Enforce typing with mypy (#341)

* Enforce typing with mypy

.circleci/config.yml

@@ -29,5 +29,6 @@ jobs:
           key: 'tox-{{ checksum "requirements/base.txt" }}-{{ checksum "requirements/testing.txt" }}-{{ checksum "requirements/development.txt" }}-{{ checksum "requirements/production.txt" }}'
           paths:
             - .tox
+            - .mypy_cache
       - store_test_results:
           path: .tox/py37/artifacts/

.gitignore

@@ -3,6 +3,7 @@
 .env
 .tox/
 .venv
+.mypy_cache
 artifacts/
 
 # Editors

pyslackersweb/__init__.py

@@ -25,9 +25,9 @@
 )
 
 
-async def index(request: web.Request) -> None:
+async def index(request: web.Request) -> web.Response:
     location = request.app["website_app"].router["index"].url_for()
-    raise web.HTTPFound(location=location)
+    return web.HTTPFound(location=location)
 
 
 async def app_factory() -> web.Application:

pyslackersweb/website/__init__.py

@@ -39,7 +39,7 @@ def app_factory() -> web.Application:
     jinja2_setup(
         website,
         context_processors=[request_processor],
-        loader=FileSystemLoader([package_root / "templates"]),
+        loader=FileSystemLoader(str(package_root / "templates")),
         filters={"formatted_number": formatted_number, **FILTERS},
     )
 

pyslackersweb/website/contexts.py

@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta
+from typing import AsyncGenerator
 
 from aiohttp import ClientSession, web
 from apscheduler.schedulers.asyncio import AsyncIOScheduler
@@ -7,7 +8,7 @@
 from . import tasks
 
 
-async def background_jobs(app: web.Application) -> None:
+async def background_jobs(app: web.Application) -> AsyncGenerator[None, None]:
     scheduler = app["scheduler"]
 
     scheduler.add_job(
@@ -37,18 +38,18 @@ async def background_jobs(app: web.Application) -> None:
     yield
 
 
-async def client_session(app: web.Application) -> None:
+async def client_session(app: web.Application) -> AsyncGenerator[None, None]:
     async with ClientSession(raise_for_status=True) as session:
         app["client_session"] = session
         yield
 
 
-async def slack_client(app: web.Application) -> None:
+async def slack_client(app: web.Application) -> AsyncGenerator[None, None]:
     app["slack_client"] = SlackAPI(token=app["slack_token"], session=app["client_session"])
     yield
 
 
-async def apscheduler(app: web.Application):
+async def apscheduler(app: web.Application) -> AsyncGenerator[None, None]:
     app["scheduler"] = scheduler = AsyncIOScheduler()
     scheduler.start()
 

pyslackersweb/website/middleware.py

@@ -1,3 +1,5 @@
+import typing
+
 from uuid import uuid4
 
 from aiohttp import web
@@ -6,11 +8,14 @@
 
 
 @web.middleware
-async def request_context_middleware(request, handler):
+async def request_context_middleware(
+    request: web.Request,
+    handler: typing.Callable[[web.Request], typing.Awaitable[web.StreamResponse]],
+):
     """
     Middleware to set a context variable for the request/response cycle.
     """
-    token = REQUEST_CONTEXT.set(str(uuid4()))
+    token = REQUEST_CONTEXT.set(uuid4())
     try:
         return await handler(request)
     finally:

pyslackersweb/website/tasks.py

@@ -1,7 +1,7 @@
 import dataclasses
 import logging
 from collections import Counter
-from typing import List
+from typing import List, Awaitable, Callable
 
 import slack
 
@@ -31,7 +31,7 @@ class Channel:
     members: int
 
 
-def sync_github_repositories(app: web.Application):
+def sync_github_repositories(app: web.Application) -> Callable[[], Awaitable[None]]:
     session = app["client_session"]
 
     async def _sync_github() -> None:
@@ -70,10 +70,10 @@ async def _sync_github() -> None:
     return _sync_github
 
 
-def sync_slack_users(app: web.Application):
+def sync_slack_users(app: web.Application) -> Callable[[], Awaitable[None]]:
     client = app["slack_client"]
 
-    async def _sync_slack_users():
+    async def _sync_slack_users() -> None:
         logger.debug("Refreshing slack users cache.")
         oauth_token = app["slack_token"]
 
@@ -82,7 +82,7 @@ async def _sync_slack_users():
             return
 
         try:
-            counter = Counter()
+            counter: Counter = Counter()
             async for user in client.iter(slack.methods.USERS_LIST, minimum_time=3):
                 if user["deleted"] or user["is_bot"] or not user["tz"]:
                     continue
@@ -106,10 +106,10 @@ async def _sync_slack_users():
     return _sync_slack_users
 
 
-def sync_slack_channels(app: web.Application):
+def sync_slack_channels(app: web.Application) -> Callable[[], Awaitable[None]]:
     client = app["slack_client"]
 
-    async def _sync_slack_channel():
+    async def _sync_slack_channel() -> None:
         logger.debug("Refreshing slack channels cache.")
         oauth_token = app["slack_token"]
 

pyslackersweb/website/util/context.py

@@ -1,4 +1,5 @@
 import contextvars
 
+from uuid import uuid4
 
-REQUEST_CONTEXT = contextvars.ContextVar("REQUEST_CONTEXT", default=None)
+REQUEST_CONTEXT = contextvars.ContextVar("REQUEST_CONTEXT", default=uuid4())

requirements/testing.txt

@@ -6,3 +6,4 @@ pytest
 pytest-cov
 pytest-aiohttp
 tox==3.12.1
+mypy==0.710

tox.ini

@@ -8,9 +8,10 @@ commands = python -m pytest --verbose --cov=pyslackersweb/ --cov-report=term-mis
 
 [testenv:lint]
 deps =
-    -r requirements/production.txt
-    pylint
-commands = pylint pyslackersweb
+    -r requirements/testing.txt
+commands =
+    pylint pyslackersweb
+    mypy . --ignore-missing-imports
 
 [testenv:fmt]
 deps = black