Report DatabaseOperationalError as an HTTP Service Unavailable error

Closes #12736

trytond/trytond/backend/postgresql/database.py

@@ -24,6 +24,7 @@ except ImportError:
     PYDATE, PYDATETIME, PYTIME, PYINTERVAL = None, None, None, None
 from psycopg2 import DataError as DatabaseDataError
 from psycopg2 import IntegrityError as DatabaseIntegrityError
+from psycopg2 import InterfaceError
 from psycopg2 import OperationalError as DatabaseOperationalError
 from psycopg2 import ProgrammingError
 from psycopg2.errors import QueryCanceled as DatabaseTimeoutError
@@ -291,7 +292,10 @@ class Database(DatabaseInterface):
         return conn
 
     def put_connection(self, connection, close=False):
-        connection.reset()
+        try:
+            connection.reset()
+        except InterfaceError:
+            pass
         self._connpool.putconn(connection, close=close)
 
     def close(self):

trytond/trytond/transaction.py

@@ -238,8 +238,9 @@ class Transaction(object):
                         else:
                             self.rollback()
                     finally:
-                        self.database.put_connection(
-                            self.connection, self.close)
+                        if self.connection:
+                            self.database.put_connection(
+                                self.connection, self.close)
                 finally:
                     self.database = None
                     self.readonly = False
@@ -357,7 +358,8 @@ class Transaction(object):
             datamanager.tpc_abort(self)
         Cache.rollback(self)
         self._clear_log_records()
-        self.connection.rollback()
+        if self.connection:
+            self.connection.rollback()
 
     def join(self, datamanager):
         try:

trytond/trytond/wsgi.py

@@ -26,6 +26,7 @@ try:
 except ImportError:
     from werkzeug.wsgi import SharedDataMiddleware
 
+from trytond import backend
 from trytond.config import config
 from trytond.protocols.jsonrpc import JSONProtocol
 from trytond.protocols.wrappers import (
@@ -111,6 +112,10 @@ class TrytondWSGI(object):
             logger.debug(
                 "Exception when processing %s", request, exc_info=True)
             return e
+        except backend.DatabaseOperationalError as e:
+            logger.debug(
+                "Exception when processing %s", request, exc_info=True)
+            return exceptions.ServiceUnavailable(description=str(e))
         except Exception as e:
             logger.debug(
                 "Exception when processing %s", request, exc_info=True)