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-rw-r--r--share/common/utils/share_lock.py77
1 files changed, 77 insertions, 0 deletions
diff --git a/share/common/utils/share_lock.py b/share/common/utils/share_lock.py
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+++ b/share/common/utils/share_lock.py
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+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (c) 2017-2018 Wind River Systems, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
+import time
+
+import redis
+
+from common.config.config import REDIS_HOST, REDIS_PORT, REDIS_PASSWD
+
+
+class SharedLock:
+ def __init__(self, lock_key, host=REDIS_HOST, port=REDIS_PORT, password=REDIS_PASSWD, db=9, lock_timeout=5 * 60):
+ self.lock_key = lock_key
+ self.lock_timeout = lock_timeout
+ self.redis = redis.Redis(host=host, port=port, db=db, password=password)
+ self.acquire_time = -1
+
+ def acquire(self):
+ begin = now = int(time.time())
+ while (now - begin) < self.lock_timeout:
+
+ result = self.redis.setnx(self.lock_key, now + self.lock_timeout + 1)
+ if result == 1 or result is True:
+ self.acquire_time = now
+ return True
+
+ current_lock_timestamp = self.redis.get(self.lock_key)
+ if not current_lock_timestamp:
+ time.sleep(1)
+ continue
+
+ current_lock_timestamp = int(current_lock_timestamp)
+
+ if now > current_lock_timestamp:
+ next_lock_timestamp = self.redis.getset(self.lock_key, now + self.lock_timeout + 1)
+ if not next_lock_timestamp:
+ time.sleep(1)
+ continue
+ next_lock_timestamp = int(next_lock_timestamp)
+
+ if next_lock_timestamp == current_lock_timestamp:
+ self.acquire_time = now
+ return True
+ else:
+ time.sleep(1)
+ continue
+ return False
+
+ def release(self):
+ now = int(time.time())
+ if now > self.acquire_time + self.lock_timeout:
+ # key expired, do nothing and let other clients handle it
+ return
+ self.acquire_time = None
+ self.redis.delete(self.lock_key)
+
+
+def do_biz_with_share_lock(lock_name, callback):
+ lock = SharedLock(lock_name)
+ try:
+ if not lock.acquire():
+ raise Exception(lock_name + " timeout")
+ callback()
+ except Exception as e:
+ raise e
+ finally:
+ lock.release()