Migrate CKAN to S6 supervisor

ckan/Dockerfile

@@ -13,7 +13,7 @@ RUN \
  # Add edge/testing repository
  echo '@edge http://dl-cdn.alpinelinux.org/alpine/edge/testing' >>/etc/apk/repositories \
  # Install runtime dependencies
- && apk --no-cache add geos@edge libjpeg-turbo libmagic libpq mailcap py2-pip zlib
+ && apk --no-cache add geos@edge libjpeg-turbo libmagic libpq mailcap py2-pip s6 zlib
 
 RUN \
  # Install build dependencies
@@ -47,8 +47,9 @@ RUN \
  && find /srv/ckan/src -name '.git*' -exec rm -rf {} + \
  && rm -rf /root/.cache
 
+COPY docker/ /
+
 VOLUME ["/etc/ckan", "/srv/ckan/storage"]
 EXPOSE 8080
 
-USER ckan
-CMD ["paster", "serve", "/etc/ckan/ckan.ini"]
+CMD ["s6-svscan", "/etc/services.d"]

ckan/docker/etc/services.d/.s6-svscan/finish

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+/bin/true

ckan/docker/etc/services.d/ckan/run

@@ -0,0 +1,5 @@
+#!/bin/execlineb -P
+
+fdmove -c 2 1
+s6-setuidgid 8003:8003
+/usr/bin/paster serve /etc/ckan/ckan.ini