def test_from_list():
entries = [LogEntry(1, 1), LogEntry(2, 3)]
l1 = RaftLog.from_list(entries)
assert l1 == entries
def test_leader_interaction():
"""Note: this test does look at the internals of the leader. This
could possibly be avoided, but the gains of that are not clear to
me yet.
"""
config = gen_config(3)
follower_ids = [1, 2]
leader_id = 0
leader = (RaftServer(leader_id,
config)._set_log(RaftLog.from_list([LogEntry(1, 1)
]))._set_leader())
assert all(leader.state.nextIndex[i] == 1 for i in follower_ids)
assert all(leader.state.matchIndex[i] == 0 for i in follower_ids)
step_server(leader)
ms = get_all_messages(leader)
assert [m.recver_id for m in ms] == follower_ids
assert all(m.payload == AppendEntries(leader_id, 1, 1, [], 0) for m in ms)
assert all(leader.state.matchIndex[i] == 0 for i in follower_ids)
assert all(leader.state.nextIndex[i] == 1 for i in follower_ids)
# send to everyone again
step_server(leader)
ms = get_all_messages(leader)
assert [m.recver_id for m in ms] == follower_ids
send_message(leader, Message(1, 0, 0, AppendEntriesReply(False, -1, 1)))
step_server(leader)
ms = get_all_messages(leader)
assert [m.recver_id for m in ms] == follower_ids
assert all(leader.state.matchIndex[i] == 0 for i in follower_ids)
assert leader.state.nextIndex[1] == 0
assert leader.state.nextIndex[2] == 1
msd = {m.recver_id: m.payload for m in ms}
assert msd[1] == AppendEntries(leader_id, 0, -1, [LogEntry(1, 1)], 0)
assert msd[2] == AppendEntries(leader_id, 1, 1, [], 0)
send_message(leader, Message(1, 0, 0, AppendEntriesReply(True, 1, -1)))
step_server(leader)
ms = get_all_messages(leader)
assert [m.recver_id for m in ms] == [
1,
2,
] # 1 now synched, but send empty appendEntries
assert leader.state.matchIndex[1] == 1
assert leader.state.matchIndex[2] == 0
assert leader.state.nextIndex[1] == 1
assert leader.state.nextIndex[2] == 1
# assume leader had some entries added
leader.log.append_entries(1, 1, [LogEntry(1, 2), LogEntry(1, 3)])
assert leader.log == [LogEntry(1, 1), LogEntry(1, 2), LogEntry(1, 3)]
step_server(leader)
ms = get_all_messages(leader)
assert [m.recver_id for m in ms] == follower_ids
assert leader.state.matchIndex[1] == 1
assert leader.state.matchIndex[2] == 0
msd = {m.recver_id: m.payload for m in ms}
assert msd[1] == AppendEntries(
leader_id, 1, 1, [LogEntry(1, 2), LogEntry(1, 3)], 0)
# leader still has not heard from 2, so nextIndex not yet lowered
assert msd[2] == AppendEntries(
leader_id, 1, 1, [LogEntry(1, 2), LogEntry(1, 3)], 0)
# tell leader we can't add the entry at index 1
send_message(leader, Message(2, 0, 0, AppendEntriesReply(False, -1, 1)))
step_server(leader)
ms = get_all_messages(leader)
assert [m.recver_id for m in ms] == follower_ids
assert leader.state.matchIndex[1] == 1
assert leader.state.matchIndex[2] == 0
msd = {m.recver_id: m.payload for m in ms}
print(msd)
assert msd[1] == AppendEntries(
leader_id, 1, 1, [LogEntry(1, 2), LogEntry(1, 3)], 0)
# leader still has not heard from 2, so nextIndex not yet lowered
assert msd[2] == AppendEntries(
leader_id, 0, -1,
[LogEntry(1, 1), LogEntry(1, 2),
LogEntry(1, 3)], 0)
def test_follower_interaction():
"""Note: this test does look at the internals of the follower. This
could possibly be avoided, but the gains of that are not clear to
me yet.
