Google Pub Sub Listen Message Activity¶

Introduction¶

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

Prerequisites¶

To use the Listen Message activity, these prerequisites must be met:

• A Private Agent version 10.68 or later (for 10.x Private Agents) or 11.6 or later (for 11.x Private Agents). For Private Agent Groups that contain multiple agents, the Private Agent version must be 10.78 or later (for 10.x Private Agents), or 11.8 or later (for 11.x Private Agents).

• To fully benefit from the listening service's load-balancing and fault-tolerance features, it is recommended to have a minimum of two Private Agents in the Agent Group.

• The Private Agent must have the listening service enabled as described in Enable the Listening Service on the Agent. This is a manual step in configuration and is not enabled by default.

• Once an operation is deployed, the Cloud Studio project must have the listening service enabled at both the operation level and the activity level as described in Enable the Listening Service on the Operation and Activity. This is manual step performed at the time of project design or project management.

Create a Google Pub Sub Listen Message Activity¶

An instance of a Google Pub Sub Listen Message activity is created from a Google Pub Sub connection using its Listen 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 Create an Activity Instance in Component Reuse.

An existing Google Pub Sub Listen 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 Listen Message Activity¶

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

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

• Step 2: Review the Data Schemas
  Any request or response schemas 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 Listen Message activity depends on the Choose Subscription option selected:

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

• 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 Listen 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.

  • 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 consume.

• Auto Acknowledge Message Select to enable automatic acknowledgement of retrieved messages. This option generates a response for each acknowledged message and may cause longer processing times.

• 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.

  • 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.

• Auto Acknowledge Message Select to enable automatic acknowledgement of retrieved messages. This option generates a response for each acknowledged message and may cause longer processing times.

• 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 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.

  The Listen Message activity uses JSON in its response schema.

• 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 Listen Message activity, you first configure an operation, and then deploy the operation and enable events.

Configure an Operation¶

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 Listen 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)
• Two-transformation 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.

Deploy the Operation and Enable Events¶

Once the operation is configured, deploy it. Deploying the operation activates a toggle that is present at the bottom of the operation on the design canvas. By default, event listening is disabled.

To enable event listening for the operation, click the toggle:

When event listening is enabled, the operation will run when it is triggered by the configured event.

After the operation triggers, you can validate behavior by checking the operation logs. A log entry is made for every message processed by the listening operation.

Administrators can also enable or disable event listening from the Management Console Projects page.