dbm CacheManager crashes if tmp disappears

[aiguofer]

I have an app running on an OpenStack image and it recently started misbehaving. When I looked into it, I found this in the logs:

  File "./segmentation/customer_data.py", line 9, in __init__
    self.weights = get_product_line_prices(weights)
  File "/usr/lib/python2.7/site-packages/beaker/cache.py", line 595, in cached
    return cache[0].get_value(cache_key, createfunc=go)
  File "/usr/lib/python2.7/site-packages/beaker/cache.py", line 318, in get
    return self._get_value(key, **kw).get_value()
  File "/usr/lib/python2.7/site-packages/beaker/container.py", line 330, in get_value
    self.namespace.acquire_read_lock()
  File "/usr/lib/python2.7/site-packages/beaker/container.py", line 204, in acquire_read_lock
    self.access_lock.acquire_read_lock()
  File "/usr/lib/python2.7/site-packages/beaker/synchronization.py", line 154, in acquire_read_lock
    x = self.do_acquire_read_lock(wait)
  File "/usr/lib/python2.7/site-packages/beaker/synchronization.py", line 241, in do_acquire_read_lock
    filedescriptor = self._open(os.O_CREAT | os.O_RDONLY)
  File "/usr/lib/python2.7/site-packages/beaker/synchronization.py", line 236, in _open
    filedescriptor = os.open(self.filename, mode)
OSError: [Errno 2] No such file or directory: '/tmp/cache/lock/1/13/13c02d91731613ece4c33248c0afe6a63a60b5d3.lock'

Here, get_product_line_prices is cached with @cache.cache('meh', expire=60*60*24*7) and the CacheManager is instanciated with:

cache_opts = {
    'cache.type': 'dbm',
    'cache.data_dir': '/tmp/cache/data',
    'cache.lock_dir': '/tmp/cache/lock'
}

cache = CacheManager(**parse_cache_config_options(cache_opts))

It seems that somehow my tmp dir was cleared; Should this be handled by the FileSynchronizer?

[tanmainaik]

Any updates on this issue. Am facing the same issue.

[amol-]

I'll try to address this during the weekend, if you want to submit a pull request with a fix to speed up the release process I can review it earlier.

[amol-]

https://github.com/bbangert/beaker/commit/1eed92a92fc119dfcaeb2153b86683a4e381cb6e should cope with this case at minimal performance impact as it's only performed when the directory does not exists and when opening the file already failed.