Add a specific exception for 'unknown database' errors

Add an exception filter to distinguish 'unknown database' errors from
other DBAPIError's. This effectively means we no longer
unconditionally print a traceback to logs, when someone tries to
connect to a database, that does not exist, but just raise a specific
exception instead and let the caller handle it.

Closes-Bug: #1631033

Change-Id: Iebc1ec1e8153917fbcde116d04bc171272993bbd

1 files changed, 12 insertions, 0 deletions

diff --git a/oslo_db/exception.py b/oslo_db/exception.py
index 2d118cd..e66fe98 100644
--- a/oslo_db/exception.py
+++ b/oslo_db/exception.py
@@ -155,6 +155,18 @@ class DBNonExistentTable(DBError):
         super(DBNonExistentTable, self).__init__(inner_exception)
 
 
+class DBNonExistentDatabase(DBError):
+    """Database does not exist.
+
+    :param database: database name
+    :type database: str
+    """
+
+    def __init__(self, database, inner_exception=None):
+        self.database = database
+        super(DBNonExistentDatabase, self).__init__(inner_exception)
+
+
 class DBDeadlock(DBError):
 
     """Database dead lock error.