Middleware starlettify (#8)

drop with_plugins from middleware

Author: tomwojcik

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.5.0
+    hooks:
+      - id: check-merge-conflict
+      - id: debug-statements
+      - id: no-commit-to-branch
+
+  - repo: https://github.com/ambv/black
+    rev: 19.10b0
+    hooks:
+      - id: black

README.md

@@ -3,14 +3,11 @@
 [![PyPI version](https://badge.fury.io/py/starlette-context.svg)](https://badge.fury.io/py/starlette-context)
 [![PyPI license](https://img.shields.io/pypi/l/ansicolortags.svg)](https://pypi.python.org/pypi/ansicolortags/)
 [![codecov](https://codecov.io/gh/tomwojcik/starlette-context/branch/master/graph/badge.svg)](https://codecov.io/gh/tomwojcik/starlette-context)
+[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 
 # starlette context
 Middleware for Starlette that allows you to store and access the context data of a request. Can be used with logging so logs automatically use request headers such as x-request-id or x-correlation-id.
 
-### Motivation
-
-I use FastAPI. I needed something that will allow me to log with context data. Right now I can just `log.info('Message')` and I have log (in ELK) with request id and correlation id. I don't even think about passing this data to logger. It's there automatically.
-  
 ### Installation 
 
 `$ pip install starlette-context`
@@ -30,33 +27,39 @@ https://github.com/MagicStack/contextvars
 All other dependencies from `requirements-dev.txt` are only needed to run tests or examples. Test/dev env is dockerized if you want to try them yourself.
 
