import assets through importlib - so assets are packages as well

.vscode/launch.json

@@ -0,0 +1,20 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Python: FastAPI",
+            "type": "python",
+            "request": "launch",
+            "module": "uvicorn",
+            "args": [
+                "coordinates_transformation_api.main:start",
+                "--reload"
+            ],
+            "jinja": true,
+            "justMyCode": true
+        }
+    ]
+}

coordinates_transformation_api/main.py

@@ -4,6 +4,10 @@
 import yaml
 import uvicorn
 
+from importlib import resources as impresources
+from . import assets
+
+
 default_headers = {"API-Version": "2.0.1"}
 
 app = FastAPI(docs_url="/api")
@@ -81,12 +85,12 @@ async def transform():
 
 
 def custom_openapi():
-    with open("openapi.yaml", "rb") as openapi:
-        return yaml.load(openapi, yaml.SafeLoader)
+    oas_file_resource = (impresources.files(assets) / "openapi.yaml")
+    with oas_file_resource.open("rb") as oas_file:
+        return yaml.load(oas_file, yaml.SafeLoader)
 
 
 app.openapi = custom_openapi
 
-
 def start():
     uvicorn.run("coordinates_transformation_api.main:app", workers=2, host="0.0.0.0", port=8000, reload=True)

pyproject.toml

@@ -37,3 +37,6 @@ enabled = true
 [tool.setuptools.packages.find]
 include = ["coordinates_transformation_api*"]  # package names should match these glob patterns (["*"] by default)
 exclude = []  # exclude packages matching these glob patterns (empty by default)
+
+[tool.setuptools.package-data]
+"coordinates_transformation_api.assets" = ["*"]