Commit 661032df authored by Willem Thiart's avatar Willem Thiart
Browse files

Fix current_idx management

The node tells the leader what's current_idx is using the appendentries
response.
parent fd1f0286
......@@ -46,7 +46,6 @@ void raft_node_set_next_idx(raft_node_t* me_, int nextIdx)
me->next_idx = nextIdx < 1 ? 1 : nextIdx;
}
int raft_node_get_match_idx(raft_node_t* me_)
{
raft_node_private_t* me = (raft_node_private_t*)me_;
......@@ -59,7 +58,6 @@ void raft_node_set_match_idx(raft_node_t* me_, int matchIdx)
me->match_idx = matchIdx;
}
void* raft_node_get_udata(raft_node_t* me_)
{
raft_node_private_t* me = (raft_node_private_t*)me_;
......
......@@ -95,7 +95,7 @@ void raft_become_leader(raft_server_t* me_)
if (me->nodeid != i)
{
raft_node_t* node = raft_get_node(me_, i);
raft_node_set_next_idx(node, raft_get_current_idx(me_));
raft_node_set_next_idx(node, raft_get_current_idx(me_) + 1);
raft_node_set_match_idx(node, 0);
raft_send_appendentries(me_, i);
}
......@@ -192,13 +192,21 @@ int raft_recv_appendentries_response(raft_server_t* me_,
/* If AppendEntries fails because of log inconsistency:
decrement nextIndex and retry (§5.3) */
assert(0 <= raft_node_get_next_idx(node));
raft_node_set_next_idx(node, r->current_idx + 1);
int next_idx = raft_node_get_next_idx(node);
assert(0 <= next_idx);
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_idx);
return 0;
}
assert(r->current_idx <= raft_get_current_idx(me_));
/* response to a repeat transmission -- ignore */
if (raft_node_get_match_idx(node) == r->current_idx)
return 0;
......@@ -258,7 +266,7 @@ int raft_recv_appendentries(
if (ae->term < me->current_term)
{
__log(me_, "AE term is less than current term");
goto fail;
goto fail_with_current_idx;
}
/* Not the first appendentries we've received */
......@@ -270,15 +278,22 @@ int raft_recv_appendentries(
if (!e)
{
__log(me_, "AE no log at prev_idx %d", ae->prev_log_idx);
goto fail;
goto fail_with_current_idx;
}
/* 2. Reply false if log doesn't contain an entry at prevLogIndex
whose term matches prevLogTerm (§5.3) */
if (raft_get_current_idx(me_) < ae->prev_log_idx)
goto fail_with_current_idx;
if (e->term != ae->prev_log_term)
{
__log(me_, "AE term doesn't match prev_idx (ie. %d vs %d)",
e->term, ae->prev_log_term);
assert(me->commit_idx < ae->prev_log_idx);
/* Delete all the following log entries because they don't match */
log_delete(me->log, ae->prev_log_idx);
r->current_idx = ae->prev_log_idx - 1;
goto fail;
}
}
......@@ -286,14 +301,24 @@ int raft_recv_appendentries(
/* 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) */
if (ae->n_entries == 0 && 0 < ae->prev_log_idx && ae->prev_log_idx + 1 < raft_get_current_idx(me_))
{
assert(me->commit_idx < ae->prev_log_idx + 1);
log_delete(me->log, ae->prev_log_idx + 1);
}
r->current_idx = ae->prev_log_idx;
int i;
for (i = 0; i < ae->n_entries; i++)
{
msg_entry_t* ety = &ae->entries[i];
int ety_index = ae->prev_log_idx + 1 + i;
raft_entry_t* existing_ety = raft_get_entry_from_idx(me_, ety_index);
r->current_idx = ety_index;
if (existing_ety && existing_ety->term != ety->term)
{
assert(me->commit_idx < ety_index);
log_delete(me->log, ety_index);
break;
}
......@@ -306,7 +331,9 @@ int raft_recv_appendentries(
{
int e = raft_append_entry(me_, &ae->entries[i]);
if (-1 == e)
goto fail;
goto fail_with_current_idx;
r->current_idx = ae->prev_log_idx + 1 + i;
}
/* 4. If leaderCommit > commitIndex, set commitIndex =
......@@ -321,13 +348,13 @@ int raft_recv_appendentries(
me->current_leader = node;
r->success = 1;
r->current_idx = raft_get_current_idx(me_);
r->first_idx = ae->prev_log_idx + 1;
return 0;
fail_with_current_idx:
r->current_idx = raft_get_current_idx(me_);
fail:
r->success = 0;
r->current_idx = raft_get_current_idx(me_);
r->first_idx = 0;
return -1;
}
......
