apollo/README.md

# Apollo CLI

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Apollo CLI brings together your GraphQL clients and servers with tools for validating your schema, linting your operations for compatibility with your server, and generating static types for improved client-side type safety.

<!-- toc -->
* [Apollo CLI](#apollo-cli)
* [Usage](#usage)
* [Commands](#commands)
* [Configuration](#configuration)
* [Code Generation](#code-generation)
* [Contributing](#contributing)
<!-- tocstop -->

# Usage

<!-- usage -->
```sh-session
$ npm install -g apollo
$ apollo COMMAND
running command...
$ apollo (-v|--version|version)
apollo/2.10.2 darwin-x64 node-v11.14.0
$ apollo --help [COMMAND]
USAGE
  $ apollo COMMAND
...
```
<!-- usagestop -->

# Commands

<!-- commands -->
* [`apollo client:check`](#apollo-clientcheck)
* [`apollo client:codegen [OUTPUT]`](#apollo-clientcodegen-output)
* [`apollo client:download-schema OUTPUT`](#apollo-clientdownload-schema-output)
* [`apollo client:extract OUTPUT`](#apollo-clientextract-output)
* [`apollo client:push`](#apollo-clientpush)
* [`apollo help [COMMAND]`](#apollo-help-command)
* [`apollo plugins`](#apollo-plugins)
* [`apollo plugins:install PLUGIN...`](#apollo-pluginsinstall-plugin)
* [`apollo plugins:link PLUGIN`](#apollo-pluginslink-plugin)
* [`apollo plugins:uninstall PLUGIN...`](#apollo-pluginsuninstall-plugin)
* [`apollo plugins:update`](#apollo-pluginsupdate)
* [`apollo service:check`](#apollo-servicecheck)
* [`apollo service:download OUTPUT`](#apollo-servicedownload-output)
* [`apollo service:push`](#apollo-servicepush)

## `apollo client:check`

Check a client project against a pushed service

```
USAGE
  $ apollo client:check

OPTIONS
  -c, --config=config                    Path to your Apollo config file
  -t, --tag=tag                          The published service tag for this client
  --clientName=clientName                Name of the client that the queries will be attached to

  --clientReferenceId=clientReferenceId  Reference id for the client which will match ids from client traces, will use
                                         clientName if not provided

  --clientVersion=clientVersion          The version of the client that the queries will be attached to

  --endpoint=endpoint                    The url of your service

  --excludes=excludes                    Glob of files to exclude for GraphQL operations. Caveat: this doesn't currently
                                         work in watch mode

  --header=header                        Additional header to send to server for introspectionQuery. May be used
                                         multiple times to add multiple headers. NOTE: The `--endpoint` flag is REQUIRED
                                         if using the `--header` flag.

  --includes=includes                    Glob of files to search for GraphQL operations. This should be used to find
                                         queries *and* any client schema extensions

  --key=key                              The API key for the Apollo Engine service

  --queries=queries                      Deprecated in favor of the includes flag

  --tagName=tagName                      Name of the template literal tag used to identify template literals containing
                                         GraphQL queries in Javascript/Typescript code
```

_See code: [src/commands/client/check.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/client/check.ts)_

