Re: [Tarantool-patches] [PATCH v4 09/12] raft: introduce raft_start/stop_candidate

[Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Thanks for working on this!

See 3 comments below.

>  src/lib/raft/raft.c   | 83 ++++++++++++++++++++++++++++---------------
>  src/lib/raft/raft.h   | 13 +++++++
>  test/unit/raft.c      | 33 +++++++++++++++--
>  test/unit/raft.result | 10 +++++-
>  4 files changed, 108 insertions(+), 31 deletions(-)
> 
> diff --git a/src/lib/raft/raft.c b/src/lib/raft/raft.c
> index e9ce8cade..b21693642 100644
> --- a/src/lib/raft/raft.c
> +++ b/src/lib/raft/raft.c
> @@ -848,38 +848,65 @@ raft_cfg_is_enabled(struct raft *raft, bool is_enabled)

<...>

> +
> +void
> +raft_stop_candidate(struct raft *raft, bool demote)

1. For flags we usually use 'is', 'do', 'has' and similar prefixes.

> +{
> +	if (!raft->is_candidate)
> +		return;
> +	raft->is_candidate = false;
> +	if (raft->state != RAFT_STATE_LEADER) {
> +		/* Do not wait for anything while being a voter. */
> +		raft_ev_timer_stop(raft_loop(), &raft->timer);
> +	}
> +	if (raft->state != RAFT_STATE_FOLLOWER) {
> +		if (raft->state == RAFT_STATE_LEADER) {
> +			if (!demote) {
> +				/*
> +				 * Remain leader until someone
> +				 * triggers new elections.
> +				 */
> +				return;
> +			}
> +			raft->leader = 0;
>  		}
> +		raft->state = RAFT_STATE_FOLLOWER;
> +		/* State is visible and changed - broadcast. */
> +		raft_schedule_broadcast(raft);
>  	}
>  }
>  
> diff --git a/src/lib/raft/raft.h b/src/lib/raft/raft.h
> index a5f7e08d9..69dec63c6 100644
> --- a/src/lib/raft/raft.h
> +++ b/src/lib/raft/raft.h
> @@ -327,6 +327,19 @@ raft_cfg_is_enabled(struct raft *raft, bool is_enabled);
>  void
>  raft_cfg_is_candidate(struct raft *raft, bool is_candidate);
>  
> +/**
> + * Make the instance a candidate.
> + */
> +void
> +raft_start_candidate(struct raft *raft);
> +
> +/**
> + * Make the instance stop taking part in new elections.
> + * @param demote whether to stop being a leader immediately or not.
> + */
> +void
> +raft_stop_candidate(struct  raft *raft, bool demote);

2. Double whitespace after 'struct'.

> +
>  /** Configure Raft leader election timeout. */
>  void
>  raft_cfg_election_timeout(struct raft *raft, double timeout);
> diff --git a/test/unit/raft.c b/test/unit/raft.c
> index 0306cefcd..575886932 100644
> --- a/test/unit/raft.c
> +++ b/test/unit/raft.c
> @@ -1296,15 +1296,43 @@ raft_test_term_filter(void)
>  	ok(!raft_is_node_outdated(&node.raft, 3), "node doesn't become "
>  						  "outdated");
>  
> -

3. This probably should be in the previous commit.

>  	raft_node_destroy(&node);
>  	raft_finish_test();
>  }