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Version: v1

Extending the Docker Image

For hosted accounts, if you want to use a third-party module please get in touch!

browserless includes a few extra packages that make it easy to get going with most of the use-cases we've seen. However if you're using the /function API, or other API's wherein you want to load npm modules, then you'll need to extend our image so that you can install these dependencies. The process if fairly easy in docker to do so.

1. Create your own Dockerfile

First, you'll want to write your own Dockerfile. In the example below, we're going to add the aws-sdk module.

FROM browserless/chrome:latest

# Install the AWS SDK
RUN npm install aws-sdk

Feel free to change the FROM value here. It's generally a good practice to "pin" this version to value that won't change. For instance, if we want to use version 1.15.0 of browserless, and puppeteer 1.19.0, we'd have done:

FROM browserless/chrome:1.15.0-puppeteer-1.19.0

# Install the AWS SDK
RUN npm install aws-sdk

In either case, save your file and let's proceed.

2. Build the docker image

Once the you have the file saved, it's as simple as building the image.

$ docker build -t my/browserless:latest .

Here, we're using a "dumby" user of my and a repo of browserless, tagging it as the `latest. Feel free to change these however you see fit, especially if you want to push this built image into docker's public cloud or your own private image registry.

It'll likely take a few minutes to pull all the dependencies locally and build, however subsequent builds will be much quicker since they'll have a local cache.

3. Run the image

Now that you have a custom-built version you can apply all the same arguments to your start command (all environment variables and so on apply), you'll simply change the image you're running when you startup (note that we're whitelisting this new module, allowing browserless to execute it for security purposes).

Here's an example of running the newly built image with the module whitelisted.

$ docker run -p 3000:3000 -e FUNCTION_EXTERNALS='["aws-sdk"]' my/browserless:latest

Now your calls to /function and others will have access to the aws-sdk module:

$ curl -X POST \
http://localhost:3000/function \
-H 'Content-Type: application/javascript' \
-d 'const aws = require('\''aws-sdk'\'');

module.exports = async () => {
const data = Object.keys(aws);

return {
type: '\''text/plain'\'',

That's it! If you need to add more simply install your modules in the Dockerfile, build the image, and run it!