Add request.id

sanic/config.py

@@ -40,6 +40,7 @@
     "REAL_IP_HEADER": None,
     "PROXIES_COUNT": None,
     "FORWARDED_FOR_HEADER": "X-Forwarded-For",
+    "REQUEST_ID_HEADER": "X-Request-ID",
     "FALLBACK_ERROR_FORMAT": "html",
     "REGISTER": True,
 }

sanic/request.py

@@ -1,4 +1,5 @@
 import email.utils
+import uuid
 
 from collections import defaultdict, namedtuple
 from http.cookies import SimpleCookie
@@ -51,6 +52,7 @@ class Request:
     __slots__ = (
         "__weakref__",
         "_cookies",
+        "_id",
         "_ip",
         "_parsed_url",
         "_port",
@@ -82,6 +84,7 @@ def __init__(self, url_bytes, headers, version, method, transport, app):
         self.raw_url = url_bytes
         # TODO: Content-Encoding detection
         self._parsed_url = parse_url(url_bytes)
+        self._id = None
         self.app = app
 
         self.headers = headers
@@ -110,6 +113,10 @@ def __repr__(self):
         class_name = self.__class__.__name__
         return f"<{class_name}: {self.method} {self.path}>"
 
+    @classmethod
+    def generate_id(*_):
+        return uuid.uuid4()
+
     async def respond(
         self, response=None, *, status=200, headers=None, content_type=None
     ):
@@ -148,6 +155,26 @@ async def receive_body(self):
         if not self.body:
             self.body = b"".join([data async for data in self.stream])
 
+    @property
+    def id(self):
+        if not self._id:
+            self._id = self.headers.get(
+                self.app.config.REQUEST_ID_HEADER,
+                self.__class__.generate_id(self),
+            )
+
+            # Try casting to a UUID or an integer
+            if isinstance(self._id, str):
+                try:
+                    self._id = uuid.UUID(self._id)
+                except ValueError:
+                    try:
+                        self._id = int(self._id)
+                    except ValueError:
+                        ...
+
+        return self._id
+
     @property
     def json(self):
         if self.parsed_json is None:

tests/test_request.py

@@ -0,0 +1,76 @@
+from unittest.mock import Mock
+from uuid import UUID, uuid4
+
+import pytest
+
+from sanic import Sanic, response
+from sanic.request import Request, uuid
+
+
+def test_no_request_id_not_called(monkeypatch):
+    monkeypatch.setattr(uuid, "uuid4", Mock())
+    request = Request(b"/", {}, None, "GET", None, None)
+
+    assert request._id is None
+    uuid.uuid4.assert_not_called()
+
+
+def test_request_id_generates_from_request(monkeypatch):
+    monkeypatch.setattr(Request, "generate_id", Mock())
+    Request.generate_id.return_value = 1
+    request = Request(b"/", {}, None, "GET", None, Mock())
+
+    for _ in range(10):
+        request.id
+    Request.generate_id.assert_called_once_with(request)
+
+
+def test_request_id_defaults_uuid():
+    request = Request(b"/", {}, None, "GET", None, Mock())
+
+    assert isinstance(request.id, UUID)
+
+    # Makes sure that it has been cached and not called multiple times
+    assert request.id == request.id == request._id
+
+
+@pytest.mark.parametrize(
+    "request_id,expected_type",
+    (
+        (99, int),
+        (uuid4(), UUID),
+        ("foo", str),
+    ),
+)
+def test_request_id(request_id, expected_type):
+    app = Sanic("req-generator")
+
+    @app.get("/")
+    async def get(request):
+        return response.empty()
+
+    request, _ = app.test_client.get(
+        "/", headers={"X-REQUEST-ID": f"{request_id}"}
+    )
+    assert request.id == request_id
+    assert type(request.id) == expected_type
+
+
+def test_custom_generator():
+    REQUEST_ID = 99
+
+    class FooRequest(Request):
+        @classmethod
+        def generate_id(cls, request):
+            return int(request.headers["some-other-request-id"]) * 2
+
+    app = Sanic("req-generator", request_class=FooRequest)
+
+    @app.get("/")
+    async def get(request):
+        return response.empty()
+
+    request, _ = app.test_client.get(
+        "/", headers={"SOME-OTHER-REQUEST-ID": f"{REQUEST_ID}"}
+    )
+    assert request.id == REQUEST_ID * 2