machi/src/machi_proxy_flu1_client.erl
2015-12-02 15:35:38 +09:00

512 lines
18 KiB
Erlang

%% -------------------------------------------------------------------
%%
%% 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 may (?) 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.
%%
%% For a higher level interface, see {@link machi_cr_client}.
%% For a lower level interface, see {@link machi_flu1_client}.
-module(machi_proxy_flu1_client).
-behaviour(gen_server).
-include("machi.hrl").
-include("machi_projection.hrl").
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-ifdef(PULSE).
-compile({parse_transform, pulse_instrument}).
-include_lib("pulse_otp/include/pulse_otp.hrl").
-endif.
-endif. % TEST.
-export([start_link/1]).
%% FLU1 API
-export([
%% File API
append_chunk/4, append_chunk/5,
append_chunk/6, append_chunk/7,
append_chunk_extra/5, append_chunk_extra/6,
append_chunk_extra/7, append_chunk_extra/8,
read_chunk/6, read_chunk/7,
checksum_list/3, checksum_list/4,
list_files/2, list_files/3,
wedge_status/1, wedge_status/2,
%% %% Projection API
get_epoch_id/1, get_epoch_id/2,
get_latest_epochid/2, get_latest_epochid/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,
kick_projection_reaction/2, kick_projection_reaction/3,
%% Common API
quit/1,
%% Internal API
write_chunk/5, write_chunk/6,
trim_chunk/5, trim_chunk/6,
%% Helpers
stop_proxies/1, start_proxies/1
]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-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) ->
append_chunk_extra(PidSpec, EpochID,
?DEFAULT_COC_NAMESPACE, ?DEFAULT_COC_LOCATOR,
Prefix, Chunk, 0, Timeout).
%% @doc Append a chunk (binary- or iolist-style) of data to a file
%% with `Prefix'.
append_chunk(PidSpec, EpochID, CoC_Namespace, CoC_Locator, Prefix, Chunk) ->
append_chunk(PidSpec, EpochID, CoC_Namespace, CoC_Locator, Prefix, Chunk, infinity).
%% @doc Append a chunk (binary- or iolist-style) of data to a file
%% with `Prefix'.
append_chunk(PidSpec, EpochID, CoC_Namespace, CoC_Locator, Prefix, Chunk, Timeout) ->
append_chunk_extra(PidSpec, EpochID,
CoC_Namespace, CoC_Locator,
Prefix, Chunk, 0, Timeout).
%% @doc Append a chunk (binary- or iolist-style) of data to a file
%% with `Prefix'.
append_chunk_extra(PidSpec, EpochID, Prefix, Chunk, ChunkExtra)
when is_integer(ChunkExtra), ChunkExtra >= 0 ->
append_chunk_extra(PidSpec, EpochID,
?DEFAULT_COC_NAMESPACE, ?DEFAULT_COC_LOCATOR,
Prefix, Chunk, ChunkExtra, infinity).
%% @doc Append a chunk (binary- or iolist-style) of data to a file
%% with `Prefix'.
append_chunk_extra(PidSpec, EpochID, Prefix, Chunk, ChunkExtra, Timeout) ->
append_chunk_extra(PidSpec, EpochID,
?DEFAULT_COC_NAMESPACE, ?DEFAULT_COC_LOCATOR,
Prefix, Chunk, ChunkExtra, Timeout).
append_chunk_extra(PidSpec, EpochID, CoC_Namespace, CoC_Locator,
Prefix, Chunk, ChunkExtra) ->
append_chunk_extra(PidSpec, EpochID, CoC_Namespace, CoC_Locator,
Prefix, Chunk, ChunkExtra, infinity).
append_chunk_extra(PidSpec, EpochID, CoC_Namespace, CoC_Locator,
Prefix, Chunk, ChunkExtra, Timeout) ->
gen_server:call(PidSpec, {req, {append_chunk_extra, EpochID,
CoC_Namespace, CoC_Locator,
Prefix, Chunk, ChunkExtra}},
Timeout).
%% @doc Read a chunk of data of size `Size' from `File' at `Offset'.
read_chunk(PidSpec, EpochID, File, Offset, Size, Opts) ->
read_chunk(PidSpec, EpochID, File, Offset, Size, Opts, infinity).
