Made pylint happy.

pgbouncemgr/drop_privileges.py

@@ -3,7 +3,7 @@
 
 """Functionality to drop privileges to those of a specified user/group id."""
 
-from os import setuid, setgid, setuid, setgroups, getuid, geteuid, getgroups
+from os import setuid, setgid, setgroups, getuid, geteuid, getgroups
 from pwd import getpwnam, getpwuid
 from grp import getgrnam, getgrgid
 from pgbouncemgr.logger import format_ex

pgbouncemgr/manager.py

@@ -6,7 +6,7 @@
 
 from time import sleep
 from argparse import ArgumentParser
-from pgbouncemgr.logger import Logger, ConsoleLog, SyslogLog, format_ex
+from pgbouncemgr.logger import Logger, ConsoleLog, SyslogLog
 from pgbouncemgr.config import Config
 from pgbouncemgr.state import State
 from pgbouncemgr.drop_privileges import drop_privileges

pgbouncemgr/node_config.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# no-pylint: disable=missing-docstring,too-many-instance-attributes
+# no-pylint: disable=missing-docstring,too-many-instance-attributes,too-few-public-methods
 
 import os
 from pgbouncemgr.config import InvalidConfigValue

pgbouncemgr/node_poller.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# no-pylint: disable=missing-docstring
+# no-pylint: disable=missing-docstring,too-few-public-methods
 
 class NodePoller():
     """The NodePoller is used to poll all the nodes that are available

pgbouncemgr/postgres.py

@@ -4,9 +4,9 @@
 """This module provides various classes that uare used for connecting to
    a PostgreSQL or pgbouncer server."""
 
-import psycopg2
 import multiprocessing
-from psycopg2.extras imoprt LogicalReplicationConnection
+import psycopg2
+from psycopg2.extras import LogicalReplicationConnection
 from pgbouncemgr.logger import format_ex
 
 
@@ -39,6 +39,10 @@ CONNECTED = 'CONNECTED'
 REUSED = 'REUSED'
 RECONNECTED = 'RECONNECTED'
 
+# The properties that can be used in a configuration object to
+# define connection parameters for psycopg2.
+CONNECTION_PARAMS = ['host', 'port', 'connect_timeout', 'user', 'password']
+
 class PgConnection():
     """Implements a connection to a PostgreSQL server."""
     def __init__(self, config):
@@ -47,10 +51,17 @@ class PgConnection():
         self.conn = None
 
     def _create_conn_params(self, config):
-        """Use only connection parameters that don't have value None."""
+        """Extract all connection parameters from the provided configuration,
-        return dict(
+           that don't have value of None."""
-            (k, v) for k, v in config.items()
+        conn_params = {}
-            if v is not None)
+        for key in CONNECTION_PARAMS:
+            if not hasattr(config, key):
+                continue
+            value = getattr(config, key)
+            if value is None:
+                continue
+            conn_params[key] = value
+        return conn_params
 
     def connect(self):
         """Connect to the database server. When a connection exists,
@@ -142,6 +153,31 @@ class PgReplicationConnection(PgConnection):
 
         return status
 
+# The query that is used to check if pgbouncer is connected to the expected
+# backend server. We don't really have a unique identifier for the node to
+# work with there, but we can request the server host + port to see if they
+# match those of the expected node. Additionally, a check is done to see if
+# the node is running as a primary node.
+#
+# It would be really nice if it were possible to retrieve the system_id
+# and timeline_id for the backend server, but that is only possible when
+# using a replication connection. Pgbouncer (through which we are connected
+# when running this query) does not support pooled replication connections.
+VERIFY_QUERY = """
+    SELECT CASE
+      WHEN (
+        inet_server_addr() IS DISTINCT FROM %(host)s OR
+        inet_server_port() IS DISTINCT FROM %(port)s)
+      THEN format(
+        'connected to wrong server: %%s:%%s (expected %%s:%%s)',
+        inet_server_addr(), inet_server_port(), %(host)s, %(port)s)
+      WHEN pg_is_in_recovery()
+      THEN format(
+        'server %%s:%%s is not running as primary',
+        %(host)s, %(port)s)
+      ELSE NULL
+    END
+"""
 
 class PgConnectionViaPgbouncer(PgConnection):
     """This PostgreSQL connection class is used to setup a connection
@@ -158,8 +194,8 @@ class PgConnectionViaPgbouncer(PgConnection):
 