## `apollo client:codegen [OUTPUT]`

Generate static types for GraphQL queries. Can use the published schema in Apollo Engine or a downloaded schema.

```
USAGE
  $ apollo client:codegen [OUTPUT]

ARGUMENTS
  OUTPUT
      Directory to which generated files will be written.
      - For TypeScript/Flow generators, this specifies a directory relative to each source file by default.
      - For TypeScript/Flow generators with the "outputFlat" flag is set, and for the Swift generator, this specifies a 
      file or directory (absolute or relative to the current working directory) to which:
         - a file will be written for each query (if "output" is a directory)
         - all generated types will be written
      - For all other types, this defines a file (absolute or relative to the current working directory) to which all 
      generated types are written.

OPTIONS
  -c, --config=config                        Path to your Apollo config file
  -t, --tag=tag                              The published service tag for this client

  --[no-]addTypename                         [default: true] Automatically add __typename to your queries, can be unset
                                             with --no-addTypename

  --clientName=clientName                    Name of the client that the queries will be attached to

  --clientReferenceId=clientReferenceId      Reference id for the client which will match ids from client traces, will
                                             use clientName if not provided

  --clientVersion=clientVersion              The version of the client that the queries will be attached to

  --customScalarsPrefix=customScalarsPrefix  Include a prefix when using provided types for custom scalars

  --endpoint=endpoint                        The url of your service

  --excludes=excludes                        Glob of files to exclude for GraphQL operations. Caveat: this doesn't
                                             currently work in watch mode

  --globalTypesFile=globalTypesFile          By default, TypeScript will put a file named "globalTypes.ts" inside the
                                             "output" directory. Set "globalTypesFile" to specify a different path.

  --header=header                            Additional header to send to server for introspectionQuery. May be used
                                             multiple times to add multiple headers. NOTE: The `--endpoint` flag is
                                             REQUIRED if using the `--header` flag.

  --includes=includes                        Glob of files to search for GraphQL operations. This should be used to find
                                             queries *and* any client schema extensions

  --key=key                                  The API key for the Apollo Engine service

  --localSchemaFile=localSchemaFile          Path to your local GraphQL schema file (introspection result or SDL)

  --mergeInFieldsFromFragmentSpreads         Merge fragment fields onto its enclosing type

  --namespace=namespace                      The namespace to emit generated code into.

  --only=only                                Parse all input files, but only output generated code for the specified
                                             file [Swift only]

  --operationIdsPath=operationIdsPath        Path to an operation id JSON map file. If specified, also stores the
                                             operation ids (hashes) as properties on operation types [currently
                                             Swift-only]

  --outputFlat                               By default, TypeScript/Flow will put each generated file in a directory
                                             next to its source file using the value of the "output" as the directory
                                             name. Set "outputFlat" to put all generated files in the directory relative
                                             to the current working directory defined by "output".

  --passthroughCustomScalars                 Use your own types for custom scalars

  --queries=queries                          Deprecated in favor of the includes flag

  --tagName=tagName                          Name of the template literal tag used to identify template literals
                                             containing GraphQL queries in Javascript/Typescript code

  --target=target                            (required) Type of code generator to use (swift | typescript | flow |
                                             scala)

  --useFlowExactObjects                      Use Flow exact objects for generated types [flow only]

  --useFlowReadOnlyTypes                     Use Flow read only types for generated types [flow only]

  --watch                                    Watch for file changes and reload codegen

ALIASES
  $ apollo codegen:generate
```

_See code: [src/commands/client/codegen.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/client/codegen.ts)_

## `apollo client:download-schema OUTPUT`

Download a schema from engine or a GraphQL endpoint.

```
USAGE
  $ apollo client:download-schema OUTPUT

ARGUMENTS
  OUTPUT  [default: schema.json] Path to write the introspection result to

OPTIONS
  -c, --config=config                    Path to your Apollo config file
  -t, --tag=tag                          The published service tag for this client
  --clientName=clientName                Name of the client that the queries will be attached to

  --clientReferenceId=clientReferenceId  Reference id for the client which will match ids from client traces, will use
                                         clientName if not provided

  --clientVersion=clientVersion          The version of the client that the queries will be attached to

  --endpoint=endpoint                    The url of your service

  --excludes=excludes                    Glob of files to exclude for GraphQL operations. Caveat: this doesn't currently
                                         work in watch mode

  --header=header                        Additional header to send to server for introspectionQuery. May be used
                                         multiple times to add multiple headers. NOTE: The `--endpoint` flag is REQUIRED
                                         if using the `--header` flag.

  --includes=includes                    Glob of files to search for GraphQL operations. This should be used to find
                                         queries *and* any client schema extensions

  --key=key                              The API key for the Apollo Engine service

  --queries=queries                      Deprecated in favor of the includes flag

  --tagName=tagName                      Name of the template literal tag used to identify template literals containing
                                         GraphQL queries in Javascript/Typescript code
```

_See code: [src/commands/client/download-schema.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/client/download-schema.ts)_

## `apollo client:extract OUTPUT`

Extract queries from a client

```
USAGE
  $ apollo client:extract OUTPUT

ARGUMENTS
  OUTPUT  [default: manifest.json] Path to write the extracted queries to

OPTIONS
  -c, --config=config                    Path to your Apollo config file
  -t, --tag=tag                          The published service tag for this client
  --clientName=clientName                Name of the client that the queries will be attached to

  --clientReferenceId=clientReferenceId  Reference id for the client which will match ids from client traces, will use
                                         clientName if not provided

  --clientVersion=clientVersion          The version of the client that the queries will be attached to

  --endpoint=endpoint                    The url of your service

  --excludes=excludes                    Glob of files to exclude for GraphQL operations. Caveat: this doesn't currently
                                         work in watch mode

  --header=header                        Additional header to send to server for introspectionQuery. May be used
                                         multiple times to add multiple headers. NOTE: The `--endpoint` flag is REQUIRED
                                         if using the `--header` flag.

  --includes=includes                    Glob of files to search for GraphQL operations. This should be used to find
                                         queries *and* any client schema extensions

  --key=key                              The API key for the Apollo Engine service

  --queries=queries                      Deprecated in favor of the includes flag

  --tagName=tagName                      Name of the template literal tag used to identify template literals containing
                                         GraphQL queries in Javascript/Typescript code
```

