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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (the "License"); you may not use this file except in
%% compliance with the License. You may obtain a copy of the License at
%% http://www.mozilla.org/MPL/
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
%% License for the specific language governing rights and limitations
%% under the License.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developer of the Original Code is VMware, Inc.
%% Copyright (c) 2007-2010 VMware, Inc. All rights reserved.
%%
-module(rabbit_mirror_queue_master).
-export([init/2, terminate/1, delete_and_terminate/1,
purge/1, publish/4, publish_delivered/5, fetch/2, ack/2,
tx_publish/5, tx_ack/3, tx_rollback/2, tx_commit/4,
requeue/3, len/1, is_empty/1, dropwhile/2,
set_ram_duration_target/2, ram_duration/1,
needs_idle_timeout/1, idle_timeout/1, handle_pre_hibernate/1,
status/1]).
-export([start/1, stop/0]).
-export([promote_backing_queue_state/5]).
-behaviour(rabbit_backing_queue).
-include("rabbit.hrl").
-record(state, { gm,
coordinator,
backing_queue,
backing_queue_state,
set_delivered,
fakes
}).
%% ---------------------------------------------------------------------------
%% Backing queue
%% ---------------------------------------------------------------------------
start(_DurableQueues) ->
%% This will never get called as this module will never be
%% installed as the default BQ implementation.
exit({not_valid_for_generic_backing_queue, ?MODULE}).
stop() ->
%% Same as start/1.
exit({not_valid_for_generic_backing_queue, ?MODULE}).
init(#amqqueue { arguments = Args } = Q, Recover) ->
{ok, CPid} = rabbit_mirror_queue_coordinator:start_link(Q, undefined),
GM = rabbit_mirror_queue_coordinator:get_gm(CPid),
{_Type, Nodes} = rabbit_misc:table_lookup(Args, <<"x-mirror">>),
[rabbit_mirror_queue_coordinator:add_slave(CPid, binary_to_atom(Node, utf8))
|| {longstr, Node} <- Nodes],
{ok, BQ} = application:get_env(backing_queue_module),
BQS = BQ:init(Q, Recover),
#state { gm = GM,
coordinator = CPid,
backing_queue = BQ,
backing_queue_state = BQS,
set_delivered = 0,
fakes = sets:new() }.
promote_backing_queue_state(CPid, BQ, BQS, GM, Fakes) ->
#state { gm = GM,
coordinator = CPid,
backing_queue = BQ,
backing_queue_state = BQS,
set_delivered = BQ:len(BQS),
fakes = Fakes }.
terminate(State = #state { backing_queue = BQ, backing_queue_state = BQS }) ->
%% Backing queue termination. The queue is going down but
%% shouldn't be deleted. Most likely safe shutdown of this
%% node. Thus just let some other slave take over.
State #state { backing_queue_state = BQ:terminate(BQS) }.
delete_and_terminate(State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS }) ->
ok = gm:broadcast(GM, delete_and_terminate),
State #state { backing_queue_state = BQ:delete_and_terminate(BQS),
set_delivered = 0 }.
purge(State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS }) ->
ok = gm:broadcast(GM, {set_length, 0}),
{Count, BQS1} = BQ:purge(BQS),
{Count, State #state { backing_queue_state = BQS1,
set_delivered = 0 }}.
publish(Msg = #basic_message { guid = Guid },
MsgProps, ChPid, State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS }) ->
ok = gm:broadcast(GM, {publish, false, Guid, MsgProps, ChPid}),
BQS1 = BQ:publish(Msg, MsgProps, ChPid, BQS),
State #state { backing_queue_state = BQS1 }.
publish_delivered(AckRequired, Msg = #basic_message { guid = Guid },
MsgProps, ChPid,
State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS }) ->
ok = gm:broadcast(GM, {publish, {true, AckRequired}, Guid, MsgProps, ChPid}),
{AckTag, BQS1} = BQ:publish_delivered(AckRequired, Msg, MsgProps, ChPid, BQS),
{AckTag, State #state { backing_queue_state = BQS1 }}.
dropwhile(Fun, State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS,
set_delivered = SetDelivered }) ->
Len = BQ:len(BQS),
BQS1 = BQ:dropwhile(Fun, BQS),
Dropped = Len - BQ:len(BQS1),
SetDelivered1 = lists:max([0, SetDelivered - Dropped]),
ok = gm:broadcast(GM, {set_length, BQ:len(BQS1)}),
State #state { backing_queue_state = BQS1,
set_delivered = SetDelivered1 }.
