erlang: Client refactor, part 1
- Client is no longer a separate process.
- Simplified constructors moved into another module.
- All functions and exceptions return the new client,
to allow for future statefulness in the client.
NOTE: With the new library and old gen-code, attempting to call a
nonexistent function will result in an exit.
TODO: fix docs and tests (tether test is not meaningful)
git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@990979 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/erl/README b/lib/erl/README
index ddb6946..667c549 100644
--- a/lib/erl/README
+++ b/lib/erl/README
@@ -25,32 +25,19 @@
Example session using thrift_client:
-118> f(), {ok, C} = thrift_client:start_link("localhost", 9090, thriftTest_thrif
-t).
-{ok,<0.271.0>}
-119> thrift_client:call(C, testVoid, []).
+1> {ok, C0} = thrift_client_util:new("localhost", 9090, thriftTest_thrift, []), ok.
+ok
+2> {C1, R1} = thrift_client:call(C0, testVoid, []), R1.
{ok,ok}
-120> thrift_client:call(C, testVoid, [asdf]).
+3> {C2, R2} = thrift_client:call(C1, testVoid, [asdf]), R2.
{error,{bad_args,testVoid,[asdf]}}
-121> thrift_client:call(C, testI32, [123]).
+4> {C3, R3} = thrift_client:call(C2, testI32, [123]), R3.
{ok,123}
-122> thrift_client:call(C, testOneway, [1]).
+5> {C4, R4} = thrift_client:call(C3, testOneway, [1]), R4.
{ok,ok}
-123> catch thrift_client:call(C, testXception, ["foo"]).
+6> {C5, R5} = thrift_client:call(C4, testXception, ["foo"]), R5.
{error,{no_function,testXception}}
-124> catch thrift_client:call(C, testException, ["foo"]).
+7> {C6, R6} = thrift_client:call(C5, testException, ["foo"]), R6.
{ok,ok}
-125> catch thrift_client:call(C, testException, ["Xception"]).
-{xception,1001,"This is an Xception"}
-126> thrift_client:call(C, testException, ["Xception"]).
-
-=ERROR REPORT==== 24-Feb-2008::23:00:23 ===
-Error in process <0.269.0> with exit value: {{nocatch,{xception,1001,"This is an
- Xception"}},[{thrift_client,call,3},{erl_eval,do_apply,5},{shell,exprs,6},{shel
-l,eval_loop,3}]}
-
-** exited: {{nocatch,{xception,1001,"This is an Xception"}},
- [{thrift_client,call,3},
- {erl_eval,do_apply,5},
- {shell,exprs,6},
- {shell,eval_loop,3}]} **
+8> {C7, R7} = (catch thrift_client:call(C6, testException, ["Xception"])), R7.
+{exception,{xception,1001,<<"Xception">>}}
diff --git a/lib/erl/src/thrift_client.erl b/lib/erl/src/thrift_client.erl
index 07c9f48..e5a9d71 100644
--- a/lib/erl/src/thrift_client.erl
+++ b/lib/erl/src/thrift_client.erl
@@ -19,370 +19,123 @@
-module(thrift_client).
--behaviour(gen_server).
-
%% API
--export([start_link/2, start_link/3, start_link/4,
- start/3, start/4,
- call/3, cast/3, send_call/3, close/1]).
-
-%% gen_server callbacks
--export([init/1, handle_call/3, handle_cast/2, handle_info/2,
- terminate/2, code_change/3]).
-
+-export([new/2, call/3, send_call/3, close/1]).
-include("thrift_constants.hrl").
-include("thrift_protocol.hrl").
--record(state, {service, protocol, seqid}).
-
-%%====================================================================
-%% API
-%%====================================================================
-%%--------------------------------------------------------------------
-%% Function: start_link() -> {ok,Pid} | ignore | {error,Error}
-%% Description: Starts the server as a linked process.
-%%--------------------------------------------------------------------
-start_link(Host, Port, Service) when is_integer(Port), is_atom(Service) ->
- start_link(Host, Port, Service, []).
-
-start_link(Host, Port, Service, Options) ->
- start(Host, Port, Service, [{monitor, link} | Options]).
-
-start_link(ProtocolFactory, Service) ->
- start(ProtocolFactory, Service, [{monitor, link}]).
