puppeteer/docs/troubleshooting.md

# Troubleshooting

<!-- GEN:toc -->
- [Chrome headless doesn't launch on Windows](#chrome-headless-doesnt-launch-on-windows)
- [Chrome headless doesn't launch on UNIX](#chrome-headless-doesnt-launch-on-unix)
- [Chrome is downloaded but fails to launch on Node.js 14](#chrome-is-downloaded-but-fails-to-launch-on-nodejs-14)
- [Setting Up Chrome Linux Sandbox](#setting-up-chrome-linux-sandbox)
  * [[recommended] Enable user namespace cloning](#recommended-enable-user-namespace-cloning)
  * [[alternative] Setup setuid sandbox](#alternative-setup-setuid-sandbox)
- [Running Puppeteer on Travis CI](#running-puppeteer-on-travis-ci)
- [Running Puppeteer on CircleCI](#running-puppeteer-on-circleci)
- [Running Puppeteer in Docker](#running-puppeteer-in-docker)
  * [Running on Alpine](#running-on-alpine)
    - [Tips](#tips)
- [Running Puppeteer in the cloud](#running-puppeteer-in-the-cloud)
  * [Running Puppeteer on Google App Engine](#running-puppeteer-on-google-app-engine)
  * [Running Puppeteer on Google Cloud Functions](#running-puppeteer-on-google-cloud-functions)
  * [Running Puppeteer on Heroku](#running-puppeteer-on-heroku)
  * [Running Puppeteer on AWS Lambda](#running-puppeteer-on-aws-lambda)
- [Code Transpilation Issues](#code-transpilation-issues)
<!-- GEN:stop -->

## Chrome headless doesn't launch on Windows

Some [chrome policies](https://support.google.com/chrome/a/answer/7532015) might enforce running Chrome/Chromium
with certain extensions.

Puppeteer passes `--disable-extensions` flag by default and will fail to launch when such policies are active.

To work around this, try running without the flag:

```js
const browser = await puppeteer.launch({
  ignoreDefaultArgs: ['--disable-extensions'],
});
```

> Context: [issue 3681](https://github.com/puppeteer/puppeteer/issues/3681#issuecomment-447865342).

## Chrome headless doesn't launch on UNIX

Make sure all the necessary dependencies are installed. You can run `ldd chrome | grep not` on a Linux
machine to check which dependencies are missing. The common ones are provided below.

<details>
<summary>Debian (e.g. Ubuntu) Dependencies</summary>

```
ca-certificates
fonts-liberation
libappindicator3-1
libasound2
libatk-bridge2.0-0
libatk1.0-0
libc6
libcairo2
libcups2
libdbus-1-3
libexpat1
libfontconfig1
libgbm1
libgcc1
libglib2.0-0
libgtk-3-0
libnspr4
libnss3
libpango-1.0-0
libpangocairo-1.0-0
libstdc++6
libx11-6
libx11-xcb1
libxcb1
libxcomposite1
libxcursor1
libxdamage1
libxext6
libxfixes3
libxi6
libxrandr2
libxrender1
libxss1
libxtst6
lsb-release
wget
xdg-utils
```
</details>

<details>
<summary>CentOS Dependencies</summary>

```
alsa-lib.x86_64
atk.x86_64
cups-libs.x86_64
gtk3.x86_64
ipa-gothic-fonts
libXcomposite.x86_64
libXcursor.x86_64
libXdamage.x86_64
libXext.x86_64
libXi.x86_64
libXrandr.x86_64
libXScrnSaver.x86_64
libXtst.x86_64
pango.x86_64
xorg-x11-fonts-100dpi
xorg-x11-fonts-75dpi
xorg-x11-fonts-cyrillic
xorg-x11-fonts-misc
xorg-x11-fonts-Type1
xorg-x11-utils
```

After installing dependencies you need to update nss library using this command

```
yum update nss -y
```
</details>

<details>
  <summary>Check out discussions</summary>

- [#290](https://github.com/puppeteer/puppeteer/issues/290) - Debian troubleshooting <br/>
- [#391](https://github.com/puppeteer/puppeteer/issues/391) - CentOS troubleshooting <br/>
- [#379](https://github.com/puppeteer/puppeteer/issues/379) - Alpine troubleshooting <br/>
</details>