%% @doc Read a chunk of data of size `Size' from `File' at `Offset'.
read_chunk(PidSpec, EpochID, File, Offset, Size, Opts, Timeout) ->
gen_server:call(PidSpec, {req, {read_chunk, EpochID, File, Offset, Size, Opts}},
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 `epoch_id()' of the FLU's current/latest projection.
get_epoch_id(PidSpec) ->
get_epoch_id(PidSpec, infinity).
%% @doc Get the `epoch_id()' of the FLU's current/latest projection.
get_epoch_id(PidSpec, Timeout) ->
gen_server:call(PidSpec, {req, {get_epoch_id}}, Timeout).
%% @doc Get the latest epoch number + checksum from the FLU's projection store.
get_latest_epochid(PidSpec, ProjType) ->
get_latest_epochid(PidSpec, ProjType, infinity).
%% @doc Get the latest epoch number + checksum from the FLU's projection store.
get_latest_epochid(PidSpec, ProjType, Timeout) ->
gen_server:call(PidSpec, {req, {get_latest_epochid, 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) ->
case gen_server:call(PidSpec, {req, {write_projection, ProjType, Proj}},
Timeout) of
{error, written}=Err ->
Epoch = Proj#projection_v1.epoch_number,
case read_projection(PidSpec, ProjType, Epoch, Timeout) of
{ok, Proj2} when Proj2 == Proj ->
%% The proxy made (at least) two attempts to write
%% this projection. An earlier one appeared to
%% have failed, so the proxy retried. The later
%% attempt returned to us {error,written} because
%% the earlier attempt was actually received &
%% processed by the server. So, we consider this
%% a successful write.
ok;
_ ->
Err
end;
Else ->
Else
end.
%% @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 Kick (politely) the remote chain manager to react to a
%% projection change.
kick_projection_reaction(PidSpec, Options) ->
kick_projection_reaction(PidSpec, Options, infinity).
%% @doc Kick (politely) the remote chain manager to react to a
%% projection change.
kick_projection_reaction(PidSpec, Options, Timeout) ->
gen_server:call(PidSpec, {req, {kick_projection_reaction, Options}},
Timeout).
%% @doc Quit & close the connection to remote FLU and stop our
%% proxy process.
quit(PidSpec) ->
gen_server:call(PidSpec, quit, infinity).
%% @doc Write a chunk (binary- or iolist-style) of data to a file
%% with `Prefix' at `Offset'.
write_chunk(PidSpec, EpochID, File, Offset, Chunk) ->
write_chunk(PidSpec, EpochID, File, Offset, Chunk, infinity).
%% @doc Write a chunk (binary- or iolist-style) of data to a file
%% with `Prefix' at `Offset'.
write_chunk(PidSpec, EpochID, File, Offset, Chunk, Timeout) ->
case gen_server:call(PidSpec, {req, {write_chunk, EpochID, File, Offset, Chunk}},
Timeout) of
{error, written}=Err ->
Size = byte_size(Chunk),
case read_chunk(PidSpec, EpochID, File, Offset, Size, [], Timeout) of
{ok, {[{File, Offset, Chunk2, _}], []}} when Chunk2 == Chunk ->
%% See equivalent comment inside write_projection().
ok;
_ ->
Err
end;
Else ->
Else
end.
trim_chunk(PidSpec, EpochID, File, Offset, Size) ->
trim_chunk(PidSpec, EpochID, File, Offset, Size, infinity).
%% @doc Write a chunk (binary- or iolist-style) of data to a file
%% with `Prefix' at `Offset'.
trim_chunk(PidSpec, EpochID, File, Offset, Chunk, Timeout) ->
gen_server:call(PidSpec,
{req, {trim_chunk, EpochID, File, Offset, Chunk}},
Timeout).
%%%%%%%%%%%%%%%%%%%%%%%%%%%
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) ->
io:format(user, "~s:handle_info: ~p\n", [?MODULE, _Info]),
{noreply, S}.
terminate(_Reason, _S) ->
ok.
code_change(_OldVsn, S, _Extra) ->
{ok, S}.
%%%%%%%%%%%%%%%%%%%%%%%%%%%
do_req(Req, S) ->
do_req(Req, 1, S).
do_req(Req, Depth, S) ->
S2 = try_connect(S),
Fun = make_req_fun(Req, S2),
case connected_p(S2) of
true ->
case Fun() of
ok ->
{ok, S2};
T when element(1, T) == ok ->
{T, S2};
TheErr ->
case get(bad_sock) of
Bad when Bad == S2#state.sock ->
do_req_retry(Req, Depth, TheErr, S2);
_ ->
{TheErr, S2}
end
end;
false ->
{{error, partition}, S2}
end.
do_req_retry(_Req, 2, Err, S) ->
{Err, disconnect(S)};
do_req_retry(Req, Depth, _Err, S) ->
do_req(Req, Depth + 1, try_connect(disconnect(S))).
make_req_fun({append_chunk_extra, EpochID, CoC_Namespace, CoC_Locator,
Prefix, Chunk, ChunkExtra},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:append_chunk_extra(Sock, EpochID, CoC_Namespace, CoC_Locator,
Prefix, Chunk, ChunkExtra)
end;
make_req_fun({read_chunk, EpochID, File, Offset, Size, Opts},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:read_chunk(Sock, EpochID, File, Offset, Size, Opts) end;
make_req_fun({write_chunk, EpochID, File, Offset, Chunk},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:write_chunk(Sock, EpochID, File, Offset, Chunk) end;
make_req_fun({trim_chunk, EpochID, File, Offset, Size},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:trim_chunk(Sock, EpochID, File, Offset, Size) end;
make_req_fun({checksum_list, EpochID, File},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:checksum_list(Sock, EpochID, File) end;
make_req_fun({list_files, EpochID},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:list_files(Sock, EpochID) end;
make_req_fun({wedge_status},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:wedge_status(Sock) end;
make_req_fun({get_epoch_id},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> case Mod:read_latest_projection(Sock, private) of
{ok, P} ->
#projection_v1{epoch_number=Epoch,
epoch_csum=CSum} = P,
{ok, {Epoch, CSum}};
Error ->
Error
end
end;
make_req_fun({get_latest_epochid, ProjType},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:get_latest_epochid(Sock, ProjType) end;
make_req_fun({read_latest_projection, ProjType},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:read_latest_projection(Sock, ProjType) end;
make_req_fun({read_projection, ProjType, Epoch},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:read_projection(Sock, ProjType, Epoch) end;
make_req_fun({write_projection, ProjType, Proj},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:write_projection(Sock, ProjType, Proj) end;
make_req_fun({get_all_projections, ProjType},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:get_all_projections(Sock, ProjType) end;
make_req_fun({list_all_projections, ProjType},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:list_all_projections(Sock, ProjType) end;
make_req_fun({kick_projection_reaction, Options},
#state{sock=Sock,i=#p_srvr{proto_mod=Mod}}) ->
fun() -> Mod:kick_projection_reaction(Sock, Options) end.
connected_p(#state{sock=SockMaybe,
i=#p_srvr{proto_mod=Mod}=_I}=_S) ->
Mod:connected_p(SockMaybe).
try_connect(#state{sock=undefined,
i=#p_srvr{proto_mod=Mod}=P}=S) ->
Sock = Mod:connect(P),
S#state{sock=Sock};
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=undefined}=S) ->
S;
disconnect(#state{sock=Sock,
i=#p_srvr{proto_mod=Mod}=_I}=S) ->
Mod:disconnect(Sock),
S#state{sock=undefined}.
stop_proxies(undefined) ->
[];
stop_proxies(ProxiesDict) ->
orddict:fold(
fun(_K, Pid, _Acc) ->
_ = (catch machi_proxy_flu1_client:quit(Pid))
end, [], ProxiesDict).
start_proxies(MembersDict) ->
Proxies = orddict:fold(
fun(K, P, Acc) ->
{ok, Pid} = machi_proxy_flu1_client:start_link(P),
[{K, Pid}|Acc]
end, [], orddict:to_list(MembersDict)),
orddict:from_list(Proxies).