-
-%%
-%% Splits client options into protocol options and transport options
-%%
-%% split_options([Options...]) -> {ProtocolOptions, TransportOptions}
-%%
-split_options(Options) ->
- split_options(Options, [], [], []).
-
-split_options([], ClientIn, ProtoIn, TransIn) ->
- {ClientIn, ProtoIn, TransIn};
-
-split_options([Opt = {OptKey, _} | Rest], ClientIn, ProtoIn, TransIn)
- when OptKey =:= monitor ->
- split_options(Rest, [Opt | ClientIn], ProtoIn, TransIn);
-
-split_options([Opt = {OptKey, _} | Rest], ClientIn, ProtoIn, TransIn)
- when OptKey =:= strict_read;
- OptKey =:= strict_write ->
- split_options(Rest, ClientIn, [Opt | ProtoIn], TransIn);
-
-split_options([Opt = {OptKey, _} | Rest], ClientIn, ProtoIn, TransIn)
- when OptKey =:= framed;
- OptKey =:= connect_timeout;
- OptKey =:= sockopts ->
- split_options(Rest, ClientIn, ProtoIn, [Opt | TransIn]).
+-record(tclient, {service, protocol, seqid}).
-%%--------------------------------------------------------------------
-%% Function: start() -> {ok,Pid} | ignore | {error,Error}
-%% Description: Starts the server as an unlinked process.
-%%--------------------------------------------------------------------
+new(Protocol, Service)
+ when is_atom(Service) ->
+ {ok, #tclient{protocol = Protocol,
+ service = Service,
+ seqid = 0}}.
-%% Backwards-compatible starter for the common-case of socket transports
-start(Host, Port, Service, Options)
- when is_integer(Port), is_atom(Service), is_list(Options) ->
- {ClientOpts, ProtoOpts, TransOpts} = split_options(Options),
-
- {ok, TransportFactory} =
- thrift_socket_transport:new_transport_factory(Host, Port, TransOpts),
-
- {ok, ProtocolFactory} = thrift_binary_protocol:new_protocol_factory(
- TransportFactory, ProtoOpts),
-
- start(ProtocolFactory, Service, ClientOpts).
-
-
-%% ProtocolFactory :: fun() -> thrift_protocol()
-start(ProtocolFactory, Service, ClientOpts)
- when is_function(ProtocolFactory), is_atom(Service) ->
- {Starter, Opts} =
- case lists:keysearch(monitor, 1, ClientOpts) of
- {value, {monitor, link}} ->
- {start_link, []};
- {value, {monitor, tether}} ->
- {start, [{tether, self()}]};
- _ ->
- {start, []}
- end,
-
- Connect =
- case lists:keysearch(connect, 1, ClientOpts) of
- {value, {connect, Choice}} ->
- Choice;
- _ ->
- %% By default, connect at creation-time.
- true
- end,
-
-
- Started = gen_server:Starter(?MODULE, [Service, Opts], []),
-
- if
- Connect ->
- case Started of
- {ok, Pid} ->
- case gen_server:call(Pid, {connect, ProtocolFactory}) of
- ok ->
- {ok, Pid};
- Error ->
- Error
- end;
- Else ->
- Else
- end;
- true ->
- Started
+-spec call(#tclient{}, atom(), list()) -> {#tclient{}, {ok, term()} | {error, term()}}.
+call(Client = #tclient{}, Function, Args)
+ when is_atom(Function), is_list(Args) ->
+ case send_function_call(Client, Function, Args) of
+ {Client1, ok} ->
+ receive_function_result(Client1, Function);
+ Else ->
+ Else
end.
--spec call(term(), atom(), list()) -> {ok, term()} | {error, term()}.
-call(Client, Function, Args)
- when is_pid(Client), is_atom(Function), is_list(Args) ->
- case gen_server:call(Client, {call, Function, Args}) of
- R = {ok, _} -> R;
- R = {error, _} -> R;
- {exception, Exception} -> throw(Exception)
- end.
-
--spec cast(term(), atom(), list()) -> ok.
-cast(Client, Function, Args)
- when is_pid(Client), is_atom(Function), is_list(Args) ->
- gen_server:cast(Client, {call, Function, Args}).
