T36032 User.username should be unique

api/db.py

@@ -33,6 +33,12 @@ def _get_collection(self, model):
         col = self.COLLECTIONS[model]
         return self._db[col]
 
+    async def create_indexes(self):
+        """Create indexes for models"""
+        for model in self.COLLECTIONS:
+            col = self._get_collection(model)
+            model.create_indexes(col)
+
     async def find_all(self, model):
         """Find all objects of a given model"""
         col = self._get_collection(model)

api/main.py

@@ -15,6 +15,7 @@
     SecurityScopes
 )
 from bson import ObjectId, errors
+from pymongo.errors import DuplicateKeyError
 from .auth import Authentication, Token
 from .db import Database
 from .models import Node, Regression, User, Password, get_model_from_kind
@@ -35,6 +36,12 @@ async def pubsub_startup():
     pubsub = await PubSub.create()
 
 
+@app.on_event('startup')
+async def create_indexes():
+    """Startup event handler to create database indexes"""
+    await db.create_indexes()
+
+
 async def get_current_user(
         security_scopes: SecurityScopes,
         token: str = Depends(auth.oauth2_scheme)):
@@ -86,6 +93,11 @@ async def post_user(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail=str(error)
         ) from error
+    except DuplicateKeyError as error:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=f"{username} is already taken. Try with different username."
+        ) from error
     await pubsub.publish_cloudevent('user', {'op': operation,
                                              'id': str(obj.id)})
     return obj

api/models.py

@@ -86,8 +86,12 @@ class DatabaseModel(ModelId):
     def update(self):
         """Method to update model"""
 
+    @classmethod
+    def create_indexes(cls, collection):
+        """Method to create indexes"""
+
 
-class User(ModelId):
+class User(DatabaseModel):
     """API user model"""
     username: str
     hashed_password: str = Field(description='Hash of the plaintext password')
@@ -100,6 +104,11 @@ class User(ModelId):
         description='True if superuser otherwise False'
     )
 
+    @classmethod
+    def create_indexes(cls, collection):
+        """Create an index to bind unique constraint to username"""
+        collection.create_index("username", unique=True)
+
 
 class KernelVersion(BaseModel):
     """Linux kernel version model"""

test/conftest.py

@@ -11,6 +11,7 @@
 """pytest fixtures for KernelCI API"""
 
 from unittest.mock import AsyncMock
+import asyncio
 import fakeredis.aioredis
 from fastapi.testclient import TestClient
 import pytest
@@ -35,6 +36,20 @@ def client():
     return TestClient(app)
 
 
+@pytest.fixture
+def event_loop():
+    """Create an instance of the default event loop for each test case.
+    This is a workaround to prevent the default event loop to be closed by
+    async pubsub tests. It was causing other tests unable to run.
+    The issue has already been reported here:
+    https://github.com/pytest-dev/pytest-asyncio/issues/371
+    """
+    loop = asyncio.new_event_loop()
+    asyncio.set_event_loop(loop)
+    yield loop
+    loop.close()
+
+
 @pytest.fixture
 def mock_db_create(mocker):
     """Mocks async call to Database class method used to create object"""