Add HTTP resync endpoint for manual rotation triggering

Expose port 8080 with `/resync` endpoint to trigger on-demand WireGuard rotations. Add RESYNC_PORT and RESYNC_BIND environment variables. Implement thread-safe rotation locking to prevent concurrent runs. Update README with endpoint usage examples.

Dockers/gluetun-pia-wireguard-rotator/entrypoint.py

@@ -8,9 +8,12 @@ import os
 import re
 import subprocess
 import sys
+import threading
 import time
 from datetime import datetime
+import http.server
 from pathlib import Path
+from typing import Any
 from zoneinfo import ZoneInfo
 
 from croniter import croniter
@@ -19,6 +22,9 @@ import pia
 
 EXIT_RATE_LIMITED = pia.EXIT_RATE_LIMITED
 
+_ROTATION_LOCK = threading.Lock()
+_RESYNC_EVENT = threading.Event()
+
 CRON_MACROS = {
     "@yearly": "0 0 1 1 *",
     "@annually": "0 0 1 1 *",
@@ -81,6 +87,68 @@ def unhealthy_cooldown_seconds() -> float:
     return max(0.0, float(os.environ.get("UNHEALTHY_ROTATE_COOLDOWN", "60")))
 
 
+def resync_port() -> int | None:
+    raw = os.environ.get("RESYNC_PORT", "8080").strip()
+    if not raw:
+        return None
+    try:
+        port = int(raw)
+    except ValueError as exc:
+        raise SystemExit(f"Invalid RESYNC_PORT '{raw}' (expected integer)") from exc
+    if not (1 <= port <= 65535):
+        raise SystemExit(f"Invalid RESYNC_PORT {port} (expected 1-65535)")
+    return port
+
+
+def resync_bind_address() -> str:
+    return os.environ.get("RESYNC_BIND", "0.0.0.0").strip() or "0.0.0.0"
+
+
+class ResyncHandler(http.server.BaseHTTPRequestHandler):
+    def _respond(self, status: int, body: dict[str, Any]) -> None:
+        self.send_response(status)
+        self.send_header("Content-Type", "application/json")
+        self.end_headers()
+        self.wfile.write(json.dumps(body).encode("utf-8"))
+
+    def _path(self) -> str:
+        return self.path.split("?", 1)[0]
+
+    def do_GET(self) -> None:  # noqa: N802
+        path = self._path()
+        if path == "/resync":
+            _RESYNC_EVENT.set()
+            self._respond(202, {"status": "accepted", "message": "Resync requested"})
+        elif path == "/":
+            self._respond(
+                200,
+                {
+                    "service": "gluetun-pia-wireguard-rotator",
+                    "endpoints": ["/resync"],
+                },
+            )
+        else:
+            self._respond(404, {"error": "not found"})
+
+    def do_POST(self) -> None:  # noqa: N802
+        path = self._path()
+        if path == "/resync":
+            _RESYNC_EVENT.set()
+            self._respond(202, {"status": "accepted", "message": "Resync requested"})
+        else:
+            self._respond(404, {"error": "not found"})
+
+    def log_message(self, fmt: str, *args: Any) -> None:
+        log(fmt % args)
+
+
+def start_resync_server(port: int, bind: str) -> None:
+    server = http.server.HTTPServer((bind, port), ResyncHandler)
+    thread = threading.Thread(target=server.serve_forever, daemon=True, name="resync-http")
+    thread.start()
+    log(f"Resync endpoint listening on http://{bind}:{port}/resync")
+
+
 def gluetun_container_name() -> str:
     return os.environ.get("GLUETUN_CONTAINER", "m3u-filter-vpn").strip() or "m3u-filter-vpn"
 
@@ -142,6 +210,12 @@ def run_rotation(reason: str, extra_args: list[str] | None = None) -> None:
         raise SystemExit(f"Rotation failed with exit code {result.returncode}")
 
 
+def run_rotation_locked(reason: str, extra_args: list[str] | None = None) -> None:
+    """Run a rotation while holding the global lock to avoid concurrent runs."""
+    with _ROTATION_LOCK:
+        run_rotation(reason, extra_args)
+
+
 def wait_until_healthy_or_timeout(timeout_s: float) -> str | None:
     """Sleep up to timeout_s, returning early if Gluetun becomes non-unhealthy."""
     deadline = time.time() + timeout_s
@@ -161,7 +235,7 @@ def handle_unhealthy() -> None:
     """Two-step recovery: re-auth best server, then runner-up if still unhealthy."""
     log(f"Gluetun container {gluetun_container_name()} is unhealthy; starting recovery")
 
-    run_rotation(
+    run_rotation_locked(
         "Unhealthy recovery step 1: force rotate to best server (new keypair)",
         ["--force"],
     )
@@ -180,7 +254,7 @@ def handle_unhealthy() -> None:
     else:
         log("Still unhealthy; step 2 without exclude (no server_ip in state)")
 
-    run_rotation(
+    run_rotation_locked(
         "Unhealthy recovery step 2: force rotate to runner-up",
         exclude_args,
     )
@@ -193,30 +267,50 @@ def main() -> None:
     expr = resolve_cron_expr()
     tz = zone()
     interval = health_check_interval()
+    port = resync_port()
+    bind = resync_bind_address()
     # Fail fast on bad cron / TZ before rotating.
     nxt = next_run(expr, datetime.now(tz))
     log(
         f"Starting gluetun PIA WireGuard rotator "
-        f"(TZ={tz.key}, ROTATE_CRON='{expr}', HEALTH_CHECK_INTERVAL={interval:g}s)"
+        f"(TZ={tz.key}, ROTATE_CRON='{expr}', HEALTH_CHECK_INTERVAL={interval:g}s, "
+        f"RESYNC_PORT={port or 'off'})"
     )
     log(f"Next scheduled rotation at {nxt.isoformat(timespec='seconds')}")
 
-    run_rotation("Running rotation on startup", ["--force"])
+    if port:
+        start_resync_server(port, bind)
+
+    run_rotation_locked("Running rotation on startup", ["--force"])
     nxt = next_run(expr, datetime.now(tz))
 
+    step = min(interval, 1.0)
     while True:
-        time.sleep(interval)
+        # Sleep in short chunks so a resync request wakes us early.
+        deadline = time.time() + interval
+        while time.time() < deadline and not _RESYNC_EVENT.is_set():
+            remaining = deadline - time.time()
+            time.sleep(min(step, remaining, 1.0))
+
         now = datetime.now(tz)
 
+        if _RESYNC_EVENT.is_set():
+            _RESYNC_EVENT.clear()
+            run_rotation_locked("Resync requested via HTTP", ["--force"])
+            nxt = next_run(expr, datetime.now(tz))
+            log(f"Next scheduled rotation at {nxt.isoformat(timespec='seconds')}")
+            continue
+
         status = gluetun_health_status()
         if status == "unhealthy":
             handle_unhealthy()
+            _RESYNC_EVENT.clear()
             nxt = next_run(expr, datetime.now(tz))
             log(f"Next scheduled rotation at {nxt.isoformat(timespec='seconds')}")
             continue
 
         if now >= nxt:
-            run_rotation("Running scheduled rotation", ["--skip-same-server"])
+            run_rotation_locked("Running scheduled rotation", ["--skip-same-server"])
             nxt = next_run(expr, datetime.now(tz))
             log(f"Next scheduled rotation at {nxt.isoformat(timespec='seconds')}")