%% ------------------------------------------------------------------- %% %% Copyright (c) 2007-2015 Basho Technologies, Inc. All Rights Reserved. %% %% This file is provided 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. %% %% ------------------------------------------------------------------- %% @doc Erlang API for the Machi FLU TCP protocol version 1, with a %% proxy-process style API for hiding messy details such as TCP %% connection/disconnection with the remote Machi server. %% %% Machi is intentionally avoiding using distributed Erlang for %% Machi's communication. This design decision makes Erlang-side code %% more difficult & complex, but it's the price to pay for some %% language independence. Later in Machi's life cycle, we need to %% (re-)implement some components in a non-Erlang/BEAM-based language. %% %% This module implements a "man in the middle" proxy between the %% Erlang client and Machi server (which is on the "far side" of a TCP %% connection to somewhere). This proxy process will always execute %% on the same Erlang node as the Erlang client that uses it. The %% proxy is intended to be a stable, long-lived process that survives %% TCP communication problems with the remote server. -module(machi_proxy_flu1_client). -behaviour(gen_server). -include("machi.hrl"). -include("machi_projection.hrl"). -ifdef(TEST). -include_lib("eunit/include/eunit.hrl"). -endif. % TEST. -export([start_link/1]). %% FLU1 API -export([ %% File API append_chunk/4, append_chunk/5, read_chunk/5, read_chunk/6, checksum_list/3, checksum_list/4, list_files/2, list_files/3, wedge_status/1, wedge_status/2, %% %% Projection API get_latest_epoch/2, get_latest_epoch/3, read_latest_projection/2, read_latest_projection/3, read_projection/3, read_projection/4, write_projection/3, write_projection/4, get_all_projections/2, get_all_projections/3, list_all_projections/2, list_all_projections/3, %% Common API quit/1 ]). %% gen_server callbacks -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]). -define(FLU_C, machi_flu1_client). -record(state, { i :: #p_srvr{}, sock :: 'undefined' | port() }). %% @doc Start a local, long-lived process that will be our steady %% & reliable communication proxy with the fickle & flaky %% remote Machi server. start_link(#p_srvr{}=I) -> gen_server:start_link(?MODULE, [I], []). %% @doc Append a chunk (binary- or iolist-style) of data to a file %% with `Prefix'. append_chunk(PidSpec, EpochID, Prefix, Chunk) -> append_chunk(PidSpec, EpochID, Prefix, Chunk, infinity). %% @doc Append a chunk (binary- or iolist-style) of data to a file %% with `Prefix'. append_chunk(PidSpec, EpochID, Prefix, Chunk, Timeout) -> gen_server:call(PidSpec, {req, {append_chunk, EpochID, Prefix, Chunk}}, Timeout). %% @doc Read a chunk of data of size `Size' from `File' at `Offset'. read_chunk(PidSpec, EpochID, File, Offset, Size) -> read_chunk(PidSpec, EpochID, File, Offset, Size, infinity). %% @doc Read a chunk of data of size `Size' from `File' at `Offset'. read_chunk(PidSpec, EpochID, File, Offset, Size, Timeout) -> gen_server:call(PidSpec, {req, {read_chunk, EpochID, File, Offset, Size}}, Timeout). %% @doc Fetch the list of chunk checksums for `File'. checksum_list(PidSpec, EpochID, File) -> checksum_list(PidSpec, EpochID, File, infinity). %% @doc Fetch the list of chunk checksums for `File'. checksum_list(PidSpec, EpochID, File, Timeout) -> gen_server:call(PidSpec, {req, {checksum_list, EpochID, File}}, Timeout). %% @doc Fetch the list of all files on the remote FLU. list_files(PidSpec, EpochID) -> list_files(PidSpec, EpochID, infinity). %% @doc Fetch the list of all files on the remote FLU. list_files(PidSpec, EpochID, Timeout) -> gen_server:call(PidSpec, {req, {list_files, EpochID}}, Timeout). %% @doc Fetch the wedge status from the remote FLU. wedge_status(PidSpec) -> wedge_status(PidSpec, infinity). %% @doc Fetch the wedge status from the remote FLU. wedge_status(PidSpec, Timeout) -> gen_server:call(PidSpec, {req, {wedge_status}}, Timeout). %% @doc Get the latest epoch number + checksum from the FLU's projection store. get_latest_epoch(PidSpec, ProjType) -> get_latest_epoch(PidSpec, ProjType, infinity). %% @doc Get the latest epoch number + checksum from the FLU's projection store. get_latest_epoch(PidSpec, ProjType, Timeout) -> gen_server:call(PidSpec, {req, {get_latest_epoch, ProjType}}, Timeout). %% @doc Get the latest projection from the FLU's projection store for `ProjType' read_latest_projection(PidSpec, ProjType) -> read_latest_projection(PidSpec, ProjType, infinity). %% @doc