_See code: [src/commands/client/extract.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/client/extract.ts)_

## `apollo client:push`

Push a service to Engine

```
USAGE
  $ apollo client:push

OPTIONS
  -c, --config=config                    Path to your Apollo config file
  -t, --tag=tag                          The published service tag for this client
  --clientName=clientName                Name of the client that the queries will be attached to

  --clientReferenceId=clientReferenceId  Reference id for the client which will match ids from client traces, will use
                                         clientName if not provided

  --clientVersion=clientVersion          The version of the client that the queries will be attached to

  --endpoint=endpoint                    The url of your service

  --excludes=excludes                    Glob of files to exclude for GraphQL operations. Caveat: this doesn't currently
                                         work in watch mode

  --header=header                        Additional header to send to server for introspectionQuery. May be used
                                         multiple times to add multiple headers. NOTE: The `--endpoint` flag is REQUIRED
                                         if using the `--header` flag.

  --includes=includes                    Glob of files to search for GraphQL operations. This should be used to find
                                         queries *and* any client schema extensions

  --key=key                              The API key for the Apollo Engine service

  --queries=queries                      Deprecated in favor of the includes flag

  --tagName=tagName                      Name of the template literal tag used to identify template literals containing
                                         GraphQL queries in Javascript/Typescript code
```

_See code: [src/commands/client/push.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/client/push.ts)_

## `apollo help [COMMAND]`

display help for apollo

```
USAGE
  $ apollo help [COMMAND]

ARGUMENTS
  COMMAND  command to show help for

OPTIONS
  --all  see all commands in CLI
```

_See code: [@oclif/plugin-help](https://github.com/oclif/plugin-help/blob/v2.1.6/src/commands/help.ts)_

## `apollo plugins`

list installed plugins

```
USAGE
  $ apollo plugins

OPTIONS
  --core  show core plugins

EXAMPLE
  $ apollo plugins
```

_See code: [@oclif/plugin-plugins](https://github.com/oclif/plugin-plugins/blob/v1.7.8/src/commands/plugins/index.ts)_

## `apollo plugins:install PLUGIN...`

installs a plugin into the CLI

```
USAGE
  $ apollo plugins:install PLUGIN...

ARGUMENTS
  PLUGIN  plugin to install

OPTIONS
  -f, --force    yarn install with force flag
  -h, --help     show CLI help
  -v, --verbose

DESCRIPTION
  Can be installed from npm or a git url.

  Installation of a user-installed plugin will override a core plugin.

  e.g. If you have a core plugin that has a 'hello' command, installing a user-installed plugin with a 'hello' command 
  will override the core plugin implementation. This is useful if a user needs to update core plugin functionality in 
  the CLI without the need to patch and update the whole CLI.

ALIASES
  $ apollo plugins:add

EXAMPLES
  $ apollo plugins:install myplugin 
  $ apollo plugins:install https://github.com/someuser/someplugin
  $ apollo plugins:install someuser/someplugin
```

_See code: [@oclif/plugin-plugins](https://github.com/oclif/plugin-plugins/blob/v1.7.8/src/commands/plugins/install.ts)_

## `apollo plugins:link PLUGIN`

links a plugin into the CLI for development

```
USAGE
  $ apollo plugins:link PLUGIN

ARGUMENTS
  PATH  [default: .] path to plugin

OPTIONS
  -h, --help     show CLI help
  -v, --verbose

DESCRIPTION
  Installation of a linked plugin will override a user-installed or core plugin.

  e.g. If you have a user-installed or core plugin that has a 'hello' command, installing a linked plugin with a 'hello' 
  command will override the user-installed or core plugin implementation. This is useful for development work.

EXAMPLE
  $ apollo plugins:link myplugin
```

_See code: [@oclif/plugin-plugins](https://github.com/oclif/plugin-plugins/blob/v1.7.8/src/commands/plugins/link.ts)_

## `apollo plugins:uninstall PLUGIN...`

removes a plugin from the CLI

```
USAGE
  $ apollo plugins:uninstall PLUGIN...

ARGUMENTS
  PLUGIN  plugin to uninstall

OPTIONS
  -h, --help     show CLI help
  -v, --verbose

ALIASES
  $ apollo plugins:unlink
  $ apollo plugins:remove
```