         # Secondly, override parameters to redirect the connection to
         # the pgbouncer instance.
-        self.conn_params["host"] = pgbouncer_config["host"] 
+        self.conn_params["host"] = pgbouncer_config["host"]
-        self.conn_params["port"] = pgbouncer_config["port"] 
+        self.conn_params["port"] = pgbouncer_config["port"]
 
         # Note that we don't setup a replication connection here. This is
         # unfortunately not possible, because pgbouncer does not support
@@ -178,7 +214,7 @@ class PgConnectionViaPgbouncer(PgConnection):
         # then stall for quite a while. For swift operation of backend
         # switching, we therefore use the timeout setup here, to reconfigure
         # the system more quickly.
-        # 
+        #
         # Note that in most situations this shouldn't be an issue, since we
         # will always reload pgbouncer after a configuration change and the
         # connection from below will, because of that, work as intended
@@ -207,9 +243,9 @@ class PgConnectionViaPgbouncer(PgConnection):
                     self.disconnect()
                     return report_func(False, exception)
 
-             # When the verify query did not return an error message, then we
+            # When the verify query did not return an error message, then we
-             # are in the green.
+            # are in the green.
-             return report_func(True, None)
+            return report_func(True, None)
 
         parent_conn, child_conn = multiprocessing.Pipe()
         def report_func(true_or_false, exception):
@@ -238,7 +274,7 @@ class PgBouncerConsoleConnection(PgConnection):
 
         # For the console connection, the database name "pgbouncer"
         # must be used.
-        self.conn_params["dbname"] = "pgbouncer" 
+        self.conn_params["dbname"] = "pgbouncer"
 
         # The default ping query does not work when connected to the
         # pgbouncer console. Here's a simple replacement for it.
@@ -251,7 +287,7 @@ class PgBouncerConsoleConnection(PgConnection):
            transaction. Transactions are not supported by the pgbouncer
            console."""
         result = super().connect()
-		self.conn.autocommit = True
+        self.conn.autocommit = True
         return result
 
     def reload(self):
@@ -268,4 +304,3 @@ class PgBouncerConsoleConnection(PgConnection):
         except Exception as exception:
             raise ReloadingPgbouncerFailed(
                 "An exception occurred: %s" % format_ex(exception))
-                 

pgbouncemgr/state.py

@@ -113,8 +113,8 @@ class State():
         state = State(logger)
         for node_id, settings in config.nodes.items():
             node_config = NodeConfig(node_id)
-            for k, v in settings.items():
+            for key, value in settings.items():
-                setattr(node_config, k, v)
+                setattr(node_config, key, value)
             state.add_node(node_config)
         return state
 
@@ -241,9 +241,9 @@ class State():
                 "node id: node config changed? (leader_node_id=%s)" %
                 leader_node_id)
             raise UnknownLeaderNodeId(leader_node_id)
-        if self._leader_node_id == leader_node_id:
+        if self._leader_node_id == node.node_id:
             return
-        self._leader_node_id = leader_node_id
+        self._leader_node_id = node.node_id
         self.modified = True
 
     @property

pgbouncemgr/state_store.py

@@ -2,7 +2,6 @@
 # no-pylint: disable=missing-docstring,broad-except,too-many-instance-attributes
 
 import json
-from datetime import datetime
 from os import rename
 from os.path import isfile
 from pgbouncemgr.logger import format_ex
@@ -71,5 +70,5 @@ class StateStore():
             rename(swap_path, self.path)
         except Exception as exception:
             raise StateStoreException(
-                "Storing state to file (%s) failed: %s" % (
+                "Storing state to file (%s) failed: %s" %
-                self.path, format_ex(exception)))
+                (self.path, format_ex(exception)))