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raft_server.c
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raft_server.c
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/**
* Copyright (c) 2013, Willem-Hendrik Thiart
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* @file
* @brief Implementation of a Raft server
* @author Willem Thiart [email protected]
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
/* for varags */
#include <stdarg.h>
#include "raft.h"
#include "raft_log.h"
#include "raft_private.h"
#ifndef min
#define min(a, b) ((a) < (b) ? (a) : (b))
#endif
#ifndef max
#define max(a, b) ((a) < (b) ? (b) : (a))
#endif
static void raft_reset_node_indices(raft_server_t *me_, int max_idx);
static void __log(raft_server_t *me_, raft_node_t* node, const char *fmt, ...)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
if (me->cb.log == NULL) return;
char buf[1024];
va_list args;
va_start(args, fmt);
vsprintf(buf, fmt, args);
me->cb.log(me_, node, me->udata, buf);
va_end(args);
}
void raft_randomize_election_timeout(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
/* [election_timeout, 2 * election_timeout) */
me->election_timeout_rand = me->election_timeout + rand() % me->election_timeout;
__log(me_, NULL, "randomize election timeout to %d", me->election_timeout_rand);
}
raft_server_t* raft_new()
{
raft_server_private_t* me =
(raft_server_private_t*)calloc(1, sizeof(raft_server_private_t));
if (!me)
return NULL;
me->current_term = 0;
me->voted_for = -1;
me->timeout_elapsed = 0;
me->request_timeout = 200;
me->election_timeout = 1000;
raft_randomize_election_timeout((raft_server_t*)me);
me->log = log_new();
if (!me->log) {
free(me);
return NULL;
}
me->voting_cfg_change_log_idx = -1;
raft_set_state((raft_server_t*)me, RAFT_STATE_FOLLOWER);
me->leader_id = -1;
me->snapshot_in_progress = 0;
raft_set_snapshot_metadata((raft_server_t*)me, 0, 0);
return (raft_server_t*)me;
}
void raft_set_callbacks(raft_server_t* me_, raft_cbs_t* funcs, void* udata)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
memcpy(&me->cb, funcs, sizeof(raft_cbs_t));
me->udata = udata;
log_set_callbacks(me->log, &me->cb, me_);
raft_reset_node_indices(me_, raft_get_current_idx(me_));
}
void raft_free(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
log_free(me->log);
free(me_);
}
void raft_clear(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
me->current_term = 0;
me->voted_for = -1;
me->timeout_elapsed = 0;
raft_randomize_election_timeout(me_);
me->voting_cfg_change_log_idx = -1;
raft_set_state((raft_server_t*)me, RAFT_STATE_FOLLOWER);
me->leader_id = -1;
me->commit_idx = 0;
me->last_applied_idx = 0;
me->num_nodes = 0;
me->node_id = -1;
log_clear(me->log);
}
int raft_delete_entry_from_idx(raft_server_t* me_, int idx)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
assert(raft_get_commit_idx(me_) < idx);
if (idx <= me->voting_cfg_change_log_idx)
me->voting_cfg_change_log_idx = -1;
return log_delete(me->log, idx);
}
int raft_election_start(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
__log(me_, NULL, "election starting: %d %d, term: %d ci: %d",
me->election_timeout_rand, me->timeout_elapsed, me->current_term,
raft_get_current_idx(me_));
return raft_become_candidate(me_);