_See code: [@oclif/plugin-plugins](https://github.com/oclif/plugin-plugins/blob/v1.7.8/src/commands/plugins/uninstall.ts)_

## `apollo plugins:update`

update installed plugins

```
USAGE
  $ apollo plugins:update

OPTIONS
  -h, --help     show CLI help
  -v, --verbose
```

_See code: [@oclif/plugin-plugins](https://github.com/oclif/plugin-plugins/blob/v1.7.8/src/commands/plugins/update.ts)_

## `apollo service:check`

Check a service against known operation workloads to find breaking changes

```
USAGE
  $ apollo service:check

OPTIONS
  -c, --config=config                                            Path to your Apollo config file
  -t, --tag=tag                                                  The published tag to check this service against
  --endpoint=endpoint                                            The url of your service

  --header=header                                                Additional header to send to server for
                                                                 introspectionQuery. May be used multiple times to add
                                                                 multiple headers. NOTE: The `--endpoint` flag is
                                                                 REQUIRED if using the `--header` flag.

  --json                                                         Output result in json, which can then be parsed by CLI
                                                                 tools such as jq.

  --key=key                                                      The API key for the Apollo Engine service

  --localSchemaFile=localSchemaFile                              Path to your local GraphQL schema file (introspection
                                                                 result or SDL)

  --markdown                                                     Output result in markdown.

  --queryCountThreshold=queryCountThreshold                      Minimum number of requests within the requested time
                                                                 window for a query to be considered.

  --queryCountThresholdPercentage=queryCountThresholdPercentage  Number of requests within the requested time window for
                                                                 a query to be considered, relative to total request
                                                                 count. Expected values are between 0 and 0.05 (minimum
                                                                 5% of total request volume)

  --validationPeriod=validationPeriod                            The size of the time window with which to validate the
                                                                 schema against. You may provide a number (in seconds),
                                                                 or an ISO8601 format duration for more granularity
                                                                 (see: https://en.wikipedia.org/wiki/ISO_8601#Durations)

ALIASES
  $ apollo schema:check
```

_See code: [src/commands/service/check.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/service/check.ts)_

## `apollo service:download OUTPUT`

Download the schema from your GraphQL endpoint.

```
USAGE
  $ apollo service:download OUTPUT

ARGUMENTS
  OUTPUT  [default: schema.json] Path to write the introspection result to

OPTIONS
  -c, --config=config      Path to your Apollo config file
  -k, --skipSSLValidation  Allow connections to an SSL site without certs
  -t, --tag=tag            [default: current] The published tag to check this service against
  --endpoint=endpoint      The url of your service

  --header=header          Additional header to send to server for introspectionQuery. May be used multiple times to add
                           multiple headers. NOTE: The `--endpoint` flag is REQUIRED if using the `--header` flag.

  --key=key                The API key for the Apollo Engine service

ALIASES
  $ apollo schema:download
```

_See code: [src/commands/service/download.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/service/download.ts)_

## `apollo service:push`

Push a service to Engine

```
USAGE
  $ apollo service:push

OPTIONS
  -c, --config=config                Path to your Apollo config file
  -t, --tag=tag                      [default: current] The tag to publish this service to
  --endpoint=endpoint                The url of your service

  --header=header                    Additional header to send to server for introspectionQuery. May be used multiple
                                     times to add multiple headers. NOTE: The `--endpoint` flag is REQUIRED if using the
                                     `--header` flag.

  --key=key                          The API key for the Apollo Engine service

  --localSchemaFile=localSchemaFile  Path to your local GraphQL schema file (introspection result or SDL)

ALIASES
  $ apollo schema:publish
```

_See code: [src/commands/service/push.ts](https://github.com/apollographql/apollo-tooling/blob/master/packages/apollo/src/commands/service/push.ts)_
<!-- commandsstop -->

# Configuration

The Apollo CLI and VS Code extension can be configured with an Apollo config file. Apollo configuration is stored as a plain object in an `apollo.config.js` file which exports the configuration. For more information about configuring an Apollo project, see: https://bit.ly/2ByILPj.

> Note: the use of the `apollo` key in the project's package.json file for configuration is deprecated, and will no longer be supported in Apollo v3

You'll need to set up your Apollo configuration for all the features of the Apollo CLI and VS Code extension to work correctly. For full details on how to do that, [visit our docs](https://www.apollographql.com/docs/references/apollo-config.html). A basic configuration (`apollo.config.js` style) looks something like this:

```js
module.exports = {
  client: {
    name: "My Client Project",
    service: "my-service-name"
  }
};
```

# Code Generation

## Accompanying Libraries

See [Apollo iOS](https://github.com/apollographql/apollo-ios) for details on the mapping from GraphQL results to Swift types, as well as runtime support for executing queries and mutations. For Scala, see [React Apollo Scala.js](https://github.com/apollographql/react-apollo-scalajs) for details on how to use generated Scala code in a Scala.js app with Apollo Client.

