Files
stack/docs/compaction-refresh/probes/p3_generation_broker.py
2026-07-17 19:37:56 -05:00

118 lines
4.5 KiB
Python

#!/usr/bin/env python3
"""P3 broker prototype: peercred-keyed runtime_generation and lease revocation."""
from __future__ import annotations
import argparse
import json
import os
import socket
import struct
from pathlib import Path
from typing import Any
def proc_starttime(pid: int) -> int:
text = Path(f"/proc/{pid}/stat").read_text()
close = text.rfind(")")
return int(text[close + 2 :].split()[19])
def emit(log: Path, value: dict[str, Any]) -> None:
with log.open("a", encoding="utf-8") as out:
out.write(json.dumps(value, sort_keys=True) + "\n")
def main() -> None:
parser = argparse.ArgumentParser()
parser.add_argument("--socket", required=True)
parser.add_argument("--log", required=True)
ns = parser.parse_args()
socket_path = Path(ns.socket)
log_path = Path(ns.log)
socket_path.parent.mkdir(parents=True, exist_ok=True)
os.chmod(socket_path.parent, 0o700)
socket_path.unlink(missing_ok=True)
log_path.unlink(missing_ok=True)
server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
server.bind(str(socket_path))
os.chmod(socket_path, 0o600)
server.listen(8)
generations: dict[tuple[int, int], int] = {}
lease_state: dict[tuple[int, int], str] = {}
emit(log_path, {"event": "listen", "pid": os.getpid(), "socket": str(socket_path)})
while True:
conn, _ = server.accept()
with conn:
raw = conn.getsockopt(socket.SOL_SOCKET, socket.SO_PEERCRED, 12)
pid, uid, gid = struct.unpack("3i", raw)
starttime = proc_starttime(pid)
request = json.loads(conn.makefile("r", encoding="utf-8").readline())
if request.get("action") == "shutdown-broker":
conn.sendall(b'{"ok":true}\n')
break
identity = (pid, starttime)
if request.get("action") == "promote-probe":
generation = generations.get(identity, 0)
lease_state[identity] = "VERIFIED"
record = {
"event": "probe_lease_promoted",
"peercred": {"pid": pid, "uid": uid, "gid": gid},
"starttime_ticks": starttime,
"generation": generation,
"new_lease_state": "VERIFIED",
}
emit(log_path, record)
conn.sendall((json.dumps(record, sort_keys=True) + "\n").encode())
continue
if request.get("action") == "source-invalid":
old_lease = lease_state.get(identity, "NONE")
lease_state[identity] = "REVOKED"
record = {
"event": "source_invalidation_revoke",
"peercred": {"pid": pid, "uid": uid, "gid": gid},
"starttime_ticks": starttime,
"generation": generations.get(identity, 0),
"source_reason": request.get("reason"),
"prior_lease": old_lease,
"new_lease_state": "REVOKED",
"promotion": False,
}
emit(log_path, record)
conn.sendall((json.dumps(record, sort_keys=True) + "\n").encode())
continue
if request.get("action") != "lifecycle":
conn.sendall(b'{"ok":false,"reason":"invalid-action"}\n')
continue
old_generation = generations.get(identity, 0)
old_lease = lease_state.get(identity, "NONE")
new_generation = old_generation + 1
generations[identity] = new_generation
# Every lifecycle boundary revokes first. A start establishes a new
# UNVERIFIED incarnation; it never inherits prior VERIFIED state.
lease_state[identity] = "UNVERIFIED" if request.get("phase") == "start" else "REVOKED"
record = {
"event": "runtime_generation_bump",
"peercred": {"pid": pid, "uid": uid, "gid": gid},
"starttime_ticks": starttime,
"phase": request.get("phase"),
"reason": request.get("reason"),
"old_generation": old_generation,
"new_generation": new_generation,
"prior_lease": old_lease,
"prior_lease_revoked": True,
"new_lease_state": lease_state[identity],
}
emit(log_path, record)
conn.sendall((json.dumps(record, sort_keys=True) + "\n").encode())
server.close()
socket_path.unlink(missing_ok=True)
if __name__ == "__main__":
main()