Creating OpenLineage Extractors
This skill guides you through creating custom OpenLineage extractors to capture lineage from Airflow operators that do not have built-in support.
When to Use Each Approach
| Scenario | Approach |
|---|---|
| Operator you own or maintain | OpenLineage Methods (recommended) |
| Third-party operator you cannot modify | Custom Extractor |
| Need column-level lineage | OpenLineage Methods or Custom Extractor |
| Complex extraction logic | OpenLineage Methods or Custom Extractor |
| Simple table-level lineage | Inlets/Outlets (simplest, lowest priority) |
Approach 1: OpenLineage Methods (recommended)
python
from airflow.models import BaseOperator
class MyCustomOperator(BaseOperator):
def __init__(self, source_table: str, target_table: str, **kwargs):
super().__init__(**kwargs)
self.source_table = source_table
self.target_table = target_table
self._rows_processed = 0
def execute(self, context):
self._rows_processed = self._process_data()
return self._rows_processed
def get_openlineage_facets_on_start(self):
from openlineage.client.event_v2 import Dataset
from airflow.providers.openlineage.extractors import OperatorLineage
return OperatorLineage(
inputs=[Dataset(namespace="postgres://db", name=self.source_table)],
outputs=[Dataset(namespace="postgres://db", name=self.target_table)],
)
def get_openlineage_facets_on_complete(self, task_instance):
from openlineage.client.event_v2 import Dataset
from openlineage.client.facet_v2 import output_statistics_output_dataset
from airflow.providers.openlineage.extractors import OperatorLineage
return OperatorLineage(
inputs=[Dataset(namespace="postgres://db", name=self.source_table)],
outputs=[
Dataset(
namespace="postgres://db",
name=self.target_table,
facets={
"outputStatistics": output_statistics_output_dataset.OutputStatisticsOutputDatasetFacet(
rowCount=self._rows_processed
)
},
)
],
)
Approach 2: Custom Extractors
python
from airflow.providers.openlineage.extractors.base import BaseExtractor, OperatorLineage
from openlineage.client.event_v2 import Dataset
class MyOperatorExtractor(BaseExtractor):
@classmethod
def get_operator_classnames(cls) -> list[str]:
return ["MyCustomOperator"]
def _execute_extraction(self) -> OperatorLineage | None:
source_table = self.operator.source_table
target_table = self.operator.target_table
return OperatorLineage(
inputs=[Dataset(namespace="postgres://mydb:5432", name=f"public.{source_table}")],
outputs=[Dataset(namespace="postgres://mydb:5432", name=f"public.{target_table}")],
)
def extract_on_complete(self, task_instance) -> OperatorLineage | None:
return None
Registering Extractors
Configuration file:
ini
[openlineage] extractors = mypackage.extractors.MyOperatorExtractor;mypackage.extractors.AnotherExtractor
Environment variable:
bash
AIRFLOW__OPENLINEAGE__EXTRACTORS='mypackage.extractors.MyOperatorExtractor;mypackage.extractors.AnotherExtractor'