Parent Run Facet

Commonly, scheduler systems like Apache Airflow will trigger processes on remote systems, such as on Apache Spark or Apache Beam jobs. Those systems might have their own OpenLineage integration and report their own job runs and dataset inputs/outputs. The ParentRunFacet allows those downstream jobs to report which jobs spawned them to preserve job hierarchy. To do that, the scheduler system should have a way to pass its own job and run id to the child job.

In addition to the information about the direct job that spawned the current job, contained in job and run fields, the ParentRunFacet optionally contains information about the root job contained in the root field. The root job represents the initial operation that started the whole chain of parent-child jobs - for example, the Airflow DAG execution that eventually spawned Airflow tasks which then spawned Spark jobs.

The job and run objects, both at the parent level and at the root level, can also optionally carry a facets field. This lets a producer forward a selected subset of facets from that parent/root job or run into the child event, for convenience - for example, when the child cannot reliably resolve the parent's own event to look them up itself.

This mechanism is not designed to replace the information contained in the parent run's own event, and should not be treated as a source of truth if the two ever differ. In practice, the forwarded facets and the parent's own event should never diverge, but the specification only defines the shape of this field - it cannot guarantee that every implementation keeps the forwarded values in sync with the parent's own event. Resolving the parent run's own event remains the authoritative way to get full information.

Example:

{
  ...
  "run": {
    "facets": {
      "parent": {
        "job": {
          "name": "the-execution-parent-job", 
          "namespace": "the-namespace",
          "facets": {
            "jobType": {
              "processingType": "BATCH",
              "integration": "AIRFLOW",
              "jobType": "TASK"
            }
          }
        },
        "run": {
          "runId": "f99310b4-3c3c-1a1a-2b2b-c1b95c24ff11"
        },
        "root": {
          "job": {
            "name": "the-top-level-job",
            "namespace": "another-namespace"
          },
          "run": {
            "runId": "f1234567-4f4f-1a1a-2b2b-abcdef123456",
            "facets": {
                "processing_engine": {
                    "version": "2.5.0",
                    "name": "Spark",
                    "openlineageAdapterVersion": "1.23.0"
                }
            }
          }
        }
      }
    }
  }
  ...
}

The facet specification can be found here.