lazyatom/dokku-chrome

A headless chrome service for dokku

dokku chrome

A headless browser service for dokku which can be used by applications to generate PDFs, take screenshots and so on.

This service runs a Chrome browser via the browserless/chrome image from Docker. This image is kindly provided by browserless, and if you are planning to use it as part of a commercial service, you must purchase a license. However, it is free for use by open-source projects.

One of the main benefits of the browserless docker image is that it includes a REST API which can be used to easily generate PDFs, screenshots and so on. REST API documentation can be found at https://docs.browserless.io/docs/pdf.html

Requirements

• dokku 0.8.1+
• docker 1.8.x

Installation

# on 0.4.x+
sudo dokku plugin:install https://github.com/lazyatom/dokku-chrome.git chrome

Commands

chrome:app-links <app>          List all chrome service links for a given app
chrome:create <name>            Create a chrome service with environment variables
chrome:destroy <name>           Delete the service, delete the data and stop its container if there are no links left
chrome:enter <name> [command]   Enter or run a command in a running chrome service container
chrome:exists <service>         Check if the chrome service exists
chrome:expose <name> [port]     Expose a chrome service on custom port if provided (random port otherwise)
chrome:info <name>              Print the connection information
chrome:link <name> <app>        Link the chrome service to the app
chrome:linked <name> <app>      Check if the chrome service is linked to an app
chrome:list                     List all chrome services
chrome:logs <name> [-t]         Print the most recent log(s) for this service
chrome:promote <name> <app>     Promote service <name> as CHROME_URL in <app>
chrome:restart <name>           Graceful shutdown and restart of the chrome service container
chrome:start <name>             Start a previously stopped chrome service
chrome:stop <name>              Stop a running chrome service
chrome:unexpose <name>          Unexpose a previously exposed chrome service
chrome:unlink <name> <app>      Unlink the chrome service from the app
chrome:upgrade <name>           Upgrade service <service> to the specified version

Rsage

# Create a chrome service named lolipop
dokku chrome:create lolipop

# You can also specify the image and image
# version to use for the service
# it *must* be compatible with the
# official browserless/chrome image
export CHROME_IMAGE="browserless/chrome"
export CHROME_IMAGE_VERSION="1.6.2"
dokku chrome:create lolipop

# You can also specify custom environment
# variables to start the chrome service
# in semi-colon separated form
export CHROME_CUSTOM_ENV="MAX_CONCURRENT_SESSIONS=10"
dokku chrome:create lolipop

# Get connection information as follows
dokku chrome:info lolipop

# You can also retrieve a specific piece of service info via flags
dokku chrome:info lolipop --config-dir
dokku chrome:info lolipop --data-dir
dokku chrome:info lolipop --dsn
dokku chrome:info lolipop --exposed-ports
dokku chrome:info lolipop --id
dokku chrome:info lolipop --internal-ip
dokku chrome:info lolipop --links
dokku chrome:info lolipop --service-root
dokku chrome:info lolipop --status
dokku chrome:info lolipop --version

# A bash prompt can be opened against a running service
# filesystem changes will not be saved to disk
dokku chrome:enter lolipop

# You may also run a command directly against the service
# filesystem changes will not be saved to disk
dokku chrome:enter lolipop ls -lah /

# A chrome service can be linked to a
# container this will use native docker
# links via the docker-options plugin
# here we link it to our 'playground' app
# NOTE: this will restart your app
dokku chrome:link lolipop playground

# The following environment variables will be set automatically by docker (not
# on the app itself, so they won’t be listed when calling dokku config)
#
#   DOKKU_CHROME_LOLIPOP_NAME=/random_name/CHROME
#   DOKKU_CHROME_LOLIPOP_PORT=tcp://172.17.0.1:3000
#   DOKKU_CHROME_LOLIPOP_PORT_3000_TCP=tcp://172.17.0.1:3000
#   DOKKU_CHROME_LOLIPOP_PORT_3000_TCP_PROTO=tcp
#   DOKKU_CHROME_LOLIPOP_PORT_3000_TCP_PORT=3000
#   DOKKU_CHROME_LOLIPOP_PORT_3000_TCP_ADDR=172.17.0.1
#
# and the following will be set on the linked application by default
#
#   CHROME_URL=http://dokku-chrome-lolipop:3000
#
# NOTE: the host exposed here only works internally in docker containers. If
# you want your container to be reachable from outside, you should use `expose`.

# Another service can be linked to your app
dokku chrome:link other_service playground

# Since CHROME_URL is already in use, another environment variable will be
# generated automatically
#
#   DOKKU_CHROME_BLUE_URL=http://dokku-chrome-other-service:3000

# You can then promote the new service to be the primary one
# NOTE: this will restart your app
dokku chrome:promote other_service playground

# This will replace CHROME_URL with the url from other_service and generate
# another environment variable to hold the previous value if necessary.
# you could end up with the following for example:
#
#   CHROME_URL=http://dokku-chrome-other-service:3000
#   DOKKU_CHROME_BLUE_URL=http://dokku-chrome-other-service:3000
#   DOKKU_CHROME_SILVER_URL=http://dokku-chrome-lolipop:3000

# You can also unlink a chrome service
# NOTE: this will restart your app and unset related environment variables
dokku chrome:unlink lolipop playground

# You can tail logs for a particular service
dokku chrome:logs lolipop
dokku chrome:logs lolipop -t # to tail

# Finally, you can destroy the container
dokku chrome:destroy lolipop

Disabling docker pull calls

If you wish to disable the docker pull calls that the plugin triggers, you may set the CHROME_DISABLE_PULL environment variable to true. Once disabled, you will need to pull the service image you wish to deploy as shown in the stderr output.

Please ensure the proper images are in place when docker pull is disabled.

Thanks

This plugin was extensively based on the official storage plugins for dokku (e.g. https://github.com/dokku/dokku-postgres) -- thanks to the authors of those plugins for all their hard work!

dokku-chrome's Issues

How to change download path

Hello! I'm using Watir with dokku chrome and so far it's amazing. But I have an issue of how to store the download files or change the default. I enable a storage folder on the app that is linked to store the files. Any help will be appreciated.

An example of how I'm running the test:

chrome_url = ENV['CHROME_URL']
@download_directory = Rails.env.production? ? "#{Rails.root.to_s}/storage" : "#{Rails.root.to_s}/tmp"
prefs = {
   'download' => {
      'default_directory' => @download_directory,
      'prompt_for_download' => false,
      'directory_upgrade' => true,
   },
}

args = [ '--headless', '--no-sandbox']

@browser = Watir::Browser.new(:chrome, options: {prefs: prefs, args: args}, url: "#{chrome_url}/webdriver")
@browser.goto "https://www.dwsamplefiles.com/?dl_id=176"

Selenium/Watir with dokku-chrome

Probably a long-shot question... the Readme isn't clear on how dokku-chrome is not supposed to be used. So I'd like to clarify.

I have a Rails web app running inside dokku, the web app has webdrivers and watir (which basically is built on top of Selenium) in Gemfile. When the web app runs, it tries to open a headless Chrome browser to read a web page. But even after installing dokku-chrome, the app would throw this error: "Failed to find Chrome binary". So is dokku-chrome supposed to provide a Chrome binary inside dokku? If not, any idea how a Chrome binary could be installed in dokku?

Appreciate any pointer.

Could not find an executable for the browser

I am trying to access chrome executable to work. Is there any way I can get BROWSER_PATH for the chrome installed ?