Add ZooKeeper backend to examples

Change-Id: I8c9408465392307ede2ff61e0524700e4c51ccad

taskflow/examples/example_utils.py

@@ -61,6 +61,12 @@ def _make_conf(backend_uri):
             'path': parsed_url.path,
             'connection': backend_uri,
         }
+    elif backend_type in ('zookeeper',):
+        conf = {
+            'path': parsed_url.path,
+            'hosts': parsed_url.netloc,
+            'connection': backend_uri,
+        }
     else:
         conf = {
             'connection': backend_uri,

taskflow/examples/resume_from_backend.py

@@ -44,6 +44,19 @@ import example_utils  # noqa
 # to start an engine, have a task stop the engine from doing future work (if
 # a multi-threaded engine is being used, then the currently active work is not
 # preempted) and then resume the work later.
+#
+# Usage:
+#
+#   With a filesytem directory as backend
+#
+#     python taskflow/examples/resume_from_backend.py
+#
+#   With ZooKeeper as backend
+#
+#     python taskflow/examples/resume_from_backend.py \
+#       zookeeper://127.0.0.1:2181/taskflow/resume_from_backend/
+#
+
 
 ### UTILITY FUNCTIONS #########################################