Functions: improve existing sample (GoogleCloudPlatform#2220)

* improved example

* reformat

* updated code

* remove extra exclamation mark

functions/helloworld/main.py

@@ -1,4 +1,4 @@
-# Copyright 2018 Google LLC
+# Copyright 2019 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the 'License');
 # you may not use this file except in compliance with the License.
@@ -80,17 +80,23 @@ def hello_http(request):
 
 
 # [START functions_helloworld_pubsub]
-def hello_pubsub(data, context):
+def hello_pubsub(event, context):
     """Background Cloud Function to be triggered by Pub/Sub.
     Args:
-         data (dict): The dictionary with data specific to this type of event.
+         event (dict):  The dictionary with data specific to this type of
+         event. The `data` field contains the PubsubMessage message. The
+         `attributes` field will contain custom attributes if there are any.
          context (google.cloud.functions.Context): The Cloud Functions event
-         metadata.
+         metadata. The `event_id` field contains the Pub/Sub message ID. The
+         `timestamp` field contains the publish time.
     """
     import base64
 
-    if 'data' in data:
-        name = base64.b64decode(data['data']).decode('utf-8')
+    print("""This Function was triggered by messageId {} published at {}
+    """.format(context.event_id, context.timestamp))
+
+    if 'data' in event:
+        name = base64.b64decode(event['data']).decode('utf-8')
     else:
         name = 'World'
     print('Hello {}!'.format(name))

functions/helloworld/main_test.py

@@ -1,4 +1,4 @@
-# Copyright 2018 Google LLC
+# Copyright 2019 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the 'License');
 # you may not use this file except in compliance with the License.

functions/helloworld/sample_pubsub_test.py

@@ -1,4 +1,4 @@
-# Copyright 2018 Google LLC
+# Copyright 2019 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the 'License');
 # you may not use this file except in compliance with the License.
@@ -14,25 +14,31 @@
 
 # [START functions_pubsub_unit_test]
 import base64
+import mock
 
 import main
 
 
+mock_context = mock.Mock()
+mock_context.event_id = '617187464135194'
+mock_context.timestamp = '2019-07-15T22:09:03.761Z'
+
+
 def test_print_hello_world(capsys):
     data = {}
 
     # Call tested function
-    main.hello_pubsub(data, None)
+    main.hello_pubsub(data, mock_context)
     out, err = capsys.readouterr()
-    assert out == 'Hello World!\n'
+    assert 'Hello World!' in out
 
 
 def test_print_name(capsys):
     name = 'test'
     data = {'data': base64.b64encode(name.encode())}
 
     # Call tested function
-    main.hello_pubsub(data, None)
+    main.hello_pubsub(data, mock_context)
     out, err = capsys.readouterr()
-    assert out == 'Hello {}!\n'.format(name)
+    assert 'Hello {}!\n'.format(name) in out
 # [END functions_pubsub_unit_test]

functions/helloworld/sample_pubsub_test_system.py

@@ -1,4 +1,4 @@
-# Copyright 2018 Google LLC
+# Copyright 2019 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the 'License');
 # you may not use this file except in compliance with the License.
@@ -58,5 +58,5 @@ def test_print_name(publisher_client):
         start_time
     ], stdout=subprocess.PIPE)
     logs = str(log_process.communicate()[0])
-    assert 'Hello, {}!'.format(name) in logs
+    assert 'Hello {}!'.format(name) in logs
 # [END functions_pubsub_system_test]