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#ask-ai
Title
# ask-ai
j

Jérôme MONTIGNY

02/19/2024, 10:15 AM
How does define_asset_job knows which dbt tests should be run ?
s

Scout

02/19/2024, 10:15 AM
The
define_asset_job
function in Dagster is used to define a job from a selection of assets. When integrating with dbt, Dagster's dbt integration can load all dbt tests as Asset Checks, which are a way to validate the data against certain conditions or expectations. According to the documentation, when loading a dbt project into the asset graph, Dagster can now load all dbt tests as Asset Checks if asset checks are enabled. This means that the dbt tests associated with the dbt models will be automatically recognized as Asset Checks and will be executed when the corresponding dbt models are materialized. To enable dbt tests as Asset Checks, you would typically define a
DagsterDbtTranslator
with
DagsterDbtTranslatorSettings
that have asset checks enabled. Here is an example from the documentation:
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python from pathlib import Path from dagster import AssetExecutionContext from dagster_dbt import (     DagsterDbtTranslator,     DagsterDbtTranslatorSettings,     DbtCliResource,     dbt_assets, )  manifest_path = Path("path/to/dbt_project/target/manifest.json") dagster_dbt_translator = DagsterDbtTranslator(     settings=DagsterDbtTranslatorSettings(enable_asset_checks=True) )  @dbt_assets(     manifest=manifest_path,     dagster_dbt_translator=dagster_dbt_translator, ) def my_dbt_assets(context: AssetExecutionContext, dbt: DbtCliResource):     yield from dbt.cli(["build"], context=context).stream()
In this example, enabling asset checks in the
DagsterDbtTranslatorSettings
allows the dbt tests to be loaded as Asset Checks. When you define an asset job using
define_asset_job
, you can specify a selection of assets to materialize. If the dbt tests are enabled as Asset Checks, they will be associated with the dbt models and run accordingly. If you want to run a subset of dbt tests or customize which tests are run, you may need to use additional selection criteria or settings. However, the documentation does not provide a detailed example of how to select specific dbt tests using
define_asset_job
. If you need to run only a subset of dbt tests as Asset Checks, you might need to look for more specific guidance or examples in the Dagster documentation or community discussions.
j

Jérôme MONTIGNY

02/19/2024, 10:20 AM
@Scout can you give me an example about how to use define_asset_jobs to run tests as well ?
s

Scout

02/19/2024, 10:20 AM
The documentation does not provide a direct example of using
define_asset_job
to run dbt tests as part of an asset job. However, I can explain the general approach based on how Dagster integrates with dbt and how asset jobs are defined. When you use dbt with Dagster, you can define assets that correspond to dbt models, and you can also define asset checks that correspond to dbt tests. If you have enabled asset checks when setting up your dbt assets, the dbt tests will be automatically loaded as asset checks. Here's a conceptual example of how you might set up dbt assets and checks in Dagster:
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python from dagster_dbt import dbt_cli_resource, dbt_run_op, dbt_test_op  # Define your dbt CLI resource dbt_cli = dbt_cli_resource.configured(     {"project_dir": "path/to/dbt/project", "profiles_dir": "path/to/dbt/profiles"} )  # Define an operation that runs dbt models (equivalent to `dbt run`) run_models = dbt_run_op.configured(     {"models": ["my_model"]}, name="run_my_model" )  # Define an operation that runs dbt tests (equivalent to `dbt test`) test_models = dbt_test_op.configured(     {"models": ["my_model"]}, name="test_my_model" )  # Define a job that runs the dbt run operation followed by the dbt test operation from dagster import job  @job(resource_defs={"dbt": dbt_cli}) def my_dbt_job():     test_models(start_after=run_models())
In this example,
my_dbt_job
is a job that first runs a dbt model with
run_models
and then runs the associated dbt tests with
test_models
. The
start_after
argument ensures that the tests are run after the models have been materialized. However, this example uses the
@job
decorator rather than
define_asset_job
. The
define_asset_job
function is specifically used to create jobs from a selection of assets, and it automatically infers the execution order based on asset dependencies. If you have defined your dbt models as assets and the tests as asset checks, then running the asset job should automatically run the associated tests as checks. If you need to define an asset job that includes dbt tests, you would typically set up your dbt assets and checks as described in the dbt integration documentation, and then use
define_asset_job
to create a job that targets the assets corresponding to your dbt models. The associated dbt tests (now asset checks) would be run as part of the asset materialization process. Please refer to the Dagster documentation or community resources for more specific examples or guidance on integrating dbt tests with Dagster asset jobs.