Use shared util helper for driver name + config extraction

Change-Id: I43465b8f5868e64bdf38d2873417a8a4a403a23b

taskflow/jobs/backends/__init__.py

@@ -16,7 +16,6 @@
 
 import contextlib
 
-import six
 from stevedore import driver
 
 from taskflow import exceptions as exc
@@ -51,16 +50,7 @@ def fetch(name, conf, namespace=BACKEND_NAMESPACE, **kwargs):
     is ``{'a': 'b', 'c': 'd'}`` to the constructor of that board
     instance (also including the name specified).
     """
-    if isinstance(conf, six.string_types):
-        conf = {'board': conf}
-    board = conf['board']
-    try:
-        uri = misc.parse_uri(board)
-    except (TypeError, ValueError):
-        pass
-    else:
-        board = uri.scheme
-        conf = misc.merge_uri(uri, conf.copy())
+    board, conf = misc.extract_driver_and_conf(conf, 'board')
     LOG.debug('Looking for %r jobboard driver in %r', board, namespace)
     try:
         mgr = driver.DriverManager(namespace, board,

taskflow/persistence/backends/__init__.py

@@ -16,7 +16,6 @@
 
 import contextlib
 
-import six
 from stevedore import driver
 
 from taskflow import exceptions as exc
@@ -51,30 +50,21 @@ def fetch(conf, namespace=BACKEND_NAMESPACE, **kwargs):
     is ``{'a': 'b', 'c': 'd'}`` to the constructor of that persistence backend
     instance.
     """
-    if isinstance(conf, six.string_types):
-        conf = {'connection': conf}
-    backend_name = conf['connection']
-    try:
-        uri = misc.parse_uri(backend_name)
-    except (TypeError, ValueError):
-        pass
-    else:
-        backend_name = uri.scheme
-        conf = misc.merge_uri(uri, conf.copy())
+    backend, conf = misc.extract_driver_and_conf(conf, 'connection')
     # If the backend is like 'mysql+pymysql://...' which informs the
     # backend to use a dialect (supported by sqlalchemy at least) we just want
     # to look at the first component to find our entrypoint backend name...
-    if backend_name.find("+") != -1:
-        backend_name = backend_name.split("+", 1)[0]
-    LOG.debug('Looking for %r backend driver in %r', backend_name, namespace)
+    if backend.find("+") != -1:
+        backend = backend.split("+", 1)[0]
+    LOG.debug('Looking for %r backend driver in %r', backend, namespace)
     try:
-        mgr = driver.DriverManager(namespace, backend_name,
+        mgr = driver.DriverManager(namespace, backend,
                                    invoke_on_load=True,
                                    invoke_args=(conf,),
                                    invoke_kwds=kwargs)
         return mgr.driver
     except RuntimeError as e:
-        raise exc.NotFound("Could not find backend %s: %s" % (backend_name, e))
+        raise exc.NotFound("Could not find backend %s: %s" % (backend, e))
 
 
 @contextlib.contextmanager

taskflow/utils/misc.py

@@ -112,6 +112,19 @@ def countdown_iter(start_at, decr=1):
         start_at -= decr
 
 
+def extract_driver_and_conf(conf, conf_key):
+    """Common function to get a driver name and its configuration."""
+    if isinstance(conf, six.string_types):
+        conf = {conf_key: conf}
+    maybe_uri = conf[conf_key]
+    try:
+        uri = parse_uri(maybe_uri)
+    except (TypeError, ValueError):
+        return (maybe_uri, conf)
+    else:
+        return (uri.scheme, merge_uri(uri, conf.copy()))
+
+
 def reverse_enumerate(items):
     """Like reversed(enumerate(items)) but with less copying/cloning..."""
     for i in countdown_iter(len(items)):