This patch adds the ability to register a should_snapshot callback,
that can be used in order to avoid snapshotting on certain cases
decided by the library client.
Signed-off-by: Patrik Cyvoct <patrik@ptrk.io>
---
libfloat.h | 92 ++++++++++++++++++++++++++++++------------------------
log.c | 11 ++++++-
2 files changed, 61 insertions(+), 42 deletions(-)
diff --git a/libfloat.h b/libfloat.h
index 9a529b4..06d51e2 100644
--- a/libfloat.h
+++ b/libfloat.h
@@ -32,35 +32,36 @@ typedef enum {
struct libfloat_ctx_s {
struct {
- libfloat_term_t term; /*!< Current term */
- libfloat_node_id_t voted_for; /*!< Last Node ID we voted for (0 if no current vote) */
- libfloat_entry_id_t commit_index; /*!< Last log we applied */
- khash_t(libfloat_entry_id_t) *log; /*!< Hashtable of current log */
+ libfloat_term_t term; /*!< Current term */
+ libfloat_node_id_t voted_for; /*!< Last Node ID we voted for (0 if no current vote) */
+ libfloat_entry_id_t commit_index; /*!< Last log we applied */
+ khash_t(libfloat_entry_id_t) *log; /*!< Hashtable of current log */
struct {
- libfloat_entry_id_t index; /*!< Last index of the snapshot */
- libfloat_term_t term; /*!< Last term of the snapshot */
+ libfloat_entry_id_t index; /*!< Last index of the snapshot */
+ libfloat_term_t term; /*!< Last term of the snapshot */
+ libfloat_entry_id_t last_checked_index; /*!< Last checked index of the snapshot, used if should_snapshot is defined */
} snapshot;
} persistent;
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 */
- const char *last_election_reason; /*!< Last reason we had an election */
- time_t last_election_duration; /*!< Time it took to elect a leader for the last election */
+ 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 */
+ const char *last_election_reason; /*!< Last reason we had an election */
+ time_t last_election_duration; /*!< Time it took to elect a leader for the last election */
} stat;
struct {
- uint32_t election_timeout; /*!< Timeout for RAFT election (ms) */
- uint32_t log_commit_timeout; /*!< Timeout for log application (s) */
- uint32_t compact_every_n_log; /*!< Snapshot every N logs */
- bool avoid_congestion; /*!< Avoid spamming AE to nodes already behind */
- uint32_t sanity_timeout; /*!< Timeout before a leader steps-down if it can't reach any other nodes (sec) */
- bool optimistic_replication; /*!< Do we assume that nodes are gonna replicate the log or not */
- uint32_t max_logs_per_ae; /*!< Max number of logs to be sent per AE request */
- bool do_revert; /*!< Whether or not to revert logs */
- uint32_t deep_sleep_time; /*!< Time with no activity before a cluster goes in deep-sleep mode */
+ uint32_t election_timeout; /*!< Timeout for RAFT election (ms) */
+ uint32_t log_commit_timeout; /*!< Timeout for log application (s) */
+ uint32_t compact_every_n_log; /*!< Snapshot every N logs */
+ bool avoid_congestion; /*!< Avoid spamming AE to nodes already behind */
+ uint32_t sanity_timeout; /*!< Timeout before a leader steps-down if it can't reach any other nodes (sec) */
+ bool optimistic_replication; /*!< Do we assume that nodes are gonna replicate the log or not */
+ uint32_t max_logs_per_ae; /*!< Max number of logs to be sent per AE request */
+ bool do_revert; /*!< Whether or not to revert logs */
+ uint32_t deep_sleep_time; /*!< Time with no activity before a cluster goes in deep-sleep mode */
struct {
uint32_t election_timeout;
@@ -70,35 +71,35 @@ struct libfloat_ctx_s {
} original;
} conf;
- libfloat_raft_state_t state; /*!< Current state of the node */
- size_t n_nodes; /*!< Number of nodes in the cluster */
- khash_t(libfloat_node_id_t) *nodes; /*!< Hashtable of nodes */
- libfloat_node_t *leader; /*!< Current Leader (can be NULL) */
- libfloat_node_t *me; /*!< My node in the cluster */
-
- uint32_t timeout_elapsed; /*!< Current time elasped between two heartbeats */
