gearman-coffee
gearman-coffee is an implementation of the Gearman protocol in CoffeeScript. It exposes a conventional Node library for creating Gearman workers and clients, and listening for events related to both. It aims to be a very a lightweight wrapper around the protocol itself.
Installation
npm install gearman-coffee
Workers
Workers are created with the name and function that they perform:
worker = new Worker 'reverse', (payload, worker) ->
return worker.error 'No payload' unless payload?
reversed = payload.toString("utf-8").split('').reverse().join ''
worker.complete reversed
The worker function itself is passed an object that contains the following convenience methods:
warning(warning)
: sends a 'WORK_WARNING' packetstatus(num,den)
: sends a 'WORK_STATUS' packetdata(data)
: sends a 'WORK_DATA' packeterror([warning])
: sends an optional 'WORK_WARNING' before 'WORK_FAIL'complete([data])
: sends an optional 'WORK_DATA' before 'WORK_COMPLETE'done([warning])
: calls error
if warning passed, otherwise complete
The exact meaning of these is best documented on the Gearman website itself: http://gearman.org/index.php?id=protocol.
Workers optionally take a hash of options. These options control the Gearman server connection settings as well as debug output and retry behavior:
default_options =
host: 'localhost'
port: 4730
debug: false
max_retries: 0
worker = new Worker 'unstable', (payload, worker) ->
return worker.error() if Math.random() < 0.5
worker.done()
, default_options
Clients
Clients are used to submit work to Gearman. By default they connect to Gearman at localhost:4730
:
default_options =
host: 'localhost'
port: 4730
debug: false
client = new Client default_options
The submitJob
method of the client takes in the name of the worker and the workload you'd like to send. It returns an EventEmitter that relays Gearman server notifications:
client.submitJob('reverse', 'kitteh')
.on 'created', (handle) -> # JOB_CREATED
.on 'data', (handle, data) -> # WORK_DATA
.on 'warning', (handle, warning) -> # WORK_WARNING
.on 'status', (handle, num, den) -> # WORK_STATUS
.on 'complete', (handle, data) -> # WORK_COMPLETE
.on 'fail', (handle) -> # WORK_FAIL
License
MIT