(maint) Make Docker Postgres configurable

 - Prior to this commit, the wait script would wait on the host named
   'postgres' with a fixed port of '5432', which is quite inflexible.

   In testing the Pupperware stack, it's necessary to change the host
   to `postgres.local` to align with other hosts.

   This will allow that configuration change to be made more easily
   at runtime

docker/README.md

@@ -30,9 +30,17 @@ The following environment variables are supported:
 
   Set to 'false' to skip acquiring SSL certificates from a Puppet Server. Defaults to 'true'.
 
+- `PUPPETDB_POSTGRES_HOSTNAME`
+
+  The DNS name of the Postgres host to use when performing initial health checks and when connecting to the database. Defaults to 'postgres'.
+
+- `PUPPETDB_POSTGRES_PORT`
+
+  The port of the Postgres host to use when performing initial health checks and when connecting to the database. Defaults to '5432'.
+
 - `PUPPETDB_DATABASE_CONNECTION`
 
-  The value for the 'subname' field in puppetdb/conf.d/database.conf. Defaults to '//postgres:5432/puppetdb'.
+  The value for the 'subname' field in puppetdb/conf.d/database.conf. Defaults to '//$PUPPETDB_POSTGRES_HOSTNAME:$PUPPETDB_POSTGRES_PORT/puppetdb', which is '//postgres:5432/puppetdb' by default
 
 - `PUPPETDB_USER`
 

docker/puppetdb/Dockerfile

@@ -25,7 +25,9 @@ ENV PUPPERWARE_ANALYTICS_STREAM="$pupperware_analytics_stream"
 ENV PUPPERWARE_ANALYTICS_ENABLED=false
 
 ENV PUPPETDB_VERSION="$version"
-ENV PUPPETDB_DATABASE_CONNECTION="//postgres:5432/puppetdb"
+ENV PUPPETDB_POSTGRES_HOSTNAME="postgres"
+ENV PUPPETDB_POSTGRES_PORT="5432"
+ENV PUPPETDB_DATABASE_CONNECTION="//${PUPPETDB_POSTGRES_HOSTNAME}:${PUPPETDB_POSTGRES_PORT}/puppetdb"
 ENV PUPPETDB_USER=puppetdb
 ENV PUPPETDB_PASSWORD=puppetdb
 ENV PUPPETDB_NODE_TTL=7d

docker/puppetdb/docker-entrypoint.d/20-wait-for-hosts.sh

@@ -40,7 +40,7 @@ PUPPETSERVER_HOSTNAME="${PUPPETSERVER_HOSTNAME:-puppet}"
 CONSUL_HOSTNAME="${CONSUL_HOSTNAME:-consul}"
 CONSUL_PORT="${CONSUL_PORT:-8500}"
 
-wait_for_host_port "postgres" "5432" $PUPPETDB_WAITFORPOSTGRES_SECONDS
+wait_for_host_port "${PUPPETDB_POSTGRES_HOSTNAME:-postgres}" "${PUPPETDB_POSTGRES_PORT:-5432}" $PUPPETDB_WAITFORPOSTGRES_SECONDS
 
 if [ "$USE_PUPPETSERVER" = true ]; then
   wait_for_host $PUPPETSERVER_HOSTNAME