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Monorepo for wisp.place. A static site hosting service built on top of the AT Protocol.
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3.0 kB · 84 lines
Python
12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485#!/usr/bin/env python3"""Report private app health without exposing ports or sending health payloads."""
import concurrent.futuresimport jsonimport subprocessimport sysimport urllib.parseimport urllib.request
def healthy(app, body): expected = "healthy" if app in ("firehose-service", "webhook-service") else "ok" return isinstance(body, dict) and body.get("status") == expected
def active_leader(body): return ( healthy("firehose-service", body) and body.get("ready") is True and body.get("leadership", {}).get("state") == "acquired" )
def ping(url): parsed = urllib.parse.urlsplit(url) if ( parsed.scheme != "https" or parsed.netloc != "uptime.betterstack.com" or not parsed.path.startswith("/api/v1/heartbeat/") or parsed.query or parsed.fragment ): raise ValueError("invalid heartbeat destination") with urllib.request.urlopen(url, timeout=10) as response: if response.status != 200: raise ValueError("heartbeat rejected")
def probe(check, leader_url): app = check["app"] try: container = json.loads(subprocess.check_output( ["docker", "inspect", check["container"]], timeout=5, stderr=subprocess.DEVNULL, ))[0] if not container["State"]["Running"]: raise ValueError("container stopped") network = check.get("network", "proxy_network") address = container["NetworkSettings"]["Networks"][network]["IPAddress"] if not address: raise ValueError("missing container address") # Resolve the address each time: container replacement must not stale the probe. url = f'http://{address}:{check["port"]}{check["path"]}' opener = urllib.request.build_opener(urllib.request.ProxyHandler({})) with opener.open(url, timeout=10) as response: if response.status != 200 or response.url != url: raise ValueError("invalid health response") body = json.load(response) if not healthy(app, body): raise ValueError("degraded app") ping(check["heartbeat_url"]) if app == "firehose-service" and active_leader(body): ping(leader_url) print(f"{app}: healthy; heartbeat accepted", flush=True) return True except Exception as error: # Exceptions may contain secret heartbeat URLs; log only their class. print(f"{app}: probe failed ({type(error).__name__}); heartbeat withheld", flush=True) return False
def main(): with open(sys.argv[1]) as source: config = json.load(source) with concurrent.futures.ThreadPoolExecutor(max_workers=3) as pool: results = list(pool.map( lambda check: probe(check, config.get("leader_heartbeat_url")), config["checks"], )) return 0 if all(results) else 1
if __name__ == "__main__": sys.exit(main())