Add dbt quickstart example for already existing Dagster project

docs/content/integrations/dbt/quickstart.mdx

@@ -58,6 +58,67 @@ dagster-dbt project scaffold --project-name my-dagster-project --dbt-project-dir
 
 This creates a directory called `my-dagster-project/` inside the current directory. The `my-dagster-project/` directory contains a set of files that define a Dagster project.
 
+</TabItem>
+<TabItem name="Option 2: Use an existing Dagster project">
+
+### Option 2: Use an existing Dagster project
+
+You can use an existing Dagster project to run your dbt project. To do so, you'll need to add some objects using the [dagster-dbt library](/\_apidocs/libraries/dagster-dbt) and update your `Definitions` object. This example assumes that your existing Dagster project includes both `assets.py` and `definitions.py` files.
+
+1. Change directories to the Dagster project directory:
+
+   ```shell
+   cd my-dagster-project/
+   ```
+
+2. Create a Python file named `project.py` and add the following code. The DbtProject object is a representation of your dbt project that assist with managing manifest.json preparation.
+
+   ```python file=/integrations/dbt/quickstart.py startafter=start_dbt_project_example endbefore=end_dbt_project_example
+   from pathlib import Path
+
+       from dagster_dbt import DbtProject
+
+       RELATIVE_PATH_TO_MY_DBT_PROJECT = "./my-dbt-project"
+
+       my_project = DbtProject(
+           project_dir=Path(__file__)
+           .joinpath("..", RELATIVE_PATH_TO_MY_DBT_PROJECT)
+           .resolve(),
+       )
+   ```
+
+3. In your `assets.py` file, add the following code. Using the `dbt_assets` decorator allows Dagster to create a definition for how to compute a set of dbt resources, described by a manifest.json.
+
+   ```python file=/integrations/dbt/quickstart.py startafter=start_dbt_assets_example endbefore=end_dbt_assets_example
+   from dagster import AssetExecutionContext
+       from dagster_dbt import DbtCliResource, dbt_assets
+
+       from .project import my_project
+
+       @dbt_assets(manifest=my_project.manifest_path)
+       def my_dbt_assets(context: AssetExecutionContext, dbt: DbtCliResource):
+           yield from dbt.cli(["build"], context=context).stream()
+   ```
+
+4. In your `definitions.py` file, update your Definitions object to include the newly created objects.
+
+   ```python file=/integrations/dbt/quickstart.py startafter=start_dbt_definitions_example endbefore=end_dbt_definitions_example
+   from dagster import Definitions
+       from dagster_dbt import DbtCliResource
+
+       from .assets import my_dbt_assets
+       from .project import my_project
+
+       defs = Definitions(
+           assets=[my_dbt_assets],
+           resources={
+               "dbt": DbtCliResource(project_dir=my_project),
+           },
+       )
+   ```
+
+With these changes, your existing Dagster project is ready to run your dbt project.
+
 </TabItem>
 </TabGroup>
 

examples/docs_snippets/docs_snippets/integrations/dbt/quickstart.py

@@ -1,3 +1,4 @@
+# pyright: reportMissingImports=false
 # ruff: isort: skip_file
 
 # start_example
@@ -40,3 +41,50 @@ def my_dbt_assets(context: AssetExecutionContext, dbt: DbtCliResource):
     },
 )
 # end_example
+
+
+def dbt_project_example():
+    # start_dbt_project_example
+    from pathlib import Path
+
+    from dagster_dbt import DbtProject
+
+    RELATIVE_PATH_TO_MY_DBT_PROJECT = "./my-dbt-project"
+
+    my_project = DbtProject(
+        project_dir=Path(__file__)
+        .joinpath("..", RELATIVE_PATH_TO_MY_DBT_PROJECT)
+        .resolve(),
+    )
+    # end_dbt_project_example
+
+
+def dbt_assets_example():
+    # start_dbt_assets_example
+    from dagster import AssetExecutionContext
+    from dagster_dbt import DbtCliResource, dbt_assets
+
+    from .project import my_project
+
+    @dbt_assets(manifest=my_project.manifest_path)
+    def my_dbt_assets(context: AssetExecutionContext, dbt: DbtCliResource):
+        yield from dbt.cli(["build"], context=context).stream()
+
+    # end_dbt_assets_example
+
+
+def dbt_definitions_example():
+    # start_dbt_definitions_example
+    from dagster import Definitions
+    from dagster_dbt import DbtCliResource
+
+    from .assets import my_dbt_assets
+    from .project import my_project
+
+    defs = Definitions(
+        assets=[my_dbt_assets],
+        resources={
+            "dbt": DbtCliResource(project_dir=my_project),
+        },
+    )
+    # end_dbt_definitions_example