Docs: profile overrides (#19)

* overrides in readme

* profile overrides in docs

---------

Co-authored-by: Nico Gelders <[email protected]>

README.md

@@ -39,7 +39,7 @@ Here's an example of how to use prefect-dbt-flow to create a Prefect flow for yo
 
 ```python
 from prefect_dbt_flow import dbt_flow
-from prefect_dbt_flow.dbt import DbtProfile, DbtProject, DbtDagOptions
+from prefect_dbt_flow.dbt import DbtProfile, DbtProject
 
 my_flow = dbt_flow(
     project=DbtProject(
@@ -49,13 +49,18 @@ my_flow = dbt_flow(
     ),
     profile=DbtProfile(
         target="dev",
+        overrides={
+            "type": "duckdb",
+            "path": "path_to/duckdb.db",
+        },
     ),
 )
 
 if __name__ == "__main__":
     my_flow()
 ```
-![jaffle_shop_dag](https://raw.githubusercontent.com/datarootsio/prefect-dbt-flow/main/docs/images/jaffle_shop_dag.png)
+
+<img src="https://raw.githubusercontent.com/datarootsio/prefect-dbt-flow/main/docs/images/jaffle_shop_dag.png" alt="jaffle_shop_dag" width="100%">
 
 For more information consult the [docs](https://datarootsio.github.io/prefect-dbt-flow/)
 

docs/profile_overrides.md

@@ -0,0 +1,70 @@
+# Profile overrides
+
+When using dbt, you might want to dynamically change the profile configuration based for example on the environment you are running in. Also some profile configurations might be sensitive and you might not want to store them in your repository. Profile overrides allow you to inject profile configurations via python code, at runtime. In this section we will show you how to use profile overrides.
+
+## Basic usage
+
+To override a profile you must past the `DbtProfile` dataclass to the dbt_flow function.
+
+Profile overrides handle the following cases:
+
+ - When a `profile.yml` is detected in the configured `profiles_dir` it will read in the profile and override the values with the values in the `overrides` dict. The values that are not overridden will be kept as is.
+ - When no `profile.yml` is detected it will create a new `profile.yml` with the values in the `overrides` dict. In this case you need to provide all the values needed for your dbt adapter.
+
+## Example
+
+
+Contents of `path_to/jaffle_shop/profile.yml` BEFORE override:
+```yaml
+example_jaffle_shop:
+  target: dev
+  outputs:
+    dev:
+      type: postgres
+      host: data-db
+      port: 5432
+      dbname: data
+```
+
+Configuring the profile overrides:
+```python
+import os
+
+from prefect import variables
+from prefect.blocks.system import Secret
+
+postgres_user = variables.get("POSTGRES_USER")
+postgres_pw = Secret.load("POSTGRES_PASSWORD").get()
+
+my_flow = dbt_flow(
+    project=DbtProject(
+        ...,
+        profiles_dir="path_to/jaffle_shop",
+    ),
+    profile=DbtProfile(
+        target="dev",
+        overrides={
+            "user": postgres_user,
+            "password": postgres_pw,
+            "schema": os.environ["POSTGRES_SCHEMA"],
+            "connect_timeout": 30,
+        },
+    ),
+)
+```
+
+Contents of `path_to/jaffle_shop/profile.yml` AFTER override:
+```yaml
+example_jaffle_shop:
+  target: dev
+  outputs:
+    dev:
+      type: postgres
+      host: data-db
+      port: 5432
+      dbname: data
+      user: admin
+      password: super-secret-password
+      schema: example
+      connect_timeout: 30
+```

mkdocs.yml

@@ -47,6 +47,7 @@ nav:
       - Getting started: getting_started.md
       - How it works: how_it_works.md
       - DAG integration: dag_integration.md
+      - Profile overrides: profile_overrides.md
       - Changelog: https://github.com/datarootsio/prefect-dbt-flow/releases
       - License: license.md
   - API:

tests/test_flow.py

@@ -3,6 +3,7 @@
 import duckdb
 import pytest
 from prefect.task_runners import SequentialTaskRunner
+from prefect.testing.utilities import prefect_test_harness
 
 from prefect_dbt_flow import dbt_flow
 from prefect_dbt_flow.dbt import DbtDagOptions, DbtProfile, DbtProject
@@ -11,6 +12,12 @@
 JAFFLE_SHOP_PATH = Path(__file__).parent.parent / "examples" / "jaffle_shop_duckdb"
 
 
+@pytest.fixture(autouse=True, scope="session")
+def prefect_test_fixture():
+    with prefect_test_harness():
+        yield
+
+
 @pytest.fixture
 def duckdb_db_file(monkeypatch, tmp_path: Path):
     duckdb_db_file = tmp_path / "dbt_test.duckdb"