}
void raft_become_leader(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int i;
__log(me_, NULL, "becoming leader term:%d", raft_get_current_term(me_));
raft_set_state(me_, RAFT_STATE_LEADER);
me->timeout_elapsed = 0;
for (i = 0; i < me->num_nodes; i++)
{
raft_node_t* node = me->nodes[i];
if (raft_is_self(me_, node) || !raft_node_is_active(node))
continue;
raft_node_set_next_idx(node, raft_get_current_idx(me_) + 1);
raft_node_set_match_idx(node, 0);
raft_send_appendentries(me_, node);
}
}
int raft_become_candidate(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int i;
__log(me_, NULL, "becoming candidate");
int e = raft_set_current_term(me_, raft_get_current_term(me_) + 1);
if (0 != e)
return e;
for (i = 0; i < me->num_nodes; i++)
raft_node_vote_for_me(me->nodes[i], 0);
raft_vote_for_nodeid(me_, me->node_id);
me->leader_id = -1;
raft_set_state(me_, RAFT_STATE_CANDIDATE);
raft_randomize_election_timeout(me_);
me->timeout_elapsed = 0;
for (i = 0; i < me->num_nodes; i++)
{
raft_node_t* node = me->nodes[i];
if (!raft_is_self(me_, node) &&
raft_node_is_active(node) &&
raft_node_is_voting(node))
{
raft_send_requestvote(me_, node);
}
}
return 0;
}
void raft_become_follower(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
__log(me_, NULL, "becoming follower");
raft_set_state(me_, RAFT_STATE_FOLLOWER);
raft_randomize_election_timeout(me_);
me->timeout_elapsed = 0;
}
int raft_periodic(raft_server_t* me_, int msec_since_last_period)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
raft_node_t *my_node = raft_get_my_node((void *)me);
me->timeout_elapsed += msec_since_last_period;
/* Only one voting node means it's safe for us to become the leader */
if (1 == raft_get_num_voting_nodes(me_) &&
my_node &&
raft_node_is_voting(my_node) &&
/*
* Check when node is voting but not active:
* This occurs when we have just two nodes and this node was previously
* removed and then added back. In response to 'remove' log entry,
* this node is marked inactive but then becomes the leader. Eventually,
* when the log entries are applied, the node gets removed while being
* the leader. Probably needs a better solution.
*/
raft_node_is_active(my_node) &&
!raft_is_leader(me_))
raft_become_leader(me_);
if (me->state == RAFT_STATE_LEADER)
{
if (me->request_timeout <= me->timeout_elapsed)
raft_send_appendentries_all(me_);
}
else if (me->election_timeout_rand <= me->timeout_elapsed &&
/* Don't become the leader when building snapshots or bad things will
* happen when we get a client request */
!raft_snapshot_is_in_progress(me_))
{
if (1 < raft_get_num_voting_nodes(me_) &&
my_node && raft_node_is_voting(my_node))
{
int e = raft_election_start(me_);
if (0 != e)
return e;
}
}
if (me->last_applied_idx < raft_get_commit_idx(me_) &&
!raft_snapshot_is_in_progress(me_))
{
int e = raft_apply_all(me_);
if (0 != e)
return e;
}
return 0;
}
raft_entry_t* raft_get_entry_from_idx(raft_server_t* me_, int etyidx)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
return log_get_at_idx(me->log, etyidx);
}
/* Returns nonzero if we've got the term at idx or zero otherwise. */
int raft_get_entry_term(raft_server_t* me_, int idx, int* term)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int got = 1;
