Get started with Airflow using the Astro CLI
One of the Astro CLI's main features is its ability to run Airflow on your local computer. After you install the Astro CLI and Docker Desktop, follow these steps to quickly build a project and run Airflow locally.
- The Astro CLI
- Docker Desktop (v18.09 or higher).
Step 1: Create an Astro project
An Astro project contains the set of files necessary to run Airflow, including dedicated folders for your DAG files, plugins, and dependencies. All new Astro projects contain two example DAGs. This set of files builds a Docker image that you can both run on your local machine with Airflow and deploy to Astro.
astro dev init
This command generates the following files in the directory:
├── .env # Local environment variables
├── dags # Where your DAGs go
│ ├── example-dag-basic.py # Example DAG that showcases a simple ETL data pipeline
│ └── example-dag-advanced.py # Example DAG that showcases more advanced Airflow features, such as the TaskFlow API
├── Dockerfile # For the Astro Runtime Docker image, environment variables, and overrides
├── include # For any other files you'd like to include
├── plugins # For any custom or community Airflow plugins
│ └── example-plugin.py
├── tests # For any DAG unit test files to be run with pytest
│ └── test_dag_integrity.py # Test that checks for basic errors in your DAGs
├── airflow_settings.yaml # For your Airflow connections, variables and pools (local only)
├── packages.txt # For OS-level packages
└── requirements.txt # For Python packages
Step 2: Run Airflow locally
Running your project locally allows you to test your DAGs before you deploy them to a production environment. While this step is not required for deploying and running your code on Astro, Astronomer recommends always using the Astro CLI to test locally before deploying.
To start running your project in a local Airflow environment, run the following command from your project directory:
astro dev start
This command builds your project and spins up 4 Docker containers on your machine, each for a different Airflow component:
- Postgres: Airflow's metadata database
- Webserver: The Airflow component responsible for rendering the Airflow UI
- Scheduler: The Airflow component responsible for monitoring and triggering tasks
- Triggerer: The Airflow component responsible for running Triggers and signaling tasks to resume when their conditions have been met. The triggerer is used exclusively for tasks that are run with deferrable operators
After your project builds successfully, open the Airflow UI in your web browser at
Find your DAGs in the
dagsdirectory in the Airflow UI.
In this directory, you can find several example DAGs including
example-dag-basicDAG, which was generated with your Astro project. To provide a basic demonstration of an ETL pipeline, this DAG creates an example JSON string, calculates a value based on the string, and prints the results of the calculation to the Airflow logs.
The Astro CLI uses port
8080 for the Airflow webserver and port
5432 for the Airflow metadata database by default. If these ports are already in use on your local computer, an error message might appear. To resolve this error message, see Test and troubleshoot locally.
Step 3: Develop locally with the CLI
astro dev command options include a number of other useful subcommands that you can use while developing locally.
astro dev restart
You must restart your environment to apply changes from any of the following files in your Astro project:
To restart your local Airflow environment, run:
astro dev restart
This command rebuilds your image and restarts the Docker containers running on your local machine with the new image. Alternatively, you can run
astro dev stop to stop your Docker containers without restarting your environment, then run
astro dev start when you want to restart.
astro dev stop
Run the following to pause all Docker containers running your local Airflow environment.
astro dev stop
astro dev kill, this command does not prune mounted volumes and delete data associated with your local Postgres database. If you run this command, Airflow connections and task history will be preserved.
This command can be used regularly with
astro dev start and
astro dev restart during local development.
astro dev kill
When you want to force-stop all four Docker containers for your local Airflow environment, use the following command.
astro dev kill
astro dev kill also deletes all data associated with your local
Postgres database which includes Airflow connections, logs, and task history.
After you have finished Getting Started with the CLI, you can configure your CLI to locally debug your Airflow environment, authenticate to cloud services to test your DAGs with data stored on the cloud, or you can learn more about developing DAGs with Astro.