teacup_nats

A Teacup based Erlang client library for NATS high performance messaging platform.

NEWS

Getting Started

teacup_nats requires Erlang/OTP 18.0+. It uses rebar3 as the build tool and is available on hex.pm. Just include the following in your rebar.config:

{deps, [teacup_nats]}.

teacup_nats depends on the teacup app to be started. Include it in your .app.src file:

...
  {applications,
   [kernel,
    stdlib,
    teacup
   ]},
...

Or, start it manually:

ok = application:start(teacup).

rebar3 has a nice way of starting apps in the shell, you can try:

$ rebar3 shell --apps teacup

TODO

API

Aysnchronous Connection

When using asycnhronous connections, you need to wait for a {Conn, ready} message before publishing messages, subcribing to/unsubscribing from subjects.

Sample

main() ->
    % Connect to the NATS server
    {ok, Conn} = tcnats:connect(<<"demo.nats.io">>, 4222),
    % When the connection is OK to use, a `ready` message is sent, wait for it
    ready_loop(Conn).

ready_loop(Conn) ->
    receive
        {Conn, ready} ->
            % It&#39;s OK to use the connection now
            % Publish some message
            tcnats:pub(Conn, <<"teacup.control">>, #{payload => <<"start">>}),
            % subscribe to some subject
            tcnats:sub(Conn, <<"foo.*">>),
            loop(Conn)
    end.

loop(Conn) ->
    receive
        {Conn, {msg, Subject, _ReplyTo, Payload}} ->
            % Do something with the received message
            io:format("~p: ~p~n", [Subject, Payload]),
            loop(Conn)
    end.

Synchronous Connection

In order to activate the synchronous mode, just pass #{verbose => true to tcnats:connect.

Connect, publish, subscribe and unsubscribe operations block and return either ok on success or {error, Reason :: term()} on failure.

Sample

main() ->
    % Connect to the NATS server
    {ok, Conn} = tcnats:connect(<<"demo.nats.io">>, 4222, #{verbose => true}),
    % The connection is OK to use
    % Publish some message
    ok = tcnats:pub(Conn, <<"teacup.control">>, #{payload => <<"start">>}),
    % subscribe to some subject
    ok = tcnats:sub(Conn, <<"foo.*">>),
    loop(Conn).

loop(Conn) ->
    receive
        {Conn, {msg, Subject, _ReplyTo, Payload}} ->
            % Do something with the received message
            io:format("~p: ~p~n", [Subject, Payload]),
            loop(Conn)
    end.

License

Copyright (c) 2016, Yuce Tekol <yucetekol@gmail.com>.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.

* The names of its contributors may not be used to endorse or promote
  products derived from this software without specific prior written
  permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.