main: Support specifying db spec explicitly

main.py

@@ -28,6 +28,9 @@
 # Maximum time for pulling maximum amount of submissions from the queue
 LOAD_QUEUE_TIMEOUT_SEC = float(os.environ["KCIDB_LOAD_QUEUE_TIMEOUT_SEC"])
 
+# The specification for the database submissions should be loaded into
+DATABASE = os.environ["KCIDB_DATABASE"]
+
 # Minimum time between loading submissions into the database
 DATABASE_LOAD_PERIOD = datetime.timedelta(
     seconds=int(os.environ["KCIDB_DATABASE_LOAD_PERIOD_SEC"])
@@ -102,9 +105,14 @@ def get_smtp_password():
     return _SMTP_PASSWORD
 
 
-def get_load_queue_subscriber():
+def get_load_queue_subscriber(database):
     """
     Create or get the cached subscriber object for the submission queue.
+
+    Args:
+        database:   The specification for the database the data from the queue
+                    will be loaded into. Used to retrieve the accepted I/O
+                    schema version.
     """
     # It's alright, pylint: disable=global-statement
     global _LOAD_QUEUE_SUBSCRIBER
@@ -113,7 +121,7 @@ def get_load_queue_subscriber():
             PROJECT_ID,
             os.environ["KCIDB_LOAD_QUEUE_TOPIC"],
             os.environ["KCIDB_LOAD_QUEUE_SUBSCRIPTION"],
-            schema=get_db_client().get_schema()[1]
+            schema=get_db_client(database).get_schema()[1]
         )
     return _LOAD_QUEUE_SUBSCRIBER
 
@@ -150,24 +158,37 @@ def get_db_credentials():
     atexit.register(os.remove, pgpass_filename)
 
 
-def get_db_client():
-    """Create or retrieve the cached database client."""
+def get_db_client(database):
+    """
+    Create or retrieve the cached database client.
+
+    Args:
+        database:   The specification for the database the client should
+                    connect to.
+    """
     # It's alright, pylint: disable=global-statement
     global _DB_CLIENT
     if _DB_CLIENT is None:
         # Get the credentials
         get_db_credentials()
         # Create the client
-        _DB_CLIENT = kcidb.db.Client(os.environ["KCIDB_DATABASE"])
+        _DB_CLIENT = kcidb.db.Client(database)
+    assert _DB_CLIENT.database == database
     return _DB_CLIENT
 
 
-def get_oo_client():
-    """Create or retrieve the cached OO database client."""
+def get_oo_client(database):
+    """
+    Create or retrieve the cached OO database client.
+
+    Args:
+        database:   The specification for the database the client should
+                    connect to.
+    """
     # It's alright, pylint: disable=global-statement
     global _OO_CLIENT
     if _OO_CLIENT is None:
-        _OO_CLIENT = kcidb.oo.Client(get_db_client())
+        _OO_CLIENT = kcidb.oo.Client(get_db_client(database))
     return _OO_CLIENT
 
 
@@ -255,8 +276,8 @@ def kcidb_load_queue(event, context):
     if it stayed unmodified for at least DATABASE_LOAD_PERIOD.
     """
     # pylint: disable=too-many-locals
-    subscriber = get_load_queue_subscriber()
-    db_client = get_db_client()
+    subscriber = get_load_queue_subscriber(DATABASE)
+    db_client = get_db_client(DATABASE)
     io_schema = db_client.get_schema()[1]
     publisher = get_updated_queue_publisher()
     # Do nothing, if updated recently
@@ -336,7 +357,7 @@ def kcidb_spool_notifications(event, context):
     Spool notifications about objects matching patterns arriving from a Pub
     Sub subscription
     """
-    oo_client = get_oo_client()
+    oo_client = get_oo_client(DATABASE)
     spool_client = get_spool_client()
     # Reset the ORM cache
     oo_client.reset_cache()