@google-cloud/profiler/README.md

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# [Stackdriver Profiler: Node.js Client](https://github.com/googleapis/cloud-profiler-nodejs)

[![release level](https://img.shields.io/badge/release%20level-general%20availability%20%28GA%29-brightgreen.svg?style=flat)](https://cloud.google.com/terms/launch-stages)
[![npm version](https://img.shields.io/npm/v/@google-cloud/profiler.svg)](https://www.npmjs.org/package/@google-cloud/profiler)
[![codecov](https://img.shields.io/codecov/c/github/googleapis/cloud-profiler-nodejs/master.svg?style=flat)](https://codecov.io/gh/googleapis/cloud-profiler-nodejs)




Adds support for Stackdriver Profiler to Node.js applications


* [Stackdriver Profiler Node.js Client API Reference][client-docs]
* [Stackdriver Profiler Documentation][product-docs]
* [github.com/googleapis/cloud-profiler-nodejs](https://github.com/googleapis/cloud-profiler-nodejs)

Read more about the client libraries for Cloud APIs, including the older
Google APIs Client Libraries, in [Client Libraries Explained][explained].

[explained]: https://cloud.google.com/apis/docs/client-libraries-explained

**Table of contents:**


* [Quickstart](#quickstart)
  * [Before you begin](#before-you-begin)
  * [Installing the client library](#installing-the-client-library)

* [Samples](#samples)
* [Versioning](#versioning)
* [Contributing](#contributing)
* [License](#license)

## Quickstart

### Before you begin

1.  [Select or create a Cloud Platform project][projects].
1.  [Enable the Stackdriver Profiler API][enable_api].
1.  [Set up authentication with a service account][auth] so you can access the
    API from your local workstation.

### Installing the client library

```bash
npm install @google-cloud/profiler
```


### Prerequisites

1. Your application will need to be using Node.js 10.4.1 or greater or Node.js
12. The profiler will not be enabled when using earlier versions of 10 because
versions of Node.js 10 prior to 10.4.1 are impacted by
[this](https://bugs.chromium.org/p/chromium/issues/detail?id=847863) issue,
which can cause garbage collection to take several minutes when heap profiling
is enabled.

1. `@google-cloud/profiler` depends on the
[`pprof`](https://www.npmjs.com/package/pprof) module, a module with a native
component that is used to collect profiles with v8's CPU and Heap profilers.
You may need to install additional dependencies to build the `pprof` module.
    * For Linux: `pprof` has prebuilt binaries available for Linux and Alpine
    Linux for Node 10 and 12. No additional dependencies are required.
    * For other environments: when using `@google-cloud/profiler` on environments
    that `pprof` does not have prebuilt binaries for, the module
    [`node-gyp`](https://www.npmjs.com/package/node-gyp) will be used to
    build binaries. See `node-gyp`'s
    [documentation](https://github.com/nodejs/node-gyp#installation)
    for information on dependencies required to build binaries with `node-gyp`.

1. You will need a project in the [Google Developers Console][cloud-console].
Your application can run anywhere, but the profiler data is associated with a
particular project.

1. You will need to enable the Stackdriver Profiler API for your project.

### Basic Set-up

1. Install `@google-cloud/profiler` with [`npm`](https://www.npmjs.com) or add
to your [`package.json`](https://docs.npmjs.com/files/package.json#dependencies).

    ```sh
    # Install through npm while saving to the local 'package.json'
    npm install --save @google-cloud/profiler
    ```

2. Include and start the profiler at the beginning of your application:

    ```js
    require('@google-cloud/profiler').start().catch((err) => {
    console.log(`Failed to start profiler: ${err}`);
    });
    ```

    Some environments require a configuration to be passed to the `start()`
    function. For more details on this, see instructions for running
    [outside of Google Cloud Platform](#running-elsewhere), on
    [App Engine flexible environment](#running-on-app-engine-flexible-environment),
    on [Google Compute Engine](#running-on-google-compute-engine),
    and on [Google Container Engine](#running-on-google-container-engine).

