Analyzing caching issues

[zopyx]

We configured node.ext.ldap according

https://pypi.python.org/pypi/node.ext.ldap#caching-support

However I can not see any cached entries in Memcached using
stats cachedump 1000

on the Memcached console.

Is there any reasonable way to analyze/debug the caching other than taking pdb? Some logging available?

[rnixx]

Not really. But actually it would be a good feature to get some cache validation/stats via API.

[rnixx]

are you using node.ext.ldap in conjunction with pas.plugins.ldap or standalone? Are you using it in Plone?

[zopyx]

Using it in Plone but outside PAS.

[rnixx]

pas.plugins.ldap registers it's cache provider factory (https://github.com/collective/pas.plugins.ldap/blob/master/src/pas/plugins/ldap/cache.py#L15) here https://github.com/collective/pas.plugins.ldap/blob/master/src/pas/plugins/ldap/configure.zcml#L30

Cache provider looked happens here https://github.com/bluedynamics/node.ext.ldap/blob/master/src/node/ext/ldap/base.py#L125 if you still need to hook up with pdb.

Hope this helps in the meantime (until some cache verification API is implemented)

[zopyx]

Obviously the document registration of the memcached factory did not work for me.

For the sake of completeness: as a workaround I implemented the following:

<utility
  provides="node.ext.ldap.interfaces.ICacheProviderFactory"
  factory=".caching.MemcachedProviderFactory"
/>

@implementer(ICacheProviderFactory)
class MemcachedProviderFactory(object):
    """Memcached cache provider factory.
    """

    def __init__(self, servers=['127.0.0.1:11211']):
        self.servers = None
        servers = os.environ.get('MEMCACHED_SERVERS')
        if not servers:
            LOG.warn('No memcached servers configured')
            return
        servers = servers.split(',')
        for server in servers:
            if ':' not in server:
                raise ValueError('Unable to parse "{}" for memcached configuration. {}'.format(
                    server, config_help))
            ip, port = server.split(':')
            if not is_int(port):
                raise ValueError('Unable to parse "{}" for memcached configuration. {}'.format(
                    server, config_help))
        LOG.info('Configured memcached servers : {}'.format(servers))
        self.servers = servers

    def __call__(self):
        if self.servers:
            return Memcached(self.servers)
        else:
            return NullCache()