Revision 5d6fb8eb lib/jstore.py
| b/lib/jstore.py | ||
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| 69 | 69 |
return _ReadNumericFile(constants.JOB_QUEUE_VERSION_FILE) |
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def InitAndVerifyQueue(exclusive):
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def InitAndVerifyQueue(must_lock):
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"""Open and lock job queue. |
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If necessary, the queue is automatically initialized. |
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@type exclusive: bool |
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@param exclusive: Whether to lock the queue in exclusive mode. Shared |
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mode otherwise. |
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@type must_lock: bool |
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@param must_lock: Whether an exclusive lock must be held. |
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@rtype: utils.FileLock |
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@return: Lock object for the queue. This can be used to change the |
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locking mode. |
| ... | ... | |
| 93 | 92 |
# Lock queue |
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queue_lock = utils.FileLock(constants.JOB_QUEUE_LOCK_FILE) |
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try: |
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# Determine locking function and call it |
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if exclusive: |
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fn = queue_lock.Exclusive |
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# The queue needs to be locked in exclusive mode to write to the serial and |
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# version files. |
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if must_lock: |
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queue_lock.Exclusive(blocking=True) |
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holding_lock = True |
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else: |
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fn = queue_lock.Shared |
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fn(blocking=False) |
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# Verify version |
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version = ReadVersion() |
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if version is None: |
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# Write new version file |
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utils.WriteFile(constants.JOB_QUEUE_VERSION_FILE, |
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data="%s\n" % constants.JOB_QUEUE_VERSION) |
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# Read again |
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try: |
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queue_lock.Exclusive(blocking=False) |
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holding_lock = True |
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except errors.LockError: |
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# Ignore errors and assume the process keeping the lock checked |
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# everything. |
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holding_lock = False |
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if holding_lock: |
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# Verify version |
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version = ReadVersion() |
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if version is None: |
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# Write new version file |
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utils.WriteFile(constants.JOB_QUEUE_VERSION_FILE, |
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data="%s\n" % constants.JOB_QUEUE_VERSION) |
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if version != constants.JOB_QUEUE_VERSION: |
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raise errors.JobQueueError("Found job queue version %s, expected %s",
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version, constants.JOB_QUEUE_VERSION) |
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# Read again |
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version = ReadVersion() |
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serial = ReadSerial() |
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if serial is None: |
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# Write new serial file |
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utils.WriteFile(constants.JOB_QUEUE_SERIAL_FILE, |
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data="%s\n" % 0) |
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if version != constants.JOB_QUEUE_VERSION: |
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raise errors.JobQueueError("Found job queue version %s, expected %s",
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version, constants.JOB_QUEUE_VERSION) |
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# Read again |
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serial = ReadSerial() |
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if serial is None: |
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# Write new serial file |
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utils.WriteFile(constants.JOB_QUEUE_SERIAL_FILE, |
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data="%s\n" % 0) |
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# Read again |
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serial = ReadSerial() |
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if serial is None: |
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# There must be a serious problem |
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raise errors.JobQueueError("Can't read/parse the job queue serial file")
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if serial is None:
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# There must be a serious problem
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raise errors.JobQueueError("Can't read/parse the job queue serial file")
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except: |
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queue_lock.Close() |
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