Get the latest projection from the FLU's projection store for `ProjType' read_latest_projection(PidSpec, ProjType, Timeout) -> gen_server:call(PidSpec, {req, {read_latest_projection, ProjType}}, Timeout). %% @doc Read a projection `Proj' of type `ProjType'. read_projection(PidSpec, ProjType, Epoch) -> read_projection(PidSpec, ProjType, Epoch, infinity). %% @doc Read a projection `Proj' of type `ProjType'. read_projection(PidSpec, ProjType, Epoch, Timeout) -> gen_server:call(PidSpec, {req, {read_projection, ProjType, Epoch}}, Timeout). %% @doc Write a projection `Proj' of type `ProjType'. write_projection(PidSpec, ProjType, Proj) -> write_projection(PidSpec, ProjType, Proj, infinity). %% @doc Write a projection `Proj' of type `ProjType'. write_projection(PidSpec, ProjType, Proj, Timeout) -> gen_server:call(PidSpec, {req, {write_projection, ProjType, Proj}}, Timeout). %% @doc Get all projections from the FLU's projection store. get_all_projections(PidSpec, ProjType) -> get_all_projections(PidSpec, ProjType, infinity). %% @doc Get all projections from the FLU's projection store. get_all_projections(PidSpec, ProjType, Timeout) -> gen_server:call(PidSpec, {req, {get_all_projections, ProjType}}, Timeout). %% @doc Get all epoch numbers from the FLU's projection store. list_all_projections(PidSpec, ProjType) -> list_all_projections(PidSpec, ProjType, infinity). %% @doc Get all epoch numbers from the FLU's projection store. list_all_projections(PidSpec, ProjType, Timeout) -> gen_server:call(PidSpec, {req, {list_all_projections, ProjType}}, Timeout). %% @doc Quit & close the connection to remote FLU and stop our %% proxy process. quit(PidSpec) -> gen_server:call(PidSpec, quit, infinity). %%%%%%%%%%%%%%%%%%%%%%%%%%% init([I]) -> S0 = #state{i=I}, S1 = try_connect(S0), {ok, S1}. handle_call({req, Req}, _From, S) -> {Reply, NewS} = do_req(Req, S), {reply, Reply, NewS}; handle_call(quit, _From, S) -> {stop, normal, ok, disconnect(S)}; handle_call(_Request, _From, S) -> Reply = ok, {reply, Reply, S}. handle_cast(_Msg, S) -> {noreply, S}. handle_info(_Info, S) -> {noreply, S}. terminate(_Reason, _S) -> ok. code_change(_OldVsn, S, _Extra) -> {ok, S}. %%%%%%%%%%%%%%%%%%%%%%%%%%% do_req(Req, S) -> S2 = try_connect(S), Fun = make_req_fun(Req, S2), case connected_p(S2) of true -> case Fun() of T when element(1, T) == ok -> {T, S2}; Else -> case get(bad_sock) of Bad when Bad == S2#state.sock -> {Else, disconnect(S2)}; _ -> {Else, S2} end end; false -> {{error, partition}, S2} end. make_req_fun({append_chunk, EpochID, Prefix, Chunk}, #state{sock=Sock}) -> fun() -> ?FLU_C:append_chunk(Sock, EpochID, Prefix, Chunk) end; make_req_fun({read_chunk, EpochID, File, Offset, Size}, #state{sock=Sock}) -> fun() -> ?FLU_C:read_chunk(Sock, EpochID, File, Offset, Size) end; make_req_fun({checksum_list, EpochID, File}, #state{sock=Sock}) -> fun() -> ?FLU_C:checksum_list(Sock, EpochID, File) end; make_req_fun({list_files, EpochID}, #state{sock=Sock}) -> fun() -> ?FLU_C:list_files(Sock, EpochID) end; make_req_fun({wedge_status}, #state{sock=Sock}) -> fun() -> ?FLU_C:wedge_status(Sock) end; make_req_fun({get_latest_epoch, ProjType}, #state{sock=Sock}) -> fun() -> ?FLU_C:get_latest_epoch(Sock, ProjType) end; make_req_fun({read_latest_projection, ProjType}, #state{sock=Sock}) -> fun() -> ?FLU_C:read_latest_projection(Sock, ProjType) end; make_req_fun({read_projection, ProjType, Epoch}, #state{sock=Sock}) -> fun() -> ?FLU_C:read_projection(Sock, ProjType, Epoch) end; make_req_fun({write_projection, ProjType, Proj}, #state{sock=Sock}) -> fun() -> ?FLU_C:write_projection(Sock, ProjType, Proj) end; make_req_fun({get_all_projections, ProjType}, #state{sock=Sock}) -> fun() -> ?FLU_C:get_all_projections(Sock, ProjType) end; make_req_fun({list_all_projections, ProjType}, #state{sock=Sock}) -> fun() -> ?FLU_C:list_all_projections(Sock, ProjType) end. connected_p(#state{sock=SockMaybe, i=#p_srvr{proto=ipv4}=_I}=_S) -> is_port(SockMaybe); connected_p(#state{i=#p_srvr{proto=disterl, name=_NodeName}=_I}=_S) -> true. %% case net_adm:ping(NodeName) of %% ping -> %% true; %% _ -> %% false %% end. try_connect(#state{sock=undefined, i=#p_srvr{proto=ipv4, address=Host, port=TcpPort}=_I}=S) -> try Sock = machi_util:connect(Host, TcpPort), S#state{sock=Sock} catch _:_ -> S end; try_connect(S) -> %% If we're connection-based, we're already connected. %% If we're not connection-based, then there's nothing to do. S. disconnect(#state{sock=Sock, i=#p_srvr{proto=ipv4}=_I}=S) -> (catch gen_tcp:close(Sock)), S#state{sock=undefined}; disconnect(S) -> S.