......@@ -746,24 +746,16 @@ void TestRaft_follower_recv_appendentries_reply_false_if_doesnt_have_log_at_prev
CuAssertTrue(tc, 0 == aer.success);
}
/* 5.3 */
void TestRaft_follower_recv_appendentries_delete_entries_if_conflict_with_new_entries(
CuTest * tc)
static raft_entry_t* __entries_for_conflict_tests(
CuTest * tc,
raft_server_t* r,
char** strs)
{
msg_appendentries_t ae;
msg_appendentries_response_t aer;
raft_entry_t *ety_appended;
void *r = raft_new();
raft_add_node(r, (void*)1, 1);
raft_add_node(r, (void*)2, 0);
raft_set_current_term(r, 1);
raft_entry_t ety;
raft_entry_t *ety_appended;
/* increase log size */
char *str1 = "111";
char *str1 = strs[0];
ety.data.buf = str1;
ety.data.len = 3;
ety.id = 1;
......@@ -772,7 +764,7 @@ void TestRaft_follower_recv_appendentries_delete_entries_if_conflict_with_new_en
CuAssertTrue(tc, 1 == raft_get_log_count(r));
/* this log will be overwritten by the appendentries below */
char *str2 = "222";
char *str2 = strs[1];
ety.data.buf = str2;
ety.data.len = 3;
ety.id = 2;
......@@ -783,7 +775,7 @@ void TestRaft_follower_recv_appendentries_delete_entries_if_conflict_with_new_en
CuAssertTrue(tc, !strncmp(ety_appended->data.buf, str2, 3));
/* this log will be overwritten by the appendentries below */
char *str3 = "333";
char *str3 = strs[2];
ety.data.buf = str3;
ety.data.len = 3;
ety.id = 3;
......@@ -793,6 +785,25 @@ void TestRaft_follower_recv_appendentries_delete_entries_if_conflict_with_new_en
CuAssertTrue(tc, NULL != (ety_appended = raft_get_entry_from_idx(r, 3)));
CuAssertTrue(tc, !strncmp(ety_appended->data.buf, str3, 3));
return ety_appended;
}
/* 5.3 */
void TestRaft_follower_recv_appendentries_delete_entries_if_conflict_with_new_entries(
CuTest * tc)
{
msg_appendentries_t ae;
msg_appendentries_response_t aer;
void *r = raft_new();
raft_add_node(r, (void*)1, 1);
raft_add_node(r, (void*)2, 0);
raft_set_current_term(r, 1);
char* strs[] = {"111", "222", "333"};
raft_entry_t *ety_appended = __entries_for_conflict_tests(tc, r, strs);
/* pass a appendentry that is newer */
msg_entry_t mety;
......@@ -813,7 +824,36 @@ void TestRaft_follower_recv_appendentries_delete_entries_if_conflict_with_new_en
CuAssertTrue(tc, 1 == aer.success);
CuAssertTrue(tc, 2 == raft_get_log_count(r));
CuAssertTrue(tc, NULL != (ety_appended = raft_get_entry_from_idx(r, 1)));
CuAssertTrue(tc, !strncmp(ety_appended->data.buf, str1, 3));
CuAssertTrue(tc, !strncmp(ety_appended->data.buf, strs[0], 3));
}
void TestRaft_follower_recv_appendentries_delete_entries_if_current_idx_greater_than_prev_log_idx(
CuTest * tc)
{
msg_appendentries_t ae;
msg_appendentries_response_t aer;
void *r = raft_new();
raft_add_node(r, (void*)1, 1);
raft_add_node(r, (void*)2, 0);
raft_set_current_term(r, 1);
char* strs[] = {"111", "222", "333"};
raft_entry_t *ety_appended = __entries_for_conflict_tests(tc, r, strs);
memset(&ae, 0, sizeof(msg_appendentries_t));
ae.term = 2;
ae.prev_log_idx = 1;
ae.prev_log_term = 1;
ae.entries = NULL;
ae.n_entries = 0;
raft_recv_appendentries(r, 1, &ae, &aer);
CuAssertTrue(tc, 1 == aer.success);
CuAssertTrue(tc, 1 == raft_get_log_count(r));
CuAssertTrue(tc, NULL != (ety_appended = raft_get_entry_from_idx(r, 1)));
CuAssertTrue(tc, !strncmp(ety_appended->data.buf, strs[0], 3));
}
void TestRaft_follower_recv_appendentries_add_new_entries_not_already_in_log(
......@@ -1783,7 +1823,7 @@ void TestRaft_leader_recv_appendentries_response_jumps_to_lower_next_idx(
raft_set_current_term(r, 2);
raft_set_commit_idx(r, 0);
/* append entries - we need two */
/* append entries */
raft_entry_t ety;
ety.term = 1;
ety.id = 1;
......@@ -1805,7 +1845,7 @@ void TestRaft_leader_recv_appendentries_response_jumps_to_lower_next_idx(
/* become leader sets next_idx to current_idx */
raft_become_leader(r);
raft_node_t* node = raft_get_node(r, 1);
CuAssertIntEquals(tc, 4, raft_node_get_next_idx(node));