3. If you are running your application locally, or on a machine where you are
using the [Google Cloud SDK][gcloud-sdk], make sure to log in with the
application default credentials:

    ```sh
    gcloud beta auth application-default login
    ```

    Alternatively, you can set `GOOGLE_APPLICATION_CREDENTIALS`. For more
    details on this, see [Running elsewhere](#running-elsewhere)

### Configuration

See [the default configuration](https://github.com/googleapis/cloud-profiler-nodejs/blob/master/src/config.ts) for a list of possible
configuration options. These options can be passed to the agent through the
object argument to the start command shown below:

```js
await require('@google-cloud/profiler').start({disableTime: true});
```

Alternatively, you can provide the configuration through a config file. This
can be useful if you want to load our module using `--require` on the command
line (which requires and starts the agent) instead of editing your main script.
The `GCLOUD_PROFILER_CONFIG` environment variable should point to your
configuration file.

```bash
export GCLOUD_PROFILER_CONFIG=./path/to/your/profiler/configuration.js
```

#### Changing log level

The profiler writes log statements to the console log for diagnostic purposes.
By default, the log level is set to warn. You can adjust this by setting
`logLevel` in the config. Setting `logLevel` to 0 will disable logging,
1 sets log level to error, 2 sets it to warn (default), 3 sets it to info,
and 4 sets it to debug.

So, for example, to start the profiler with the log level at debug, you would
do this:

```js
await require('@google-cloud/profiler').start({logLevel: 4});
```

#### Disabling heap or time profile collection

By default, the profiler collects both heap profiles, which show memory
allocations, and time profiles, which capture how much wall-clock time is spent
in different locations of the code. Using the configuration, it is possible to
disable the collection of either type of profile.

To disable time profile collection, set `disableTime` to true:

```js
await require('@google-cloud/profiler').start({disableTime: true});
```

To disable heap profile collection, set `disableHeap` to true:

```js
await require('@google-cloud/profiler').start({disableHeap: true});
```

### Running on Google Cloud Platform

There are three different services that can host Node.js applications within
Google Cloud Platform: Google App Engine flexible environment, Google Compute
Engine, and Google Container Engine. After installing `@google-cloud/profiler`
in your project and ensuring that the environment you are using uses a
supported version of Node.js, follow the service-specific instructions to
enable the profiler.

#### Running on App Engine flexible environment

To enable the profiling agent for a Node.js program running in the App Engine
flexible environment, import the agent at the top of your application’s main
script or entry point by including the following code snippet:

```js
require('@google-cloud/profiler').start();
```

You can specify which version of Node.js you're using by adding a snippet like
the following to your `package.json`:

```json
"engines": {
    "node": ">=10.4.1"
}
```
The above snippet will ensure that you're using 10.4.1 or greater.

Deploy your application to App Engine Flexible environment as usual.

#### Running on Google Compute Engine

To enable the profiling agent for a Node.js program running in the Google
Compute Engine environment, import the agent at the top of your application’s
main script or entry point by including the following code snippet:

```js
require('@google-cloud/profiler').start({
serviceContext: {
    service: 'your-service',
    version: '1.0.0'
}
});
```

#### Running on Google Container Engine

To enable the profiling agent for a Node.js program running in the Google
Container Engine environment, import the agent at the top of your application’s
main script or entry point by including the following code snippet:

```js
require('@google-cloud/profiler').start({
serviceContext: {
    service: 'your-service',
    version: '1.0.0'
}
});
```

#### Running on Istio

On Istio, the GCP Metadata server may not be available for a few seconds after
your application has started. When this occurs, the profiling agent may fail
to start because it cannot initialize required fields. One can retry when
starting the profiler with the following snippet.

```js
const profiler = require('@google-cloud/profiler');
async function startProfiler() {
for (let i = 0; i < 3; i++) {
    try {
    await profiler.start({
        serviceContext: {
        service: 'your-service',
        version: '1.0.0',
        },
    });
    } catch(e) {
    console.log(`Failed to start profiler: ${e}`);
    }

    // Wait for 1 second before trying again.
    await new Promise(r => setTimeout(r, 1000));
}
}
startProfiler();

```


### Running elsewhere

You can still use `@google-cloud/profiler` if your application is running
outside of Google Cloud Platform, for example, running locally, on-premise, or
on another cloud provider.

1. You will need to specify your project id and the service you want the
collected profiles to be associated with, and (optionally) the version of
the service when starting the profiler:

```js
    await require('@google-cloud/profiler').start({
    projectId: 'project-id',
    serviceContext: {
        service: 'your-service',
        version: '1.0.0'
    }
    });
```
2. You will need to provide credential for your application.

* If you are running your application on a development machine or test
environment where you are using the [`gcloud` command line tools][gcloud-sdk],
and are logged using `gcloud beta auth application-default login`, you
already have sufficient credentials, and a service account key is not
required.

