From 22c5f043aa0ab007d9a23b7b08ae9ff2824ff52e Mon Sep 17 00:00:00 2001
From: allegroai <>
Date: Sun, 31 May 2020 14:00:14 +0300
Subject: [PATCH] Fix detached mode to correctly use cache folder slots

---
 trains_agent/commands/worker.py  |  7 +++++--
 trains_agent/helper/singleton.py | 23 +++++++++++++++++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/trains_agent/commands/worker.py b/trains_agent/commands/worker.py
index e1fb92e..8e74e91 100644
--- a/trains_agent/commands/worker.py
+++ b/trains_agent/commands/worker.py
@@ -737,6 +737,8 @@ class Worker(ServiceCommandSection):
                 # in detached mode
                 # fully detach stdin.stdout/stderr and leave main process, running in the background
                 daemonize_process(out_file.fileno())
+                # make sure we update the singleton lock file to the new pid
+                Singleton.update_pid_file()
                 # reprint headers to std file (we are now inside the daemon process)
                 print("Worker \"{}\" :".format(self.worker_id))
                 self._session.print_configuration()
@@ -2277,8 +2279,9 @@ class Worker(ServiceCommandSection):
             else:
                 worker_name = '{}:cpu'.format(worker_name)
 
-        self.worker_id, worker_slot = Singleton.register_instance(unique_worker_id=worker_id, worker_name=worker_name,
-                                                                  api_client=self._session.api_client)
+        self.worker_id, worker_slot = Singleton.register_instance(
+            unique_worker_id=worker_id, worker_name=worker_name, api_client=self._session.api_client)
+
         if self.worker_id is None:
             error('Instance with the same WORKER_ID [{}] is already running'.format(worker_id))
             exit(1)
diff --git a/trains_agent/helper/singleton.py b/trains_agent/helper/singleton.py
index ec3a7a9..8507c9e 100644
--- a/trains_agent/helper/singleton.py
+++ b/trains_agent/helper/singleton.py
@@ -18,6 +18,24 @@ class Singleton(object):
     _pid_file = None
     _lock_file_name = sep+prefix+sep+'global.lock'
     _lock_timeout = 10
+    _pid = None
+
+    @classmethod
+    def update_pid_file(cls):
+        new_pid = str(os.getpid())
+        if not cls._pid_file or cls._pid == new_pid:
+            return
+        old_name = cls._pid_file.name
+        parts = cls._pid_file.name.split(os.path.sep)
+        parts[-1] = parts[-1].replace(cls.sep + cls._pid + cls.sep, cls.sep + new_pid + cls.sep)
+        new_pid_file = os.path.sep.join(parts)
+        cls._pid = new_pid
+        cls._pid_file.name = new_pid_file
+        # we need to rename to match new pid
+        try:
+            os.rename(old_name, new_pid_file)
+        except:
+            pass
 
     @classmethod
     def register_instance(cls, unique_worker_id=None, worker_name=None, api_client=None):
@@ -124,8 +142,9 @@ class Singleton(object):
             unique_worker_id = worker_name + cls.worker_name_sep + str(cls.instance_slot)
 
         # create lock
-        cls._pid_file = NamedTemporaryFile(dir=cls._get_temp_folder(),
-                                           prefix=cls.prefix + cls.sep + str(os.getpid()) + cls.sep, suffix=cls.ext)
+        cls._pid = str(os.getpid())
+        cls._pid_file = NamedTemporaryFile(
+            dir=cls._get_temp_folder(), prefix=cls.prefix + cls.sep + cls._pid + cls.sep, suffix=cls.ext)
         cls._pid_file.write(('{}\n{}'.format(unique_worker_id, cls.instance_slot)).encode())
         cls._pid_file.flush()
         cls.worker_id = unique_worker_id