Merge branch 'refs/heads/main' into feat/serve-env-doc

Author: matthewelwell

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.11.2
+    rev: v0.11.6
     hooks:
       - id: ruff
       - id: ruff-format

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.12-slim as application
+FROM python:3.12-slim AS application
 
 WORKDIR /app
 
@@ -10,7 +10,6 @@ ENV PATH="$VIRTUAL_ENV/bin:$PATH"
 COPY src /app/src
 COPY requirements.lock pyproject.toml /app/
 RUN pip install --no-cache-dir -r requirements.lock
-RUN edge-proxy-render-config
 
 EXPOSE 8000
 

pyproject.toml

@@ -36,9 +36,6 @@ dev-dependencies = [
 [tool.ruff]
 line-length = 88
 
-[tool.ruff.lint.isort]
-known-first-party = ['fastapi_utils']
-
 [tool.ruff.lint.mccabe]
 max-complexity = 10
 

src/edge_proxy/environments.py

@@ -1,8 +1,10 @@
 from typing import Any, Optional
 from datetime import datetime
+from email.utils import formatdate
 from functools import lru_cache
 
 import httpx
+import starlette.status
 import structlog
 from flag_engine.engine import (
     get_environment_feature_state,
@@ -22,7 +24,7 @@
     map_traits_to_response_data,
 )
 from edge_proxy.models import IdentityWithTraits
-from edge_proxy.settings import AppSettings
+from edge_proxy.settings import AppSettings, EnvironmentKeyPair
 
 logger = structlog.get_logger(__name__)
 
@@ -58,9 +60,7 @@ async def refresh_environment_caches(self):
         received_error = False
         for key_pair in self.settings.environment_key_pairs:
             try:
-                environment_document = await self._fetch_document(
-                    key_pair.server_side_key
-                )
+                environment_document = await self._fetch_document(key_pair)
                 if self.cache.put_environment(
                     environment_api_key=key_pair.client_side_key,
                     environment_document=environment_document,
@@ -156,11 +156,39 @@ def get_environment(
                         return environment_document
             raise FlagsmithUnknownKeyError(server_side_key)
 
-    async def _fetch_document(self, server_side_key: str) -> dict[str, Any]:
+    async def _fetch_document(self, key_pair: EnvironmentKeyPair) -> dict[str, Any]:
+        headers = {
+            "X-Environment-Key": key_pair.server_side_key,
+        }
+        environment_document = self.cache.get_environment(
+            environment_api_key=key_pair.client_side_key
+        )
+        if environment_document:
+            updated_at: str = environment_document.get("updated_at")
+            if updated_at:
+                try:
+                    epoch_seconds = datetime.fromisoformat(updated_at).timestamp()
+                    # Same implementation as https://docs.djangoproject.com/en/4.2/ref/utils/#django.utils.http.http_date
+                    headers["If-Modified-Since"] = formatdate(
+                        epoch_seconds, usegmt=True
+                    )
+                except ValueError:
+                    logger.warning(
+                        f"failed to parse updated_at, environment={key_pair.client_side_key} updated_at={updated_at}"
+                    )
+            else:
+                logger.warning(
+                    f"received environment with no updated_at: {key_pair.client_side_key}"
+                )
         response = await self._client.get(
             url=f"{self.settings.api_url}/environment-document/",
-            headers={"X-Environment-Key": server_side_key},
+            headers=headers,
         )
+        if response.status_code == starlette.status.HTTP_304_NOT_MODIFIED:
+            assert environment_document, (
+                f"GET /environment-document returned 304 without a cached document. environment={key_pair.client_side_key}"
+            )
+            return environment_document
         response.raise_for_status()
         return orjson.loads(response.text)
 

src/edge_proxy/server.py

@@ -1,14 +1,14 @@
 from datetime import datetime, timedelta
+import asyncio
 
 import httpx
-import structlog
+from contextlib import asynccontextmanager
 from fastapi import FastAPI, Header
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.middleware.gzip import GZipMiddleware
 from fastapi.responses import ORJSONResponse, Response
 
 from edge_proxy.health_check.responses import HealthCheckResponse
-from fastapi_utils.tasks import repeat_every
 
 from edge_proxy.cache import LocalMemEnvironmentsCache
 from edge_proxy.environments import EnvironmentService
@@ -24,7 +24,23 @@
     httpx.AsyncClient(timeout=settings.api_poll_timeout_seconds),
     settings,
 )
-app = FastAPI()
+
+
+async def poll_environments():
+    while True:
+        await environment_service.refresh_environment_caches()
+        await asyncio.sleep(settings.api_poll_frequency_seconds)
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    await environment_service.refresh_environment_caches()
+    poll = asyncio.create_task(poll_environments())
+    yield
+    poll.cancel()
+
+
+app = FastAPI(lifespan=lifespan)
 
 
 @app.exception_handler(FlagsmithUnknownKeyError)
@@ -120,16 +136,6 @@ async def environment_document(
     return ORJSONResponse(status_code=401, content=None)
 
 
-@app.on_event("startup")
-@repeat_every(
-    seconds=settings.api_poll_frequency_seconds,
-    raise_exceptions=True,
-    logger=structlog.get_logger(__name__),
-)
-async def refresh_cache():
-    await environment_service.refresh_environment_caches()
-
-
 app.add_middleware(
     CORSMiddleware,
     allow_origins=settings.allow_origins,

src/edge_proxy/settings.py

@@ -59,7 +59,13 @@ def json_config_settings_source() -> dict[str, Any]:
     at the project's root.
     """
     encoding = "utf-8"
-    return json.loads(Path(CONFIG_PATH).read_text(encoding))
+    try:
+        config = json.loads(Path(CONFIG_PATH).read_text(encoding))
+        logger.info(f"Loaded configuration from {CONFIG_PATH}")
+        return config
+    except FileNotFoundError:
+        logger.info(f"Configuration file at {CONFIG_PATH} not found")
+        return {}
 
 
 class EnvironmentKeyPair(BaseModel):

src/fastapi_utils/LICENSE

@@ -91,6 +91,7 @@
 
 
 environment_1 = {
+    "updated_at": "1969-07-20T20:17:40Z",
     "feature_states": [
         _environment_feature_state_1,
         _environment_feature_state_2,