 ### Example
-**examples/simple_examples/set_context_in_middleware.py**
 
 ```python
 from starlette.applications import Starlette
+from starlette.middleware import Middleware
 from starlette.requests import Request
 from starlette.responses import JSONResponse
 
 import uvicorn
 from starlette_context import context, plugins
 from starlette_context.middleware import ContextMiddleware
 
+middleware = [
+    Middleware(
+        ContextMiddleware,
+        plugins=(
+            plugins.RequestIdPlugin(),
+            plugins.CorrelationIdPlugin()
+        )
+    )
+]
 
-app = Starlette(debug=True)
-app.add_middleware(ContextMiddleware.with_plugins(  # easily extensible
-    plugins.RequestIdPlugin,  # request id
-    plugins.CorrelationIdPlugin  # correlation id
-))
+app = Starlette(middleware=middleware)
 
 
-@app.route('/')
+@app.route("/")
 async def index(request: Request):
     return JSONResponse(context.data)
 
 
 uvicorn.run(app, host="0.0.0.0")
+
 ```
-In this example the response containes a json with
+In this example the response contains a json with
 ```json
 {
   "X-Correlation-ID":"5ca2f0b43115461bad07ccae5976a990",

examples/example_with_exception_handling/app.py

@@ -2,6 +2,7 @@
 
 from starlette.applications import Starlette
 from starlette.exceptions import HTTPException
+from starlette.middleware import Middleware
 from starlette.middleware.base import (
     BaseHTTPMiddleware,
     RequestResponseEndpoint,
@@ -14,15 +15,6 @@
 from examples.example_with_exception_handling.logger import log
 from starlette_context import middleware, plugins
 
-app = Starlette(debug=True)
-
-
-@app.route("/")
-async def index(request: Request):
-    log.info("pre exception")
-    _ = 1 / 0
-    return JSONResponse({"wont reach this place": None})
-
 
 class ExceptionHandlingMiddleware(BaseHTTPMiddleware):
     @staticmethod
@@ -54,15 +46,28 @@ async def dispatch(
 
 
 # middleware order is important! exc handler has to be topmost
+middleware = [
+    Middleware(
+        middleware.ContextMiddleware,
+        plugins=(
+            plugins.CorrelationIdPlugin(),
+            plugins.RequestIdPlugin(),
+            plugins.DateHeaderPlugin(),
+            plugins.ForwardedForPlugin(),
+            plugins.UserAgentPlugin(),
+        ),
+    ),
+    Middleware(ExceptionHandlingMiddleware),
+]
+
+app = Starlette(debug=True, middleware=middleware)
+
+
+@app.route("/")
+async def index(request: Request):
+    log.info("pre exception")
+    _ = 1 / 0
+    return JSONResponse({"wont reach this place": None})
+
 
-app.add_middleware(ExceptionHandlingMiddleware)
-app.add_middleware(
-    middleware.ContextMiddleware.with_plugins(
-        plugins.UserAgentPlugin,
-        plugins.ForwardedForPlugin,
-        plugins.DateHeaderPlugin,
-        plugins.RequestIdPlugin,
-        plugins.CorrelationIdPlugin,
-    )
-)
 uvicorn.run(app, host="0.0.0.0")

examples/example_with_logger/app.py

@@ -1,27 +1,32 @@
 from starlette.applications import Starlette
+from starlette.middleware import Middleware
 from starlette.requests import Request
 from starlette.responses import JSONResponse
 
 import uvicorn
 from examples.example_with_logger.logger import log
 from starlette_context import context, middleware, plugins
 
-app = Starlette(debug=True)
+middleware = [
+    Middleware(
+        middleware.ContextMiddleware,
+        plugins=(
+            plugins.CorrelationIdPlugin(),
+            plugins.RequestIdPlugin(),
+            plugins.DateHeaderPlugin(),
+            plugins.ForwardedForPlugin(),
+            plugins.UserAgentPlugin(),
+        ),
+    )
+]
+
+app = Starlette(debug=True, middleware=middleware)
 
 
 @app.route("/")
-async def index(request: Request):
+async def index(_: Request):
     log.info("Log from view")
     return JSONResponse(context.data)
 
 
-app.add_middleware(
-    middleware.ContextMiddleware.with_plugins(
-        plugins.CorrelationIdPlugin,
-        plugins.RequestIdPlugin,
-        plugins.DateHeaderPlugin,
-        plugins.ForwardedForPlugin,
-        plugins.UserAgentPlugin,
-    )
-)
 uvicorn.run(app, host="0.0.0.0")

examples/simple_examples/set_context_in_middleware.py

@@ -1,17 +1,20 @@
 from starlette.applications import Starlette
+from starlette.middleware import Middleware
 from starlette.requests import Request
 from starlette.responses import JSONResponse
 
 import uvicorn
 from starlette_context import context, plugins
 from starlette_context.middleware import ContextMiddleware
 
-app = Starlette(debug=True)
-app.add_middleware(
-    ContextMiddleware.with_plugins(
-        plugins.RequestIdPlugin, plugins.CorrelationIdPlugin
+middleware = [
+    Middleware(
+        ContextMiddleware,
+        plugins=(plugins.RequestIdPlugin(), plugins.CorrelationIdPlugin()),
     )
-)
+]
+
+app = Starlette(debug=True, middleware=middleware)
 
 
 @app.route("/")

requirements-dev.txt

@@ -20,3 +20,4 @@ autoflake
 mypy
 black
 isort
+pre-commit-hooks

setup.py

@@ -2,7 +2,7 @@
 
 import setuptools
 
-VERSION = "0.2.0"
+VERSION = "0.2.1"
 
 
 def get_long_description():

starlette_context/ctx.py

@@ -23,7 +23,14 @@ def data(self) -> dict:
         """
         Dump this to json. Object itself it not serializable.
         """
-        return _request_scope_context_storage.get()
+        try:
+            return _request_scope_context_storage.get()
+        except LookupError as e:
+            raise RuntimeError(
+                "You didn't use ContextMiddleware or "
+                "you're trying to access `context` object "
+                "outside of the request-response cycle."
+            ) from e
 
     def copy(self) -> dict:
         """

starlette_context/middleware.py

@@ -1,5 +1,5 @@
 from contextvars import Token
-from typing import List, Type, Union
+from typing import Optional, Sequence
 
 from starlette.middleware.base import (
     BaseHTTPMiddleware,
@@ -18,20 +18,13 @@ class ContextMiddleware(BaseHTTPMiddleware):
     If not used, you won't be able to use context object.
     """
 
-    plugins: List[Plugin] = []
-
-    @classmethod
-    def with_plugins(
-        cls, *plugins: Union[Plugin, Type[Plugin]]
-    ) -> Type["ContextMiddleware"]:
-        for plugin in plugins:
-            if isinstance(plugin, Plugin):
-                cls.plugins.append(plugin)
-            elif issubclass(plugin, Plugin):
-                cls.plugins.append(plugin())
-            else:
-                raise TypeError("Only plugins are allowed.")
-        return cls
+    def __init__(
+        self, plugins: Optional[Sequence[Plugin]] = None, *args, **kwargs
+    ) -> None:
+        super().__init__(*args, **kwargs)
+        self.plugins = plugins or ()
+        if not all([isinstance(plugin, Plugin) for plugin in self.plugins]):
+            raise TypeError("This is not a valid instance of a plugin")
 
     async def set_context(self, request: Request) -> dict:
         """

tests/conftest.py

@@ -32,7 +32,7 @@ def headers():
 
 @pytest.fixture(scope="function", autouse=True)
 def mocked_middleware() -> middleware.ContextMiddleware:
-    return middleware.ContextMiddleware(MagicMock())
+    return middleware.ContextMiddleware(app=MagicMock())
 
 
 @pytest.fixture(scope="function", autouse=True)