Prefect Connector | OpenMetadata Pipeline Guide

In this section, we provide guides and references to use the Prefect connector. The connector ingests flows as Pipelines, each flow’s tasks (from its most recent run) as Tasks, and flow run history as Pipeline Status. It connects to either Prefect Cloud or a self-hosted Prefect Server over the Prefect REST API. Configure and schedule Prefect metadata workflows from the OpenMetadata UI:

• Requirements
• Metadata Ingestion
• Troubleshooting

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Requirements

The Prefect connector reads flows, deployments, and run history through the Prefect REST API. The connector requires no database-level grants, access is controlled entirely by the credentials used to call the API.

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Prefect Cloud

The API key must belong to a service account or user with at least Viewer access to the workspace identified by the configured Account ID and Workspace ID. Viewer access is sufficient to list flows and read their deployments, flow runs, task runs, and asset materializations (for lineage).

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Self-Hosted Prefect Server

If the server has Basic Auth enabled via PREFECT_SERVER_API_AUTH_STRING, provide the same user:password value as the Basic Auth String. If the server has no auth enabled, leave the field empty and requests are sent without credentials.

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Lineage

Table-to-table lineage is built from two sources, tried in order:

1. Assets API (Prefect Cloud only): exact upstream and downstream table pairs read from a flow run’s asset materializations, when the flow uses @materialize or asset_deps.
2. Lineage tags (Cloud and self-hosted): tag a flow, deployment, or task run with om-source:<database>.<schema>.<table> and om-destination:<database>.<schema>.<table>. Every detected source is linked to every detected destination. This requires the Database Service Name(s) to be configured in the pipeline service’s lineage settings so the tagged tables can be resolved to existing OpenMetadata Table entities.

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Metadata Ingestion

To ingest metadata from Prefect, you need to create a service connection. The service connects Prefect with OpenMetadata. Once you create a service, OpenMetadata automatically starts ingesting metadata.

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Step 1: Add New Service

1. Navigate to Settings > Services.
2. Click Add New Service.

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Step 2: Select a Service and Connector

From the service type dropdown, select Pipeline Services, then click the Prefect connector tile.

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Step 3: Add Service Name and Description

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

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Step 4: Configure Connection Options

Specify your source credentials and verify the connection.

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Enter Connection Details

Enter the connection details for Prefect. A help panel displays inline guidance for each field.

• Host and Port (required): Prefect API base URL. Use https://api.prefect.cloud for Prefect Cloud, or your self-hosted server URL, for example http://localhost:4200.
• Authentication (required): Choose the authentication type that matches your Prefect deployment:
  • Prefect Cloud:
    • Prefect API Key: API key for Prefect Cloud authentication.
    • Account ID: Found in the URL: app.prefect.cloud/account/{accountId}.
    • Workspace ID: Found in the URL after /workspaces/{workspaceId}.
  • Prefect Server:
    • Basic Auth String (optional): The PREFECT_SERVER_API_AUTH_STRING value in user:password format. Leave empty if the server has no auth enabled.
• Number of Status (optional, default 10, max 100): Number of past flow run statuses to ingest per flow.
• Verify SSL (optional): Client SSL verification mode for the Prefect API connection. Choose from:
  • No SSL (default): Plain HTTP connection.
  • Ignore: Accept HTTPS without validating the certificate (not recommended outside of testing).
  • Validate: Validate the certificate using the CA cert provided in SSL Configuration.
• SSL Configuration (optional): CA certificate (and, for mutual TLS, client certificate and key) used when Verify SSL is set to Validate.
• Default Pipeline Filter Pattern (optional): Regex pattern to include or exclude flows by name. Supports includes and excludes arrays.

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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 assets OpenMetadata ingests from your Prefect service. Filter patterns use regular expressions applied to flow names.

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How Filter Patterns Work

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

Rules match asset names using one of five expressions:

• contains: matches any name containing the value. For example, sales matches my_sales_data and sales_2024.
• starts with: matches names beginning with the value. For example, prod_ matches prod_db and prod_schema.
• 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.

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Filter Options

The Pipeline section includes the following filter options:

• Pipeline: Controls which flows OpenMetadata ingests from Prefect.

Each section provides the following controls:

• Scan Mode: Choose between the following scan modes:
  • Scan all: Ingests every asset of that type the connector can access. This is the default.
  • Only specific: Enables include rules so only assets matching at least one rule are ingested.
• Always exclude: Add permanent exclusion rules (shown in red). Assets 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. Added rules appear as chips. An asset is included if it matches any rule.

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Step 6: Create & Deploy

Click Create & Deploy to deploy the agent and start the first metadata ingestion run. OpenMetadata 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 Settings > Services and select your service.

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Configure Metadata Agent and Schedule Ingestion

The Metadata Agent extracts pipelines, tasks, and other structural metadata from your source and keeps your OpenMetadata catalog in sync. It powers discovery, lineage, and governance across your data assets. When you click Create & Deploy, OpenMetadata 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. Navigate to Settings > Services and select the service type.
2. Click the service you have added.
3. Select the Agents tab and click Add Agent > Metadata. 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
     Ownership Update Mode	replace	Set how owners from source metadata update Pipeline owners. In replace mode, resolved owners from the current source replace existing owners. In append mode, resolved owners are appended to active existing Pipeline owners.
     Db Service Names	—	List of database service names used for lineage resolution.
     Storage Service Names	—	List of storage service names used for lineage resolution.
     Messaging Service Names	—	List of messaging service names used for lineage resolution.
     Status Lookback Days	1	Number of days of pipeline run status history to ingest. Only runs within the last N days will be fetched.
     Include Lineage	On	Turn off to stop fetching lineage from pipelines.
     Mark Deleted Pipeline	On	Soft-delete pipelines in OpenMetadata when they are removed from the source. Associated entities like lineage are also deleted.
     Include UnDeployed Pipelines	On	Toggle whether un-deployed pipelines should be ingested. If set to false, only deployed pipelines will be ingested.

     
   • Filter Patterns: Apply include or exclude rules to scope which pipelines this agent ingests. These follow the same filter options described in Step 5: Configure Ingestion Options.
   • 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 OpenMetadata. When off, OpenMetadata only updates fields that have no existing value.
     Override Lineage	Off	When on, existing lineage is replaced with newly extracted lineage on each run.

     
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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