CuAssertIntEquals(tc, 5, raft_node_get_next_idx(node));
CuAssertTrue(tc, NULL != (ae = sender_poll_msg_data(sender)));
/* FIRST entry log application */
......@@ -1813,8 +1853,8 @@ void TestRaft_leader_recv_appendentries_response_jumps_to_lower_next_idx(
* server will be waiting for response */
raft_send_appendentries(r, 1);
CuAssertTrue(tc, NULL != (ae = sender_poll_msg_data(sender)));
CuAssertIntEquals(tc, 3, ae->prev_log_term);
CuAssertIntEquals(tc, 3, ae->prev_log_idx);
CuAssertIntEquals(tc, 4, ae->prev_log_term);
CuAssertIntEquals(tc, 4, ae->prev_log_idx);
/* receive mock success responses */
memset(&aer, 0, sizeof(msg_appendentries_response_t));
......@@ -1832,6 +1872,86 @@ void TestRaft_leader_recv_appendentries_response_jumps_to_lower_next_idx(
CuAssertTrue(tc, NULL == sender_poll_msg_data(sender));
}
void TestRaft_leader_recv_appendentries_response_decrements_to_lower_next_idx(
CuTest * tc)
{
raft_cbs_t funcs = {
.send_appendentries = sender_appendentries,
.log = NULL
};
msg_appendentries_response_t aer;
void *sender = sender_new(NULL);
void *r = raft_new();
raft_add_node(r, (void*)1, 1);
raft_add_node(r, (void*)2, 0);
raft_set_callbacks(r, &funcs, sender);
raft_set_current_term(r, 2);
raft_set_commit_idx(r, 0);
/* append entries */
raft_entry_t ety;
ety.term = 1;
ety.id = 1;
ety.data.buf = "aaaa";
ety.data.len = 4;
raft_append_entry(r, &ety);
ety.term = 2;
ety.id = 2;
raft_append_entry(r, &ety);
ety.term = 3;
ety.id = 3;
raft_append_entry(r, &ety);
ety.term = 4;
ety.id = 4;
raft_append_entry(r, &ety);
msg_appendentries_t* ae;
/* become leader sets next_idx to current_idx */
raft_become_leader(r);
raft_node_t* node = raft_get_node(r, 1);
CuAssertIntEquals(tc, 5, raft_node_get_next_idx(node));
CuAssertTrue(tc, NULL != (ae = sender_poll_msg_data(sender)));
/* FIRST entry log application */
/* send appendentries -
* server will be waiting for response */
raft_send_appendentries(r, 1);
CuAssertTrue(tc, NULL != (ae = sender_poll_msg_data(sender)));
CuAssertIntEquals(tc, 4, ae->prev_log_term);
CuAssertIntEquals(tc, 4, ae->prev_log_idx);
/* receive mock success responses */
memset(&aer, 0, sizeof(msg_appendentries_response_t));
aer.term = 2;
aer.success = 0;
aer.current_idx = 4;
raft_recv_appendentries_response(r, 1, &aer);
CuAssertIntEquals(tc, 4, raft_node_get_next_idx(node));
/* see if new appendentries have appropriate values */
CuAssertTrue(tc, NULL != (ae = sender_poll_msg_data(sender)));
CuAssertIntEquals(tc, 3, ae->prev_log_term);
CuAssertIntEquals(tc, 3, ae->prev_log_idx);
/* receive mock success responses */
memset(&aer, 0, sizeof(msg_appendentries_response_t));
aer.term = 2;
aer.success = 0;
aer.current_idx = 4;
raft_recv_appendentries_response(r, 1, &aer);
CuAssertIntEquals(tc, 3, raft_node_get_next_idx(node));
/* see if new appendentries have appropriate values */
CuAssertTrue(tc, NULL != (ae = sender_poll_msg_data(sender)));
CuAssertIntEquals(tc, 2, ae->prev_log_term);
CuAssertIntEquals(tc, 2, ae->prev_log_idx);
CuAssertTrue(tc, NULL == sender_poll_msg_data(sender));
}
void TestRaft_leader_recv_appendentries_response_retry_only_if_leader(CuTest * tc)
{
raft_cbs_t funcs = {
......@@ -2080,16 +2200,16 @@ void TestRaft_leader_recv_appendentries_response_increment_idx_of_node(
raft_set_current_term(r, 1);
raft_node_t* p = raft_get_node(r, 1);
CuAssertTrue(tc, 1 == raft_node_get_next_idx(p));
CuAssertIntEquals(tc, 1, raft_node_get_next_idx(p));
/* receive mock success responses */
msg_appendentries_response_t aer;
aer.term = 1;
aer.success = 1;
aer.current_idx = 1;
aer.first_idx = 1;
aer.current_idx = 0;
aer.first_idx = 0;
raft_recv_appendentries_response(r, 1, &aer);
CuAssertTrue(tc, 2 == raft_node_get_next_idx(p));
CuAssertIntEquals(tc, 1, raft_node_get_next_idx(p));
}
void TestRaft_leader_recv_appendentries_response_drop_message_if_term_is_old(
......
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