api: create database indexes on startup

Implement method Database.create_indexes to create
indexes on model collections. Implement
User.create_index to bind unique constraint
to username field.

Signed-off-by: Jeny Sadadia <[email protected]>

Author: Jeny Sadadia

api/db.py

@@ -32,6 +32,12 @@ 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

@@ -37,6 +37,12 @@ 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)):

api/models.py

@@ -81,8 +81,12 @@ class DatabaseModel(ModelId):
     def update(self):
         """Method to update model"""
 
+    @classmethod
+    def create_indexes(cls, collection):
+        """Method to create index"""
+
 
-class User(ModelId):
+class User(DatabaseModel):
     """API user model"""
     username: str
     hashed_password: str = Field(description='Hash of the plaintext password')
@@ -95,6 +99,11 @@ 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 Revision(BaseModel):
     """Linux kernel Git revision model"""