postgres timeouts (#4988)

* added `connect_timeout` and `statement_timeout` to postgres

* change default statement_timeout to 5

collectors/python.d.plugin/postgres/postgres.chart.py

@@ -17,6 +17,12 @@ except ImportError:
 from bases.FrameworkServices.SimpleService import SimpleService
 
 
+DEFAULT_PORT = 5432
+DEFAULT_USER = 'postgres'
+DEFAULT_CONNECT_TIMEOUT = 2       # seconds
+DEFAULT_STATEMENT_TIMEOUT = 5000  # ms
+
+
 WAL = 'WAL'
 ARCHIVE = 'ARCHIVE'
 BACKENDS = 'BACKENDS'
@@ -787,6 +793,7 @@ class Service(SimpleService):
         self.do_table_stats = configuration.pop('table_stats', False)
         self.do_index_stats = configuration.pop('index_stats', False)
         self.databases_to_poll = configuration.pop('database_poll', None)
+        self.statement_timeout = configuration.pop('statement_timeout', DEFAULT_STATEMENT_TIMEOUT)
         self.configuration = configuration
 
         self.conn = None
@@ -811,11 +818,15 @@ class Service(SimpleService):
             self.conn = None
 
         try:
-            params = dict(user='postgres',
-                          database=None,
-                          password=None,
-                          host=None,
-                          port=5432)
+            params = dict(
+                host=None,
+                port=DEFAULT_PORT,
+                database=None,
+                user=DEFAULT_USER,
+                password=None,
+                connect_timeout=DEFAULT_CONNECT_TIMEOUT,
+                options='-c statement_timeout={0}'.format(self.statement_timeout),
+            )
             params.update(self.configuration)
 
             self.conn = psycopg2.connect(**params)

collectors/python.d.plugin/postgres/postgres.conf

@@ -63,11 +63,13 @@
 #
 # Connections can be configured with the following options:
 #
-#     database    : 'example_db_name'
-#     user        : 'example_user'
-#     password    : 'example_pass'
-#     host        : 'localhost'
-#     port        : 5432
+#     database            : 'example_db_name'
+#     user                : 'example_user'
+#     password            : 'example_pass'
+#     host                : 'localhost'
+#     port                : 5432
+#     connect_timeout     : 2     # in seconds, default is 2
+#     statement_timeout   : 2000  # in ms, default is 2000
 #
 # Additionally, the following options allow selective disabling of charts
 #