raft_entry_t* ety = raft_get_entry_from_idx(me_, idx);
if (ety)
*term = ety->term;
else if (idx == log_get_base(me->log))
*term = log_get_base_term(me->log);
else
got = 0;
return got;
}
int raft_voting_change_is_in_progress(raft_server_t* me_)
{
return ((raft_server_private_t*)me_)->voting_cfg_change_log_idx != -1;
}
int raft_recv_appendentries_response(raft_server_t* me_,
raft_node_t* node,
msg_appendentries_response_t* r)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
__log(me_, node,
"received appendentries response %s ci:%d rci:%d 1stidx:%d",
r->success == 1 ? "SUCCESS" : "fail",
raft_get_current_idx(me_),
r->current_idx,
r->first_idx);
if (!node)
return -1;
if (!raft_is_leader(me_))
return RAFT_ERR_NOT_LEADER;
/* If response contains term T > currentTerm: set currentTerm = T
and convert to follower (§5.3) */
if (me->current_term < r->term)
{
int e = raft_set_current_term(me_, r->term);
if (0 != e)
return e;
raft_become_follower(me_);
me->leader_id = -1;
return 0;
}
else if (me->current_term != r->term)
return 0;
int match_idx = raft_node_get_match_idx(node);
if (0 == r->success)
{
/* If AppendEntries fails because of log inconsistency:
decrement nextIndex and retry (§5.3) */
int next_idx = raft_node_get_next_idx(node);
assert(0 < next_idx);
/* Stale response -- ignore */
assert(match_idx <= next_idx - 1);
if (match_idx == next_idx - 1)
return 0;
if (r->current_idx < next_idx - 1)
raft_node_set_next_idx(node, min(r->current_idx + 1, raft_get_current_idx(me_)));
else
raft_node_set_next_idx(node, next_idx - 1);
/* retry */
raft_send_appendentries(me_, node);
return 0;
}
if (!raft_node_is_voting(node) &&
!raft_voting_change_is_in_progress(me_) &&
raft_get_current_idx(me_) <= r->current_idx + 1 &&
!raft_node_is_voting_committed(node) &&
me->cb.node_has_sufficient_logs &&
0 == raft_node_has_sufficient_logs(node)
)
{
int e = me->cb.node_has_sufficient_logs(me_, me->udata, node);
if (0 == e)
raft_node_set_has_sufficient_logs(node);
}
if (r->current_idx <= match_idx)
return 0;
assert(r->current_idx <= raft_get_current_idx(me_));
raft_node_set_next_idx(node, r->current_idx + 1);
raft_node_set_match_idx(node, r->current_idx);
/* Update commit idx */
int point = r->current_idx;
if (point && raft_get_commit_idx(me_) < point)
{
int term;
int got = raft_get_entry_term(me_, point, &term);
if (got && term == me->current_term)
{
int i, votes = 1;
for (i = 0; i < me->num_nodes; i++)
{
raft_node_t* tmpnode = me->nodes[i];
if (!raft_is_self(me_, tmpnode) &&
raft_node_is_active(tmpnode) &&
raft_node_is_voting(tmpnode) &&
point <= raft_node_get_match_idx(tmpnode))
{
votes++;
}
}
if (raft_get_num_voting_nodes(me_) / 2 < votes)
raft_set_commit_idx(me_, point);
}
}
/* Aggressively send remaining entries */
if (raft_node_get_next_idx(node) <= raft_get_current_idx(me_))
raft_send_appendentries(me_, node);
/* periodic applies committed entries lazily */
return 0;
}
int raft_recv_appendentries(
raft_server_t* me_,
raft_node_t* node,
msg_appendentries_t* ae,
msg_appendentries_response_t *r
)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int e = 0;
if (0 < ae->n_entries)
__log(me_, node, "recvd appendentries t:%d ci:%d lc:%d pli:%d plt:%d #%d",
ae->term,
raft_get_current_idx(me_),
ae->leader_commit,
ae->prev_log_idx,
