Fix: Unkwnown hashes raised exception

Problem: Many crawlers called URLs that do not exist on CRNs.

The current implementation raises an error when the hash of the VM cannot be found, which fills the logs on Sentry.

Solution: Return an HTTP Not Found status instead.

src/aleph/vm/orchestrator/views/__init__.py

@@ -11,7 +11,7 @@
 import aiodns
 import aiohttp
 from aiohttp import web
-from aiohttp.web_exceptions import HTTPNotFound
+from aiohttp.web_exceptions import HTTPBadRequest, HTTPNotFound
 from aleph_message.exceptions import UnknownHashError
 from aleph_message.models import ItemHash, MessageType
 from pydantic import ValidationError
@@ -65,7 +65,13 @@ async def run_code_from_path(request: web.Request) -> web.Response:
     path = request.match_info["suffix"]
     path = path if path.startswith("/") else f"/{path}"
 
-    message_ref = ItemHash(request.match_info["ref"])
+    try:
+        message_ref = ItemHash(request.match_info["ref"])
+    except UnknownHashError as e:
+        raise HTTPBadRequest(
+            reason="Invalid message reference", text=f"Invalid message reference: {request.match_info['ref']}"
+        ) from e
+
     pool: VmPool = request.app["vm_pool"]
     return await run_code_on_request(message_ref, path, pool, request)
 
@@ -98,8 +104,10 @@ async def run_code_from_hostname(request: web.Request) -> web.Response:
             try:
                 message_ref = ItemHash(await get_ref_from_dns(domain=f"_aleph-id.{request.host}"))
                 logger.debug(f"Using DNS TXT record to obtain '{message_ref}'")
-            except aiodns.error.DNSError as error:
-                raise HTTPNotFound(reason="Invalid message reference") from error
+            except aiodns.error.DNSError:
+                return HTTPNotFound(reason="Invalid message reference")
+            except UnknownHashError:
+                return HTTPNotFound(reason="Invalid message reference")
 
     pool = request.app["vm_pool"]
     return await run_code_on_request(message_ref, path, pool, request)

tests/supervisor/views/test_run_code.py

@@ -0,0 +1,46 @@
+import pytest
+from aiohttp import ClientResponseError, web
+from aiohttp.test_utils import make_mocked_request
+from aiohttp.web_exceptions import HTTPBadRequest
+from aleph_message.exceptions import UnknownHashError
+from aleph_message.models import ItemHash
+
+from aleph.vm.conf import settings
+from aleph.vm.orchestrator.views import run_code_from_path
+
+
+@pytest.mark.asyncio
+async def test_run_code_from_invalid_path(aiohttp_client):
+    """
+    Test that the run_code_from_path endpoint raises the right
+    error on invalid paths.
+    """
+    item_hash = "invalid-item-hash"
+    with pytest.raises(UnknownHashError):
+        assert ItemHash(item_hash).is_storage(item_hash)
+
+    app = web.Application()
+
+    app.router.add_route("*", "/vm/{ref}{suffix:.*}", run_code_from_path),
+    client = await aiohttp_client(app)
+
+    invalid_hash_request: web.Request = make_mocked_request(
+        "GET",
+        "/vm/" + item_hash,
+        match_info={
+            "ref": item_hash,
+            "suffix": "/some/suffix",
+        },
+        headers={"Host": settings.DOMAIN_NAME},
+        app=app,
+    )
+    with pytest.raises(HTTPBadRequest):
+        await run_code_from_path(invalid_hash_request)
+
+    # Calling the view from an HTTP client should result in a Bad Request error.
+    resp = await client.get("/vm/" + item_hash + "/some/suffix")
+    assert resp.status == HTTPBadRequest.status_code
+    text = await resp.text()
+    assert text == f"Invalid message reference: {item_hash}"
+    with pytest.raises(ClientResponseError):
+        resp.raise_for_status()