Update all generated readme auth instructions [(#1121)](GoogleCloudPl…

…atform/python-docs-samples#1121)

Change-Id: I03b5eaef8b17ac3dc3c0339fd2c7447bd3e11bd2

samples/snippets/README.rst

@@ -17,34 +17,12 @@ Setup
 Authentication
 ++++++++++++++
 
-Authentication is typically done through `Application Default Credentials`_,
-which means you do not have to change the code to authenticate as long as
-your environment has credentials. You have a few options for setting up
-authentication:
+This sample requires you to have authentication setup. Refer to the
+`Authentication Getting Started Guide`_ for instructions on setting up
+credentials for applications.
 
-#. When running locally, use the `Google Cloud SDK`_
-
- .. code-block:: bash
-
- gcloud auth application-default login
-
-
-#. When running on App Engine or Compute Engine, credentials are already
- set-up. However, you may need to configure your Compute Engine instance
- with `additional scopes`_.
-
-#. You can create a `Service Account key file`_. This file can be used to
- authenticate to Google Cloud Platform services from any environment. To use
- the file, set the ``GOOGLE_APPLICATION_CREDENTIALS`` environment variable to
- the path to the key file, for example:
-
- .. code-block:: bash
-
- export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service_account.json
-
-.. _Application Default Credentials: https://cloud.google.com/docs/authentication#getting_credentials_for_server-centric_flow
-.. _additional scopes: https://cloud.google.com/compute/docs/authentication#using
-.. _Service Account key file: https://developers.google.com/identity/protocols/OAuth2ServiceAccount#creatinganaccount
+.. _Authentication Getting Started Guide:
+ https://cloud.google.com/docs/authentication/getting-started
 
 Install Dependencies
 ++++++++++++++++++++
@@ -93,7 +71,10 @@ To run this sample:
 
  $ python publisher.py
 
- usage: publisher.py [-h] {list,create,delete,publish} ...
+ usage: publisher.py [-h]
+ project
+ {list,create,delete,publish,publish-with-futures,publish-with-batch-settings}
+ ...
  
  This application demonstrates how to perform basic operations on topics
  with the Cloud Pub/Sub API.
@@ -102,12 +83,18 @@ To run this sample:
  at https://cloud.google.com/pubsub/docs.
  
  positional arguments:
- {list,create,delete,publish}
- list Lists all Pub/Sub topics in the current project.
+ project Your Google Cloud project ID
+ {list,create,delete,publish,publish-with-futures,publish-with-batch-settings}
+ list Lists all Pub/Sub topics in the given project.
  create Create a new Pub/Sub topic.
  delete Deletes an existing Pub/Sub topic.
- publish Publishes a message to a Pub/Sub topic with the given
- data.
+ publish Publishes multiple messages to a Pub/Sub topic.
+ publish-with-futures
+ Publishes multiple messages to a Pub/Sub topic and
+ prints their message IDs.
+ publish-with-batch-settings
+ Publishes multiple messages to a Pub/Sub topic with
+ batch settings.
  
  optional arguments:
  -h, --help show this help message and exit
@@ -124,7 +111,9 @@ To run this sample:
 
  $ python subscriber.py
 
- usage: subscriber.py [-h] {list,create,delete,receive} ...
+ usage: subscriber.py [-h]
+ project {list,create,delete,receive,receive-flow-control}
+ ...
  
  This application demonstrates how to perform basic operations on
  subscriptions with the Cloud Pub/Sub API.
@@ -133,11 +122,15 @@ To run this sample:
  at https://cloud.google.com/pubsub/docs.
  
  positional arguments:
- {list,create,delete,receive}
+ project Your Google Cloud project ID
+ {list,create,delete,receive,receive-flow-control}
  list Lists all subscriptions for a given topic.
  create Create a new pull subscription on the given topic.
  delete Deletes an existing Pub/Sub topic.
- receive Receives a message from a pull subscription.
+ receive Receives messages from a pull subscription.
+ receive-flow-control
+ Receives messages from a pull subscription with flow
+ control.
  
  optional arguments:
  -h, --help show this help message and exit
@@ -155,6 +148,7 @@ To run this sample:
  $ python iam.py
 
  usage: iam.py [-h]
+ project
  {get-topic-policy,get-subscription-policy,set-topic-policy,set-subscription-policy,check-topic-permissions,check-subscription-permissions}
  ...
  
@@ -165,6 +159,7 @@ To run this sample:
  at https://cloud.google.com/pubsub/docs.
  
  positional arguments:
+ project Your Google Cloud project ID
  {get-topic-policy,get-subscription-policy,set-topic-policy,set-subscription-policy,check-topic-permissions,check-subscription-permissions}
  get-topic-policy Prints the IAM policy for the given topic.
  get-subscription-policy