coordinator.py 文件源码

def handle(self):
        if not hookenv.is_leader():
            return  # Only the leader can grant requests.

        self.msg('Leader handling coordinator requests')

        # Clear our grants that have been released.
        for unit in self.grants.keys():
            for lock, grant_ts in list(self.grants[unit].items()):
                req_ts = self.requests.get(unit, {}).get(lock)
                if req_ts != grant_ts:
                    # The request timestamp does not match the granted
                    # timestamp. Several hooks on 'unit' may have run
                    # before the leader got a chance to make a decision,
                    # and 'unit' may have released its lock and attempted
                    # to reacquire it. This will change the timestamp,
                    # and we correctly revoke the old grant putting it
                    # to the end of the queue.
                    ts = datetime.strptime(self.grants[unit][lock],
                                           _timestamp_format)
                    del self.grants[unit][lock]
                    self.released(unit, lock, ts)

        # Grant locks
        for unit in self.requests.keys():
            for lock in self.requests[unit]:
                self.grant(lock, unit)