## Chrome is downloaded but fails to launch on Node.js 14

If you get an error that looks like this when trying to launch Chromium:

```
(node:15505) UnhandledPromiseRejectionWarning: Error: Failed to launch the browser process!
spawn /Users/.../node_modules/puppeteer/.local-chromium/mac-756035/chrome-mac/Chromium.app/Contents/MacOS/Chromium ENOENT
```

This means that the browser was downloaded but failed to be extracted correctly. The most common cause is a bug in Node.js v14.0.0 which broke `extract-zip`, the module Puppeteer uses to extract browser downloads into the right place. The bug was fixed in Node.js v14.1.0, so please make sure you're running that version or higher. Alternatively, if you cannot upgrade, you could downgrade to Node.js v12, but we recommend upgrading when possible.


## Setting Up Chrome Linux Sandbox

In order to protect the host environment from untrusted web content, Chrome uses [multiple layers of sandboxing](https://chromium.googlesource.com/chromium/src/+/HEAD/docs/linux/sandboxing.md). For this to work properly,
the host should be configured first. If there's no good sandbox for Chrome to use, it will crash
with the error `No usable sandbox!`.

If you **absolutely trust** the content you open in Chrome, you can launch Chrome
with the `--no-sandbox` argument:

```js
const browser = await puppeteer.launch({args: ['--no-sandbox', '--disable-setuid-sandbox']});
```

> **NOTE**: Running without a sandbox is **strongly discouraged**. Consider configuring a sandbox instead.

There are 2 ways to configure a sandbox in Chromium.

### [recommended] Enable [user namespace cloning](http://man7.org/linux/man-pages/man7/user_namespaces.7.html)

User namespace cloning is only supported by modern kernels. Unprivileged user namespaces are generally fine to enable,
but in some cases they open up more kernel attack surface for (unsandboxed) non-root processes to elevate to
kernel privileges.

```bash
sudo sysctl -w kernel.unprivileged_userns_clone=1
```

### [alternative] Setup [setuid sandbox](https://chromium.googlesource.com/chromium/src/+/HEAD/docs/linux_suid_sandbox_development.md)

The setuid sandbox comes as a standalone executable and is located next to the Chromium that Puppeteer downloads. It is
fine to re-use the same sandbox executable for different Chromium versions, so the following could be
done only once per host environment:

```bash
# cd to the downloaded instance
cd <project-dir-path>/node_modules/puppeteer/.local-chromium/linux-<revision>/chrome-linux/
sudo chown root:root chrome_sandbox
sudo chmod 4755 chrome_sandbox
# copy sandbox executable to a shared location
sudo cp -p chrome_sandbox /usr/local/sbin/chrome-devel-sandbox
# export CHROME_DEVEL_SANDBOX env variable
export CHROME_DEVEL_SANDBOX=/usr/local/sbin/chrome-devel-sandbox
```

You might want to export the `CHROME_DEVEL_SANDBOX` env variable by default. In this case, add the following to the `~/.bashrc`
or `.zshenv`:

```bash
export CHROME_DEVEL_SANDBOX=/usr/local/sbin/chrome-devel-sandbox
```


## Running Puppeteer on Travis CI

> 👋 We run our tests for Puppeteer on Travis CI - see our [`.travis.yml`](https://github.com/puppeteer/puppeteer/blob/main/.travis.yml) for reference.

Tips-n-tricks:
- [xvfb](https://en.wikipedia.org/wiki/Xvfb) service should be launched in order to run Chromium in non-headless mode
- Runs on Xenial Linux on Travis by default
- Runs `npm install` by default
- `node_modules` is cached by default

`.travis.yml` might look like this:

```yml
language: node_js
node_js: node
services: xvfb

script:
  - npm run test
```

## Running Puppeteer on CircleCI

Running Puppeteer smoothly on CircleCI requires the following steps:

1. Start with a [NodeJS
   image](https://circleci.com/docs/2.0/circleci-images/#nodejs) in your config
   like so:
   ```yaml
   docker:
     - image: circleci/node:12 # Use your desired version
       environment:
         NODE_ENV: development # Only needed if puppeteer is in `devDependencies`
   ```
1. Dependencies like `libXtst6` probably need to be installed via `apt-get`,
   so use the
   [threetreeslight/puppeteer](https://circleci.com/orbs/registry/orb/threetreeslight/puppeteer)
   orb
   ([instructions](https://circleci.com/orbs/registry/orb/threetreeslight/puppeteer#quick-start)),
   or paste parts of its
   [source](https://circleci.com/orbs/registry/orb/threetreeslight/puppeteer#orb-source)
   into your own config.
1. Lastly, if you’re using Puppeteer 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.

