NSQ Client for Node.JS

A simple implementation of the NSQ-V2 protocol using native Buffer objects, based entirely upon the protocol documentation found in Bitly's GitHub project.

NSQClient

Publisher/Producer examples/publish.js

var Crypto = require("crypto");
var NSQClient = require("../index");
var Util = require("util");

var client = new NSQClient({
  debug : true
});
client.on("error", function(err) {
    console.log("ERROR " + Util.inspect(err));
});
client.on("debug", function(event) {
    console.log("DEBUG " + Util.inspect(event));
});

var topics = process.argv.slice(2);
function randomishTopic() {
    var i = Math.floor(Math.random() * topics.length);
    return topics[i];
}

setInterval(function() {
    client.publish(randomishTopic(), { date : Date.now(), meh : Crypto.randomBytes(8).toString("hex") });
}, 50);

process.once("SIGINT", function() {
    process.once("SIGINT", process.exit);

    console.log();
    console.log("Closing client connections");
    console.log("Press CTL-C again to force quit");
    client.close(function() {
        process.exit();
    });
});

Subscriber/Consumer examples/subscribe.js

var NSQClient = require("../index");
var OS = require("os");
var Util = require("util");

var client = new NSQClient({
  debug : true
});

var channel = OS.hostname();

// Debugging Output
client.on("error", function(error) {
    console.log("ERROR " + Util.inspect(error));
});
client.on("debug", function(event) {
    console.log("DEBUG " + Util.inspect(event));
});

// Subscribe to topics defined on stdin
process.argv.slice(2).forEach(function(topic) {
    console.log("Subscribing to " + topic + "/" + channel);
    var subscriber = client.subscribe(topic, channel, {
        ephemeral : true
    });
    subscriber.on("message", function(message) {
        message.finish();
    });
});

process.once("SIGINT", function() {
    process.once("SIGINT", process.exit);

    console.log();
    console.log("Closing client connections");
    console.log("Press CTL-C again to force quit");
    client.close(function() {
        process.exit();
    });
});

TODO

• MPUB
• Clustered operation
  • Discover nsqd instances and available topics with the nsqlookupd API
  • Provide schemes for nsqd failover, message de-duping

MIT License

Copyright (c) 2014 John Manero, Dynamic Network Services Inc.

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.

Changes

0.0.1

First release.

• Single connections (Connection Objects) are stable.
• Clustering is functional, but not well exercised or particularly robust.
• NO TESTS FOR YOU! (Soup Nazi says: "Needs tests!")

0.0.2

Small improvement to Connection API: publish method now accepts topic strings:

client.publish(*topic*, message, callback)

1.0.0

• Major overhaul of the Protocol state machine
  • TCP failure tolerance and reconnection
  • Proper transaction handling for REQ/REP Commands (IDENTIFY, SUB, PUB, CLS)
  • Error response handling
• Separation of the Connection controller from NSQClient. An instance of NSQClient now stores connection data for a single nsqd endpoint and provides methods to create/access a dedicated publisher Connection and to create subscriber Connections.
• Subscriber state-machine
  • Wrap and manage the ready-state of subscriber Connection
  • Handle re-subscription on re-connection of the underlying Protocol
  • Handle clean un-subscription on close of the underlying Connection
• Use int64-native to handle message timestamps