Adding etcd endpoint discovery via SRV records to locksmithd

[Ashley Lowde]

Hi All,

While setting up a cluster today with locksmithd using etcd for locking I found that locksmithd doesn't include support for discovery of etcd endpoints via SRV records. As per https://github.com/coreos/bugs/issues/1535 it'd be a nice feature to have. 

It looks like that would be a fairly straightforward patch, but does anyone have any advice/history regarding this feature that I should know before preparing a PR?

Thanks,

Ashley