feat: expose user agent

harp/__init__.py

@@ -30,8 +30,20 @@
 import os
 from subprocess import check_output
 
+from packaging.version import InvalidVersion, Version
+
 ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 
+
+def _parse_version(version: str, /, *, default=None) -> Version:
+    try:
+        return Version(version)
+    except InvalidVersion:
+        if "-" in version:
+            return _parse_version(version.rsplit("-", 1)[0], default=default)
+        return default
+
+
 # last release
 __title__ = "Core"
 __version__ = "0.4.0"
@@ -42,13 +54,16 @@
     with open(os.path.join(ROOT_DIR, "version.txt")) as f:
         __version__ = f.read().strip()
 
+__parsed_version__ = _parse_version(__version__)
+
 # override with current development version/revision if available (disabled in CI, for docs)
 if not os.environ.get("CI", False) and os.path.exists(os.path.join(ROOT_DIR, ".git")):
     __revision__ = check_output(["git", "rev-parse", "HEAD"], cwd=ROOT_DIR).decode("utf-8").strip()
     try:
         __version__ = (
             check_output(["git", "describe", "--tags", "--always", "--dirty"], cwd=ROOT_DIR).decode("utf-8").strip()
         )
+        __parsed_version__ = _parse_version(__version__, default=__parsed_version__)
     except Exception:
         __version__ = __revision__[:7]
 
@@ -75,11 +90,14 @@ def run(config: Config):
     asyncio.run(server.serve())
 
 
+print(__parsed_version__)
+
 __all__ = [
     "Config",
     "ROOT_DIR",
     "__revision__",
     "__version__",
+    "__parsed_version__",
     "get_logger",
     "run",
 ]

harp_apps/proxy/controllers.py

@@ -7,7 +7,7 @@
 from httpx import AsyncClient, codes
 from whistle import IAsyncEventDispatcher
 
-from harp import get_logger
+from harp import __parsed_version__, get_logger
 from harp.asgi.events import MessageEvent, TransactionEvent
 from harp.http import HttpRequest, HttpResponse
 from harp.http.requests import WrappedHttpRequest
@@ -24,6 +24,9 @@ class HttpProxyController:
     """Controller name, also refered as endpoint name (for example in
     :class:`Transaction <harp.models.Transaction>`)."""
 
+    user_agent: str = None
+    """User agent to use when proxying requests (will default to harp/<version>)."""
+
     _dispatcher: Optional[IAsyncEventDispatcher] = None
     """Event dispatcher for this controller."""
 
@@ -43,6 +46,10 @@ def __init__(self, url, *, http_client: AsyncClient, dispatcher=None, name=None)
 
         self.parsed_url = urlparse(self.url)
 
+        # we only expose minimal information about the exact version
+        if not self.user_agent:
+            self.user_agent = f"harp/{__parsed_version__.major}.{__parsed_version__.minor}"
+
     async def adispatch(self, event_id, event=None):
         """
         Shortcut method to dispatch an event using the controller's dispatcher, if there is one.
@@ -74,6 +81,10 @@ async def __call__(self, request: HttpRequest):
             if header.startswith("x-harp-"):
                 tags[header[7:]] = request.headers.pop(header)
 
+        # override user agent (later, may be customizable behavior)
+        if self.user_agent:
+            request.headers["user-agent"] = self.user_agent
+
         transaction = await self._create_transaction_from_request(request, tags=tags)
         await request.join()
         url = urljoin(self.url, request.path) + (f"?{urlencode(request.query)}" if request.query else "")

harp_apps/proxy/tests/test_controllers_http_proxy.py

@@ -1,4 +1,4 @@
-from unittest.mock import ANY, AsyncMock
+from unittest.mock import ANY, AsyncMock, patch
 
 import pytest
 import respx
@@ -22,6 +22,12 @@ def dispatcher(self):
 class HttpProxyControllerTestFixtureMixin(ControllerTestFixtureMixin):
     ControllerType = HttpProxyController
 
+    @pytest.fixture(autouse=True)
+    def setup(self):
+        # forces the user agent to be a known value, even if versions are incremented
+        with patch("harp_apps.proxy.controllers.HttpProxyController.user_agent", "test/1.0"):
+            yield
+
     def mock_http_endpoint(self, url, /, *, status=200, content=""):
         """Make sure you decorate your tests function using this with respx.mock decorator, otherwise the real network
         will be called and you may have some headaches..."""
@@ -117,14 +123,14 @@ async def test_basic_get(self, database_url, dispatcher: AsyncEventDispatcher):
         }
 
         # request
-        assert (await storage.get_blob(request.headers)).data == b"host: example.com"
+        assert (await storage.get_blob(request.headers)).data == b"host: example.com\nuser-agent: test/1.0"
         assert (await storage.get_blob(request.body)).data == b""
         assert request.to_dict(omit_none=False) == {
             "id": 1,
             "transaction_id": ANY,
             "kind": "request",
             "summary": "GET / HTTP/1.1",
-            "headers": "5b5fa853da2315f3639fd85d183307b0db6fcfa9",
+            "headers": "ecd46dd3023926417e1205b219aec4c2b9e0dab0",
             "body": "adc83b19e793491b1c6ea0fd8b46cd9f32e592fc",
             "created_at": ANY,
         }
@@ -175,15 +181,15 @@ async def test_get_with_tags(self, database_url, dispatcher: AsyncEventDispatche
         }
 
         assert (await storage.get_blob(request.headers)).data == (
-            b"accept: application/json\nvary: custom\nhost: example.com"
+            b"accept: application/json\nvary: custom\nhost: example.com\nuser-agent: test/1.0"
         )
         assert (await storage.get_blob(request.body)).data == b""
         assert request.to_dict(omit_none=False) == {
             "id": 1,
             "transaction_id": ANY,
             "kind": "request",
             "summary": "GET / HTTP/1.1",
-            "headers": "3215728a5aed81014fd90307f48fe439e785e64a",
+            "headers": "885ad9e4633a3c038f13c32e4ee48fc9221c0152",
             "body": "adc83b19e793491b1c6ea0fd8b46cd9f32e592fc",
             "created_at": ANY,
         }