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https://github.com/cainus/Prozess

kafka library for node.js
https://github.com/cainus/Prozess

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kafka library for node.js

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Prozess
=======
[![Build
Status](https://secure.travis-ci.org/cainus/Prozess.png?branch=master)](http://travis-ci.org/cainus/Prozess)
[![Coverage Status](https://coveralls.io/repos/cainus/Prozess/badge.png?branch=master)](https://coveralls.io/r/cainus/Prozess)

Prozess is a Kafka library for node.js

[Kafka](http://incubator.apache.org/kafka/index.html) is a persistent, efficient, distributed publish/subscribe messaging system.

There are two low-level clients: The Producer and the Consumer:

##Producer example:

```javascript
var Producer = require('Prozess').Producer;

var producer = new Producer('social', {host : 'localhost'});
producer.connect();
console.log("producing for ", producer.topic);
producer.on('error', function(err){
console.log("some general error occurred: ", err);
});
producer.on('brokerReconnectError', function(err){
console.log("could not reconnect: ", err);
console.log("will retry on next send()");
});

setInterval(function(){
var message = { "thisisa" : "test " + new Date()};
producer.send(JSON.stringify(message), function(err){
if (err){
console.log("send error: ", err);
} else {
console.log("message sent");
}
});
}, 1000);
```

##Consumer example:

```javascript
var Consumer = require('Prozess').Consumer;

var options = {host : 'localhost', topic : 'social', partition : 0, offset : 0};
var consumer = new Consumer(options);
consumer.connect(function(err){
if (err) { throw err; }
console.log("connected!!");
setInterval(function(){
console.log("===================================================================");
console.log(new Date());
console.log("consuming: " + consumer.topic);
consumer.consume(function(err, messages){
console.log(err, messages);
});
}, 7000);
});

```

A `Consumer` can be constructed with the following options (default values as
shown below):

```javascript
var options = {
topic: 'test',
partition: 0,
host: 'localhost',
port: 9092,
offset: null, // Number, String or BigNum
maxMessageSize: Consumer.MAX_MESSAGE_SIZE,
polling: Consumer.DEFAULT_POLLING_INTERVAL
};
```

##Documentation

### `var producer = new Producer(options)`

```ocaml
type Message := String | Buffer

Producer := ({
topic: String,
partition?: Number,
host?: String,
port?: Number,
connectionCache?: Boolean
}) => EventEmitter & {
connect: () => void,
send: (Array | Message, opts?: {
partition?: Number,
topic?: String
}, cb: Callback<>) => void
}
```

To create a `producer` you must call `Producer()` with various
options. The only required argument is the topic your
producing to.

```js
var Producer = require('prozess').Producer

var producer = new Producer({ topic: 'foos' })
```

#### `options.topic`

`options.topic` must be a `String` and is the topic
in kafka that you will producer to

#### `options.partition`

`options.partition` is an optional `Number` and
defaults to `0`. You can specify this if you want
to change which `partition` you publish to.

#### `options.host` and `options.port`

`options.host` determines the host location of the
kafka node you are connecting to and `options.port`
determines the port.

These default to `"localhost"` and `9092` which are
the default kafka ports.

#### `options.connectionCache`

`options.connectionCache` is a `Boolean` you can set
to opt in into connection caching. By default `prozess`
will create one TCP connection per topic.

If you set `options.connectionCache` to true then
`prozess` will use one TCP connection per host & port.

#### `producer.connect(Callback)`

You can call `producer.connect(cb)` to open your connection
to kafka, the `cb` you pass in will be called once the
connection is open.

You must call `.connect()` before calling `.send()`

#### `producer.send(Message, opts?: Object, Callback)`

To produce messages to kafka you should call `.send()` with
either an array of `String`'s or a single `String`.

You can pass `.send()` an optional options argument to
customize the `topic` & `partition` for this single `send()`
request.

You must also supply a `Callback` to handle any asynchronous
errors.

##Installation:

npm install prozess

##Checkout the code and run the tests:

$ git clone https://github.com/cainus/Prozess.git
$ cd Prozess ; make test-cov && open coverage.html

##Kafka Compatability matrix:


Kakfa 0.8.0 ReleaseNot Supported


Kafka 0.7.2 ReleaseSupported

Kafka 0.7.1 ReleaseSupported

Kafka 0.7.0 ReleaseSupported

kafka-0.6Not Supported

kafka-0.05Not Supported

Versions taken from http://incubator.apache.org/kafka/downloads.html