cached values. The directory will be
     * created if it doesn't exist.
     * @param expiration - The age (in ms) after which a cached entry is
     * invalid. Default: `24*3600*1000` (1 day).
     */
    constructor(
    /**
     * The directory under the user's home directory that will be used to
     * store cached values. The directory will be created if it doesn't
     * exist.
     */
    dirRelativeToHomeDir: string, 
    /**
     * The age (in ms) after which a cached entry is invalid. Default:
     * `24*3600*1000` (1 day).
     */
    expiration?: number);
    private hash;
    /**
     * Retrieves the value previously set for the given key, or undefined if the
     * key is not found.
     */
    get(key: string): Promise<Buffer | undefined>;
    /**
     * Set the cache key to the given value.
     * @returns a Promise that resolves when the cache entry has been persisted.
     */
    set(key: string, value: Buffer | string | Uint8Array): Promise<void>;
    /**
     * Retrieve all keys stored in the cache, including expired entries.
     */
    entries(): Promise<string[]>;
    /**
     * Deletes all cached entries from disk.
     * @param leaveEmptyDir - If true, leave the cache directory in place after
     * deleting its contents. If false, the cache directory will be removed.
     * Default: `true`.
     */
    clear({ leaveEmptyDir }?: {
        leaveEmptyDir?: boolean | undefined;
    }): Promise<void>;
}

declare interface PollResult {
    Messages: Message[];
    isFullMessageBatch?: boolean;
}

declare interface PromiseResponseMessage extends ResponseContext {
    kind: "promise";
}

declare type PropertiesExcept<T, X> = Pick<T, ExtractPropertyNamesExceptType<T, X>>;

/**
 * The type of all supported cloud providers.
 * @public
 */
export declare type Provider = "aws" | "local";

declare interface ProviderImpl<O extends CommonOptions, S> {
    name: Provider;
    defaults: Required<O>;
    initialize(serverModule: string, nonce: UUID, options: Required<O>): Promise<S>;
    costSnapshot(state: S, stats: FunctionStats): Promise<CostSnapshot>;
    cleanup(state: S, options: Required<CleanupOptions>): Promise<void>;
    logUrl(state: S): string;
    invoke(state: S, request: FunctionCall, cancel: Promise<void>): Promise<void>;
    poll(state: S, cancel: Promise<void>): Promise<PollResult>;
    responseQueueId(state: S): string;
}

/**
 * An array of all available provider.
 * @public
 */
export declare const providers: Provider[];

/**
 * `ProxyModule<M>` is the type of {@link FaastModule.functions}.
 * @remarks
 * `ProxyModule<M>` maps an imported module's functions to promise-returning or
 * async-iteratable versions of those functions. Non-function exports of the
 * module are omitted. When invoked, the functions in a `ProxyModule` invoke a
 * remote cloud function.
 * @public
 */
export declare type ProxyModule<M> = {
    [K in keyof M]: M[K] extends (...args: infer A) => infer R ? (...args: A) => Async<R> : never;
};

/**
 * Similar to {@link ProxyModule} except each function returns a {@link Detail}
 * object.
 * @remarks
 * See {@link FaastModule.functionsDetail}.
 * @public
 */
export declare type ProxyModuleDetail<M> = {
    [K in keyof M]: M[K] extends (...args: infer A) => infer R ? (...args: A) => AsyncDetail<R> : never;
};

declare interface ResponseContext {
    type: "fulfill" | "reject";
    value: string;
    callId: CallId_2;
    isErrorObject?: boolean;
    remoteExecutionStartTime?: number;
    remoteExecutionEndTime?: number;
    logUrl?: string;
    instanceId?: string;
    executionId?: string;
    memoryUsage?: NodeJS.MemoryUsage;
    timestamp?: number;
}

/**
 * Incrementally updated statistics on a set of values.
 * @public
 */
export declare class Statistics {
    /** The number of decimal places to print in {@link Statistics.toString} */
    protected printFixedPrecision: number;
    /** Number of values observed. */
    samples: number;
    /** The maximum value observed. Initialized to `Number.NEGATIVE_INFINITY`. */
    max: number;
    /** The minimum value observed. Initialized to `Number.POSITIVE_INFINITY`. */
    min: number;
    /** The variance of the values observed. */
    variance: number;
    /** The standard deviation of the values observed. */
    stdev: number;
    /** The mean (average) of the values observed. */
    mean: number;
    /**
     * Incrementally track mean, stdev, min, max, of a sequence of values.
     * @param printFixedPrecision - The number of decimal places to print in
     * {@link Statistics.toString}.
     */
    constructor(
    /** The number of decimal places to print in {@link Statistics.toString} */
    printFixedPrecision?: number);
    /** @internal */
    clone(): Statistics & this;
    /**
     * Update statistics with a new value in the sequence.
     */
    update(value: number | undefined): void;
    /**
     * Print the mean of the observations seen, with the precision specified in
     * the constructor.
     */
    toString(): string;
}