%% Sends a function call but does not read the result. This is useful
%% if you're trying to log non-oneway function calls to write-only
%% transports like thrift_disk_log_transport.
--spec send_call(term(), atom(), list()) -> ok.
-send_call(Client, Function, Args)
- when is_pid(Client), is_atom(Function), is_list(Args) ->
- gen_server:call(Client, {send_call, Function, Args}).
+-spec send_call(#tclient{}, atom(), list()) -> {#tclient{}, ok}.
+send_call(Client = #tclient{}, Function, Args)
+ when is_atom(Function), is_list(Args) ->
+ send_function_call(Client, Function, Args).
--spec close(term()) -> ok.
-close(Client) when is_pid(Client) ->
- gen_server:cast(Client, close).
+-spec close(#tclient{}) -> ok.
+close(#tclient{protocol=Protocol}) ->
+ thrift_protocol:close_transport(Protocol).
-%%====================================================================
-%% gen_server callbacks
-%%====================================================================
-
-%%--------------------------------------------------------------------
-%% Function: init(Args) -> {ok, State} |
-%% {ok, State, Timeout} |
-%% ignore |
-%% {stop, Reason}
-%% Description: Initiates the server
-%%--------------------------------------------------------------------
-init([Service, Opts]) ->
- case lists:keysearch(tether, 1, Opts) of
- {value, {tether, Pid}} ->
- erlang:monitor(process, Pid);
- _Else ->
- ok
- end,
- {ok, #state{service = Service}}.
-
-%%--------------------------------------------------------------------
-%% Function: %% handle_call(Request, From, State) -> {reply, Reply, State} |
-%% {reply, Reply, State, Timeout} |
-%% {noreply, State} |
-%% {noreply, State, Timeout} |
-%% {stop, Reason, Reply, State} |
-%% {stop, Reason, State}
-%% Description: Handling call messages
-%%--------------------------------------------------------------------
-handle_call({connect, ProtocolFactory}, _From,
- State = #state{service = Service}) ->
- case ProtocolFactory() of
- {ok, Protocol} ->
- {reply, ok, State#state{protocol = Protocol,
- seqid = 0}};
- Error ->
- {stop, normal, Error, State}
- end;
-
-handle_call({call, Function, Args}, _From, State = #state{service = Service}) ->
- Result = catch_function_exceptions(
- fun() ->
- ok = send_function_call(State, Function, Args),
- receive_function_result(State, Function)
- end,
- Service),
- {reply, Result, State};
-
-
-handle_call({send_call, Function, Args}, _From, State = #state{service = Service}) ->
- Result = catch_function_exceptions(
- fun() ->
- send_function_call(State, Function, Args)
- end,
- Service),
- {reply, Result, State}.
-
-
-%% Helper function that catches exceptions thrown by sending or receiving
-%% a function and returns the correct response for call or send_only above.
-catch_function_exceptions(Fun, Service) ->
- try
- Fun()
- catch
- throw:{return, Return} ->
- Return;
- error:function_clause ->
- ST = erlang:get_stacktrace(),
- case hd(ST) of
- {Service, function_info, [Function, _]} ->
- {error, {no_function, Function}};
- _ -> throw({error, {function_clause, ST}})
- end
- end.
-
-
-%%--------------------------------------------------------------------
-%% Function: handle_cast(Msg, State) -> {noreply, State} |
-%% {noreply, State, Timeout} |
-%% {stop, Reason, State}
-%% Description: Handling cast messages
-%%--------------------------------------------------------------------
-handle_cast({call, Function, Args}, State = #state{service = Service,
- protocol = Protocol,
- seqid = SeqId}) ->
- _Result =
- try
- ok = send_function_call(State, Function, Args),
- receive_function_result(State, Function)
- catch
- Class:Reason ->
- error_logger:error_msg("error ignored in handle_cast({cast,...},...): ~p:~p~n", [Class, Reason])
- end,
-
- {noreply, State};
-
-handle_cast(close, State=#state{protocol = Protocol}) ->
-%% error_logger:info_msg("thrift_client ~p received close", [self()]),
- {stop,normal,State};
-handle_cast(_Msg, State) ->
- {noreply, State}.
