Optimise container images: multi-stage (size reuduction) & one process per container

[spwoodcock]

Issue

Currently the web container could be optimised in two ways:

• The size could be greatly reduced from 3.9GB to around 1.5GB using a multi-stage build.
• It has three processes inside the same container: the Rails server, cgimap, and Apache. This should ideally be split out to separate containers in line with best practices (one process per container, PID 1).

Solution

• Have already done the build optimisation for the rails server in hotosm/osm-sandbox.
• I also added a small script to build the cgimap image separately:

  #!/bin/sh
  
  CGIMAP_VERSION=v2.0.0
  
  docker build \
      "https://github.com/zerebubuth/openstreetmap-cgimap.git#${CGIMAP_VERSION}" \
      --file docker/debian/Dockerfile_bookworm \
      --tag ghcr.io/hotosm/osm-sandbox/cgimap:${CGIMAP_VERSION}

• The webserver should run independently, routing to either the Rails server container, or cgimap container, depending on the route accessed. This could easily be changed to nginx from Apache too.

I plan to contribute this change, as discussed a few months ago! Finally got time to work on this 😄