fetch(AckRequired, State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS,
set_delivered = SetDelivered,
fakes = Fakes }) ->
{Result, BQS1} = BQ:fetch(AckRequired, BQS),
case Result of
empty ->
{Result, State #state { backing_queue_state = BQS1 }};
{#basic_message { guid = Guid } = Message, IsDelivered, AckTag,
Remaining} ->
SetDelivered1 = lists:max([0, SetDelivered - 1]),
case sets:is_element(Guid, Fakes) of
true ->
{BQS2, Fakes1} =
case AckRequired of
true -> {[Guid], BQS3} = BQ:ack([AckTag], BQS1),
{BQS3, Fakes};
false -> {BQS1, sets:del_element(Guid, Fakes)}
end,
ok = gm:broadcast(GM, {fetch, false, Guid, Remaining}),
fetch(AckRequired,
State #state { backing_queue_state = BQS2,
set_delivered = SetDelivered1,
fakes = Fakes1 });
false ->
ok = gm:broadcast(GM,
{fetch, AckRequired, Guid, Remaining}),
IsDelivered1 = IsDelivered orelse SetDelivered > 0,
Fakes1 = case SetDelivered + SetDelivered1 of
1 -> sets:new(); %% transition to 0
_ -> Fakes
end,
{{Message, IsDelivered1, AckTag, Remaining},
State #state { backing_queue_state = BQS1,
set_delivered = SetDelivered1,
fakes = Fakes1 }}
end
end.
ack(AckTags, State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS,
fakes = Fakes }) ->
{Guids, BQS1} = BQ:ack(AckTags, BQS),
Fakes1 = case Guids of
[] -> Fakes;
_ -> ok = gm:broadcast(GM, {ack, Guids}),
sets:difference(Fakes, sets:from_list(Guids))
end,
{Guids, State #state { backing_queue_state = BQS1, fakes = Fakes1 }}.
tx_publish(Txn, Msg, MsgProps, ChPid, #state {} = State) ->
%% gm:broadcast(GM, {tx_publish, Txn, Guid, MsgProps, ChPid})
State.
tx_ack(Txn, AckTags, #state {} = State) ->
%% gm:broadcast(GM, {tx_ack, Txn, Guids})
State.
tx_rollback(Txn, #state {} = State) ->
%% gm:broadcast(GM, {tx_rollback, Txn})
{[], State}.
tx_commit(Txn, PostCommitFun, MsgPropsFun, #state {} = State) ->
%% Maybe don't want to transmit the MsgPropsFun but what choice do
%% we have? OTOH, on the slaves, things won't be expiring on their
%% own (props are interpreted by amqqueue, not vq), so if the msg
%% props aren't quite the same, that doesn't matter.
%%
%% The PostCommitFun is actually worse - we need to prevent that
%% from being invoked until we have confirmation from all the
%% slaves that they've done everything up to there.
%%
%% In fact, transactions are going to need work seeing as it's at
%% this point that VQ mentions amqqueue, which will thus not work
%% on the slaves - we need to make sure that all the slaves do the
%% tx_commit_post_msg_store at the same point, and then when they
%% all confirm that (scatter/gather), we can finally invoke the
%% PostCommitFun.
%%
%% Another idea is that the slaves are actually driven with
%% pubacks and thus only the master needs to support txns
%% directly.
{[], State}.
requeue(AckTags, MsgPropsFun, State = #state { gm = GM,
backing_queue = BQ,
backing_queue_state = BQS }) ->
{Guids, BQS1} = BQ:requeue(AckTags, MsgPropsFun, BQS),
ok = gm:broadcast(GM, {requeue, MsgPropsFun, Guids}),
{Guids, State #state { backing_queue_state = BQS1 }}.
len(#state { backing_queue = BQ, backing_queue_state = BQS}) ->
BQ:len(BQS).
is_empty(#state { backing_queue = BQ, backing_queue_state = BQS}) ->
BQ:is_empty(BQS).
set_ram_duration_target(Target, State = #state { backing_queue = BQ,
backing_queue_state = BQS}) ->
State #state { backing_queue_state =
BQ:set_ram_duration_target(Target, BQS) }.
ram_duration(State = #state { backing_queue = BQ, backing_queue_state = BQS}) ->
{Result, BQS1} = BQ:ram_duration(BQS),
{Result, State #state { backing_queue_state = BQS1 }}.
needs_idle_timeout(#state { backing_queue = BQ, backing_queue_state = BQS}) ->
BQ:needs_idle_timeout(BQS).
idle_timeout(#state { backing_queue = BQ, backing_queue_state = BQS}) ->
BQ:idle_timeout(BQS).
handle_pre_hibernate(State = #state { backing_queue = BQ,
backing_queue_state = BQS}) ->
State #state { backing_queue_state = BQ:handle_pre_hibernate(BQS) }.
status(#state { backing_queue = BQ, backing_queue_state = BQS}) ->
BQ:status(BQS).
|
