| Conditions | 6 |
| Total Lines | 52 |
| Code Lines | 18 |
| Lines | 0 |
| Ratio | 0 % |
| Changes | 0 | ||
Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.
For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.
Commonly applied refactorings include:
If many parameters/temporary variables are present:
| 1 | #!/usr/bin/env python3 |
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| 101 | @contextmanager |
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| 102 | def redis_lock(lock_id, blocking=False, expire=True): |
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| 103 | """ |
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| 104 | This function get a lock relying on a lock name and other status. You |
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| 105 | can describe more process using the same lock name and give exclusive |
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| 106 | access to one of them. |
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| 107 | |||
| 108 | Args: |
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| 109 | lock_id (str): the name of the lock to take |
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| 110 | blocking (bool): if True, we wait until we have the block, if False |
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| 111 | we returns immediately False |
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| 112 | expire (bool): if True, lock will expire after LOCK_EXPIRE timeout, |
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| 113 | if False, it will persist until lock is released |
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| 114 | |||
| 115 | Returns: |
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| 116 | bool: True if lock acquired, False otherwise |
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| 117 | """ |
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| 118 | |||
| 119 | # read parameters from settings |
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| 120 | REDIS_CLIENT = redis.StrictRedis( |
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| 121 | host=settings.REDIS_HOST, |
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| 122 | port=settings.REDIS_PORT, |
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| 123 | db=settings.REDIS_DB) |
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| 124 | |||
| 125 | # this will be the redis lock |
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| 126 | lock = None |
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| 127 | |||
| 128 | # timeout for the lock (if expire condition) |
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| 129 | timeout_at = monotonic() + LOCK_EXPIRE - 3 |
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| 130 | |||
| 131 | if expire: |
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| 132 | lock = REDIS_CLIENT.lock(lock_id, timeout=LOCK_EXPIRE) |
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| 133 | |||
| 134 | else: |
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| 135 | lock = REDIS_CLIENT.lock(lock_id, timeout=None) |
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| 136 | |||
| 137 | status = lock.acquire(blocking=blocking) |
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| 138 | |||
| 139 | try: |
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| 140 | logger.debug("lock %s acquired is: %s" % (lock_id, status)) |
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| 141 | yield status |
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| 142 | |||
| 143 | finally: |
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| 144 | # we take advantage of using add() for atomic locking |
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| 145 | # don't release the lock if we didn't acquire it |
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| 146 | if status and ((monotonic() < timeout_at and expire) or not expire): |
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| 147 | logger.debug("Releasing lock %s" % lock_id) |
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| 148 | # don't release the lock if we exceeded the timeout |
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| 149 | # to lessen the chance of releasing an expired lock |
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| 150 | # owned by someone else |
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| 151 | # if no timeout and lock is taken, release it |
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| 152 | lock.release() |
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| 153 |