## `gql` template support

If the source file for generation is a JavaScript or TypeScript file, the codegen will try to extrapolate the queries inside the [gql tag](https://github.com/apollographql/graphql-tag) templates.

The tag name is configurable using the CLI `--tagName` option.

## Typescript and Flow

When using the codegen command with Typescript or Flow, make sure to add the `__typename` introspection field to every selection set within your graphql operations.

If you're using a client like `apollo-client` that does this automatically for your GraphQL operations, pass in the `--addTypename` option to `apollo codegen:generate` to make sure the generated Typescript and Flow types have the `__typename` field as well. This is required to ensure proper type generation support for `GraphQLUnionType` and `GraphQLInterfaceType` fields.

## Why is the \_\_typename field required?

Using the type information from the GraphQL schema, we can infer the possible types for fields. However, in the case of a `GraphQLUnionType` or `GraphQLInterfaceType`, there are multiple types that are possible for that field. This is best modeled using a disjoint union with the `__typename`
as the discriminant.

For example, given a schema:

```graphql
...

interface Character {
  name: String!
}

type Human implements Character {
  homePlanet: String
}

type Droid implements Character {
  primaryFunction: String
}

...
```

Whenever a field of type `Character` is encountered, it could be either a Human or Droid. Human and Droid objects
will have a different set of fields. Within your application code, when interacting with a `Character` you'll want to make sure to handle both of these cases.

Given this query:

```graphql
query Characters {
  characters(episode: NEW_HOPE) {
    name

    ... on Human {
      homePlanet
    }

    ... on Droid {
      primaryFunction
    }
  }
}
```

Apollo Codegen will generate a union type for Character.

```javascript
export type CharactersQuery = {
  characters: Array<
    | {
        __typename: "Human",
        name: string,
        homePlanet: ?string
      }
    | {
        __typename: "Droid",
        name: string,
        primaryFunction: ?string
      }
  >
};
```

This type can then be used as follows to ensure that all possible types are handled:

```javascript
function CharacterFigures({ characters }: CharactersQuery) {
  return characters.map(character => {
    switch (character.__typename) {
      case "Human":
        return (
          <HumanFigure
            homePlanet={character.homePlanet}
            name={character.name}
          />
        );
      case "Droid":
        return (
          <DroidFigure
            primaryFunction={character.primaryFunction}
            name={character.name}
          />
        );
    }
  });
}
```

# Contributing

[![Build Status](https://circleci.com/gh/apollographql/apollo-tooling.svg?style=svg)](https://circleci.com/gh/apollographql/apollo-tooling)

This repo is composed of multiple packages managed by Lerna. The `apollo-cli` contains the core CLI commands. The `apollo-codegen-core` package contains all the compiler APIs needed to implement code generation support for new languages. The other `apollo-codegen-*` packages implement code generation support for individual languages.

Running tests locally:

```
npm install
npm test
```

You can also run `npm` commands within package folders after you have bootstrapped the repository (part of `npm install`).

> Note: if you have issues, try `npm run clean && npm i` to get a fresh install of the packages. Occasionally problems arise when removed dependencies stay around

## Nock tests

To display the debugging messages for nock, run the following command:

```bash
DEBUG=nock.* npm test
```

It can also be helpful to print standard out during testing. To enable logging, add the following configuration to the `stdout` function call during test creation:

```
.stdout({ print: true })
```

## Active Development / Debugging

To simplify the development process, you may want to step through and debug commands whose behavior you're modifying. To do this, run the executable with node in debug mode like so, where `<command>` is a valid CLI command like `client:check` or `service:push`:

```
node --inspect-brk=9002 packages/apollo/bin/run <command>
```

If you're using VS Code, you can run the included "Attach to CLI Debugger" launch task and debug right from VS Code! Otherwise, you may use the (Chrome inspector)[https://nodejs.org/en/docs/guides/debugging-getting-started/] or other Node debugger of your choice.

## Publishing

- Make sure the `CHANGELOG.md` is updated with all changes committed since the last release. Make sure the versions for each package to update are correct, and there's a blank `Upcoming` section for future work.
- Run `npm run release` to publish the individual packages.

## Maintainers

- [@jbaxleyiii](https://github.com/jbaxleyiii) (Apollo)
- [@trevor-scheer](https://github.com/trevor-scheer) (Apollo)