/**
 * A decorator for rate limiting, concurrency limiting, retry, memoization, and
 * on-disk caching. See {@link Limits}.
 * @remarks
 * When programming against cloud services, databases, and other resources, it
 * is often necessary to control the rate of request issuance to avoid
 * overwhelming the service provider. In many cases the provider has built-in
 * safeguards against abuse, which automatically fail requests if they are
 * coming in too fast. Some systems don't have safeguards and precipitously
 * degrade their service level or fail outright when faced with excessive load.
 *
 * With faast.js it becomes very easy to (accidentally) generate requests from
 * thousands of cloud functions. The `throttle` function can help manage request
 * flow without resorting to setting up a separate service. This is in keeping
 * with faast.js' zero-ops philosophy.
 *
 * Usage is simple:
 *
 * ```typescript
 * async function operation() { ... }
 * const throttledOperation = throttle({ concurrency: 10, rate: 5 }, operation);
 * for(let i = 0; i < 100; i++) {
 *     // at most 10 concurrent executions at a rate of 5 invocations per second.
 *     throttledOperation();
 * }
 * ```
 *
 * Note that each invocation to `throttle` creates a separate function with a
 * separate limits. Therefore it is likely that you want to use `throttle` in a
 * global context, not within a dynamic context:
 *
 * ```typescript
 * async function operation() { ... }
 * for(let i = 0; i < 100; i++) {
 *     // WRONG - each iteration creates a separate throttled function that's only called once.
 *     const throttledOperation = throttle({ concurrency: 10, rate: 5 }, operation);
 *     throttledOperation();
 * }
 * ```
 *
 * A better way to use throttle avoids creating a named `operation` function
 * altogether, ensuring it cannot be accidentally called without throttling:
 *
 * ```typescript
 * const operation = throttle({ concurrency: 10, rate: 5 }, async () => {
 *     ...
 * });
 * ```
 *
 * Throttle supports functions with arguments automatically infers the correct
 * type for the returned function:
 *
 * ```typescript
 * // `operation` inferred to have type (str: string) => Promise<string>
 * const operation = throttle({ concurrency: 10, rate: 5 }, async (str: string) => {
 *     return string;
 * });
 * ```
 *
 * In addition to limiting concurrency and invocation rate, `throttle` also
 * supports retrying failed invocations, memoizing calls, and on-disk caching.
 * See {@link Limits} for details.
 *
 * @param limits - see {@link Limits}.
 * @param fn - The function to throttle. It can take any arguments, but must
 * return a Promise (which includes `async` functions).
 * @returns Returns a throttled function with the same signature as the argument
 * `fn`.
 * @public
 */
export declare function throttle<A extends any[], R>(limits: Limits, fn: (...args: A) => Promise<R>): (...args: A) => Promise<R>;

declare type UUID = string;

declare class Wrapper {
    executing: boolean;
    selected: boolean;
    protected verbose: boolean;
    protected funcs: ModuleType;
    protected child?: childProcess.ChildProcess;
    protected childPid?: number;
    protected log: (msg: string) => void;
    protected queue: AsyncIterableQueue<Message>;
    readonly options: Required<WrapperOptions>;
    protected monitoringTimer?: NodeJS.Timer;
    constructor(fModule: ModuleType, options?: WrapperOptions);
    protected lookupFunction(request: object): AnyFunction;
    protected stopCpuMonitoring(): void;
    protected startCpuMonitoring(pid: number, callId: string): void;
    stop(): void;
    execute(callingContext: CallingContext, { errorCallback, onMessage, measureCpuUsage }: WrapperExecuteOptions): Promise<void>;
    protected logLines: (msg: string) => void;
    protected setupChildProcess(): childProcess.ChildProcess;
}

declare interface WrapperExecuteOptions {
    errorCallback?: ErrorCallback;
    onMessage: MessageCallback;
    measureCpuUsage?: boolean;
}

declare interface WrapperOptions {
    /**
     * Logging function for console.log/warn/error output. Only available in
     * child process mode. This is mainly useful for debugging the "local"
     * mode which runs code locally. In real clouds the logs will end up in the
     * cloud logging service (e.g. Cloudwatch Logs).
     * Defaults to console.log.
     */
    wrapperLog?: (msg: string) => void;
    childProcess?: boolean;
    childProcessMemoryLimitMb?: number;
    childProcessTimeoutMs?: number;
    childProcessEnvironment?: {
        [key: string]: string;
    };
    childDir?: string;
    wrapperVerbose?: boolean;
    validateSerialization?: boolean;
}

export { }