~ne02ptzero/libfloat

ref: c93ce23cec30a46ea6bd54d341f22cb6d582bbd9 libfloat/raft.c -rw-r--r-- 4.1 KiB
c93ce23c — Louis Solofrizzo log: Add helpers for human readable consistency types 2 months ago
                                                                                
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#include "internal.h"

bool libfloat_am_i_leader(libfloat_ctx_t *ctx)
{
    return ctx->state == RAFT_STATE_LEADER;
}

void libfloat_become_leader(libfloat_ctx_t *ctx)
{
    libfloat_node_t     *node;

    ctx->state = RAFT_STATE_LEADER;

    if (ctx->become_leader_cb != NULL && ctx->leader != ctx->me)
        ctx->become_leader_cb(ctx);

    ctx->leader = ctx->me;

    for_every_node(ctx, node, {
        /* Let's notify all the nodes */
        if (node != ctx->me)
            libfloat_send_append_entries(ctx, node, true);
    });

    ctx->me->is_up_to_date = 1;
}

void libfloat_become_candidate(libfloat_ctx_t *ctx)
{
    DEBUG(ctx, "Becoming candidate");
    ctx->state = RAFT_STATE_CANDIDATE;
    ctx->election_timeout_rand = ctx->conf.election_timeout + ctx->rand() % ctx->conf.election_timeout;
}

void libfloat_become_follower(libfloat_ctx_t *ctx)
{
    DEBUG(ctx, "Becoming follower");
    ctx->state = RAFT_STATE_FOLLOWER;
    ctx->election_timeout_rand = ctx->conf.election_timeout + ctx->rand() % ctx->conf.election_timeout;
    libfloat_vote_for(ctx, 0);
}

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;
}

void libfloat_send_append_entries_to_all(libfloat_ctx_t *ctx)
{
    libfloat_node_t     *node;

    for_every_node(ctx, node, {
        if (node != ctx->me)
            libfloat_send_append_entries(ctx, node, false);
    });
}

void libfloat_set_current_term(libfloat_ctx_t *ctx, libfloat_term_t term)
{
    ctx->persistent.term = term;
    ctx->write_current_term(ctx, ctx->persistent.term);
}

void libfloat_set_current_commit_index(libfloat_ctx_t *ctx, libfloat_entry_id_t id)
{
    if (id <= ctx->persistent.commit_index)
        return;

    ctx->persistent.commit_index = id;
    ctx->write_commit_index(ctx, ctx->persistent.commit_index);
}

const char *libfloat_cluster_state_to_str(libfloat_ctx_t *ctx)
{
    switch (ctx->state)
    {
        case RAFT_STATE_NONE:
            return "NONE";
        case RAFT_STATE_FOLLOWER:
            return "FOLLOWER";
        case RAFT_STATE_CANDIDATE:
            return "CANDIDATE";
        case RAFT_STATE_LEADER:
            return "LEADER";
    }

    return NULL;
}

void libfloat_reload_state(libfloat_ctx_t *ctx)
{
    ctx->persistent.term = ctx->get_current_term(ctx);
    ctx->persistent.voted_for = ctx->get_vote(ctx);
    ctx->persistent.commit_index = ctx->get_commit_index(ctx);
    if (!ctx->get_last_snapshot(ctx, &ctx->persistent.snapshot.index, &ctx->persistent.snapshot.term))
    {
        /* No snapshot to load, let's set the defaults */
        ctx->persistent.snapshot.index = 0;
        ctx->persistent.snapshot.term = 0;
    }

    /* when reloading a snapshot, ctx may have older logs and we want to drop them */
    if (kh_size(ctx->persistent.log) > 0)
    {
        libfloat_log_memory_cleanup(ctx);
    }

    /* XXX some part of code try to load missing log but other not */
    for (size_t i = ctx->persistent.snapshot.index + 1; i <= ctx->persistent.commit_index; i++)
    {
        libfloat_log_entry_t    *log;
        khint_t                 iterator;
        int                     absent;

        log = ctx->calloc(1, sizeof(*log));
        log->id = i;

        log->node_acks.prev = &log->node_acks;
        log->node_acks.next = &log->node_acks;

        iterator = kh_put(libfloat_entry_id_t, ctx->persistent.log, log->id, &absent);
        kh_value(ctx->persistent.log, iterator) = log;
    }
}

bool libfloat_am_i_up_to_date(libfloat_ctx_t *ctx)
{
    if (ctx->state == RAFT_STATE_LEADER)
        return true;

    return ctx->me->is_up_to_date;
}

void libfloat_debug(libfloat_ctx_t *ctx, const char *fmt, ...)
{
    va_list     ap;
    char        log[1024] = { 0 };

    va_start(ap, fmt);
    ctx->vsnprintf(log, sizeof(log), fmt, ap);
    va_end(ap);

    ctx->debug(ctx, log);
}

void libfloat_error(libfloat_ctx_t *ctx, const char *fmt, ...)
{
    va_list     ap;
    char        log[1024] = { 0 };

    va_start(ap, fmt);
    ctx->vsnprintf(log, sizeof(log), fmt, ap);
    va_end(ap);

    ctx->error(ctx, log);
}