-
-%%--------------------------------------------------------------------
-%% Function: handle_info(Info, State) -> {noreply, State} |
-%% {noreply, State, Timeout} |
-%% {stop, Reason, State}
-%% Description: Handling all non call/cast messages
-%%--------------------------------------------------------------------
-handle_info({'DOWN', MonitorRef, process, Pid, _Info}, State)
- when is_reference(MonitorRef), is_pid(Pid) ->
- %% We don't actually verify the correctness of the DOWN message.
- {stop, parent_died, State};
-
-handle_info(_Info, State) ->
- {noreply, State}.
-
-%%--------------------------------------------------------------------
-%% Function: terminate(Reason, State) -> void()
-%% Description: This function is called by a gen_server when it is about to
-%% terminate. It should be the opposite of Module:init/1 and do any necessary
-%% cleaning up. When it returns, the gen_server terminates with Reason.
-%% The return value is ignored.
-%%--------------------------------------------------------------------
-terminate(Reason, State = #state{protocol=undefined}) ->
- ok;
-terminate(Reason, State = #state{protocol=Protocol}) ->
- thrift_protocol:close_transport(Protocol),
- ok.
-
-%%--------------------------------------------------------------------
-%% Func: code_change(OldVsn, State, Extra) -> {ok, NewState}
-%% Description: Convert process state when code is changed
-%%--------------------------------------------------------------------
-code_change(_OldVsn, State, _Extra) ->
- {ok, State}.
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
-send_function_call(#state{protocol = Proto,
- service = Service,
- seqid = SeqId},
+-spec send_function_call(#tclient{}, atom(), list()) -> {#tclient{}, ok | {error, term()}}.
+send_function_call(Client = #tclient{protocol = Proto,
+ service = Service,
+ seqid = SeqId},
Function,
Args) ->
Params = Service:function_info(Function, params_type),
- {struct, PList} = Params,
- if
- length(PList) =/= length(Args) ->
- throw({return, {error, {bad_args, Function, Args}}});
- true -> ok
- end,
+ case Params of
+ no_function ->
+ {Client, {error, {no_function, Function}}};
+ {struct, PList} when length(PList) =/= length(Args) ->
+ {Client, {error, {bad_args, Function, Args}}};
+ {struct, _PList} ->
+ Begin = #protocol_message_begin{name = atom_to_list(Function),
+ type = ?tMessageType_CALL,
+ seqid = SeqId},
+ ok = thrift_protocol:write(Proto, Begin),
+ ok = thrift_protocol:write(Proto, {Params, list_to_tuple([Function | Args])}),
+ ok = thrift_protocol:write(Proto, message_end),
+ ok = thrift_protocol:flush_transport(Proto),
+ {Client, ok}
+ end.
- Begin = #protocol_message_begin{name = atom_to_list(Function),
- type = ?tMessageType_CALL,
- seqid = SeqId},
- ok = thrift_protocol:write(Proto, Begin),
- ok = thrift_protocol:write(Proto, {Params, list_to_tuple([Function | Args])}),
- ok = thrift_protocol:write(Proto, message_end),
- thrift_protocol:flush_transport(Proto),
- ok.
-
-receive_function_result(State = #state{protocol = Proto,
- service = Service},
- Function) ->
+-spec receive_function_result(#tclient{}, atom()) -> {#tclient{}, {ok, term()} | {error, term()}}.
+receive_function_result(Client = #tclient{service = Service}, Function) ->
ResultType = Service:function_info(Function, reply_type),
- read_result(State, Function, ResultType).
+ read_result(Client, Function, ResultType).
-read_result(_State,
- _Function,
- oneway_void) ->
- {ok, ok};
+read_result(Client, _Function, oneway_void) ->
+ {Client, {ok, ok}};
-read_result(State = #state{protocol = Proto,
- seqid = SeqId},
+read_result(Client = #tclient{protocol = Proto,
+ seqid = SeqId},
Function,
ReplyType) ->
case thrift_protocol:read(Proto, message_begin) of
#protocol_message_begin{seqid = RetSeqId} when RetSeqId =/= SeqId ->
- {error, {bad_seq_id, SeqId}};
+ {Client, {error, {bad_seq_id, SeqId}}};
#protocol_message_begin{type = ?tMessageType_EXCEPTION} ->
- handle_application_exception(State);
+ handle_application_exception(Client);
#protocol_message_begin{type = ?tMessageType_REPLY} ->
- handle_reply(State, Function, ReplyType)
+ handle_reply(Client, Function, ReplyType)
end.
