# Continuous Integration

Playwright tests can be executed in CI environments. We have created sample
configurations for common CI providers.

<!-- GEN:toc -->
- [Introduction](#introduction)
- [CI configurations](#ci-configurations)
  * [GitHub Actions](#github-actions)
  * [Docker](#docker)
  * [Azure Pipelines](#azure-pipelines)
  * [Travis CI](#travis-ci)
  * [CircleCI](#circleci)
  * [Bitbucket Pipelines](#bitbucket-pipelines)
  * [GitLab CI](#gitlab-ci)
- [Caching browsers](#caching-browsers)
    - [Exception: `node_modules` are cached](#exception-nodemodules-are-cached)
    - [Directories to cache](#directories-to-cache)
- [Debugging browser launches](#debugging-browser-launches)
- [Running headful](#running-headful)
<!-- GEN:stop -->

## Introduction

3 steps to get your tests running on CI:

1. **Ensure CI agent can run browsers**: Use [our Docker image](docker/README.md)
   in Linux agents. Windows and macOS agents do not require any additional dependencies.
1. **Install Playwright**: In most projects, this would be done with `npm ci`
   (or `npm install`). Playwright would install the relevant browsers automatically.
1. **Run your tests**: Use `npm test` or equivalent to execute your tests.

## CI configurations

### GitHub Actions

The [Playwright GitHub Action](https://github.com/microsoft/playwright-github-action) can be used to run Playwright tests on GitHub Actions.

```yml
steps:
  - uses: microsoft/playwright-github-action@v1
  - name: Run your tests
    run: npm test
```

We run [our tests](/.github/workflows/tests.yml) on GitHub Actions, across a matrix of 3 platforms (Windows, Linux, macOS) and 3 browsers (Chromium, Firefox, WebKit).

### Docker

We have a [pre-built Docker image](docker/README.md) which can either be used directly, or as a reference to update your existing Docker definitions.

Suggested configuration
1. By default, Docker runs a container with a `/dev/shm` shared memory space 64MB.
   This is [typically too small](https://github.com/c0b/chrome-in-docker/issues/1) for Chromium
   and will cause Chromium to crash when rendering large pages. To fix, run the container with
   `docker run --shm-size=1gb` to increase the size of `/dev/shm`. Since Chromium 65, this is no
   longer necessary. Instead, launch the browser with the `--disable-dev-shm-usage` flag:

   ```js
   const browser = await playwright.chromium.launch({
     args: ['--disable-dev-shm-usage']
   });
   ```

   This will write shared memory files into `/tmp` instead of `/dev/shm`. See
   [crbug.com/736452](https://bugs.chromium.org/p/chromium/issues/detail?id=736452) for more details.
1. Using `--ipc=host` is also recommended when using Chromium—without it Chromium can run out of memory
   and crash. Learn more about this option in [Docker docs](https://docs.docker.com/engine/reference/run/#ipc-settings---ipc).
1. Seeing other weird errors when launching Chromium? Try running your container
   with `docker run --cap-add=SYS_ADMIN` when developing locally. Since the Dockerfile
   adds a `pwuser` user as a non-privileged user, it may not have all the necessary privileges.
1. [dumb-init](https://github.com/Yelp/dumb-init) is worth checking out if you're
   experiencing a lot of zombies Chromium processes sticking around. There's special
   treatment for processes with PID=1, which makes it hard to terminate Chromium
   properly in some cases (e.g. in Docker).

### Azure Pipelines

For Windows or macOS agents, no additional configuration required, just install Playwright and run your tests.

For Linux agents, you can use [our Docker container](docker/README.md) with Azure Pipelines support for [running containerized jobs](https://docs.microsoft.com/en-us/azure/devops/pipelines/process/container-phases?view=azure-devops). Alternatively, you can refer to the [Dockerfile](docker/README.md) to see additional dependencies that need to be installed on a Ubuntu agent.

```yml
pool:
  vmImage: 'ubuntu-18.04'

container: mcr.microsoft.com/playwright:bionic

steps:
- script: npm install
- script: npm run test
```

### Travis CI

We run our tests on Travis CI over a Linux agent (Ubuntu 18.04).

Suggested configuration
1. [User namespace cloning](http://man7.org/linux/man-pages/man7/user_namespaces.7.html)
   should be enabled to support proper sandboxing
1. [xvfb](https://en.wikipedia.org/wiki/Xvfb) should be launched in order to run
   Chromium in non-headless mode (e.g. to test Chrome Extensions)
1. If your project does not have `package-lock.json`, Travis would be auto-caching
   `node_modules` directory. If you run `npm install` (instead of `npm ci`), it is
   possible that the browser binaries are not downloaded. Fix this with [these steps](#exception-nodemodules-are-cached) outlined below.

