Go Docker Router Proxy

License: MIT

System Requirements

Pathes an filenames in this guide are for Mac OS *(but with some modifications this will work on any nix system)

Go (tested with version 1.7)
dnsmasq (recommended)
apache2 (recommended)

Goal

If you are working with a lot of service-container, messing around with ports within your URLs might become unhandy.

So we created an litte script that will take care of this and allows you to handle HTTP/S-requests in an easier way.

Note: Please be aware, that SSL termination has to be handled by yourself.

How It Works

We will create an double reverse proxy, so we are able to resolve dynamic container configurations while still having an local webserver listening on port 80.

To achive this, we configure DNSmasq so it's capable of resolving an custom domain (.dock in our case but, you can choose an different one) and tell our OS to use our local DNS server for this domain.

Then we configure our existing Apache2 server to listen to any .dock domain and to proxying this request to our docker-router-proxy tool.

Our tool will be called and tries to resolve the requested domain based on started container names.

Command arguments

-debug Will print some informations for debugging in case of issues
-port Defines on wich port the proxy will listen, by default this will be :9800
-domain By defaut .dock will be used but with this parameter you can choose your own

Examples

Our current Docker process-list:

CONTAINER ID   IMAGE          COMMAND       CREATED             STATUS             PORTS                  NAMES
28ddf8dba251   ubuntu:16.04   "/bin/bash"   About an hour ago   Up About an hour   0.0.0.0:8999->80/tcp   drunk_wescoff

Our HTTP request:

GET http://drunk-wescoff.dock/

Internal name resolving:

Normalizing: drunk-wescoff.dock becomes drunk-wescoff
Lookup drunk-wescoff: no match
Fallback lookup by replacing all dashes with underscores (drunk_wescoff): Match for 0.0.0.0:8999
Proxy the current request to 0.0.0.0:8999

Install

1. Make shure you configured your $GOBIN variable

export GOBIN="/usr/local/bin"

2. Run installation

go install docker-router-proxy.go

3. Starting docker-router-proxy

docker-router-proxy

Hint: If you need docker-router-proxy on a regular base, it's recommended to add this tool to your startup-items so it will be startet once you logged on.

DNSmasq Configuration

In this step we will create a virtual domain named dock so our Docker containers will be available with names like http://my-fancy-container.dock/.

1. Add this configuration to your dnsmasq.conf configuration

address=/dock/127.0.0.1

2.1 Make shure the /etc/resolver-directory exists

mkdir -p /etc/resolver

2.2 Add an dedicated resolver for this new domain

echo "nameserver 127.0.0.1" > /etc/resolver/dock

Apache2 Configuration

1. Enable mod_mod_proxy in your httpd.conf

LoadModule proxy_module libexec/mod_proxy.so
LoadModule proxy_connect_module libexec/mod_proxy_connect.so
LoadModule proxy_http_module libexec/mod_proxy_http.so

2. Configure your reverse-proxy as vhost

<VirtualHost *:80>
    ProxyPreserveHost On
    ProxyPass / http://0.0.0.0:9800/
    ProxyPassReverse / http://0.0.0.0:9800/

    ServerName my-container.dock
    ServerAlias *.dock
</VirtualHost>

3. Restart your apache

apachectl restart

Known issues

Issue: At the moment there are some priority issues with containers that can serve HTTP and HTTPS traffic.

Workaround: Create an container for each protocol

netz98/docker-router-proxy