raft: Add new election counter metric, and fix a possible weird case with leadership v1 APPLIED

Louis Solofrizzo: 1
 raft: Add new election counter metric, and fix a possible weird case with leadership

 7 files changed, 48 insertions(+), 1 deletions(-)

[PATCH] raft: Add new election counter metric, and fix a possible weird case with leadership Export this patch

---
 CMakeLists.txt |  2 ++
 election.c     |  3 ++-
 error.c        | 16 ++++++++++++++++
 internal.h     |  7 +++++++
 libfloat.h     | 11 +++++++++++
 log.c          |  7 +++++++
 raft.c         |  3 +++
 7 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 error.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b53806a..e976f8f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,6 +19,7 @@ if (LIBFLOAT_BUILD_SHARED)
         log.c
         periodic.c
         snapshot.c
+        error.c
         externals/list.c
     )
 
@@ -36,6 +37,7 @@ add_library(float-static STATIC
     log.c
     periodic.c
     snapshot.c
+    error.c
     externals/list.c
 )
 
diff --git a/election.c b/election.c
index 95dd09b..e648421 100644
--- a/election.c
+++ b/election.c
@@ -189,6 +189,7 @@ void libfloat_request_vote_response(libfloat_ctx_t *ctx, libfloat_rpc_response_v
         {
             DEBUG(ctx, "I have a majority of votes! Assuming leadership");
             libfloat_become_leader(ctx);
+            ctx->stat.leader_election++;
         }
     }
 }
@@ -221,4 +222,4 @@ void libfloat_election_resign_receive(libfloat_ctx_t *ctx)
 {
     ERROR(ctx, "Restart election");
     libfloat_election_start(ctx);
-}
\ No newline at end of file
+}
diff --git a/error.c b/error.c
new file mode 100644
index 0000000..0eed0fb
--- /dev/null
+++ b/error.c
@@ -0,0 +1,16 @@
+#include "internal.h"
+
+static char *__error = NULL;
+
+const char *libfloat_get_error_str(void)
+{
+    const char *ret = __error;
+
+    __error = NULL;
+    return ret;
+}
+
+void libfloat_set_error_str(const char *str)
+{
+    __error = (char *)str;
+}
diff --git a/internal.h b/internal.h
index 3e1dff1..ad41067 100644
--- a/internal.h
+++ b/internal.h
@@ -80,4 +80,11 @@ void libfloat_debug(libfloat_ctx_t *ctx, const char *fmt, ...) __attribute__((fo
     } while (0)
 void libfloat_error(libfloat_ctx_t *ctx, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 
+/*!
+ * \brief Set a error to be retrieved by the caller
+ *
+ * \param[in] str String to set (Constants only)
+ */
+void libfloat_set_error_str(const char *str);
+
 #endif /* LIBFLOAT_INTERNAL_H */
diff --git a/libfloat.h b/libfloat.h
index 1717ef8..dcce50f 100644
--- a/libfloat.h
+++ b/libfloat.h
@@ -43,6 +43,10 @@ struct libfloat_ctx_s {
         } snapshot;
     } persistent;
 
+    struct {
+        uint64_t        leader_election;                /*!< Count of leader elections for this cluster */
+    } stat;
+
     struct {
         uint32_t                election_timeout;       /*!< Timeout for RAFT election (ms) */
         uint32_t                log_commit_timeout;     /*!< Timeout for log application (s) */
@@ -474,4 +478,11 @@ void libfloat_election_resign(libfloat_ctx_t *ctx);
  */
 void libfloat_election_resign_receive(libfloat_ctx_t *ctx);
 
+/*!
+ * \brief Get a string explaining an error that has happened
+ *
+ * \note This is only useful for libfloat_add_log for now
+ */
+const char *libfloat_get_error_str(void);
+
 #endif /* LIBFLOAT_H */
diff --git a/log.c b/log.c
index 7676da1..ad95bc7 100644
--- a/log.c
+++ b/log.c
@@ -11,12 +11,14 @@ bool libfloat_add_log(libfloat_ctx_t *ctx, libfloat_commit_type_t commit_type, l
     if (ctx->state != RAFT_STATE_LEADER)
     {
         ERROR(ctx ,"libfloat_add_log: Refusing write, not leader");
+        libfloat_set_error_str("Refusing write, not leader");
         return false;
     }
 
     entry = ctx->calloc(1, sizeof(*entry));
     if (entry == NULL)
     {
+        libfloat_set_error_str("Memory error");
         return false;
     }
 
@@ -24,6 +26,7 @@ bool libfloat_add_log(libfloat_ctx_t *ctx, libfloat_commit_type_t commit_type, l
     if (entry->data == NULL)
     {
         ctx->free(entry);
+        libfloat_set_error_str("Memory error");
         return false;
     }
 
@@ -74,6 +77,7 @@ bool libfloat_add_log(libfloat_ctx_t *ctx, libfloat_commit_type_t commit_type, l
         ctx->free(entry->data);
         ctx->free(entry);
         ERROR(ctx, "libfloat_add_log: Refusing write, callback returned false");
+        libfloat_set_error_str("User defined callback returned false");
         return false;
     }
 
@@ -445,6 +449,9 @@ response:
     if (node == NULL)
         node = libfloat_get_node(ctx, req->leader_id);
 
+    if (ctx->leader != node)
+        ctx->stat.leader_election++;
+
     ctx->leader = node;
     ctx->stepping_down = false;
 
diff --git a/raft.c b/raft.c
index 1515c5b..9070b2f 100644
--- a/raft.c
+++ b/raft.c
@@ -44,6 +44,9 @@ void libfloat_step_down(libfloat_ctx_t *ctx)
 {
     DEBUG(ctx, "Force stepping down");
     ctx->stepping_down = true;
+    if (ctx->state == RAFT_STATE_LEADER)
+        ctx->leader = NULL;
+
     ctx->state = RAFT_STATE_NONE;
 }
 
-- 
2.32.0