From: Louis Solofrizzo <lsolofrizzo@scaleway.com>
To: ~ne02ptzero/libfloat@lists.sr.ht
Cc: fflorensa@scaleway.com,
	lsolofrizzo@scaleway.com,
	pcyvoct@scaleway.com
Subject: [PATCH] raft: Add stat for elected leader timestamp
Date: Tue, 20 Sep 2022 11:36:06 +0200
Message-Id: <20220920093606.2906407-1-lsolofrizzo@scaleway.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

Signed-off-by: Louis Solofrizzo <lsolofrizzo@scaleway.com>
---
 libfloat.h | 1 +
 raft.c     | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/libfloat.h b/libfloat.h
index 9f8ad38..17b3c89 100644
--- a/libfloat.h
+++ b/libfloat.h
@@ -46,6 +46,7 @@ struct libfloat_ctx_s {
     struct {
         uint64_t        leader_election;                /*!< Count of leader elections for this cluster */
         uint64_t        orphans_logs;                   /*!< Count of logs that are applied on the leader only */
+        time_t          leader_election_time;           /*!< Timestamp of the last leader election */
     } stat;
 
     struct {
diff --git a/raft.c b/raft.c
index 90d5e55..2cfce3c 100644
--- a/raft.c
+++ b/raft.c
@@ -23,6 +23,7 @@ void libfloat_become_leader(libfloat_ctx_t *ctx)
     });
 
     ctx->me->is_up_to_date = 1;
+    ctx->stat.leader_election_time = ctx->time(NULL);
 }
 
 void __libfloat_become_candidate(libfloat_ctx_t *ctx, libfloat_elections_args_t *args)
@@ -30,6 +31,7 @@ void __libfloat_become_candidate(libfloat_ctx_t *ctx, libfloat_elections_args_t
     DEBUG(ctx, "Becoming candidate: reason=%s", args->reason);
     ctx->state = RAFT_STATE_CANDIDATE;
     ctx->election_timeout_rand = ctx->conf.election_timeout + ctx->rand() % ctx->conf.election_timeout;
+    ctx->stat.leader_election_time = 0;
 }
 
 void __libfloat_become_follower(libfloat_ctx_t *ctx, libfloat_elections_args_t *args)
@@ -38,6 +40,7 @@ void __libfloat_become_follower(libfloat_ctx_t *ctx, libfloat_elections_args_t *
     ctx->abort_send_snapshot(ctx);
     ctx->state = RAFT_STATE_FOLLOWER;
     ctx->election_timeout_rand = ctx->conf.election_timeout + ctx->rand() % ctx->conf.election_timeout;
+    ctx->stat.leader_election_time = 0;
     libfloat_vote_for(ctx, 0);
 }
 
@@ -49,6 +52,7 @@ void libfloat_step_down(libfloat_ctx_t *ctx)
         ctx->leader = NULL;
 
     ctx->state = RAFT_STATE_NONE;
+    ctx->stat.leader_election_time = 0;
 }
 
 void libfloat_send_append_entries_to_all(libfloat_ctx_t *ctx, bool heartbeat)
-- 
2.37.3