Google Pub/Sub Connector

This section provides guides and references to use the Google Pub/Sub connector. Configure and schedule Google Pub/Sub metadata workflows from the Collate UI:

• Requirements
• Metadata Ingestion
• Troubleshooting

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Requirements

The Google Cloud service account used for ingestion needs the following identity and access management (IAM) permissions:

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Metadata Ingestion

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Schema Registry

The built-in Google Cloud Platform (GCP) role roles/pubsub.viewer grants all of the above permissions and is the recommended role for Collate ingestion.

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Metadata Ingestion

To ingest metadata from Google Pub/Sub, you need to create a service connection. The service connects Pub/Sub with Collate. Once you create a service, Collate automatically starts ingesting metadata.

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Step 1: Add New Service

1. In the left navigation, click Connections.
2. On the Connections page, click Add New Service.

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Step 2: Select a Service and Connector

From the service type dropdown, select Messaging Services, then click the Pub/Sub connector tile.

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Step 3: Add Service Name and Description

• Enter a unique, descriptive Service Name. Collate identifies services by their service name. Enter a name that distinguishes this deployment from other Pub/Sub services you are ingesting metadata from.
• Optional: Enter a Description for the service.

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Step 4: Configure Connection Options

Specify where ingestion runs, provide your source credentials, and verify the connection.

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Select Ingestion Runner

Select an Ingestion Runner: the runner where the ingestion pipeline will execute.

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Enter Connection Details

Enter the connection details for Google Pub/Sub. The right-hand panel in the UI displays inline help for each field.

• GCP Credentials: Google Cloud service account credentials used to authenticate with Pub/Sub. Provide a service account key JSON containing type, projectId, privateKeyId, privateKey, clientEmail, and clientId. For more information, see Creating and managing service account keys.
• Project ID (optional if using inline GCP credentials): GCP Project ID where Pub/Sub topics are located. The project ID is only derived automatically when using inline service account credentials. If you’re using a credentials file path, Application Default Credentials, an external account, or the Pub/Sub emulator, you must set this field explicitly, or ingestion fails with Project ID is required.
• Host and Port (optional): Pub/Sub API endpoint. Defaults to pubsub.googleapis.com. Set to the emulator address (for example, localhost:8085) when using a local emulator.
• Use Emulator (optional): Set to true to connect to a local Pub/Sub emulator instead of the production service.
• Schema Registry Enabled (optional, default: true): Fetch topic schemas from the Pub/Sub Schema Registry. Supports Avro and Protocol Buffer schema types. Set to false if your project does not use the Schema Registry.
• Include Subscriptions (optional, default: true): Fetch subscription details for each topic. Only subscription names are persisted to topic metadata; acknowledgment deadlines, retention durations, push endpoints, and dead letter policies are read but not stored. When a subscription has a BigQuery export configuration, Collate uses it to extract lineage from the Pub/Sub topic to the target BigQuery table, though the export configuration itself is not persisted.
• Include Dead Letter Topics (optional, default: false): Include dead letter topics in metadata extraction. By default, dead letter topics are excluded to keep the topic list focused on primary business topics.

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Test Connection

Once the credentials have been added, click on Test Connection and Save the changes.

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Step 5: Configure Ingestion Options

In the What to Ingest step, use filter patterns to control which topics Collate ingests from your Pub/Sub service. Filter patterns use regular expressions applied to topic names.

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How Filter Patterns Work

• Include: Add one or more comma-separated regular expressions. Collate ingests only topics whose names match at least one expression. Leave blank to include all topics.
• Exclude: Add one or more comma-separated regular expressions. Collate skips any topic whose name matches an expression. Leave blank to exclude nothing.

Rules match topic names using one of five expressions:

• contains: matches any name containing the value. For example, orders matches my_orders_topic and orders_2024.
• starts with: matches names beginning with the value. For example, prod_ matches prod_events and prod_orders.
• ends with: matches names ending with the value. For example, _raw matches events_raw and logs_raw.
• is exactly: matches the exact name only. For example, analytics matches only analytics.
• matches regex: matches names using a regular expression. For example, ^prod_.*_v\d+$ matches prod_events_v1.

When both Include and Exclude are set, Exclude takes priority. Filter Options

• Topic: Controls which topics Collate ingests from the source.
• Scan Mode: Choose between Scan all (default) or Only specific to enable include rules.
• Always exclude: Add permanent exclusion rules. Topics matching these rules are never ingested, regardless of include rules.
• Preview: Shows a real-time summary of what will be in scope based on your current rules.
• Include rules (available only in Only specific mode): Click + Add to define a rule.

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Step 6: Create & Deploy

Click Create & Deploy to deploy the agent and start the first metadata ingestion run. Collate saves the service configuration and immediately begins pulling metadata from the source. To monitor ingestion progress or view the service you just added, go to Connections in the left navigation and select your service.

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Configure Metadata Agent and Schedule Ingestion

The Metadata Agent extracts topics, schemas, and other structural metadata from your source and keeps your Collate catalog in sync. It powers discovery, lineage, and governance across your data assets. When you click Create & Deploy, Collate automatically deploys a Metadata Agent for this service and triggers the first ingestion run. View its status and run history from the Agents tab on the service detail page. To configure the additional Metadata Agent and schedule ingestion, follow these steps:

1. In the left navigation, click Connections and select your service.
2. Click the Agents tab.
3. Click Add Agent and select Metadata from the dropdown. For some services, the dropdown is not available and clicking Add Agent takes you directly to the agent configuration page.
4. On the Configure Ingestion page, do the following and click Next.
   • Name this Ingestion: Enter a unique recognizable name for this ingestion pipeline.
   • Agent Setup: Configure the core parameters for this agent. The following fields are available:

     Field	Default	Description
     Generate Sample Data	Off	Option to turn on/off generating sample data during metadata extraction.
     Mark Deleted Topics	On	Soft-delete topics in Collate when they are removed from the source. Associated entities like sample data and lineage are also deleted.

     
   • Filter Patterns: Apply include or exclude rules to scope which topics this agent ingests. These follow the same filter options described in Step 5.
   • Scope & Behaviour: Control what metadata to include and how to handle deletions. Toggle each option on or off based on your needs:

     Toggle	Default	Description
     Enable Debug Log	Off	Sets the ingestion log level to DEBUG. Useful for troubleshooting.
     Override Metadata	Off	When on, source values overwrite existing descriptions, tags, owners, and display names in Collate. When off, Collate only updates fields that have no existing value.

     
5. On the Schedule Interval page, set when the agent runs:
   • Schedule: Choose a preset interval (Hourly, Daily, Weekly, Monthly) or enter a custom cron expression.
   • On-Demand: No automatic schedule; trigger the agent manually when needed.
   
6. Click Add to deploy the agent.

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Troubleshooting