pomerium / pomerium / 17806046267

52%

Build Type

push

github

Committed by web-flow

Commit Message

databroker: add raft leader elector (#5831)

## Summary
Add a leader elector for the clustered databroker using Raft.

We use the hashicorp/raft package. It requires several components:

* **FSM**: just ignores all changes
* **Log Store**: stores all logs in in-memory btree ordered by index
* **Snapshot Store**: discards all snapshots
* **Stable Store**: stores data in in-memory maps
* **Stream Layer**: creates TCP listeners/connections based on the
`databroker_raft_bind_address` and `raft_address` in
`databroker_cluster_nodes`. Communication is encrypted using TLS with
certificates derived from the shared key.
* **Transport**: uses a network stream with the stream layer described
above. The other settings were copied from vault.

The raft leader elector will be used if no explicit cluster leader is
defined and the `databroker_raft_bind_address` is set. If raft options
aren't set, we will pick the first node as the cluster leader.

## Related issues
-
[ENG-2724](https://linear.app/pomerium/issue/ENG-2724/databroker-implement-leader-election)


## Checklist

- [x] reference any related issues
- [x] updated unit tests
- [x] add appropriate label (`enhancement`, `bug`, `breaking`,
`dependencies`, `ci`)
- [x] ready for review

Coverage Stats

74 of 368 new or added lines in 10 files covered. (20.11%)

14 existing lines in 6 files now uncovered.

27006 of 50194 relevant lines covered (53.8%)

87.23 hits per line