dhash_wrap.py

import dhashpy

_dhash = None
_host = None
_port = None

class DHash(object):
    """Wrap the dhashpy to make the simple things simpler"""

    def __init__(self, dhash):
        self._dhash = dhash

    def watch_new(self, key):
        """Get a watch"""
        # TODO: handle exceptions?
        return dhashpy.watch_new(self._dhash, key)

    def get(self, key, return_on=dhashpy.DWATCH_EVENT_VALID):
        """get a value"""
        # TODO: handle exceptions?
        watch = self.watch_new(key)
        return dhashpy.watch_get(watch, dhashpy.DWATCH_EVENT_VALID, return_on)

    def set(self, key, value, return_on=dhashpy.DWATCH_EVENT_CONFIRMED):
        """Update a key"""
        watch = self.watch_new(key)
        res = dhashpy.watch_update(watch, return_on, value)
        # TODO: What should we return here, do we need to do things with the result
        return res

    def get_and_watch(self, key, return_on=dhashpy.DWATCH_EVENT_VALID):
        # TODO: handle exceptions?
        watch = self.watch_new(key)
        value = dhashpy.watch_get(watch, dhashpy.DWATCH_EVENT_VALID, return_on)
        return value, watch


def get_value(key):
    """Convenience to get a key value"""
    return get_dhash().get(key)

def set_value(key, value):
    """Set a value"""
    return get_dhash().set(key, value)

def get_dhash():
    global _dhash
    if not _dhash:
        raise Exception("No DHASH object available, try calling init_dhash")
    return _dhash

# This is the method that should be called to setup DHASH
def init_dhash(host, port):
    global _host, _port, _dhash
    _host = host
    _port = port
    _dhash = DHash(dhashpy.dhash_new(ipaddr=_host, port=_port))
    return _dhash