ae->prev_log_term,
ae->n_entries);
r->success = 0;
if (raft_is_candidate(me_) && me->current_term == ae->term)
{
raft_become_follower(me_);
}
else if (me->current_term < ae->term)
{
e = raft_set_current_term(me_, ae->term);
if (0 != e)
goto out;
raft_become_follower(me_);
}
else if (ae->term < me->current_term)
{
/* 1. Reply false if term < currentTerm (§5.1) */
__log(me_, node, "AE term %d is less than current term %d",
ae->term, me->current_term);
goto out;
}
/* update current leader because ae->term is up to date */
me->leader_id = raft_node_get_id(node);
me->timeout_elapsed = 0;
/* Not the first appendentries we've received */
/* NOTE: the log starts at 1 */
if (0 < ae->prev_log_idx)
{
/* 2. Reply false if log doesn't contain an entry at prevLogIndex
whose term matches prevLogTerm (§5.3) */
int term;
int got = raft_get_entry_term(me_, ae->prev_log_idx, &term);
if (!got && raft_get_current_idx(me_) < ae->prev_log_idx)
{
__log(me_, node, "AE no log at prev_idx %d", ae->prev_log_idx);
goto out;
}
else if (got && term != ae->prev_log_term)
{
__log(me_, node, "AE term doesn't match prev_term (ie. %d vs %d) ci:%d comi:%d lcomi:%d pli:%d",
term, ae->prev_log_term, raft_get_current_idx(me_),
raft_get_commit_idx(me_), ae->leader_commit, ae->prev_log_idx);
if (ae->prev_log_idx <= raft_get_commit_idx(me_))
{
/* Should never happen; something is seriously wrong! */
__log(me_, node, "AE prev conflicts with committed entry");
e = RAFT_ERR_SHUTDOWN;
goto out;
}
/* Delete all the following log entries because they don't match */
e = raft_delete_entry_from_idx(me_, ae->prev_log_idx);
goto out;
}
}
r->success = 1;
r->current_idx = ae->prev_log_idx;
/* 3. If an existing entry conflicts with a new one (same index
but different terms), delete the existing entry and all that
follow it (§5.3) */
int i;
for (i = 0; i < ae->n_entries; i++)
{
raft_entry_t* ety = &ae->entries[i];
int ety_index = ae->prev_log_idx + 1 + i;
int term;
int got = raft_get_entry_term(me_, ety_index, &term);
if (got && term != ety->term)
{
if (ety_index <= raft_get_commit_idx(me_))
{
/* Should never happen; something is seriously wrong! */
__log(me_, node, "AE entry conflicts with committed entry ci:%d comi:%d lcomi:%d pli:%d",
raft_get_current_idx(me_), raft_get_commit_idx(me_),
ae->leader_commit, ae->prev_log_idx);
e = RAFT_ERR_SHUTDOWN;
goto out;
}
e = raft_delete_entry_from_idx(me_, ety_index);
if (0 != e)
goto out;
break;
}
else if (!got && raft_get_current_idx(me_) < ety_index)
break;
r->current_idx = ety_index;
}
/* 4. Append any new entries not already in the log */
int k = ae->n_entries - i;
e = raft_append_entries(me_, &ae->entries[i], &k);
i += k;
r->current_idx = ae->prev_log_idx + i;
if (0 != e)
goto out;
/* 5. If leaderCommit > commitIndex, set commitIndex =
min(leaderCommit, index of last new entry) */
if (raft_get_commit_idx(me_) < ae->leader_commit)
{
int new_commit_idx = min(ae->leader_commit, r->current_idx);
if (raft_get_commit_idx(me_) < new_commit_idx)
raft_set_commit_idx(me_, new_commit_idx);
}
out:
r->term = me->current_term;
if (0 == r->success)
r->current_idx = raft_get_current_idx(me_);
r->first_idx = ae->prev_log_idx + 1;
return e;
}
int raft_already_voted(raft_server_t* me_)
{
return ((raft_server_private_t*)me_)->voted_for != -1;