"""
config = gen_config(3)
follower_id = 1
leader_id = 0
follower = (RaftServer(follower_id, config)._set_log(RaftLog.from_list(
[]))._set_follower())
assert follower.currentTerm == 0
assert follower.commitIndex == 0
assert follower.leaderId is None
send_message(
follower,
Message(
leader_id,
follower_id,
1,
AppendEntries(leader_id, 0, -1, [LogEntry(1, 1)], 0),
),
)
step_server(follower)
assert follower.log == [LogEntry(1, 1)]
assert follower.currentTerm == 1
assert follower.commitIndex == 0
assert follower.leaderId == leader_id
assert get_message(follower).payload == AppendEntriesReply(True, 1, -1)
## checking idempotence; doing the above again
send_message(
follower,
Message(
leader_id,
follower_id,
1,
AppendEntries(leader_id, 0, -1, [LogEntry(1, 1)], 0),
),
)
step_server(follower)
assert follower.log == [LogEntry(1, 1)]
assert follower.currentTerm == 1
assert follower.commitIndex == 0
assert follower.leaderId == leader_id
assert get_message(follower).payload == AppendEntriesReply(True, 1, -1)
# message indicating that the log entry is now committed
send_message(
follower,
Message(leader_id, follower_id, 1,
AppendEntries(leader_id, 1, 1, [], 1)),
)
step_server(follower)
assert follower.log == [LogEntry(1, 1)]
assert follower.currentTerm == 1
assert follower.commitIndex == 1 # this is the update
assert follower.leaderId == leader_id
assert get_message(follower).payload == AppendEntriesReply(True, 1, -1)
# now lengthen the log; one new entry is already commited the other not yet
send_message(
follower,
Message(
leader_id,
follower_id,
1,
AppendEntries(leader_id, 1, 1,
[LogEntry(1, 2), LogEntry(1, 3)], 2),
),
)
step_server(follower)
assert follower.log == [LogEntry(1, 1), LogEntry(1, 2), LogEntry(1, 3)]
assert follower.currentTerm == 1
assert follower.commitIndex == 2
assert follower.leaderId == leader_id # and hence has been updated
assert get_message(follower).payload == AppendEntriesReply(True, 3, -1)
# new leader, makes some changes to the log
leader_id = 2
send_message(
follower,
Message(
leader_id,
follower_id,
2,
AppendEntries(leader_id, 2, 1, [LogEntry(2, 3)], 3),
),
)
step_server(follower)
assert follower.log == [LogEntry(1, 1), LogEntry(1, 2), LogEntry(2, 3)]
assert follower.currentTerm == 2
assert follower.commitIndex == 3
assert get_message(follower).payload == AppendEntriesReply(True, 3, -1)
# send append entries from leader with old term
leader_id = 2
send_message(
follower,
Message(
leader_id,
follower_id,
0,
AppendEntries(leader_id, 2, 1, [LogEntry(2, 3)], 3),
),
)
step_server(follower)
assert follower.log == [LogEntry(1, 1), LogEntry(1, 2), LogEntry(2, 3)]
assert follower.currentTerm == 2
assert follower.commitIndex == 3
assert get_message(follower).payload == AppendEntriesReply(False, -1, 2)
print(msd)
assert msd[1] == AppendEntries(
leader_id, 1, 1, [LogEntry(1, 2), LogEntry(1, 3)], 0)
# leader still has not heard from 2, so nextIndex not yet lowered
assert msd[2] == AppendEntries(
leader_id, 0, -1,
[LogEntry(1, 1), LogEntry(1, 2),
LogEntry(1, 3)], 0)
@pytest.mark.parametrize(
"log_leader, log_follower",
[
(
RaftLog.from_list([LogEntry(1, 1),
LogEntry(2, 2),
LogEntry(3, 3)]),
RaftLog.from_list([]),
),
(
RaftLog.from_list([LogEntry(1, 1),
LogEntry(2, 2),
LogEntry(3, 3)]),
RaftLog.from_list([LogEntry(1, 1),
LogEntry(1, 2),
LogEntry(1, 2)]),
),
(
RaftLog.from_list([LogEntry(1, 1), LogEntry(2, 2)]),
RaftLog.from_list([
LogEntry(1, 1),