In this guide, we'll walk you through how to run Dagster on your local machine using the
dagster dev command.
Looking for installation help? Refer to the Dagster installation guide.
This command should be run in a Python environment where the
dagster-webserver packages are installed. Once started, the process should be kept running.
Before you can start developing, you need to tell Dagster how to find the Python code containing your assets and jobs. There are a few ways to do this, which are outlined in the tabs below.
Note: If using an example Dagster project, or if you used the
dagster CLI to create a project, you can run the
dagster dev command in the same folder as the project to load the project code.
Dagster can load a file directly as a code location. In the following example, we used the
-f argument to supply the name of the file:
dagster dev -f my_file.py
This command loads the definitions in
my_file.py as a code location in the current Python environment.
You can also include multiple files at a time, where each file will be loaded as a code location:
dagster dev -f my_file.py -f my_second_file.py
dagster dev, you may see log output that looks like this:
Using temporary directory /Users/rhendricks/tmpqs_fk8_5 for storage.
This indicates that any runs or materialized assets created during your session won't be persisted once the session ends. This can be useful when using Dagster for temporary local development or testing, when you don't care about the results being persisted.
To designate a more permanent home for your runs and assets, you can set the
DAGSTER_HOME environment variable to a folder on your filesystem. Dagster will then use the specified folder for storage on all subsequent runs of
You can optionally use a
dagster.yaml file to configure your Dagster instance - for example, to configure run concurrency limits or specify that runs should be stored in a Postgres database instead of on the filesystem.
DAGSTER_HOME environment variable is set,
dagster dev will look for a
dagster.yaml file in the
DAGSTER_HOME folder. If
DAGSTER_HOME is not set,
dagster dev will look for that file from the folder where the command was run.
For the full list of options that can be set in the
dagster.yaml file, refer to the Dagster instance documentation.
dagster dev is primarily useful for running Dagster for local development and testing, but isn't suitable for the demands of most production deployments. For example, in a production deployment, you might want to run multiple webserver replicas, have zero downtime continuous deployment of your code, or set up your Dagster daemon to automatically restart if it crashes.
For information about deploying Dagster in production, refer to the Deploying Dagster guides.