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NB !!ABANDONWARE!!

I'm not maintaining this repo anymore. Sorry.

Gearnode

Gearnode is a Node.JS client/worker module for Gearman.

NB! check out another Gearman library of mine node-gearman which is somewhat more simple than this one.

Installation

npm install gearnode

Tests

Tests are run with nodeunit

./run_tests.sh

Tests expect a Gearman daemon running on port 7003

Usage

Worker

var Gearnode = require("gearnode");

worker = new Gearnode();
worker.addServer(); // use localhost

worker.addFunction("upper", "utf-8", function(payload, job){
    var response =  payload.toUpperCase();
    job.complete(response);
});

Client

var Gearnode = require("gearnode");

client = new Gearnode();
client.addServer();

var job = client.submitJob("upper", "hello world!", {encoding:'utf-8'});

job.on("complete", function(handle, response){
    console.log(response); // HELLO WORLD!
    client.end();
});

API

Require Gearman library

var Gearnode = require("gearnode");

Create a new Gearnode worker/client

var gearnode = new Gearnode();

Add a server

gearnode.addServer([host][, port])

Where

  • host is the hostname of the Gearman server (defaults to localhost);
  • port is the Gearman port (default is 4730)

Example

gearnode.addServer(); // use default values
gearnode.addServer("gearman.lan", 7003);

Register for exceptions

Exceptions are not sent to the client by default. To turn these on use the following command.

gearnode.getExceptions([callback])

Where

  • callback is an optional callback function with params error if an error occured and success which is true if the command succeeded

Example

client = new Gearnode();
client.addServer(); // use default values
client.getExceptions();

job = client.submitJob("reverse", "Hello world!");

job.on("error", function(exception){
    console.log(exception);
});

Assign an ID for the Worker

Worker ID's identify unique workers for monitoring Gearman.

gearnode.setWorkerId(id)

Where

  • id is a string that will act as the name for the worker

Example

worker = new Gearnode();
worker.addServer(); // use default values
worker.setWorkerId("my_worker");

Submit a job

gearnode.submitJob(func, payload[, options])

Where

  • func is the function name
  • payload is either a String or a Buffer value
  • options is an optional options object (see below)

Possible option values

  • encoding - indicates the encoding for the job response (default is Buffer). Can be "utf-8", "ascii", "base64", "number" or "buffer"
  • background - if set to true, detach the job from the client (complete and error events will not be sent to the client)
  • priority - indicates the priority of the job. Possible values "low", "normal" (default) and "high"

Returns a Client Job object with the following events

  • created - when the function is queued by the server (params: handle value)
  • complete - when the function returns (params: response data in encoding specified by the options value)
  • fail - when the function fails (params: none)
  • error - when an exception is thrown (params: error string)
  • warning - when a warning is sent (params: warning string)
  • status - when the status of a long running function is updated (params: numerator numbber, denominator number)
  • data - when partial data is available (params: response data in encoding specified by the options value)

Example

client = new Gearnode();
client.addServer(); // use default values
worker.getExceptions();

job = client.submitJob("reverse", "Hello world!", {encoding:"utf-8"});

job.on("complete", function(response){
    console.log(response); // !dlrow olleH
});

job.on("fail", function(){
    console.log("Job failed :S");
});

Create a worker function

gearnode.addFunction(func_name[, encoding], worker_func)

Where

  • func_name is the name of the function to be created
  • endocing is the input encoding (default is buffer)
  • worker_func is the actual worker function

Worker function

worker_func = function(payload, job)

Where

  • payload is the data sent by the client and in the encoding specified with addFunction
  • job is a Gearman Job object that can be used to send data back

Worker Job object

Worker Job object has the following methods

  • complete(response) - send the result of the function back to the client
  • error(error) - throw an exception (and end the job with failed status)
  • fail() - end the function without response data when the function failed
  • warning(warning) - send a warning message to the client
  • data(response) - send a partial response data to the client
  • setStatus(numerator, denominator) - send a progress event to the client

Example

var Gearnode = require("gearnode");

var worker = new Gearnode();
worker.addServer();

worker.addFunction("sqr", "number", function(payload, job){
    if(payload < 0){
        job.warning("Used number is smaller than zero!");
    }
    job.complete(payload * payload);
});

Detect connection errors

When the connection is lost a "disconnect" event is emitted to the client/worker

worker.addServer("gearman.lan");
worker.on("disconnect", function(server){
    console.log("Connection lost from "+server_name);
});

License

MIT