AtHome

@Home

Tiny and elegant Cluster state manager.

• Task pulling
• Result validation
• Error retries
• Built in status

Install

npm install athome -S

Usage

const AtHome = require('athome')
const atHome = new AtHome()

const clusterId = atHome.join((n, m) => n + m)
atHome.pull(clusterId)
// Since there is no tasks, this pull will be added to pulls waiting list.

atHome.execute(3, 4)
  .then(console.log) // => 7

More realistic use case:

const AtHome = require('athome')
const atHome = new AtHome()

const functionTakesLongLongTimeRunsFarFarAway = n => new Promise(resolve => setTimeout(() => resolve(n * n), 1000))

const clusterId = atHome.join(functionTakesLongLongTimeRunsFarFarAway)

atHome.execute(8).then(console.log)
// Since there is no pulls, the task will be added to waiting list

atHome.pull(clusterId)
// A second later, output 64

With built in validator:

const AtHome = require('athome')

const atHome = new AtHome({ validator: result => result > 0 })
// result must be greater than 0

const reverse = n => new Promise(resolve => setTimeout(() => resolve(-n), 1000))
const stay = n => new Promise(resolve => setTimeout(() => resolve(n), 1000))

const reverseId = atHome.join(reverse)
const stayId = atHome.join(stay)

atHome.pull(reverseId)
atHome.pull(reverseId)
atHome.pull(stayId)


atHome.execute(-3).then(console.log)
atHome.execute(2).then(console.log)

// First -3 will go throw 1st reverse pull and output 3,
// the second 2 will go throw 2nd reverse pull and output -2,
// which will falls the validation, so it will go again with the 3rd stay pull,
// and output 2, which pass the validation.
// output: 3, 2

API Document

new Athome(options)

return atHome instance.

Options	Type	Detail	Default
validator	Function => Promise/Boolean	A function used to validate result	() => true
retries	Number	Max retries limit	5

atHome.join(clusterFunction)

Add a cluster to @Home network.

clusterFunction: function will be called with all params when this cluster is executing task.

return: String HomeID, cluster uuid

atHome.pull(id)

Pull task for this cluster, the correspond clusterFunction will be called when there is task available.

id: clutser's uuid

return: Promise<boolean> if this compute succeed

atHome.execute(data)

Execute a task.

The task will be either executed now if there is waiting pulls, or added to task waiting list for pulls.

params: params which pass to clusterFunction

return: Promise resolve the result, or reject when retries too much.

atHome.quit(id)

Remove a cluster from @Home network, this will also:

• remove the cluster from pulling list;
• fall all running task of this cluster;
  • which will then be handled by a different cluster;
  • (or reject task if the task reachs retries limit).

id: cluster's uuid

atHome.homes: Map<HomeID, Home>

Map with HomeID(uuid) and Home Instances.

Home Instance

home.id HomeID(uuid)

home.resolves number

Number of resolves.

home.rejects number

Number of rejects, include invalid response.

home.lastSeen number

Time stamp, refresh when:

• join
• pull
• finish task

Contribution

Feel free to ask any question and create pull request :D