A Docker image for ngrok v2, introspected tunnels to localhost. It's based on the excellent work of wizardapps/ngrok and fnichol/ngrok.

Features

• Small: Built using busybox.
• Simple: Just link as http or https in most cases, see below; exposes ngrok server 4040 port.
• Secure: Runs as non-root user with a random UID 6737 (to avoid mapping to an existing UID).

Configuration

To see command-line options, run docker run --rm wernight/ngrok --help.

Usage

Supposing you've an Apache or Nginx Docker container named web_service_container listening on port 80:

$ docker run --rm -it --link web_service_container wernight/ngrok ngrok http web_service_container:80

Environment variables

Please consider using directly the command-line arguments of Ngrok.

If you use the default CMD (i.e. don't specify the ngrok command-line but only wernight/ngrok), then you can use instead envrionment variables magic below.

You simply have to link the Ngrok container to the application under the app or http or https aliases, and all of the configuration will be done for you by default.

Additionally, you can specify one of several environment variable (via -e) to configure your Ngrok tunnel:

• NGROK_AUTH - Authentication key for your Ngrok account. This is needed for custom subdomains, custom domains, and HTTP authentication.
• NGROK_SUBDOMAIN - Name of the custom subdomain to use for your tunnel. You must also provide the authentication token.
• NGROK_DOMAIN - Paying Ngrok customers can specify a custom domain. Only one subdomain or domain can be specified, with the domain taking priority.
• NGROK_USERNAME - Username to use for HTTP authentication on the tunnel. You must also specify an authentication token.
• NGROK_PASSWORD - Password to use for HTTP authentication on the tunnel. You must also specify an authentication token.
• NGROK_PROTOCOL - Can either be HTTP or TCP, and it defaults to HTTP if not specified. If set to TCP, Ngrok will allocate a port instead of a subdomain and proxy TCP requests directly to your application.
• NGROK_PORT - Port to expose (defaults to 80 for HTTP protocol).

Full example

1. We'll set up a simple example HTTP server in a docker container named www:

   $ docker run -v /usr/share/nginx/html --name www_data busybox true
   $ docker run --rm --volumes-from www_data busybox /bin/sh -c 'echo "<h1>Yo</h1>" > /usr/share/nginx/html/index.html'
   $ docker run -d -p 80 --volumes-from www_data --name www nginx
   $ curl $(docker port www 80)
   <h1>Yo</h1>
   

2. Now we'll link that HTTP server into an ngrok container to expose it on the internet:

   $ docker run -d -p 4040 --link www:http --name www_ngrok wernight/ngrok
   

3. You can now access the API to find the assigned domain:

   $ curl $(docker port www_ngrok 4040)/api/tunnels
   

   or access the web UI to see requests and responses:

   $ xdg-open http://$(docker port www_ngrok 4040)
   

Helper

For common cases you may want to create an alias in your ~/.profile (or ~/.bashrc, ~/.zshrc, or equivalent):

function docker-ngrok() {
  docker run --rm -it --link "$1":http wernight/ngrok ngrok http http:80
}
# For ZSH with Oh-My-Zsh! and 'docker' plugin enabled, you can also enable auto-completion:
#compdef __docker_containers docker-ngrok

Then to the simple example just do docker-ngrok web_service_container.

Feedbacks

Report issues/questions/feature requests on GitHub Issues.

Pull requests are very welcome!