To sum up, your `.travis.yml` might look like this:

```yml
language: node_js
dist: bionic
addons:
  apt:
    packages:
    # These are required to run webkit	
    - libwoff1
    - libopus0
    - libwebp6
    - libwebpdemux2
    - libenchant1c2a
    - libgudev-1.0-0
    - libsecret-1-0
    - libhyphen0
    - libgdk-pixbuf2.0-0
    - libegl1
    - libgles2
    - libevent-2.1-6
    - libnotify4
    - libxslt1.1
    - libvpx5
    # gstreamer and plugins to support video playback in WebKit.
    - gstreamer1.0-gl
    - gstreamer1.0-plugins-base
    - gstreamer1.0-plugins-good
    - gstreamer1.0-plugins-bad
    # This is required to run chromium
    - libgbm1
    # this is needed for running headful tests
    - xvfb

# allow headful tests
before_install:
  # Enable user namespace cloning
  - "sysctl kernel.unprivileged_userns_clone=1"
  # Launch XVFB
  - "export DISPLAY=:99.0"
  - "sh -e /etc/init.d/xvfb start"
```

### CircleCI

We run our tests on CircleCI, with our [pre-built Docker image](docker/README.md). Running Playwright smoothly on CircleCI requires the following steps:

1. Use the pre-built [Docker image](docker/README.md) in your config like so:

   ```yaml
   docker:
     - image: mcr.microsoft.com/playwright:bionic
       environment:
         NODE_ENV: development # Needed if playwright is in `devDependencies`
   ```

1. If you’re using Playwright through Jest, then you may encounter an error spawning child processes:

   ```
   [00:00.0]  jest args: --e2e --spec --max-workers=36
   Error: spawn ENOMEM
      at ChildProcess.spawn (internal/child_process.js:394:11)
   ```

   This is likely caused by Jest autodetecting the number of processes on the entire machine (`36`) rather than the number allowed to your container (`2`). To fix this, set `jest --maxWorkers=2` in your test command.

### Bitbucket Pipelines

Bitbucket Pipelines can use public [Docker images as build environments](https://confluence.atlassian.com/bitbucket/use-docker-images-as-build-environments-792298897.html). To run Playwright tests on Bitbucket, use our public Docker image ([see Dockerfile](docker/README.md)).

```yml
image: mcr.microsoft.com/playwright:bionic
```

While the Docker image supports sandboxing for Chromium, it does not work in the Bitbucket Pipelines environment. To launch Chromium on Bitbucket Pipelines, use the `chromiumSandbox: false` launch argument.

```js
const { chromium } = require('playwright');
const browser = await chromium.launch({ chromiumSandbox: false });
```

### GitLab CI

To run Playwright tests on GitLab, use our public Docker image ([see Dockerfile](docker/README.md)).

```yml
stages:
  - test

tests:
  stage: test
  image: mcr.microsoft.com/playwright:bionic
  script:
    - npm install # This should install playwright
    - npm run test
```

## Caching browsers

By default, Playwright downloads browser binaries when the Playwright NPM package
is installed. The NPM packages have a `postinstall` hook that downloads the browser
binaries. This behavior can be [customized with environment variables](installation.md).

Caching browsers on CI is **strictly optional**: The `postinstall` hooks should
execute and download the browser binaries on every run.

#### Exception: `node_modules` are cached

Most CI providers cache the [npm-cache](https://docs.npmjs.com/cli-commands/cache.html)
directory (located at `$HOME/.npm`). If your CI pipelines caches the `node_modules`
directory and you run `npm install` (instead of `npm ci`), the default configuration 
**will not work**. This is because the `npm install` step will find the Playwright NPM
package on disk and not execute the `postinstall` step.

> Travis CI automatically caches `node_modules` if your repo does not have a
  `package-lock.json` file.

This behavior can be fixed with one of the following approaches:
1. Move to caching `$HOME/.npm` or the npm-cache directory. (This is the default
   behavior in most CI providers.)
1. Set `PLAYWRIGHT_BROWSERS_PATH=0` as the environment variable before running
   `npm install`. This will download the browser binaries in the `node_modules`
   directory and cache them with the package code. See [installation docs](installation.md).
1. Use `npm ci` (instead of `npm install`) which forces a clean install: by
   removing the existing `node_modules` directory. See [npm docs](https://docs.npmjs.com/cli/ci.html).
1. Cache the browser binaries, with the steps below.

#### Directories to cache

With the default behavior, Playwright downloads the browser binaries in the following
directories:

- `%USERPROFILE%\AppData\Local\ms-playwright` on Windows
- `~/Library/Caches/ms-playwright` on MacOS
- `~/.cache/ms-playwright` on Linux

To cache the browser downloads between CI runs, cache this location in your CI
configuration, against a hash of the Playwright version.

## Debugging browser launches

Playwright supports the `DEBUG` environment variable to output debug logs during execution. Setting it to `pw:browser*` is helpful while debugging `Error: Failed to launch browser` errors.

```
DEBUG=pw:browser* npm run test
```

## Running headful

By default, Playwright launches browsers in headless mode. This can be changed by passing a flag when the browser is launched.

```js
// Works across chromium, firefox and webkit
const { chromium } = require('playwright');
const browser = await chromium.launch({ headless: false });
```

On Linux agents, headful execution requires [Xvfb](https://en.wikipedia.org/wiki/Xvfb) to be installed. Our [Docker image](docker/README.md) and GitHub Action have Xvfb pre-installed. To run browsers in headful mode with Xvfb, add `xvfb-run` before the Node.js command.

```
xvfb-run node index.js
```