## Running Puppeteer in Docker

> 👋 We use [Cirrus Ci](https://cirrus-ci.org/) to run our tests for Puppeteer in a Docker container - see our [`Dockerfile.linux`](https://github.com/puppeteer/puppeteer/blob/main/.ci/node10/Dockerfile.linux) for reference.

Getting headless Chrome up and running in Docker can be tricky.
The bundled Chromium that Puppeteer installs is missing the necessary
shared library dependencies.

To fix, you'll need to install the missing dependencies and the
latest Chromium package in your Dockerfile:

```Dockerfile
FROM node:12-slim

# Install latest chrome dev package and fonts to support major charsets (Chinese, Japanese, Arabic, Hebrew, Thai and a few others)
# Note: this installs the necessary libs to make the bundled version of Chromium that Puppeteer
# installs, work.
RUN apt-get update \
    && apt-get install -y wget gnupg \
    && wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add - \
    && sh -c 'echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list' \
    && apt-get update \
    && apt-get install -y google-chrome-unstable fonts-ipafont-gothic fonts-wqy-zenhei fonts-thai-tlwg fonts-kacst fonts-freefont-ttf libxss1 \
      --no-install-recommends \
    && rm -rf /var/lib/apt/lists/*

# If running Docker >= 1.13.0 use docker run's --init arg to reap zombie processes, otherwise
# uncomment the following lines to have `dumb-init` as PID 1
# ADD https://github.com/Yelp/dumb-init/releases/download/v1.2.0/dumb-init_1.2.0_amd64 /usr/local/bin/dumb-init
# RUN chmod +x /usr/local/bin/dumb-init
# ENTRYPOINT ["dumb-init", "--"]

# Uncomment to skip the chromium download when installing puppeteer. If you do,
# you'll need to launch puppeteer with:
#     browser.launch({executablePath: 'google-chrome-unstable'})
# ENV PUPPETEER_SKIP_CHROMIUM_DOWNLOAD true

# Install puppeteer so it's available in the container.
RUN npm i puppeteer \
    # Add user so we don't need --no-sandbox.
    # same layer as npm install to keep re-chowned files from using up several hundred MBs more space
    && groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \
    && mkdir -p /home/pptruser/Downloads \
    && chown -R pptruser:pptruser /home/pptruser \
    && chown -R pptruser:pptruser /node_modules

# Run everything after as non-privileged user.
USER pptruser

CMD ["google-chrome-unstable"]
```

Build the container:

```bash
docker build -t puppeteer-chrome-linux .
```

Run the container by passing `node -e "<yourscript.js content as a string>"` as the command:

```bash
 docker run -i --init --rm --cap-add=SYS_ADMIN \
   --name puppeteer-chrome puppeteer-chrome-linux \
   node -e "`cat yourscript.js`"
```

There's a full example at https://github.com/ebidel/try-puppeteer that shows
how to run this Dockerfile from a webserver running on App Engine Flex (Node).

### Running on Alpine

The [newest Chromium package](https://pkgs.alpinelinux.org/package/edge/community/x86_64/chromium) supported on Alpine is 77, which corresponds to [Puppeteer v1.19.0](https://github.com/puppeteer/puppeteer/releases/tag/v1.19.0).

