celeryjs
v0.0.5
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A node.js Celery client with promises
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Celery.js
A node.js Celery client utilizing callbacks and promises.
Install:
npm install celeryjs
Use:
var celery = require('celeryjs');
var client = new celery.createClient({
BROKER_URL: 'amqp://celery:celery@lab-cel02',
DEFAULT_QUEUE: 'default'
});
client.on('connect', function() {
var task = client.createTask('native.platform');
task.applyAsync().then(successful);
});
function successful(message) {
console.log(message);
}
Returns:
{ status: 'SUCCESS',
traceback: null,
result: 'linux posix',
taskId: 'c141e770-182a-4fc8-af2e-9fd8e2692410',
children: [] }
##API
###require('celeryjs') ####.createClient(conf, [callback]) Emits:
connect
error
- and
end
, all mirroring the underlying amqp connection.
###Client ####.createTask(name, [options,] [callback]) #####options
task
- These are overwritten by supplying the same attributes to Task-level options
- defaults
task
: Supplied task name when created.id
: Generated uuid used internally.args
:[]
kwargs
:{}
- optional
- 'args', 'callbacks', 'chord',
- 'errbacks', 'eta', 'expires', 'id', 'kwargs',
- 'queue', 'retries', 'task', 'taskset', 'timeouts', 'utc'
broker
- amqp exchange.publish options, see here.
contentType
, default:'application/json'
requiredcontentEncoding
, default:'utf-8'
Example:
var options = {
queue: 'windows'
task: {
args: [1,2,3],
kwargs: {verbose: true}
},
broker: {
appId: 'TestApp'
}
}
####.close([callback]) alias: end
###Configuration
####supplied to createClient's conf
parameter
- debug, default:
true
- camelCaseResults, default:
true
- converts python-based response into javascript-style attributes.
- BROKER_URL, default:
'amqp://'
- DEFAULT_EXCHANGE, default:
''
- DEFAULT_EXCHANGE_TYPE, default:
'topic'
- DEFAULT_QUEUE, default:
'default'
- DEFAULT_ROUTING_KEY, default:
'default'
- RESULT_EXCHANGE, default:
'celeryresults'
- TASK_RESULT_DURABLE, default:
true
- TASK_RESULT_EXPIRES, default:
30 * 60 * 1000 // 30 minutes
- ROUTES, default:
{}
###Task
####.applyAsync([options])
Execute the task, returns a Promise
.
####.apply([options,] callback)
Execute the task with callback
.
####.delayAsync([options,] ms)
Execute the task with ms
delay, returns a Promise
.
####.delay([options,] ms, callback)
Executes the task with callback
using ms
delay.
####.mapAsync(arrayOfValues, [options,] [settle]) Executes a given task in parallel, once for each of the values in arrayOfValues.
arrayOfValues should contain elements of array
that represent the mapped args
to the celery function.
options
are task level options.
settle
(which can also be set in options
) determines if all the executing task promises should fail individually or as a group. When settle
is set to true
the returned resultsArray will contain SUCCESS and FAILURE tasks. When it's set to false
if any one task fails the whole promise fails and returns a FAILURE response.
Example:
var task = client.createTask('js.add'),
values = [ [1,2], [3,4], [5,'a']];
task.mapAsync(values, {settle: true}).then(successful).catch(errorous);
Returns:
[ { state: 'fulfilled',
value:
{ status: 'SUCCESS',
traceback: null,
result: 3,
taskId: '8fd67bde-71b4-4572-b450-6844ff626b84',
children: [] } },
{ state: 'fulfilled',
value:
{ status: 'SUCCESS',
traceback: null,
result: 7,
taskId: '8b1fc93f-985c-4aba-a99d-ba010b535ca6',
children: [] } },
{ state: 'rejected',
reason:
{ status: 'FAILURE',
traceback: 'Traceback (most recent call last....',
result: [Object],
taskId: '4554ab51-84e3-4c71-99c6-c59d47a2f0c1',
children: [] } } ]
If settle
were false
on the 3rd response would be returned and all the tasks would be marked as FAILURE.
####.map(arrayOfValues, [options,] [settle,] callback)
Same as .mapAsync
except it's handled with a function(error, results)
callback.
Example:
var task = client.createTask('js.add'),
values = [ [1,2], [3,4], [5,'a']];
task.map(values, {settle: false}, function(err, res) {
(err) ? errorous('doh!') : successful('yay!');
})
Returns:
error doh!
Setting settle
to true
returns success yay!
with an array of possible SUCCESS and FAILURE tasks.
####.times([options,] n, callback)
Executes the task n
times with callback
.
####.link(task)
Pushes a task alias
, or Array of task aliases, onto the Canvas stack.
If no task
is supplied, the underlying Cavas will act as a single task.apply()
####.s([options])
Creates an alias of task
to use with .link
A task alias
is a shallow copy of a task where the supplied options overwrite those in the original task.
If you don't have any options to change, just call task.s()
and it will be identical.
###.Canvas ####.chain(callback) Calls the linked task aliases where the result of the previous function is the last parameters for the next function.
Given:
@app.task(name='js.add')
def add(x, y):
return x + y
client.on('connect', function() {
var task = client.createTask('js.add', {queue: 'js', args: [1,2]});
task
.link([
task.s({args: [1]}),
task.s({args: [5]})
])
.Canvas
.chain(successful); // 1 + 2 = 3
}); // 3 + 1 = 4
// 4 + 5 = 9
function successful(message) {
console.log(message);
}
Returns:
{ status: 'SUCCESS',
traceback: null,
result: 9,
taskId: '8925043b-462f-470b-87eb-d7384e1f299d',
children: [] }
###Result A JSON message from amqp containing:
status
: SUCCESS or FAILURE, PENDING possible with promises.traceback
: Python stack-trace if there was an error.result
: Return value of the python program.taskId
: Internal task ID, and the same one in the message queue.children
: soon -- these are sub-tasks spawned from the original task; will be in Canvas.
##Usage Task-level Queue
var task = client.createTask('native.platform', {queue: 'windows'});
Execute-level Queue
var task = client.createTask('native.platform');
task.applyAsync(task: {queue: 'windows'});
Both return:
{ status: 'SUCCESS',
traceback: null,
result: 'windows nt 2.7',
taskId: '40a68e93-aedc-4cc2-b15c-be2ecdec82f8',
children: [] }
###Note
Attribution to: https://github.com/mher/node-celery by Mher Movsisyan for the inspiration and design pattern.
Use the one that suits your programming flow better!
Blake VandeMerwe 2014