Make pgpass location configurable.

One can use pgpass configuration parameter in the postgres
subsection of Patroni. By default pgpass is written in ~/.
Mock actual writes to pgpass in the tests.

patroni/postgresql.py

@@ -48,6 +48,7 @@ class Postgresql:
         self.replication = config['replication']
         self.superuser = config['superuser']
         self.admin = config['admin']
+        self.pgpass = config.get('pgpass', None)
         self.pg_rewind = config.get('pg_rewind', {})
         self.callback = config.get('callbacks', {})
         self.use_slots = config.get('use_slots', True)
@@ -171,12 +172,14 @@ class Postgresql:
         os.path.exists(self.trigger_file) and os.unlink(self.trigger_file)
 
     def write_pgpass(self, record):
-        pgpass = 'pgpass'
-        with open(pgpass, 'w') as f:
+        self.pgpass = self.pgpass or os.path.join(os.path.expanduser('~'), 'pgpass')
+
+        with open(self.pgpass, 'w') as f:
             os.fchmod(f.fileno(), 0o600)
             f.write('{host}:{port}:*:{user}:{password}\n'.format(**record))
+
         env = os.environ.copy()
-        env['PGPASSFILE'] = pgpass
+        env['PGPASSFILE'] = self.pgpass
         return env
 
     def sync_from_leader(self, leader):

tests/test_postgresql.py

@@ -210,10 +210,16 @@ class TestPostgresql(unittest.TestCase):
         self.assertFalse(self.p.restart())
         self.assertEquals(self.p.state, 'restart failed (restarting)')
 
+    @patch.object(builtins, 'open', MagicMock())
+    def test_write_pgpass(self):
+        self.p.write_pgpass({'host': 'localhost', 'port': '5432', 'user': 'foo', 'password': 'bar'})
+
+    @patch('patroni.postgresql.Postgresql.write_pgpass', MagicMock(return_value=dict()))
     def test_sync_from_leader(self):
         self.assertTrue(self.p.sync_from_leader(self.leader))
 
     @patch('subprocess.call', side_effect=Exception("Test"))
+    @patch('patroni.postgresql.Postgresql.write_pgpass', MagicMock(return_value=dict()))
     def test_pg_rewind(self, mock_call):
         self.assertTrue(self.p.rewind(self.leader))
         subprocess.call = mock_call
@@ -222,6 +228,7 @@ class TestPostgresql(unittest.TestCase):
     @patch('patroni.postgresql.Postgresql.rewind', return_value=False)
     @patch('patroni.postgresql.Postgresql.remove_data_directory', MagicMock(return_value=True))
     @patch('patroni.postgresql.Postgresql.single_user_mode', MagicMock(return_value=1))
+    @patch('patroni.postgresql.Postgresql.write_pgpass', MagicMock(return_value=dict()))
     def test_follow_the_leader(self, mock_pg_rewind):
         self.p.demote()
         self.p.follow_the_leader(None)
@@ -327,6 +334,7 @@ class TestPostgresql(unittest.TestCase):
         with patch('os.rename', Mock(side_effect=OSError())):
             self.p.move_data_directory()
 
+    @patch('patroni.postgresql.Postgresql.write_pgpass', MagicMock(return_value=dict()))
     def test_bootstrap(self):
         with patch('subprocess.call', Mock(return_value=1)):
             self.assertRaises(PostgresException, self.p.bootstrap)