tree f5f2a1d7bb9e36c40214fce166cb3e5dd1f2af76
parent cc6b2e6b901cfb7387bdc217c883cc0cec6ab06f
author Ryan Van Gilder <rvangild@ciena.com> 1488415165 -0800
committer khenaidoo Nursimulu <knursimu@ciena.com> 1488504582 -0800

Add consul as a config backend

Two backends available, none and consul. Can be set through the
BACKEND environment variable or the --backend flag.
Currently access to consul blocks the reactor. Requests to consul
are cached. In my conversations with Zsolt, we concluded that
blocking the reactor is fine for now to prevent multiple tasks
from modifying the config at the same time. An easier first step
to making it all twisted is to add a write queue. That comes with its
own challenges though. A longer goal would be making the entire config
access inlineCallbacks, possibly with a locking mechanism to prevent
multiple tasks from modifying the config at once.

Change-Id: Ia3132a455ca03123dbb9b2e56c9f4df1202347cd