Improve PostgreSQL error handling

Re-raise a DbConnectionError if the connection raises an error.

gramps/gen/db/exceptions.py

@@ -343,6 +343,23 @@ class PythonUpgradeRequiredError(Exception):
                      'db_python_version': self.db_python_version,
                      'current_python_version': self.current_python_version }
 
+class DbConnectionError(Exception):
+    """
+    Error used to report that a database connection failed.
+    """
+    def __init__(self, msg, settings_file):
+        Exception.__init__(self)
+        self.msg = msg
+        self.settings_file = settings_file
+
+    def __str__(self):
+        return _('Database connection failed.\n\n'
+                 '%(message)s\n'
+                 'Please check your connection settings file:\n'
+                 '%(settings_file)s') % {
+                    'message': self.msg,
+                    'settings_file': self.settings_file}
+
 if __name__ == "__main__":
     """
     Call this from the CLI (in order to find the imported modules):

gramps/gui/dbloader.py

@@ -65,7 +65,8 @@ from gramps.gen.db.exceptions import (DbUpgradeRequiredError,
                                       BsddbUpgradeRequiredError,
                                       BsddbDowngradeRequiredError,
                                       PythonUpgradeRequiredError,
-                                      PythonDowngradeError)
+                                      PythonDowngradeError,
+                                      DbConnectionError)
 from .pluginmanager import GuiPluginManager
 from .dialog import (DBErrorDialog, ErrorDialog, QuestionDialog2,
                             WarningDialog)
@@ -278,6 +279,9 @@ class DbLoader(CLIDbLoader):
         except PythonDowngradeError as msg:
             self.dbstate.no_database()
             self._warn( _("Cannot open database"), str(msg))
+        except DbConnectionError as msg:
+            self.dbstate.no_database()
+            self._warn(_("Cannot open database"), str(msg))
         except OSError as msg:
             self.dbstate.no_database()
             self._errordialog(

gramps/plugins/db/dbapi/postgresql.py

@@ -41,6 +41,7 @@ from gramps.plugins.db.dbapi.dbapi import DBAPI
 from gramps.gen.utils.configmanager import ConfigManager
 from gramps.gen.config import config
 from gramps.gen.db.dbconst import ARRAYSIZE
+from gramps.gen.db.exceptions import DbConnectionError
 from gramps.gen.const import GRAMPS_LOCALE as glocale
 _ = glocale.translation.gettext
 
@@ -91,7 +92,10 @@ class PostgreSQL(DBAPI):
         for key in config_mgr.get_section_settings('database'):
             dbkwargs[key] = config_mgr.get('database.' + key)
 
+        try:
             self.dbapi = Connection(**dbkwargs)
+        except psycopg2.OperationalError as msg:
+            raise DbConnectionError(str(msg), config_file)
 
 
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