- uint32_t election_timeout_rand; /*!< Randomized election time */
- uint32_t request_timeout; /*!< Timeout for AE */
- uint32_t logs_check; /*!< Last check counter of log stuck */
- bool stepping_down; /*!< Is the node stepping down from leadership */
- time_t lost_leader_time; /*!< Timestamp that we lost our leader */
- time_t last_log_time; /*!< Last time we applied a log */
+ libfloat_raft_state_t state; /*!< Current state of the node */
+ size_t n_nodes; /*!< Number of nodes in the cluster */
+ khash_t(libfloat_node_id_t) *nodes; /*!< Hashtable of nodes */
+ libfloat_node_t *leader; /*!< Current Leader (can be NULL) */
+ libfloat_node_t *me; /*!< My node in the cluster */
+
+ uint32_t timeout_elapsed; /*!< Current time elasped between two heartbeats */
+ uint32_t election_timeout_rand; /*!< Randomized election time */
+ uint32_t request_timeout; /*!< Timeout for AE */
+ uint32_t logs_check; /*!< Last check counter of log stuck */
+ bool stepping_down; /*!< Is the node stepping down from leadership */
+ time_t lost_leader_time; /*!< Timestamp that we lost our leader */
+ time_t last_log_time; /*!< Last time we applied a log */
#define LIBFLOAT_DEEP_SLEEP_STATE_MAX 4
- uint32_t deep_sleep_state; /*!< Deep sleep state of the cluster */
+ uint32_t deep_sleep_state; /*!< Deep sleep state of the cluster */
struct {
- bool checking; /*!< Are we checking that every node has lost the leader? */
- bool recovering; /*!< We've just recoverd a leader from a gray-failure check */
- time_t check_time; /*!< Time that we launched the check */
+ bool checking; /*!< Are we checking that every node has lost the leader? */
+ bool recovering; /*!< We've just recoverd a leader from a gray-failure check */
+ time_t check_time; /*!< Time that we launched the check */
} gray_failures;
- bool is_snapshotting; /*!< Is the cluster currently snapshotting */
- libfloat_entry_id_t snapshot_to_commit; /*!< Last log ID that is to be written after the snapshot is done */
+ bool is_snapshotting; /*!< Is the cluster currently snapshotting */
+ libfloat_entry_id_t snapshot_to_commit; /*!< Last log ID that is to be written after the snapshot is done */
- libfloat_list_t logs; /*<! Logs with commit still not acked */
+ libfloat_list_t logs; /*<! Logs with commit still not acked */
- void *udata; /*!< User data */
+ void *udata; /*!< User data */
/*!
* \brief Send a Vote Request to a node
@@ -325,6 +326,15 @@ struct libfloat_ctx_s {
*/
void (*debug)(struct libfloat_ctx_s *, const char *);
+ /*!
+ * \brief Returns wether a snapshot is needed, with the implementation left to the client
+ *
+ * \param[in] struct libfloat_ctx_s * - Cluster context
+ *
+ * \note This function will be called each compact_every_n_log
+ */
+ bool (*should_snapshot)(struct libfloat_ctx_s *);
+
/**
* The following functions are expected to behave like their counterparts in man(3)
*/
diff --git a/log.c b/log.c
index 53bf93d..d61ce49 100644
--- a/log.c
+++ b/log.c
@@ -179,7 +179,16 @@ bool libfloat_add_log(libfloat_ctx_t *ctx, libfloat_commit_type_t commit_type, l
if (ctx->conf.compact_every_n_log != 0)
{
/* User asked for snapshots, let's check it */
- if (ctx->persistent.commit_index - ctx->persistent.snapshot.index >= ctx->conf.compact_every_n_log)
+ if (ctx->should_snapshot != NULL)
+ {
+ /* If we have a should_snapshot method registered, let's check if this snapshot is needed */
+ if (ctx->persistent.commit_index - ctx->persistent.snapshot.last_checked_index >= ctx->conf.compact_every_n_log && ctx->should_snapshot(ctx))
+ {
+ ctx->append_snapshot_log(ctx, ctx->persistent.commit_index, ctx->persistent.term);
+ ctx->persistent.snapshot.last_checked_index = ctx->persistent.commit_index;
+ }
+ }
+ else if (ctx->persistent.commit_index - ctx->persistent.snapshot.index >= ctx->conf.compact_every_n_log)
{
ctx->append_snapshot_log(ctx, ctx->persistent.commit_index, ctx->persistent.term);
}
--
2.41.0