-handle_reply(State = #state{protocol = Proto,
- service = Service},
+
+handle_reply(Client = #tclient{protocol = Proto,
+ service = Service},
Function,
ReplyType) ->
{struct, ExceptionFields} = Service:function_info(Function, exceptions),
ReplyStructDef = {struct, [{0, ReplyType}] ++ ExceptionFields},
{ok, Reply} = thrift_protocol:read(Proto, ReplyStructDef),
+ ok = thrift_protocol:read(Proto, message_end),
ReplyList = tuple_to_list(Reply),
true = length(ReplyList) == length(ExceptionFields) + 1,
ExceptionVals = tl(ReplyList),
Thrown = [X || X <- ExceptionVals,
X =/= undefined],
- Result =
- case Thrown of
- [] when ReplyType == {struct, []} ->
- {ok, ok};
- [] ->
- {ok, hd(ReplyList)};
- [Exception] ->
- {exception, Exception}
- end,
- ok = thrift_protocol:read(Proto, message_end),
- Result.
+ case Thrown of
+ [] when ReplyType == {struct, []} ->
+ {Client, {ok, ok}};
+ [] ->
+ {Client, {ok, hd(ReplyList)}};
+ [Exception] ->
+ throw({Client, {exception, Exception}})
+ end.
-handle_application_exception(State = #state{protocol = Proto}) ->
- {ok, Exception} = thrift_protocol:read(Proto,
- ?TApplicationException_Structure),
+handle_application_exception(Client = #tclient{protocol = Proto}) ->
+ {ok, Exception} =
+ thrift_protocol:read(Proto, ?TApplicationException_Structure),
ok = thrift_protocol:read(Proto, message_end),
XRecord = list_to_tuple(
['TApplicationException' | tuple_to_list(Exception)]),
error_logger:error_msg("X: ~p~n", [XRecord]),
true = is_record(XRecord, 'TApplicationException'),
- {exception, XRecord}.
+ throw({Client, {exception, XRecord}}).
diff --git a/lib/erl/src/thrift_client_util.erl b/lib/erl/src/thrift_client_util.erl
new file mode 100644
index 0000000..c52bb8b
--- /dev/null
+++ b/lib/erl/src/thrift_client_util.erl
@@ -0,0 +1,61 @@
+%%
+%% Licensed to the Apache Software Foundation (ASF) under one
+%% or more contributor license agreements. See the NOTICE file
+%% distributed with this work for additional information
+%% regarding copyright ownership. The ASF licenses this file
+%% to you 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(thrift_client_util).
+
+-export([new/4]).
+
+%%
+%% Splits client options into client, protocol, and transport options
+%%
+%% split_options([Options...]) -> {ProtocolOptions, TransportOptions}
+%%
+split_options(Options) ->
+ split_options(Options, [], []).
+
+split_options([], ProtoIn, TransIn) ->
+ {ProtoIn, TransIn};
+
+split_options([Opt = {OptKey, _} | Rest], ProtoIn, TransIn)
+ when OptKey =:= strict_read;
+ OptKey =:= strict_write ->
+ split_options(Rest, [Opt | ProtoIn], TransIn);
+
+split_options([Opt = {OptKey, _} | Rest], ProtoIn, TransIn)
+ when OptKey =:= framed;
+ OptKey =:= connect_timeout;
+ OptKey =:= sockopts ->
+ split_options(Rest, ProtoIn, [Opt | TransIn]).
+
+
+%% Client constructor for the common-case of socket transports
+%% with the binary protocol
+new(Host, Port, Service, Options)
+ when is_integer(Port), is_atom(Service), is_list(Options) ->
+ {ProtoOpts, TransOpts} = split_options(Options),
+
+ {ok, TransportFactory} =
+ thrift_socket_transport:new_transport_factory(Host, Port, TransOpts),
+
+ {ok, ProtocolFactory} = thrift_binary_protocol:new_protocol_factory(
+ TransportFactory, ProtoOpts),
+
+ {ok, Protocol} = ProtocolFactory(),
+
+ thrift_client:new(Protocol, Service).