Add an APT cache proxy option and dev container

Add a Debian stable based container using apt-cacher-ng to the
`dev/docker-compose.yml` environment.

Add an option to configure an APT cache proxy to the installation.

config/defaults.yml

@@ -220,6 +220,7 @@ system_default:
   reboot_timeout: 180      # max time to wait when restarting the server
   keep_certs: false        # keep the letsencrypt certificates locally,
                            # even when using a live environment
+  apt_cacher: ~            # IP address or DNS name for an apt-cacher
 
 ###############################################################################
 # Once the system is in place, it is possible to use 'limit' for the rule,

devel/apt-cacher/Dockerfile

@@ -0,0 +1,17 @@
+# Adapted from https://docs.docker.com/engine/examples/apt-cacher-ng/
+#
+# Build: docker build -t apt-cacher .
+# Run: docker run -d -p 3142:3142 --name apt-cacher-run apt-cacher
+#
+# and then you can run containers with:
+#   docker run -t -i --rm -e http_proxy http://dockerhost:3142/ debian bash
+#
+# Here, `dockerhost` is the IP address or FQDN of a host running the Docker daemon
+# which acts as an APT proxy server.
+FROM        debian:stable
+
+VOLUME      ["/var/cache/apt-cacher-ng"]
+RUN     apt-get update && apt-get install -y apt-cacher-ng
+
+EXPOSE      3142
+CMD     chown apt-cacher-ng:root /var/cache/apt-cacher-ng && /etc/init.d/apt-cacher-ng start && tail -f /var/log/apt-cacher-ng/*

devel/docker-compose.yml

@@ -27,6 +27,15 @@ services:
     networks:
       acmenet:
         ipv4_address: 10.30.50.3
+  apt-cacher:
+    build: apt-cacher
+    ports:
+      - 3142:3142
+    volumes:
+      - apt-cache:/var/cache/apt-cacher-ng
+    networks:
+      acmenet:
+        ipv4_address: 10.30.50.4
 
 networks:
   acmenet:
@@ -35,3 +44,6 @@ networks:
       driver: default
       config:
         - subnet: 10.30.50.0/24
+
+volumes:
+  apt-cache:

install/playbooks/roles/packages/tasks/main.yml

@@ -9,6 +9,20 @@
     src: sources.list
     dest: /etc/apt/sources.list
 
+- name: Use a proxy if needed
+  when: system.apt_cacher != None
+  tags: apt
+  template:
+    src: proxy
+    dest: /etc/apt/apt.conf.d/proxy
+
+- name: Make sure no proxy is configured if not needed
+  when: system.apt_cacher == None
+  tags: apt
+  file:
+    path: /etc/apt/apt.conf.d/proxy
+    state: absent
+
 # Some cloud providers, the cache_valid_time condition
 # is not working just after the installation (vultr)
 - name: Force the packages cache update on the first installation

install/playbooks/roles/packages/templates/proxy

@@ -0,0 +1 @@
+Acquire::http { Proxy "http://{{ system.apt_cacher }}:3142"; }