Differentiate between connection address and listen address

For example you can listen on 0.0.0.0 but provide service on some
didicated ip. This should cover all possible use-cases when you are
running behind firewall, load balancer or inside for example docker.

helpers/postgresql.py

@@ -38,7 +38,7 @@ class Postgresql:
         self.config = config
 
         self.connection_string = 'postgres://{username}:{password}@{listen}/postgres'.format(
-            listen=self.config['listen'], **self.replication)
+            listen=self.config['connection_address'], **self.replication)
 
         self.conn = None
         self.cursor_holder = None
@@ -46,7 +46,7 @@ class Postgresql:
 
     def cursor(self):
         if not self.cursor_holder:
-            self.conn = psycopg2.connect('postgres://{}/postgres'.format(self.config['listen']))
+            self.conn = psycopg2.connect('postgres://{}/postgres'.format(self.config['connection_address']))
             self.conn.autocommit = True
             self.cursor_holder = self.conn.cursor()
 

postgres0.yml

@@ -6,6 +6,7 @@ etcd:
 postgresql:
   name: postgresql0
   listen: 127.0.0.1:5432
+  connection_address: 127.0.0.1:5432
   data_dir: data/postgresql0
   maximum_lag_on_failover: 1048576 # 1 megabyte in bytes
   replication:

postgres1.yml

@@ -6,6 +6,7 @@ etcd:
 postgresql:
   name: postgresql1
   listen: 127.0.0.1:5433
+  connection_address: 127.0.0.1:5433
   data_dir: data/postgresql1
   maximum_lag_on_failover: 1048576 # 1 megabyte in bytes
   replication: