Merge pull request #49 from stealthrocket/improve-error-messages

improve error messages

src/dispatch/client.py

@@ -30,24 +30,28 @@ def __init__(self, api_key: None | str = None, api_url: None | str = None):
 
             api_url: The URL of the Dispatch API to use. Uses the value of the
               DISPATCH_API_URL environment variable if set, otherwise
-              defaults to the public Dispatch API (DEFAULT_DISPATCH_API_URL).
+              defaults to the public Dispatch API (DEFAULT_API_URL).
 
         Raises:
             ValueError: if the API key is missing.
         """
+
         if not api_key:
             api_key = os.environ.get("DISPATCH_API_KEY")
         if not api_key:
-            raise ValueError("api_key is required")
+            raise ValueError(
+                "missing API key: set it with the DISPATCH_API_KEY environment variable"
+            )
 
         if not api_url:
             api_url = os.environ.get("DISPATCH_API_URL", DEFAULT_API_URL)
         if not api_url:
-            raise ValueError("api_url is required")
+            raise ValueError(
+                "missing API URL: set it with the DISPATCH_API_URL environment variable"
+            )
 
         self.api_url = api_url
         self.api_key = api_key
-
         self._init_stub()
 
     def __getstate__(self):

src/dispatch/fastapi.py

@@ -27,7 +27,7 @@ def read_root():
 from http_message_signatures import InvalidSignature
 from httpx import _urlparse
 
-from dispatch.client import DEFAULT_API_URL, Client
+from dispatch.client import Client
 from dispatch.function import Registry
 from dispatch.proto import Input
 from dispatch.sdk.v1 import function_pb2 as function_pb
@@ -70,24 +70,32 @@ def __init__(
               the value of the DISPATCH_VERIFICATION_KEY environment variable
               by default. The environment variable is expected to carry an
               Ed25519 public key in base64 or PEM format.
+              If not set, request signature verification is disabled (a warning
+              will be logged by the constructor).
 
             api_key: Dispatch API key to use for authentication. Uses the value of
               the DISPATCH_API_KEY environment variable by default.
 
             api_url: The URL of the Dispatch API to use. Uses the value of the
               DISPATCH_API_URL environment variable if set, otherwise
-              defaults to the public Dispatch API (DEFAULT_DISPATCH_API_URL).
+              defaults to the public Dispatch API (DEFAULT_API_URL).
 
         Raises:
             ValueError: If any of the required arguments are missing.
         """
         if not app:
-            raise ValueError("app is required")
+            raise ValueError(
+                "missing FastAPI app as first argument of the Dispatch constructor"
+            )
 
+        endpoint_from = "endpoint argument"
         if not endpoint:
             endpoint = os.getenv("DISPATCH_ENDPOINT_URL")
+            endpoint_from = "DISPATCH_ENDPOINT_URL"
         if not endpoint:
-            raise ValueError("endpoint is required")
+            raise ValueError(
+                "missing application endpoint: set it with the DISPATCH_ENDPOINT_URL environment variable"
+            )
 
         if not verification_key:
             try:
@@ -108,27 +116,22 @@ def __init__(
 
         parsed_url = _urlparse.urlparse(endpoint)
         if not parsed_url.netloc or not parsed_url.scheme:
-            raise ValueError("endpoint must be a full URL with protocol and domain")
+            raise ValueError(
+                f"{endpoint_from} must be a full URL with protocol and domain (e.g., https://example.com)"
+            )
 
         if verification_key:
             base64_key = base64.b64encode(verification_key.public_bytes_raw()).decode()
             logger.info("verifying request signatures using key %s", base64_key)
         else:
-            logger.warning("request verification is disabled")
-
-        if not api_key:
-            api_key = os.environ.get("DISPATCH_API_KEY")
-        if not api_url:
-            api_url = os.environ.get("DISPATCH_API_URL", DEFAULT_API_URL)
-
-        client = (
-            Client(api_key=api_key, api_url=api_url) if api_key and api_url else None
-        )
+            logger.warning(
+                "request verification is disabled because DISPATCH_VERIFICATION_KEY is not set"
+            )
 
+        client = Client(api_key=api_key, api_url=api_url)
         super().__init__(endpoint, client)
 
         function_service = _new_app(self, verification_key)
-
         app.mount("/dispatch.sdk.v1.FunctionService", function_service)
 
 

tests/test_client.py

@@ -31,7 +31,10 @@ def test_api_key_from_env(self):
     def test_api_key_missing(self):
         with self.assertRaises(ValueError) as mc:
             Client()
-        self.assertEqual(str(mc.exception), "api_key is required")
+        self.assertEqual(
+            str(mc.exception),
+            "missing API key: set it with the DISPATCH_API_KEY environment variable",
+        )
 
     def test_url_bad_scheme(self):
         with self.assertRaises(ValueError) as mc:

tests/test_fastapi.py

@@ -18,11 +18,19 @@
 from . import function_service
 
 
+def create_dispatch_instance(app, endpoint):
+    return Dispatch(
+        app,
+        endpoint=endpoint,
+        api_key="0000000000000000",
+        api_url="http://127.0.0.1:10000",
+    )
+
+
 class TestFastAPI(unittest.TestCase):
     def test_Dispatch(self):
         app = fastapi.FastAPI()
-
-        Dispatch(app, endpoint="https://127.0.0.1:9999")
+        create_dispatch_instance(app, "https://127.0.0.1:9999")
 
         @app.get("/")
         def read_root():
@@ -42,21 +50,21 @@ def read_root():
 
     def test_Dispatch_no_app(self):
         with self.assertRaises(ValueError):
-            Dispatch(None, endpoint="http://127.0.0.1:9999")
+            create_dispatch_instance(None, endpoint="http://127.0.0.1:9999")
 
     def test_Dispatch_no_endpoint(self):
         app = fastapi.FastAPI()
         with self.assertRaises(ValueError):
-            Dispatch(app, endpoint="")
+            create_dispatch_instance(app, endpoint="")
 
     def test_Dispatch_endpoint_no_scheme(self):
         app = fastapi.FastAPI()
         with self.assertRaises(ValueError):
-            Dispatch(app, endpoint="127.0.0.1:9999")
+            create_dispatch_instance(app, endpoint="127.0.0.1:9999")
 
     def test_fastapi_simple_request(self):
         app = fastapi.FastAPI()
-        dispatch = Dispatch(app, endpoint="http://127.0.0.1:9999/")
+        dispatch = create_dispatch_instance(app, endpoint="http://127.0.0.1:9999/")
 
         @dispatch.primitive_function()
         def my_function(input: Input) -> Output:
@@ -101,7 +109,9 @@ def setUp(self):
         def root():
             return "OK"
 
-        self.dispatch = Dispatch(self.app, endpoint="https://127.0.0.1:9999")
+        self.dispatch = create_dispatch_instance(
+            self.app, endpoint="https://127.0.0.1:9999"
+        )
         self.http_client = TestClient(self.app)
         self.client = function_service.client(self.http_client)
 

tests/test_full.py

@@ -32,7 +32,11 @@ class TestFullFastapi(unittest.TestCase):
     def setUp(self):
         self.app = fastapi.FastAPI()
         self.dispatch = Dispatch(
-            self.app, endpoint="http://function-service", verification_key=public_key
+            self.app,
+            endpoint="http://function-service",
+            verification_key=public_key,
+            api_key="0000000000000000",
+            api_url="http://127.0.0.1:10000",
         )
 
         http_client = TestClient(self.app, base_url="http://dispatch-service")