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% Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(mem3_sync_nodes).
-behaviour(gen_server).
-vsn(1).
-export([start_link/0]).
-export([add/1]).
-export([init/1, terminate/2, code_change/3]).
-export([handle_call/3, handle_cast/2, handle_info/2]).
-export([monitor_sync/1]).
-record(st, {
tid
}).
-record(job, {
nodes,
pid,
retry
}).
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
add(Nodes) ->
gen_server:cast(?MODULE, {add, Nodes}).
init([]) ->
{ok, #st{
tid = ets:new(?MODULE, [set, protected, {keypos, #job.nodes}])
}}.
terminate(_Reason, St) ->
[exit(Pid, kill) || #job{pid = Pid} <- ets:tab2list(St#st.tid)],
ok.
handle_call(Msg, _From, St) ->
{stop, {invalid_call, Msg}, invalid_call, St}.
handle_cast({add, Nodes}, #st{tid = Tid} = St) ->
case ets:lookup(Tid, Nodes) of
[] ->
Pid = start_sync(Nodes),
ets:insert(Tid, #job{nodes = Nodes, pid = Pid, retry = false});
[#job{retry = false} = Job] ->
ets:insert(Tid, Job#job{retry = true});
_ ->
ok
end,
{noreply, St};
handle_cast(Msg, St) ->
{stop, {invalid_cast, Msg}, St}.
handle_info({'DOWN', _, _, _, {sync_done, Nodes}}, #st{tid = Tid} = St) ->
case ets:lookup(Tid, Nodes) of
[#job{retry = true} = Job] ->
Pid = start_sync(Nodes),
ets:insert(Tid, Job#job{pid = Pid, retry = false});
_ ->
ets:delete(Tid, Nodes)
end,
{noreply, St};
handle_info({'DOWN', _, _, _, {sync_error, Nodes}}, #st{tid = Tid} = St) ->
Pid = start_sync(Nodes),
ets:insert(Tid, #job{nodes = Nodes, pid = Pid, retry = false}),
{noreply, St};
handle_info(Msg, St) ->
{stop, {invalid_info, Msg}, St}.
code_change(_OldVsn, St, _Extra) ->
{ok, St}.
start_sync(Nodes) ->
{Pid, _} = spawn_monitor(?MODULE, monitor_sync, [Nodes]),
Pid.
monitor_sync(Nodes) ->
process_flag(trap_exit, true),
Pid = spawn_link(mem3_sync, initial_sync, [Nodes]),
receive
{'EXIT', Pid, normal} ->
exit({sync_done, Nodes});
_ ->
exit({sync_error, Nodes})
end.
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