}
static int __should_grant_vote(raft_server_private_t* me, msg_requestvote_t* vr)
{
raft_node_t *my_node = raft_get_my_node((void*)me);
/* TODO: 4.2.3 Raft Dissertation:
* if a server receives a RequestVote request within the minimum election
* timeout of hearing from a current leader, it does not update its term or
* grant its vote */
if (my_node && !raft_node_is_voting(my_node))
return 0;
if (vr->term < raft_get_current_term((void*)me))
return 0;
/* TODO: if voted for is candiate return 1 (if below checks pass) */
if (raft_already_voted((void*)me))
return 0;
/* Below we check if log is more up-to-date... */
int current_idx = raft_get_current_idx((void*)me);
int term;
int got = raft_get_entry_term((void*)me, current_idx, &term);
assert(got);
if (term < vr->last_log_term)
return 1;
if (vr->last_log_term == term && current_idx <= vr->last_log_idx)
return 1;
return 0;
}
int raft_recv_requestvote(raft_server_t* me_,
raft_node_t* node,
msg_requestvote_t* vr,
msg_requestvote_response_t *r)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int e = 0;
if (!node)
node = raft_get_node(me_, vr->candidate_id);
if (raft_get_current_term(me_) < vr->term)
{
e = raft_set_current_term(me_, vr->term);
if (0 != e) {
r->vote_granted = 0;
goto done;
}
raft_become_follower(me_);
me->leader_id = -1;
}
if (__should_grant_vote(me, vr))
{
/* It shouldn't be possible for a leader or candidate to grant a vote
* Both states would have voted for themselves */
assert(!(raft_is_leader(me_) || raft_is_candidate(me_)));
e = raft_vote_for_nodeid(me_, vr->candidate_id);
if (0 == e)
r->vote_granted = 1;
else
r->vote_granted = 0;
/* there must be in an election. */
me->leader_id = -1;
me->timeout_elapsed = 0;
}
else
{
/* It's possible the candidate node has been removed from the cluster but
* hasn't received the appendentries that confirms the removal. Therefore
* the node is partitioned and still thinks its part of the cluster. It
* will eventually send a requestvote. This is error response tells the
* node that it might be removed. */
if (!node)
{
r->vote_granted = RAFT_REQUESTVOTE_ERR_UNKNOWN_NODE;
goto done;
}
else
r->vote_granted = 0;
}
done:
__log(me_, node, "node requested vote: %d replying: %s",
node == NULL ? -1 : raft_node_get_id(node),
r->vote_granted == 1 ? "granted" :
r->vote_granted == 0 ? "not granted" : "unknown");
r->term = raft_get_current_term(me_);
return e;
}
int raft_votes_is_majority(const int num_nodes, const int nvotes)
{
if (num_nodes < nvotes)
return 0;
int half = num_nodes / 2;
return half + 1 <= nvotes;
}
int raft_recv_requestvote_response(raft_server_t* me_,
raft_node_t* node,
msg_requestvote_response_t* r)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
__log(me_, node, "node responded to requestvote status: %s",
r->vote_granted == 1 ? "granted" :
r->vote_granted == 0 ? "not granted" : "unknown");
if (!raft_is_candidate(me_))
{
return 0;
}
else if (raft_get_current_term(me_) < r->term)
{
int e = raft_set_current_term(me_, r->term);
if (0 != e)
return e;
raft_become_follower(me_);
me->leader_id = -1;
return 0;
}
else if (raft_get_current_term(me_) != r->term)
{
/* The node who voted for us would have obtained our term.
* Therefore this is an old message we should ignore.
