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Diffstat (limited to 'deps/rexi/src/rexi_server.erl')
| -rw-r--r-- | deps/rexi/src/rexi_server.erl | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/deps/rexi/src/rexi_server.erl b/deps/rexi/src/rexi_server.erl new file mode 100644 index 00000000..aa417aa4 --- /dev/null +++ b/deps/rexi/src/rexi_server.erl @@ -0,0 +1,190 @@ +% Copyright 2010 Cloudant +% +% 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(rexi_server). +-behaviour(gen_server). +-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, + code_change/3]). + +-export([start_link/0, init_p/2, init_p/3]). + +-include("rexi.hrl"). +-include_lib("eunit/include/eunit.hrl"). + +-record(job, { + client::reference(), + worker::reference(), + client_pid::pid(), + worker_pid::pid() +}). + +-record(st, { + workers = ets:new(workers, [private, {keypos, #job.worker}]), + clients = ets:new(clients, [private, {keypos, #job.client}]), + errors = queue:new(), + error_limit = 20, + error_count = 0 +}). + +start_link() -> + gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). + +init([]) -> + {ok, #st{}}. + +handle_call(get_errors, _From, #st{errors = Errors} = St) -> + {reply, {ok, lists:reverse(queue:to_list(Errors))}, St}; + +handle_call(get_last_error, _From, #st{errors = Errors} = St) -> + try + {reply, {ok, queue:get_r(Errors)}, St} + catch error:empty -> + {reply, {error, empty}, St} + end; + +handle_call({set_error_limit, N}, _From, #st{error_count=Len, errors=Q} = St) -> + if N < Len -> + {NewQ, _} = queue:split(N, Q); + true -> + NewQ = Q + end, + NewLen = queue:len(NewQ), + {reply, ok, St#st{error_limit=N, error_count=NewLen, errors=NewQ}}; + +handle_call(_Request, _From, St) -> + {reply, ignored, St}. + + +handle_cast({doit, From, MFA}, St) -> + handle_cast({doit, From, undefined, MFA}, St); + +handle_cast({doit, {ClientPid, ClientRef} = From, Nonce, MFA}, State) -> + {LocalPid, Ref} = spawn_monitor(?MODULE, init_p, [From, MFA, Nonce]), + Job = #job{ + client = ClientRef, + worker = Ref, + client_pid = ClientPid, + worker_pid = LocalPid + }, + {noreply, add_job(Job, State)}; + + +handle_cast({kill, FromRef}, #st{clients = Clients} = St) -> + case find_worker(FromRef, Clients) of + #job{worker = KeyRef, worker_pid = Pid} = Job -> + erlang:demonitor(KeyRef), + exit(Pid, kill), + {noreply, remove_job(Job, St)}; + false -> + {noreply, St} + end; + +handle_cast(_, St) -> + twig:log(notice, "rexi_server ignored_cast"), + {noreply, St}. + +handle_info({'DOWN', Ref, process, _, normal}, #st{workers=Workers} = St) -> + case find_worker(Ref, Workers) of + #job{} = Job -> + {noreply, remove_job(Job, St)}; + false -> + {noreply, St} + end; + +handle_info({'DOWN', Ref, process, Pid, Error}, #st{workers=Workers} = St) -> + case find_worker(Ref, Workers) of + #job{worker_pid=Pid, worker=Ref, client_pid=CPid, client=CRef} =Job -> + case Error of #error{reason = {_Class, Reason}, stack = Stack} -> + notify_caller({CPid, CRef}, {Reason, Stack}), + St1 = save_error(Error, St), + {noreply, remove_job(Job, St1)}; + _ -> + notify_caller({CPid, CRef}, Error), + {noreply, remove_job(Job, St)} + end; + false -> + {noreply, St} + end; + +handle_info(_Info, St) -> + {noreply, St}. + +terminate(_Reason, St) -> + ets:foldl(fun(#job{worker_pid=Pid},_) -> exit(Pid,kill) end, nil, + St#st.workers), + ok. + +code_change(_OldVsn, {st, Workers}, _Extra) -> + {ok, #st{workers = Workers}}; + +code_change(_OldVsn, {st, Workers0, Errors, Limit, Count}, _Extra) -> + Jobs = [#job{worker_pid=A, worker=B, client_pid=C, client=D} + || {A, B, {C, D}} <- ets:tab2list(Workers0)], + ets:delete(Workers0), + State = #st{errors = Errors, error_limit = Limit, error_count = Count}, + ets:insert(State#st.workers, Jobs), + ets:insert(State#st.clients, Jobs), + {ok, State}; + +code_change(_OldVsn, St, _Extra) -> + {ok, St}. + +init_p(From, MFA) -> + init_p(From, MFA, undefined). + +%% @doc initializes a process started by rexi_server. +-spec init_p({pid(), reference()}, {atom(), atom(), list()}, + string() | undefined) -> any(). +init_p(From, {M,F,A}, Nonce) -> + put(rexi_from, From), + put(initial_call, {M,F,length(A)}), + put(nonce, Nonce), + try apply(M, F, A) catch exit:normal -> ok; Class:Reason -> + Stack = clean_stack(), + twig:log(error, "rexi_server ~p:~p ~100p", [Class, Reason, Stack]), + exit(#error{ + timestamp = now(), + reason = {Class, Reason}, + mfa = {M,F,A}, + nonce = Nonce, + stack = Stack + }) + end. + +%% internal + +save_error(E, #st{errors=Q, error_limit=L, error_count=C} = St) when C >= L -> + St#st{errors = queue:in(E, queue:drop(Q))}; +save_error(E, #st{errors=Q, error_count=C} = St) -> + St#st{errors = queue:in(E, Q), error_count = C+1}. + +clean_stack() -> + lists:map(fun({M,F,A}) when is_list(A) -> {M,F,length(A)}; (X) -> X end, + erlang:get_stacktrace()). + +add_job(Job, #st{workers = Workers, clients = Clients} = State) -> + ets:insert(Workers, Job), + ets:insert(Clients, Job), + State. + +remove_job(Job, #st{workers = Workers, clients = Clients} = State) -> + ets:delete_object(Workers, Job), + ets:delete_object(Clients, Job), + State. + +find_worker(Ref, Tab) -> + case ets:lookup(Tab, Ref) of [] -> false; [Worker] -> Worker end. + +notify_caller({Caller, Ref}, Reason) -> + Caller ! {Ref, {rexi_EXIT, Reason}}. |