Make sure postgresql.pgpass is a file or it does not exist (#1337)

Also make sure that it is located in the writable directory.

patroni/postgresql/config.py

@@ -6,6 +6,7 @@ import socket
 import stat
 import time
 
+from patroni.exceptions import PatroniException
 from six.moves.urllib_parse import urlparse, parse_qsl, unquote
 from urllib3.response import HTTPHeaderDict
 
@@ -334,7 +335,10 @@ class ConfigHandler(object):
         self._standby_signal = os.path.join(postgresql.data_dir, 'standby.signal')
         self._auto_conf = os.path.join(postgresql.data_dir, 'postgresql.auto.conf')
         self._auto_conf_mtime = None
-        self._pgpass = config.get('pgpass') or os.path.join(os.path.expanduser('~'), 'pgpass')
+        self._pgpass = os.path.abspath(config.get('pgpass') or os.path.join(os.path.expanduser('~'), 'pgpass'))
+        if os.path.exists(self._pgpass) and not os.path.isfile(self._pgpass):
+            raise PatroniException("'{}' exists and it's not a file, check your `postgresql.pgpass` configuration"
+                                   .format(self._pgpass))
         self._passfile = None
         self._passfile_mtime = None
         self._synchronous_standby_names = None
@@ -360,6 +364,8 @@ class ConfigHandler(object):
         if "stats_temp_directory" in self._server_parameters:
             self.try_to_create_dir(self._server_parameters["stats_temp_directory"],
                                    "'{}' is defined in stats_temp_directory, {}")
+        self.try_to_create_dir(os.path.dirname(self._pgpass),
+                               "'{}' is defined in `postgresql.pgpass`, {}")
 
     @property
     def _configuration_to_save(self):

tests/test_postgresql.py

@@ -8,7 +8,7 @@ import time
 from mock import Mock, MagicMock, PropertyMock, patch, mock_open
 from patroni.async_executor import CriticalTask
 from patroni.dcs import Cluster, ClusterConfig, Member, RemoteMember, SyncState
-from patroni.exceptions import PostgresConnectionException
+from patroni.exceptions import PostgresConnectionException, PatroniException
 from patroni.postgresql import Postgresql, STATE_REJECT, STATE_NO_RESPONSE
 from patroni.postgresql.postmaster import PostmasterProcess
 from patroni.postgresql.slots import SlotsHandler
@@ -695,3 +695,8 @@ class TestPostgresql(BaseTestPostgresql):
             self.p.cancellable.cancel()
             self.assertFalse(self.p.start())
             self.assertTrue(self.p.pending_restart)
+
+    @patch('os.path.exists', Mock(return_value=True))
+    @patch('os.path.isfile', Mock(return_value=False))
+    def test_pgpass_is_dir(self):
+        self.assertRaises(PatroniException, self.setUp)