* This happens if the network is pretty choppy. */
return 0;
}
__log(me_, node, "node responded to requestvote status:%s ct:%d rt:%d",
r->vote_granted == 1 ? "granted" :
r->vote_granted == 0 ? "not granted" : "unknown",
me->current_term,
r->term);
switch (r->vote_granted)
{
case RAFT_REQUESTVOTE_ERR_GRANTED:
if (node)
raft_node_vote_for_me(node, 1);
int votes = raft_get_nvotes_for_me(me_);
if (raft_votes_is_majority(raft_get_num_voting_nodes(me_), votes))
raft_become_leader(me_);
break;
case RAFT_REQUESTVOTE_ERR_NOT_GRANTED:
break;
case RAFT_REQUESTVOTE_ERR_UNKNOWN_NODE:
if (raft_node_is_voting(raft_get_my_node(me_)) &&
me->connected == RAFT_NODE_STATUS_DISCONNECTING)
return RAFT_ERR_SHUTDOWN;
break;
default:
assert(0);
}
return 0;
}
int raft_recv_installsnapshot(raft_server_t* me_,
raft_node_t* node,
msg_installsnapshot_t* is,
msg_installsnapshot_response_t* r)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int e;
r->term = me->current_term;
r->last_idx = is->last_idx;
r->complete = 0;
if (is->term < me->current_term)
return 0;
if (me->current_term < is->term)
{
e = raft_set_current_term(me_, is->term);
if (0 != e)
return e;
r->term = me->current_term;
}
if (!raft_is_follower(me_))
raft_become_follower(me_);
me->leader_id = raft_node_get_id(node);
me->timeout_elapsed = 0;
if (is->last_idx <= raft_get_commit_idx(me_))
{
/* Committed entries must match the snapshot. */
r->complete = 1;
return 0;
}
int term;
int got = raft_get_entry_term(me_, is->last_idx, &term);
if (got && term == is->last_term)
{
raft_set_commit_idx(me_, is->last_idx);
r->complete = 1;
return 0;
}
assert(me->cb.recv_installsnapshot);
e = me->cb.recv_installsnapshot(me_, me->udata, node, is, r);
if (e < 0)
return e;
if (e == 1)
r->complete = 1;
return 0;
}
int raft_recv_installsnapshot_response(raft_server_t* me_,
raft_node_t* node,
msg_installsnapshot_response_t *r)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
if (!node)
return -1;
if (!raft_is_leader(me_))
return RAFT_ERR_NOT_LEADER;
if (me->current_term < r->term)
{
int e = raft_set_current_term(me_, r->term);
if (0 != e)
return e;
raft_become_follower(me_);
me->leader_id = -1;
return 0;
}
else if (me->current_term != r->term)
return 0;
assert(me->cb.recv_installsnapshot_response);
int e = me->cb.recv_installsnapshot_response(me_, me->udata, node, r);
if (0 != e)
return e;
if (!r->complete)
return 0;
/* The snapshot installation is complete. Update the node state. */
if (raft_node_get_match_idx(node) < r->last_idx)
{
raft_node_set_match_idx(node, r->last_idx);
raft_node_set_next_idx(node, r->last_idx + 1);
}
if (raft_node_get_next_idx(node) <= raft_get_current_idx(me_))
raft_send_appendentries(me_, node);
return 0;
}
int raft_recv_entry(raft_server_t* me_,
msg_entry_t* ety,
msg_entry_response_t *r)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
int i;
if (raft_entry_is_voting_cfg_change(ety))
{
/* Only one voting cfg change at a time */
if (raft_voting_change_is_in_progress(me_))
return RAFT_ERR_ONE_VOTING_CHANGE_ONLY;
/* Multi-threading: need to fail here because user might be
* snapshotting membership settings. */
if (raft_snapshot_is_in_progress(me_))
return RAFT_ERR_SNAPSHOT_IN_PROGRESS;
}
if (!raft_is_leader(me_))
return RAFT_ERR_NOT_LEADER;
__log(me_, NULL, "received entry t:%d id: %d idx: %d",
me->current_term, ety->id, raft_get_current_idx(me_) + 1);
ety->term = me->current_term;
int k = 1;
int e = raft_append_entries(me_, ety, &k);
if (0 != e)
return e;
assert(k == 1);
for (i = 0; i < me->num_nodes; i++)
{
raft_node_t* node = me->nodes[i];
if (!node || raft_is_self(me_, node) ||
!raft_node_is_active(node) ||
!raft_node_is_voting(node))
continue;
/* Only send new entries.
