i am first

Dockerfile

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+FROM python:3.10
+RUN pip install fastapi uvicorn
+WORKDIR /app
+COPY server.py /app/
+ENTRYPOINT ["python3", "server.py"]

docker-compose.yaml

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+services:
+  node_exporter_relay:
+    build: ./
+    environment:
+      - NEC_HOST=0.0.0.0
+      - NEC_PORT=9100
+      - DEAD_AFTER=60
+    ports:
+      - 9100:9100
+    env_file:
+      - .env

server.py

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+from fastapi import FastAPI
+from fastapi import Request
+from fastapi.responses import Response
+from fastapi import BackgroundTasks
+import uvicorn
+import os
+from time import time
+import asyncio
+
+class Collector:
+    app = FastAPI()
+    secrets = []
+    hosts = []
+    store = {}
+    def __init__(self) -> None:
+        self.secrets = os.getenv("KEYS", "secret").split(",")
+        self.hosts = os.getenv("HOSTS", "srv").split(",")
+        self.dead_after = int(os.getenv("DEAD_AFTER", "60"))
+        self.build_routes()
+
+    def check_headers(self, request: Request):
+        if not request.headers.get("Secret", ""):
+            print("secret empty")
+            return Response(status_code=400)
+        if not request.headers.get("Host", ""):
+            print("host empty")
+            return Response(status_code=400)
+
+        if not request.headers.get("Secret", "") in self.secrets:
+            return Response(status_code=400)
+
+        if not request.headers.get("Host", "").split(":")[0] in self.hosts:
+            print(request.headers.get("Host", ""))
+            print(request.headers)
+            return Response(status_code=400)
+
+        return None
+
+    async def deadline(self, host):
+        await asyncio.sleep(self.dead_after)
+        if host in self.store:
+            if time()+1 - self.store[host]['timestamp'] > self.dead_after:
+                print(f"{host} is dead")
+                del self.store[host]
+
+
+    def build_routes(self):
+        @self.app.get("/metrics")
+        async def get(request: Request):
+            response: Response = self.check_headers(request)
+            if response:
+                return response
+
+            if request.headers.get("Host", "").split(":")[0] in self.store and self.store[request.headers.get("Host", "").split(":")[0]]['data']:
+                return Response(content=self.store[request.headers.get("Host", "").split(":")[0]]['data'], status_code=200)
+            else:
+                return Response(status_code=404)
+
+        @self.app.post("/metrics")
+        async def post(request: Request, background_tasks: BackgroundTasks):
+            response: Response = self.check_headers(request)
+            if response:
+                return response
+
+            host = request.headers.get("Host", "").split(":")[0]
+
+            self.store[host] = {
+                "data":await request.body(), 
+                "timestamp": time()
+                }
+
+            background_tasks.add_task(self.deadline, host)
+            return Response(status_code=200)
+
+if __name__ == "__main__":
+    collector = Collector()
+    uvicorn.run(collector.app, host = os.getenv("NEC_HOST", "0.0.0.0"), port = int(os.getenv("NEC_PORT", "9100")))