Conditionally import ibmdb2/ibm_db_sa

Since ibm_db_sa is not part of sqlalchemy, we need to handle the
conditional import of the module in visitor.py so we don't get an
ImportError if ibm_db_sa is not available.

Closes-Bug: #1287229

Change-Id: Ida070b629ce3b9be727ae49973bb6a71543c1dcf

1 files changed, 11 insertions, 3 deletions

diff --git a/migrate/changeset/databases/visitor.py b/migrate/changeset/databases/visitor.py
index 224c40f..c70aa6b 100644
--- a/migrate/changeset/databases/visitor.py
+++ b/migrate/changeset/databases/visitor.py
@@ -8,8 +8,7 @@ from migrate.changeset.databases import (sqlite,
                                          postgres,
                                          mysql,
                                          oracle,
-                                         firebird,
-                                         ibmdb2)
+                                         firebird)
 
 
 # Map SA dialects to the corresponding Migrate extensions
@@ -21,10 +20,19 @@ DIALECTS = {
     "mysql": mysql.MySQLDialect,
     "oracle": oracle.OracleDialect,
     "firebird": firebird.FBDialect,
-    "ibm_db_sa": ibmdb2.IBMDBDialect
 }
 
 
+# NOTE(mriedem): We have to conditionally check for DB2 in case ibm_db_sa
+# isn't available since ibm_db_sa is not packaged in sqlalchemy like the
+# other dialects.
+try:
+    from migrate.changeset.databases import ibmdb2
+    DIALECTS["ibm_db_sa"] = ibmdb2.IBMDBDialect
+except ImportError:
+    pass
+
+
 def get_engine_visitor(engine, name):
     """
     Get the visitor implementation for the given database engine.