Example Dockerfile:

```Dockerfile
FROM alpine:edge

# Installs latest Chromium (77) package.
RUN apk add --no-cache \
      chromium \
      nss \
      freetype \
      freetype-dev \
      harfbuzz \
      ca-certificates \
      ttf-freefont \
      nodejs \
      yarn

...

# Tell Puppeteer to skip installing Chrome. We'll be using the installed package.
ENV PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true \
    PUPPETEER_EXECUTABLE_PATH=/usr/bin/chromium-browser

# Puppeteer v1.19.0 works with Chromium 77.
RUN yarn add puppeteer@1.19.0

# Add user so we don't need --no-sandbox.
RUN addgroup -S pptruser && adduser -S -g pptruser pptruser \
    && mkdir -p /home/pptruser/Downloads /app \
    && chown -R pptruser:pptruser /home/pptruser \
    && chown -R pptruser:pptruser /app

# Run everything after as non-privileged user.
USER pptruser

...
```

#### Tips

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 Chrome
and will cause Chrome 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 Chrome 65, this is no
longer necessary. Instead, launch the browser with the `--disable-dev-shm-usage` flag:

```js
const browser = await puppeteer.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.

Seeing other weird errors when launching Chrome? Try running your container
with `docker run --cap-add=SYS_ADMIN` when developing locally. Since the Dockerfile
adds a `pptr` user as a non-privileged user, it may not have all the necessary privileges.

[dumb-init](https://github.com/Yelp/dumb-init) is worth checking out if you're
experiencing a lot of zombies Chrome processes sticking around. There's special
treatment for processes with PID=1, which makes it hard to terminate Chrome
properly in some cases (e.g. in Docker).

## Running Puppeteer in the cloud

### Running Puppeteer on Google App Engine

The Node.js runtime of the [App Engine standard environment](https://cloud.google.com/appengine/docs/standard/nodejs/) comes with all system packages needed to run Headless Chrome.

To use `puppeteer`, simply list the module as a dependency in your `package.json` and deploy to Google App Engine. Read more about using `puppeteer` on App Engine by following [the official tutorial](https://cloud.google.com/appengine/docs/standard/nodejs/using-headless-chrome-with-puppeteer).

### Running Puppeteer on Google Cloud Functions

The Node.js 10 runtime of [Google Cloud Functions](https://cloud.google.com/functions/docs/) comes with all system packages needed to run Headless Chrome.

To use `puppeteer`, simply list the module as a dependency in your `package.json` and deploy your function to Google Cloud Functions using the `nodejs10` runtime.

### Running Puppeteer on Heroku

Running Puppeteer on Heroku requires some additional dependencies that aren't included on the Linux box that Heroku spins up for you. To add the dependencies on deploy, add the Puppeteer Heroku buildpack to the list of buildpacks for your app under Settings > Buildpacks.

The url for the buildpack is https://github.com/jontewks/puppeteer-heroku-buildpack

Ensure that you're using `'--no-sandbox'` mode when launching Puppeteer. This can be done by passing it as an argument to your `.launch()` call: `puppeteer.launch({ args: ['--no-sandbox'] });`.

When you click add buildpack, simply paste that url into the input, and click save. On the next deploy, your app will also install the dependencies that Puppeteer needs to run.

If you need to render Chinese, Japanese, or Korean characters you may need to use a buildpack with additional font files like https://github.com/CoffeeAndCode/puppeteer-heroku-buildpack

There's also another [simple guide](https://timleland.com/headless-chrome-on-heroku/) from @timleland that includes a sample project: https://timleland.com/headless-chrome-on-heroku/.

### Running Puppeteer on AWS Lambda

AWS Lambda [limits](https://docs.aws.amazon.com/lambda/latest/dg/limits.html) deployment package sizes to ~50MB. This presents challenges for running headless Chrome (and therefore Puppeteer) on Lambda. The community has put together a few resources that work around the issues:

- https://github.com/alixaxel/chrome-aws-lambda (kept updated with the latest stable release of puppeteer)
- https://github.com/adieuadieu/serverless-chrome/blob/master/docs/chrome.md (serverless plugin - outdated)

## Code Transpilation Issues

If you are using a JavaScript transpiler like babel or TypeScript, calling `evaluate()` with an async function might not work. This is because while `puppeteer` uses `Function.prototype.toString()` to serialize functions while transpilers could be changing the output code in such a way it's incompatible with `puppeteer`.

Some workarounds to this problem would be to instruct the transpiler not to mess up with the code, for example, configure TypeScript to use latest ecma version (`"target": "es2018"`). Another workaround could be using string templates instead of functions:

```js
await page.evaluate(`(async() => {
   console.log('1');
})()`);
```