Joseph Doherty
8b6d326824
Adds an env2-owned HTTP sink container (scadabridge-env2-sfsink) whose 503 mode makes ExternalSystem.CachedCall buffer, and an EnvSoak template whose 2 s SoakTick sends one tick-numbered cached call, so loss and duplicates are countable at the sink. Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
88 lines
3.0 KiB
Python
88 lines
3.0 KiB
Python
"""Tiny HTTP sink for the env2 store-and-forward soak (ScadaBridge#116).
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POST/PUT <any path> -> 200 and the body is appended to /data/received.jsonl
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(one line: receive time, client IP, path, body), or
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503 without recording while /data/mode contains "fail".
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GET /stats -> {"mode": ..., "received": <lines>}
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GET /received -> the raw received.jsonl
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The mode switch is how the soak makes ScadaBridge buffer: a 503 is a transient
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failure, so ExternalSystem.CachedCall parks the call in store-and-forward and
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retries it; setting the mode back to "ok" lets the active node drain the buffer.
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docker exec scadabridge-env2-sfsink sh -c 'echo fail > /data/mode'
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docker exec scadabridge-env2-sfsink sh -c 'echo ok > /data/mode'
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"""
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import json
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import os
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import threading
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import time
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from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
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DATA = "/data"
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LOG = os.path.join(DATA, "received.jsonl")
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MODE = os.path.join(DATA, "mode")
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LOCK = threading.Lock()
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def mode():
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try:
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with open(MODE) as f:
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return f.read().strip() or "ok"
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except OSError:
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return "ok"
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class Handler(BaseHTTPRequestHandler):
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def _reply(self, code, obj):
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body = json.dumps(obj).encode()
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self.send_response(code)
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self.send_header("Content-Type", "application/json")
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self.send_header("Content-Length", str(len(body)))
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self.end_headers()
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self.wfile.write(body)
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def _record(self):
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length = int(self.headers.get("Content-Length") or 0)
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raw = self.rfile.read(length).decode("utf-8", "replace") if length else ""
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if mode() == "fail":
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self._reply(503, {"error": "sink in fail mode"})
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return
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try:
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body = json.loads(raw) if raw else None
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except ValueError:
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body = raw
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line = json.dumps({"at": time.time(), "client": self.client_address[0],
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"path": self.path, "body": body})
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with LOCK, open(LOG, "a") as f:
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f.write(line + "\n")
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self._reply(200, {"ok": True})
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do_POST = _record
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do_PUT = _record
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def do_GET(self):
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if self.path == "/stats":
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n = 0
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if os.path.exists(LOG):
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with open(LOG) as f:
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n = sum(1 for _ in f)
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self._reply(200, {"mode": mode(), "received": n})
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elif self.path == "/received":
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data = open(LOG).read() if os.path.exists(LOG) else ""
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self.send_response(200)
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self.send_header("Content-Type", "application/x-ndjson")
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self.send_header("Content-Length", str(len(data.encode())))
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self.end_headers()
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self.wfile.write(data.encode())
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else:
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self._reply(404, {"error": "not found"})
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def log_message(self, fmt, *args): # keep the container log quiet
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pass
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if __name__ == "__main__":
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os.makedirs(DATA, exist_ok=True)
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ThreadingHTTPServer(("0.0.0.0", 5300), Handler).serve_forever()
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