* You can provide credentials via
[Application Default Credentials][app-default-credentials]. This is the
recommended method.
        1. [Create a new JSON service account key][service-account].
        2. Copy the key somewhere your application can access it. Be sure not
        to expose the key publicly.
        3.  Set the environment variable `GOOGLE_APPLICATION_CREDENTIALS` to
        the full path to the key. The profiler will automatically look for
        this environment variable.

*  You may set the `keyFilename` or `credentials` configuration field to the
full path or contents to the key file, respectively. Setting either of these
fields will override either setting `GOOGLE_APPLICATION_CREDENTIALS` or
logging in using `gcloud`.

    This is how you would set `keyFilename`:
    ```js
    await require('@google-cloud/profiler').start({
        projectId: 'project-id',
        serviceContext: {
        service: 'your-service',
        version: '1.0.0'
        },
        keyFilename: '/path/to/keyfile'
    });
    ```

    This is how you would set  `credentials`:
    ```js
    await require('@google-cloud/profiler').start({
        projectId: 'project-id',
        serviceContext: {
        service: 'your-service',
        version: '1.0.0'
        },
        credentials: {
        client_email: 'email',
        private_key: 'private_key'
        }
    });
    ```


## Samples

Samples are in the [`samples/`](https://github.com/googleapis/cloud-profiler-nodejs/tree/master/samples) directory. The samples' `README.md`
has instructions for running the samples.

| Sample                      | Source Code                       | Try it |
| --------------------------- | --------------------------------- | ------ |
| App | [source code](https://github.com/googleapis/cloud-profiler-nodejs/blob/master/samples/app.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/cloud-profiler-nodejs&page=editor&open_in_editor=samples/app.js,samples/README.md) |
| Snippets | [source code](https://github.com/googleapis/cloud-profiler-nodejs/blob/master/samples/snippets.js) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/cloud-profiler-nodejs&page=editor&open_in_editor=samples/snippets.js,samples/README.md) |



The [Stackdriver Profiler Node.js Client API Reference][client-docs] documentation
also contains samples.

## Supported Node.js Versions

Our client libraries follow the [Node.js release schedule](https://nodejs.org/en/about/releases/).
Libraries are compatible with all current _active_ and _maintenance_ versions of
Node.js.

Client libraries targetting some end-of-life versions of Node.js are available, and
can be installed via npm [dist-tags](https://docs.npmjs.com/cli/dist-tag).
The dist-tags follow the naming convention `legacy-(version)`.

_Legacy Node.js versions are supported as a best effort:_

* Legacy versions will not be tested in continuous integration.
* Some security patches may not be able to be backported.
* Dependencies will not be kept up-to-date, and features will not be backported.

#### Legacy tags available

* `legacy-8`: install client libraries from this dist-tag for versions
  compatible with Node.js 8.

## Versioning

This library follows [Semantic Versioning](http://semver.org/).


This library is considered to be **General Availability (GA)**. This means it
is stable; the code surface will not change in backwards-incompatible ways
unless absolutely necessary (e.g. because of critical security issues) or with
an extensive deprecation period. Issues and requests against **GA** libraries
are addressed with the highest priority.





More Information: [Google Cloud Platform Launch Stages][launch_stages]

[launch_stages]: https://cloud.google.com/terms/launch-stages

## Contributing

Contributions welcome! See the [Contributing Guide](https://github.com/googleapis/cloud-profiler-nodejs/blob/master/CONTRIBUTING.md).

Please note that this `README.md`, the `samples/README.md`,
and a variety of configuration files in this repository (including `.nycrc` and `tsconfig.json`)
are generated from a central template. To edit one of these files, make an edit
to its template in this
[directory](https://github.com/googleapis/synthtool/tree/master/synthtool/gcp/templates/node_library).

## License

Apache Version 2.0

See [LICENSE](https://github.com/googleapis/cloud-profiler-nodejs/blob/master/LICENSE)

[client-docs]: https://googleapis.dev/nodejs/profiler/latest/
[product-docs]: https://cloud.google.com/profiler
[shell_img]: https://gstatic.com/cloudssh/images/open-btn.png
[projects]: https://console.cloud.google.com/project
[billing]: https://support.google.com/cloud/answer/6293499#enable-billing
[enable_api]: https://console.cloud.google.com/flows/enableapi?apiid=cloudprofiler.googleapis.com
[auth]: https://cloud.google.com/docs/authentication/getting-started