* Don't send the entry to peers who are behind, to prevent them from
* becoming congested. */
if (raft_node_get_next_idx(node) == raft_get_current_idx(me_))
raft_send_appendentries(me_, node);
}
/* if we're the only node, we can consider the entry committed */
if (1 == raft_get_num_voting_nodes(me_))
raft_set_commit_idx(me_, raft_get_current_idx(me_));
r->id = ety->id;
r->idx = raft_get_current_idx(me_);
r->term = me->current_term;
if (raft_entry_is_voting_cfg_change(ety))
me->voting_cfg_change_log_idx = raft_get_current_idx(me_);
return 0;
}
int raft_send_requestvote(raft_server_t* me_, raft_node_t* node)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
msg_requestvote_t rv;
int e = 0;
assert(node);
assert(!raft_is_self(me_, node));
__log(me_, node, "sending requestvote to: %d", raft_node_get_id(node));
rv.term = me->current_term;
rv.last_log_idx = raft_get_current_idx(me_);
rv.last_log_term = raft_get_last_log_term(me_);
rv.candidate_id = raft_get_nodeid(me_);
if (me->cb.send_requestvote)
e = me->cb.send_requestvote(me_, me->udata, node, &rv);
return e;
}
int raft_append_entries(raft_server_t* me_, raft_entry_t* entries, int *n)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
return log_append(me->log, entries, n);
}
int raft_apply_entry(raft_server_t* me_)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
if (raft_snapshot_is_in_progress(me_))
return -1;
/* Don't apply after the commit_idx */
if (me->last_applied_idx == raft_get_commit_idx(me_))
return -1;
int log_idx = me->last_applied_idx + 1;
raft_entry_t* ety = raft_get_entry_from_idx(me_, log_idx);
if (!ety)
return -1;
__log(me_, NULL, "applying log: %d, id: %d size: %d",
log_idx, ety->id, ety->data.len);
me->last_applied_idx++;
if (me->cb.applylog)
{
int e = me->cb.applylog(me_, me->udata, ety, me->last_applied_idx);
if (RAFT_ERR_SHUTDOWN == e)
return RAFT_ERR_SHUTDOWN;
}
/* voting cfg change is now complete */
if (log_idx == me->voting_cfg_change_log_idx)
me->voting_cfg_change_log_idx = -1;
if (!raft_entry_is_cfg_change(ety))
return 0;
int node_id = me->cb.log_get_node_id(me_, raft_get_udata(me_), ety, log_idx);
raft_node_t* node = raft_get_node(me_, node_id);
assert(node || ety->type == RAFT_LOGTYPE_REMOVE_NODE);
switch (ety->type) {
case RAFT_LOGTYPE_ADD_NODE:
/* Membership Change: confirm connection with cluster */
raft_node_set_has_sufficient_logs(node);
if (node_id == raft_get_nodeid(me_))
me->connected = RAFT_NODE_STATUS_CONNECTED;
break;
case RAFT_LOGTYPE_REMOVE_NODE:
/* Do not remove node if there are pending entries that affect it */
if (node && raft_node_get_offered_idx(node) == log_idx)
{
raft_remove_node(me_, node);
node = NULL;
}
break;
}
if (node)
{
raft_node_set_applied_idx(node, log_idx);
if (raft_node_get_offered_idx(node) == log_idx)
raft_node_set_offered_idx(node, -1);
}
return 0;
}
raft_entry_t* raft_get_entries_from_idx(raft_server_t* me_, int idx, int* n_etys)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
return log_get_from_idx(me->log, idx, n_etys);
}
int raft_send_installsnapshot(raft_server_t* me_, raft_node_t* node)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
msg_installsnapshot_t is = {};
is.term = me->current_term;
is.last_idx = log_get_base(me->log);
is.last_term = log_get_base_term(me->log);
__log(me_, node, "sending installsnapshot: ci:%d comi:%d t:%d lli:%d llt:%d",
raft_get_current_idx(me_),
raft_get_commit_idx(me_),
is.term,
is.last_idx,
is.last_term);
assert(me->cb.send_installsnapshot);
return me->cb.send_installsnapshot(me_, me->udata, node, &is);
}
int raft_send_appendentries(raft_server_t* me_, raft_node_t* node)
{
raft_server_private_t* me = (raft_server_private_t*)me_;
assert(node);
assert(!raft_is_self(me_, node));
if (!(me->cb.send_appendentries))
return -1;
msg_appendentries_t ae = {};