Enable etcd-dump-logs tool to decode kubernetes data objects in WAL log

[wenjiaswe]

etcd-dump-logs now is a great tool for wal log analysis. However, some kubernetes data in wal log is stored in a binary storage representation (starting kubernetes 1.6+). Output from etcd-dump-logs could not reveal kubernetes object. If we could provide an option for etcd-dump-logs to decode kubernetes object data at the same time of wal log dump, it would be very helpful for kubernetes users.

@jpbetz

[xiang90]

it seems that this should not belong to etcd repo. Or we need to provide a generic way to hook a decoder into the wal analysis tool.

[gyuho]

c.f. #8460

[wenjiaswe]

Thanks @gyuho , #8460 is a very helpful ref.

@xiang90 I agree that we should just provide a generic way to hook a decoder into etcd-dump-logs. In this particular case, auger already provide all we need to decode k8s object. I will just refactor etcd-dump-logs so it could use user specified decoder to replace meaningless hex strings with meaningful actual decoded objects whereever feasible.

[xiang90]

@wenjiaswe Thanks for the explanation. it makes sense.

[jingyih]

Addressed by #9790.