From 9f9e60336540c042c63296e815eed91c8a27ba8c Mon Sep 17 00:00:00 2001
From: Marvin Zhang <tikazyq@gmail.com>
Date: Sun, 7 Jul 2019 16:16:48 +0800
Subject: [PATCH] fixed https://github.com/tikazyq/crawlab/issues/78

---
 crawlab/app.py             |  2 +-
 crawlab/requirements.txt   |  1 +
 crawlab/tasks/scheduler.py | 18 ++++++++++++++++--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/crawlab/app.py b/crawlab/app.py
index 493c9bed..484e9234 100644
--- a/crawlab/app.py
+++ b/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)
diff --git a/crawlab/requirements.txt b/crawlab/requirements.txt
index 67c8d0db..282c4cc2 100644
--- a/crawlab/requirements.txt
+++ b/crawlab/requirements.txt
@@ -14,3 +14,4 @@ eventlet
 Celery
 Flower
 redis
+gunicorn
diff --git a/crawlab/tasks/scheduler.py b/crawlab/tasks/scheduler.py
index 16597f67..b9fcb140 100644
--- a/crawlab/tasks/scheduler.py
+++ b/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()