Use psycogreen for PG backend

Change-Id: Ia2037cf26614cb4091a5c57a94a3c3a0af0ed70c
Closes-bug: #1546976

bootstrap/playbooks/tasks/base.yaml

@@ -55,6 +55,8 @@
   - tox
   - riak
   - pbr
+  # for pg backend
+  - psycogreen
 
 # pre install solare requirements
 - shell: pip install -r https://raw.githubusercontent.com/openstack/solar/master/requirements.txt

requirements.txt

@@ -29,6 +29,7 @@ wrapt
 peewee
 # if you want to use sql + postgresql then
 # psycopg2
+# psycogreen
 
 # if you want to use lua computable inputs
 # lupa

solar/dblayer/__init__.py

@@ -64,7 +64,11 @@ elif _connection.mode == 'riak':
 
 elif _connection.mode == 'postgresql':
     # TODO: collation has to be `C`
+    import psycogreen.gevent
+    psycogreen.gevent.patch_psycopg()
+
     from solar.dblayer.sql_client import SqlClient
+
     opts = {'autocommit': False}
     opts.update(_connection_details.toDict())
     if _connection.port: