shackle

High Performance Erlang Network Client Framework

Requirements

• Erlang 16.0 +

Features

• Backpressure via backlog (OOM protection)
• Fast pool implementation (random, round_robin)
• Managed timeouts
• Multi-protocol support (SSL / TCP / UDP)
• Performance optimized
• Request pipelining

Framework goals

• reusability
• speed
• concurrency
• safety

How-to

Implementing a client

-behavior(shackle_client).
-export([
    init/0,
    setup/2,
    handle_request/2,
    handle_data/2,
    terminate/1
]).

-record(state, {
    buffer =       <<>> :: binary(),
    request_counter = 0 :: non_neg_integer()
}).

-spec init() -> {ok, State :: term()}.

init() ->
     {ok, #state {}}.

-spec setup(Socket :: inet:socket(), State :: term()) ->
    {ok, State :: term()} |
    {error, Reason :: term(), State :: term()}.

setup(Socket, State) ->
    case gen_tcp:send(Socket, <<"INIT">>) of
        ok ->
            case gen_tcp:recv(Socket, 0) of
                {ok, <<"OK">>} ->
                    {ok, State};
                {error, Reason} ->
                    {error, Reason, State}
            end;
        {error, Reason} ->
            {error, Reason, State}
    end.

-spec handle_request(Request :: term(), State :: term()) ->
    {ok, RequestId :: external_request_id(), Data :: iodata(), State :: term()}.

handle_request({Operation, A, B}, #state {
        request_counter = RequestCounter
    } = State) ->

    RequestId = request_id(RequestCounter),
    Data = request(RequestId, Operation, A, B),

    {ok, RequestId, Data, State#state {
        request_counter = RequestCounter + 1
    }}.

-spec handle_data(Data :: binary(), State :: term()) ->
    {ok, [{RequestId :: external_request_id(), Reply :: term()}], State :: term()}.

handle_data(Data, #state {
        buffer = Buffer
    } = State) ->

    Data2 = <<Buffer/binary, Data/binary>>,
    {Replies, Buffer2} = parse_replies(Data2, []),

    {ok, Replies, State#state {
        buffer = Buffer2
    }}.

-spec terminate(State :: term()) -> ok.

terminate(_State) -> ok.

Starting client pool

shackle_pool:start(pool_name(), client(), client_options(), pool_options())

client_options()

pool_options()

Calling / Casting client

1> shackle:call(pool_name, {get, <<"test">>}).
{ok, <<"bar">>}

2> {ok, ReqId} = shackle:cast(pool_name, {get, <<"foo">>}, 500).
{ok, {anchor, anchor_client, #Ref<0.0.0.2407>}}

3> shackle:receive_response(ReqId).
{ok, <<"bar">>}

Tests

make dialyzer
make elvis
make eunit
make xref

Performance testing

To run performance testing targets you must first start the server.

./bin/rebar3 as test shell
===> Verifying dependencies...
===> Compiling shackle
Erlang/OTP 18 [erts-7.3.1] [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false] [dtrace]

Eshell V7.3.1  (abort with ^G)
1> arithmetic_tcp_server:start().
ok

Then you can run the bench or profile target.

make bench
make profile

Clients

License

The MIT License (MIT)

Copyright (c) 2015-2017 Louis-Philippe Gauthier

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.