fix: save PID from Popen, check alive via os.kill, read link from log file

dashboard/plugin_api.py

@@ -5,7 +5,6 @@ import os
 import shutil
 import logging
 import time
-import threading
 from typing import Optional
 from fastapi import APIRouter
 from fastapi.responses import JSONResponse
@@ -16,6 +15,7 @@ router = APIRouter()
 _sshx_link = None
 _sshx_pid = None
 _sshx_log = "/tmp/sshx_link.log"
+_sshx_pid_file = "/tmp/sshx_link.pid"
 
 LINK_RE = re.compile(r"https://sshx\.io/s/[A-Za-z0-9_-]+")
 
@@ -39,12 +39,13 @@ def _kill_sshx():
     if _sshx_pid:
         try:
             os.kill(_sshx_pid, 15)
-        except ProcessLookupError:
+        except (ProcessLookupError, PermissionError):
             pass
-        _sshx_pid = None
+    _sshx_pid = None
     _sshx_link = None
-    if os.path.exists(_sshx_log):
-        os.remove(_sshx_log)
+    for f in [_sshx_log, _sshx_pid_file]:
+        if os.path.exists(f):
+            os.remove(f)
 
 
 def _is_alive() -> bool:
@@ -54,37 +55,49 @@ def _is_alive() -> bool:
     try:
         os.kill(_sshx_pid, 0)
         return True
-    except ProcessLookupError:
+    except (ProcessLookupError, PermissionError):
         return False
 
 
+def _read_link_from_log() -> Optional[str]:
+    if not os.path.exists(_sshx_log):
+        return None
+    try:
+        with open(_sshx_log) as f:
+            content = f.read()
+        m = LINK_RE.search(content)
+        if m:
+            return m.group(0)
+    except Exception:
+        pass
+    return None
+
+
 def _start_sshx_background():
     global _sshx_pid, _sshx_link
     _kill_sshx()
     _sshx_link = None
 
-    subprocess.Popen(
-        ["nohup", "sshx", "--quiet"],
-        stdout=open(_sshx_log, "w"),
+    log_fh = open(_sshx_log, "w")
+    proc = subprocess.Popen(
+        ["sshx", "--quiet"],
+        stdout=log_fh,
         stderr=subprocess.DEVNULL,
         stdin=subprocess.DEVNULL,
         start_new_session=True,
     )
+    _sshx_pid = proc.pid
+    with open(_sshx_pid_file, "w") as pf:
+        pf.write(str(proc.pid))
 
     for _ in range(30):
         time.sleep(1)
-        if os.path.exists(_sshx_log) and os.path.getsize(_sshx_log) > 0:
-            with open(_sshx_log) as f:
-                content = f.read().strip()
-            m = LINK_RE.search(content)
-            if m:
-                _sshx_link = m.group(0)
-                try:
-                    with open("/tmp/sshx_pid") as pf:
-                        _sshx_pid = int(pf.read().strip())
-                except Exception:
-                    pass
-                return True
+        link = _read_link_from_log()
+        if link:
+            _sshx_link = link
+            return True
+        if proc.poll() is not None:
+            return False
     return False