Reverse Proxy for custom Docker

Imagine you have added a custom service container to the Devilbox which has a project that is available via http on a very specific port in that container.

You do not want to expose this port to the host system, but rather want to make it available via the bundled web server and also be able to see it on the Devilbox intranet vhost section.

Additionally you want the project to make use of the same DNS naming scheme and also have HTTPS for it.

You can easily achieve this by setting up a reverse proxy for it.

add-your-own-docker-image

Walkthrough

Assumption

Let’s imagine you have added a custom Python Docker image to the Devilbox which starts up a Django application listening on port 3000.

env_TLD_SUFFIX: loc
Desired DNS name: my-python.loc
env-httpd-datadir on the host: ./data/www
env-httpd-template-dir: .devilbox
Listening port: 3000
Listening host: python (hostname of the Python container)

Create virtual directory

In order to create a reverse proxy for that custom container, you must add a virtual project directory without any data in it. This directory is purely for the purpose of determining the DNS name and for having the vhost-gen configuration in.

Navigate to the env-httpd-datadir directory and create your project

host> cd /path/to/devilbox
host> cd /path/to/devilbox/data/www

# Create the project directory
host> mkdir my-python

# Create the htdocs directory (to have a valid project for the Intranet page)
host> mkdir my-python/htdocs


# Create the vhost-gen directory (to be apply to apply custom templates)
host> mkdir my-python/.devilbox

This part is now sufficient to have the project visible on the Devilbox intranet.

Copy vhost-gen templates

The reverse vhost-gen templates are available in cfg/vhost-gen:

host> tree -L 1 cfg/vhost-gen/

cfg/vhost-gen/
├── apache22.yml-example-rproxy
├── apache22.yml-example-vhost
├── apache24.yml-example-rproxy
├── apache24.yml-example-vhost
├── nginx.yml-example-rproxy
├── nginx.yml-example-vhost
└── README.md

0 directories, 7 files

For this example we will copy all *-example-rproxy files into /shared/httpd/my-python/.devilbox to ensure this will work with all web servers.

host> cd /path/to/devilbox
host> cp cfg/vhost-gen/apache22.yml-example-rproxy data/www/my-python/.devilbox/apache22.yml
host> cp cfg/vhost-gen/apache24.yml-example-rproxy data/www/my-python/.devilbox/apache24.yml
host> cp cfg/vhost-gen/nginx.yml-example-rproxy data/www/my-python/.devilbox/nginx.yml

Adjust port

By default, all vhost-gen templates will forward requests to port 8000 into the PHP container. Our current example however uses port 3000 and host python, so we must change that accordingly for all three templates.

Adjust Apache 2.2 template

Open the apache22.yml vhost-gen template in your project:

host> cd /path/to/devilbox
host> vi data/www/my-python/.devilbox/apache22.yml

Find the two lines with ProxyPass and ProxyPassReverse and change the port from 8000 to 3000 and host php to python:

# ... more lines above ... #

###
### Basic vHost skeleton
###
vhost: |
  <VirtualHost __DEFAULT_VHOST__:__PORT__>
      ServerName   __VHOST_NAME__

      CustomLog  "__ACCESS_LOG__" combined
      ErrorLog   "__ERROR_LOG__"

      # Reverse Proxy definition (Ensure to adjust the port, currently '8000')
      ProxyRequests On
      ProxyPreserveHost On
      ProxyPass / http://python:3000/
      ProxyPassReverse / http://python:3000/

# ... more lines below ... #

Adjust Apache 2.4 template

Open the apache24.yml vhost-gen template in your project:

host> cd /path/to/devilbox
host> vi data/www/my-python/.devilbox/apache24.yml

Find the two lines with ProxyPass and ProxyPassReverse and change the port from 8000 to 3000 and host php to python:

# ... more lines above ... #

###
### Basic vHost skeleton
###
vhost: |
  <VirtualHost __DEFAULT_VHOST__:__PORT__>
      ServerName   __VHOST_NAME__

      CustomLog  "__ACCESS_LOG__" combined
      ErrorLog   "__ERROR_LOG__"

      # Reverse Proxy definition (Ensure to adjust the port, currently '8000')
      ProxyRequests On
      ProxyPreserveHost On
      ProxyPass / http://python:3000/
      ProxyPassReverse / http://python:3000/

# ... more lines below ... #

Adjust Nginx template

Open the nginx.yml vhost-gen template in your project:

host> cd /path/to/devilbox
host> vi data/www/my-python/.devilbox/nginx.yml

Find the line with proxy-pass and change the port from 8000 to 3000 and host php to python:

# ... more lines above ... #

###
### Basic vHost skeleton
###
vhost: |
  server {
      listen       __PORT____DEFAULT_VHOST__;
      server_name  __VHOST_NAME__;

      access_log   "__ACCESS_LOG__" combined;
      error_log    "__ERROR_LOG__" warn;

      # Reverse Proxy definition (Ensure to adjust the port, currently '8000')
      location / {
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_pass http://python:3000;
      }

# ... more lines below ... #

Restart the Devilbox

Now for the changes to take affect, simply restart the Devilbox (or start if not yet running):

host> cd /path/to/devilbox

# Stop the Devilbox
host> docker-compose stop
host> docker-compose rm -f

# Start the Devilbox (Your Python container and the PHP and HTTPD container only)
host> docker-compose up -d php httpd bind python

Visit your project

That’s it, your service application will now be available via:

http://my-python.loc

It will also be available on HTTPS. This is by default and automatically:

https://my-python.loc

setup-valid-https

And is even shown as a project in the Devilbox intranet: