Run Connectors in your Airflow

We can use Airflow in different ways:

1. We can extract metadata from it,
2. And we can use connect to the OpenMetadata UI to deploy Workflows automatically.

In this guide, we will show how to host the ingestion DAGs in your Airflow directly. Note that in each connector page (e.g., Snowflake) we are showing an example on how to prepare a YAML configuration and run it as a DAG.

Here we are going to explain that a bit deeper and show an alternative process to achieve the same result.

Python Operator

Building a DAG using the PythonOperator requires devs to install the openmetadata-ingestion package in your Airflow's environment. This is a comfortable approach if you have access to the Airflow host and can freely handle dependencies.

Installing the dependencies' is as easy as pip3 install "openmetadata-ingestion[<your-connector>]".

For example, preparing a metadata ingestion DAG with this operator will look as follows:

import pathlib
import yaml
from datetime import timedelta
from airflow import DAG

try:
    from airflow.operators.python import PythonOperator
except ModuleNotFoundError:
    from airflow.operators.python_operator import PythonOperator

from metadata.config.common import load_config_file
from metadata.ingestion.api.workflow import Workflow
from airflow.utils.dates import days_ago

default_args = {
    "owner": "user_name",
    "email": ["username@org.com"],
    "email_on_failure": False,
    "retries": 3,
    "retry_delay": timedelta(minutes=5),
    "execution_timeout": timedelta(minutes=60)
}

config = """
<your YAML configuration>
"""

def metadata_ingestion_workflow():
    workflow_config = yaml.safe_load(config)
    workflow = Workflow.create(workflow_config)
    workflow.execute()
    workflow.raise_from_status()
    workflow.print_status()
    workflow.stop()

with DAG(
    "sample_data",
    default_args=default_args,
    description="An example DAG which runs a OpenMetadata ingestion workflow",
    start_date=days_ago(1),
    is_paused_upon_creation=False,
    schedule_interval='*/5 * * * *',
    catchup=False,
) as dag:
    ingest_task = PythonOperator(
        task_id="ingest_using_recipe",
        python_callable=metadata_ingestion_workflow,
    )

Note how we are preparing the PythonOperator by passing the python_callable=metadata_ingestion_workflow as an argument, where metadata_ingestion_workflow is a function that instantiates the Workflow class and runs the whole process.

The drawback here? You need to install some requirements, which is not always possible. This is why on 0.12.1 and higher versions we introduced an alternative approach. More on that below!

Docker Operator

From version 0.12.1 we are shipping a new image openmetadata/ingestion-base, which only contains the openmetadata-ingestion package and can then be used to handle ingestions in an isolated environment.

This is useful to prepare DAGs without any installation required on the environment, although it needs for the host to have access to the Docker commands.

For example, if you are running Airflow in Docker Compose, that can be achieved preparing a volume mapping the docker.sock file with 600 permissions.

volumes:
  - /var/run/docker.sock:/var/run/docker.sock:z  # Need 666 permissions to run DockerOperator

Then, preparing a DAG looks like this:

from datetime import datetime

from airflow import models
from airflow.providers.docker.operators.docker import DockerOperator


config = """
<your YAML configuration>
"""

with models.DAG(
    "ingestion-docker-operator",
    schedule_interval='*/5 * * * *',
    start_date=datetime(2021, 1, 1),
    catchup=False,
    tags=["OpenMetadata"],
) as dag:
    DockerOperator(
        command="python main.py",
        image="openmetadata/ingestion-base:0.13.2",
        environment={"config": config, "pipelineType": "metadata"},
        docker_url="unix://var/run/docker.sock",  # To allow to start Docker. Needs chmod 666 permissions
        tty=True,
        auto_remove="True",
        network_mode="host",  # To reach the OM server
        task_id="ingest",
        dag=dag,
    )

Note that the example uses the image openmetadata/ingestion-base:0.13.2. Update that accordingly for higher version once they are released. Also, the image version should be aligned with your OpenMetadata server version to avoid incompatibilities.

Another important point here is making sure that the Airflow will be able to run Docker commands to create the task. As our example was done with Airflow in Docker Compose, that meant setting docker_url="unix://var/run/docker.sock".

The final important elements here are:

• command="python main.py": This does not need to be modified, as we are shipping the main.py script in the image, used to trigger the workflow.
• environment={"config": config, "pipelineType": "metadata"}: Again, in most cases you will just need to update the config string to point to the right connector.

Other supported values of pipelineType are usage, lineage, profiler or TestSuite. Pass the required flag depending on the type of workflow you want to execute. Make sure that the YAML config reflects what ingredients are required for your Workflow.