fixed https://github.com/tikazyq/crawlab/issues/78

crawlab/app.py

@@ -103,4 +103,4 @@ if not os.path.exists(PROJECT_LOGS_FOLDER):
 
 if __name__ == '__main__':
     # run app instance
-    app.run(host=FLASK_HOST, port=FLASK_PORT, threaded=True)
+    app.run(host=FLASK_HOST, port=FLASK_PORT)

crawlab/requirements.txt

@@ -14,3 +14,4 @@ eventlet
 Celery
 Flower
 redis
+gunicorn

crawlab/tasks/scheduler.py

@@ -1,3 +1,6 @@
+import atexit
+import fcntl
+
 import requests
 from apscheduler.schedulers.background import BackgroundScheduler
 from apscheduler.jobstores.mongodb import MongoDBJobStore
@@ -65,8 +68,19 @@ class Scheduler(object):
         print(f'running: {self.scheduler.running}')
 
     def run(self):
-        self.update()
-        self.scheduler.start()
+        f = open("scheduler.lock", "wb")
+        try:
+            fcntl.flock(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
+            self.update()
+            self.scheduler.start()
+        except:
+            pass
+
+        def unlock():
+            fcntl.flock(f, fcntl.LOCK_UN)
+            f.close()
+
+        atexit.register(unlock)
 
 
 scheduler = Scheduler()