Google Pub Sub Get Message Activity¶

Introduction¶

A Google Pub Sub Get Message activity, using its Google Pub Sub connection, retrieves messages from a subscription in Google Pub/Sub and is intended to be used as a source to provide data in an operation.

Create a Google Pub Sub Get Message Activity¶

An instance of a Google Pub Sub Get Message activity is created from a Google Pub Sub connection using its Get Message activity type.

To create an instance of an activity, drag the activity type to the design canvas or copy the activity type and paste it on the design canvas. For details, see Creating an Activity Instance in Component Reuse.

An existing Google Pub Sub Get Message activity can be edited from these locations:

• The design canvas (see Component Actions Menu in Design Canvas).
• The project pane's Components tab (see Component Actions Menu in Project Pane Components Tab).

Configure a Google Pub Sub Get Message Activity¶

Follow these steps to configure a Google Pub Sub Get Message activity:

• Step 1: Enter a Name and Specify a Subscription
  Provide a name for the activity and select a subscription.

• Step 2: Review the Data Schemas
  Any request or response schemas generated from the endpoint are displayed.

Step 1: Enter a Name and Specify a Subscription¶

In this step, provide a name for the activity and specify a subscription. Each user interface element of this step is described below.

The interface used in this step of the configuration of a Google Pub Sub Get Message activity depends on the Choose Subscription option selected:

• Inform Subscription Manually: For this option, you will manually enter the subscription containing the messages you are retrieving.

• Select Existent Subscription: This option will populate a list of existing subscriptions to choose from. To use this option, you must have the pubsub.subscriptions.list permission assigned to the service account specified in the Google Pub Sub connection.

Inform Subscription Manually¶

If Inform Subscription Manually is selected for Choose Subscription, this interface is presented:

• Name: Enter a name to identify the activity. The name must be unique for each Google Pub Sub Get Message activity and must not contain forward slashes / or colons :.

• Choose Subscription: Select the method for providing the subscription to be used in the request:

  • Inform Subscription Manually: Select to manually enter the subscription containing the messages you are retrieving.

  • Select Existent Subscription: Select to choose an existing subscription from a populated list. To use this option, you must have the pubsub.subscriptions.list permission assigned to the service account specified in the Google Pub Sub connection.

• Subscription: Enter the name of the subscription containing the messages to retrieve.

• Quantity of Messages: Enter the number of messages to retrieve in the response. The default is 1 and the maximum is 100.

• Acknowledgement Deadline in Seconds (Max: 600) Optionally, enter the amount of time (in seconds) in which messages must be acknowledged before the server redelivers them. The maximum allowed value is 600 seconds. This setting extends the ackDeadline configured in the Google Cloud Platform.

• Save & Exit: If enabled, click to save the configuration for this step and close the activity configuration.

• Next: Click to temporarily store the configuration for this step and continue to the next step. The configuration will not be saved until you click the Finished button on the last step.

• Discard Changes: After making changes, click to close the configuration without saving changes made to any step. A message asks you to confirm that you want to discard changes.

Select Existent Subscription¶

If Select Existent Subscription is selected for Choose Subscription, this interface is presented:

• Name: Enter a name to identify the activity. The name must be unique for each Google Pub Sub Get Message activity and must not contain forward slashes / or colons :.

• Choose Subscription: Select the method for providing the subscription to be used in the request:

  • Inform Subscription Manually: Select to manually enter the subscription containing the messages you are retrieving.

  • Select Existent Subscription: Select to choose an existing subscription from a populated list. To use this option, you must have the pubsub.subscriptions.list assigned to the service account specified in the Google Pub Sub connection.

• Select a Subscription: This section displays subscriptions available in the Google Pub Sub endpoint.

  • Selected Subscription: After a subscription is selected, it is listed here.

• Search: Enter any part of the subscription name into the search box to filter the list of subscriptions. The search is not case-sensitive. If subscriptions are already displayed within the table, the table results are filtered in real time with each keystroke. To reload subscriptions from the endpoint when searching, enter search criteria and then refresh, as described below.

• Refresh: Click the refresh icon or the word Refresh to reload subscriptions from the Google Pub Sub endpoint. This may be useful if subscriptions have been added to Google Pub/Sub. This action refreshes all metadata used to build the table of subscriptions displayed in the configuration.

• Selecting a Subscription: Within the table, click anywhere on a row to select a subscription. Only one subscription can be selected. The information available for each subscription is fetched from the Google Pub Sub endpoint:

  • Name: The name of the subscription.

  • Description: The description of the subscription.

  Tip

  If the table does not populate with available subscriptions, the Google Pub Sub connection may not be successful. Ensure you are connected by reopening the connection and retesting the credentials.

• Quantity of Messages: Enter the number of messages to retrieve in the response. The default is 1 and the maximum is 100.

• Acknowledgement Deadline in Seconds (Max: 600) Optionally, enter the amount of time (in seconds) in which messages must be acknowledged before the server redelivers them. The maximum allowed value is 600 seconds. This setting extends the ackDeadline configured in the Google Cloud Platform.

• Save & Exit: If enabled, click to save the configuration for this step and close the activity configuration.

• Next: Click to temporarily store the configuration for this step and continue to the next step. The configuration will not be saved until you click the Finished button on the last step.

• Discard Changes: After making changes, click to close the configuration without saving changes made to any step. A message asks you to confirm that you want to discard changes.

Step 2: Review the Data Schemas¶

Any request or response schemas generated from the endpoint are displayed. Each user interface element of this step is described below.

• Data Schemas: These data schemas are inherited by adjacent transformations and are displayed again during transformation mapping.

  The Google Pub Sub connector uses the Google Pub/Sub API. Refer to the API documentation for information on the schema nodes and fields.

  Note

  The response schema for the Get Message activity will vary depending on the configuration of the Subscription selected in Step 1: Enter a Name and Select a Subscription. If the selected subscription has a configured schema, the response schema will have a body node with the same structure as the configured schema in Google Pub/Sub. If the selected subscription does not have a configured schema, the response schema will have a body field that accepts string data (shown above).

• Refresh: Click the refresh icon or the word Refresh to regenerate schemas from the Google Pub Sub endpoint. This action also regenerates a schema in other locations throughout the project where the same schema is referenced, such as in an adjacent transformation.

• Back: Click to temporarily store the configuration for this step and return to the previous step.

• Finished: Click to save the configuration for all steps and close the activity configuration.

• Discard Changes: After making changes, click to close the configuration without saving changes made to any step. A message asks you to confirm that you want to discard changes.

Next Steps¶

After configuring a Google Pub Sub Get Message activity, complete the configuration of the operation by adding and configuring other activities, transformations, or scripts as operation steps. You can also configure the operation settings, which include the ability to chain operations together that are in the same or different workflows.

Menu actions for an activity are accessible from the project pane and the design canvas. For details, see Activity Actions Menu in Connector Basics.

Google Pub Sub Get Message activities can be used as a source with these operation patterns:

• Transformation Pattern
• Two-target Archive Pattern (as the first source only)
• Two-target HTTP Archive Pattern (as the first source only)

To use the activity with scripting functions, write the data to a temporary location and then use that temporary location in the scripting function.

When ready, deploy and run the operation and validate behavior by checking the operation logs.