Add error handling for start.set_conf_path

The `start.set_conf_path()` method will now raise a `FileNotFoundError`
if no file is found.

README.md

@@ -215,14 +215,11 @@ ENV APP_MODULE="package.custom.module:api" WORKERS_PER_CORE="2"
 
 ### Gunicorn and Uvicorn
 
-- `GUNICORN_CONF`: Path to a [Gunicorn configuration file](https://docs.gunicorn.org/en/latest/settings.html#config-file).
+- `GUNICORN_CONF`: Path to a [Gunicorn configuration file](https://docs.gunicorn.org/en/latest/settings.html#config-file). The Gunicorn command-line accepts file paths instead of module paths.
   - Default:
     - `"/app/inboard/gunicorn_conf.py"` (the default file provided with the Docker image)
   - Custom:
     - `GUNICORN_CONF="/app/package/custom_gunicorn_conf.py"`
-  - Notes
-    - Feel free to use the [`gunicorn_conf.py`](./inboard/gunicorn_conf.py) from this repo as a starting point for your own custom configuration.
-    - `GUNICORN_CONF` accepts a file path, instead of a module path, because Gunicorn is typically only run from within Docker, where the file path will be predictable.
 - `HOST`: Host IP address (inside of the container) where Gunicorn will listen for requests.
   - Default: `"0.0.0.0"`
   - Custom: _TODO_

inboard/start.py

@@ -13,14 +13,15 @@
 
 def set_conf_path(module_stem: str) -> str:
     """Set the path to a configuration file."""
-    conf_var = str(os.getenv(f"{module_stem.upper()}_CONF"))
-    if Path(conf_var).is_file():
+    conf_var = str(
+        os.getenv(f"{module_stem.upper()}_CONF", f"/app/inboard/{module_stem}_conf.py")
+    )
+    if conf_var and Path(conf_var).is_file():
         conf_path = conf_var
     elif Path(f"/app/inboard/{module_stem}_conf.py").is_file():
         conf_path = f"/app/inboard/{module_stem}_conf.py"
     else:
-        conf_path = f"/{module_stem}_conf.py"
-    os.environ[f"{module_stem.upper()}_CONF"] = conf_path
+        raise FileNotFoundError(f"Unable to find {conf_var}")
     return conf_path
 
 

tests/test_start.py

@@ -31,6 +31,12 @@ def test_set_custom_conf_path_gunicorn(
         assert "logging" not in str(gunicorn_conf_path_tmp)
         assert start.set_conf_path("gunicorn") == str(gunicorn_conf_path_tmp)
 
+    def test_set_incorrect_conf_path(self, monkeypatch: MonkeyPatch) -> None:
+        """Set path to non-existent file and raise an error."""
+        with pytest.raises(FileNotFoundError):
+            monkeypatch.setenv("GUNICORN_CONF", "/no/file/here")
+            start.set_conf_path("gunicorn")
+
 
 class TestConfigureLogging:
     """Test logging configuration methods.