This guide is applicable only to Dagster Open Source (OSS).
Workspace files contain a collection of user-defined code locations and information about where to find them. Code locations loaded via workspace files can contain either a
Definitions object or multiple repositories.
Workspace files are used by Dagster to load code locations in complex or customized environments, such as a production OSS deployment. For local development within a single Python environment,
Definitions users can use the
-f flags with our CLI tools, or set the
pyproject.toml file to avoid using command line flags entirely.
|The object that contains all the definitions defined within a code location. Definitions include assets, jobs, resources, schedules, and sensors.|
|The decorator used to define repositories. The decorator returns a |
A workspace file tells Dagster where to find code locations. By default, this is a YAML document named
workspace.yaml. For example:
# workspace.yaml load_from: - python_file: my_file.py
Each entry in a workspace file is considered a code location. A code location can contain either a single
Definitions object, a repository, or multiple repositories.
To accommodate incrementally migrating from
Definitions, code locations in a single workspace file can mix and match between definition approaches. For example,
code-location-1 could load a single
Definitions object from a file or module, and
code-location-2 could load multiple repositories.
Each code location is loaded in its own process that Dagster tools use an RPC protocol to communicate with. This process separation allows multiple code locations in different environments to be loaded independently, and ensures that errors in user code can't impact Dagster system code.
To load a code location from a Python file, use the
python_file key in
workspace.yaml. The value of
python_file should specify a path relative to
workspace.yaml leading to a file that contains a code location definition.
For example, if a code location is in
my_file.py and the file is in the same folder as
workspace.yaml, the code location could be loaded using the following:
# workspace.yaml load_from: - python_file: my_file.py
@repository to define code locations, you can identify a single repository within the module using the
attribute key. The value of this key must be the name of a repository or the name of a function that returns a
RepositoryDefinition. For example:
# workspace.yaml load_from: - python_file: relative_path: hello_world_repository.py attribute: hello_world_repository
By default, Dagster command-line tools (like
dagster-daemon run) look for workspace files (by default,
workspace.yaml) in the current directory when invoked. This allows you to launch from that directory without the need for command line arguments:
To load the
workspace.yaml file from a different folder, use the
dagster dev -w path/to/workspace.yaml
dagster dev is run, Dagster will load all the code locations defined by the workspace file. Refer to the CLI reference for more info and examples.
If a code location can't be loaded - for example, due to a syntax or some other unrecoverable error - a warning message will display in the Dagster UI. You'll be directed to a status page with a descriptive error and stack trace for any locations Dagster was unable to load.
Note: If a code location is re-named or its configuration in a workspace file is modified, you'll need to stop and re-start any running schedules or sensors in that code location. You can do this in the UI by navigating to the Deployment overview page, clicking a code location, and using the Schedules and Sensors tabs.
This is required because when you start a schedule or a sensor, a serialized representation of the entry in your workspace file is stored in a database. The Dagster daemon process uses this serialized representation to identify and load your schedule or sensor. If the code location is modified and its schedules and sensors aren't restarted, the Dagster daemon process will use an outdated serialized representation, resulting in issues.
By default, Dagster tools automatically create a process on your local machine for each of your code locations. However, it's also possible to run your own gRPC server that's responsible for serving information about your code locations. This can be useful in more complex system architectures that deploy user code separately from the Dagster webserver.
To initialize the Dagster gRPC server, run the
dagster api grpc command and include:
The following tabs demonstrate some common ways to initialize a gRPC server:
Running on a port, using a Python file:
dagster api grpc --python-file /path/to/file.py --host 0.0.0.0 --port 4266
Running on a socket, using a Python file:
dagster api grpc --python-file /path/to/file.py --host 0.0.0.0 --socket /path/to/socket
Refer to the API docs for the full list of options that can be set when running a new gRPC server.
Then, in your workspace file, configure a new gRPC server code location to load:
# workspace.yaml load_from: - grpc_server: host: localhost port: 4266 location_name: "my_grpc_server"
When running your own gRPC server within a container, you can tell the webserver that any runs launched from a code location should be launched in a container with that same image.
To do this, set the
DAGSTER_CURRENT_IMAGE environment variable to the name of the image before starting the server. After setting this environment variable for your server, the image should be listed alongside the code location on the Status page in the UI.
If you're using the built-in Helm chart, this environment variable is automatically set on each of your gRPC servers.
By default, code is loaded with
dagster-webserver's working directory as the base path to resolve any local imports in your code. Using the
working_directory key, you can specify a custom working directory for relative imports. For example:
# workspace.yaml load_from: - python_file: relative_path: hello_world_repository.py working_directory: my_working_directory/