Modified publisher with error handling [(#1568)](GoogleCloudPlatform/…

…python-docs-samples#1568)

samples/snippets/publisher.py

@@ -22,7 +22,7 @@
 """
 
 import argparse
-import concurrent.futures
+import time
 
 from google.cloud import pubsub_v1
 
@@ -130,29 +130,27 @@ def publish_messages_with_error_handler(project, topic_name):
     publisher = pubsub_v1.PublisherClient()
     topic_path = publisher.topic_path(project, topic_name)
 
-    # When you publish a message, the client returns a Future. This Future
-    # can be used to track if an error has occurred.
-    futures = []
-
-    def callback(f):
-        exc = f.exception()
-        if exc:
+    def callback(message_future):
+        if message_future.exception():
             print('Publishing message on {} threw an Exception {}.'.format(
-                topic_name, exc))
+                topic_name, message_future.exception()))
+        else:
+            print(message_future.result())
 
     for n in range(1, 10):
         data = u'Message number {}'.format(n)
         # Data must be a bytestring
         data = data.encode('utf-8')
+        # When you publish a message, the client returns a Future.
         message_future = publisher.publish(topic_path, data=data)
         message_future.add_done_callback(callback)
-        futures.append(message_future)
+
+    print('Published message IDs:')
 
     # We must keep the main thread from exiting to allow it to process
     # messages in the background.
-    concurrent.futures.wait(futures)
-
-    print('Published messages.')
+    while True:
+        time.sleep(60)
     # [END pubsub_publish_messages_error_handler]
 
 
@@ -208,6 +206,11 @@ def publish_messages_with_batch_settings(project, topic_name):
         help=publish_messages_with_futures.__doc__)
     publish_with_futures_parser.add_argument('topic_name')
 
+    publish_with_error_handler_parser = subparsers.add_parser(
+        'publish-with-error-handler',
+        help=publish_messages_with_error_handler.__doc__)
+    publish_with_error_handler_parser.add_argument('topic_name')
+
     publish_with_batch_settings_parser = subparsers.add_parser(
         'publish-with-batch-settings',
         help=publish_messages_with_batch_settings.__doc__)
@@ -227,5 +230,7 @@ def publish_messages_with_batch_settings(project, topic_name):
         publish_messages_with_custom_attributes(args.project, args.topic_name)
     elif args.command == 'publish-with-futures':
         publish_messages_with_futures(args.project, args.topic_name)
+    elif args.command == 'publish-with-error-handler':
+        publish_messages_with_error_handler(args.project, args.topic_name)
     elif args.command == 'publish-with-batch-settings':
         publish_messages_with_batch_settings(args.project, args.topic_name)

samples/snippets/publisher_test.py

@@ -95,6 +95,13 @@ def test_publish_with_batch_settings(topic, capsys):
     assert 'Published' in out
 
 
+def test_publish_with_error_handler(topic, capsys):
+    publisher.publish_messages_with_error_handler(PROJECT, TOPIC)
+
+    out, _ = capsys.readouterr()
+    assert 'Published' in out
+
+
 def test_publish_with_futures(topic, capsys):
     publisher.publish_messages_with_futures(PROJECT, TOPIC)
 

samples/snippets/requirements.txt

@@ -1,2 +1 @@
-google-cloud-pubsub==0.32.1
-futures==3.1.1; python_version < '3'
+google-cloud-pubsub==0.33.0