@nhz.io/pouch-db-job-scheduler

PouchDB Job Scheduler (replicate/sync)

Install

npm i -S @nhz.io/pouch-db-job-scheduler

Usage

• Extend Scheduler class with your desired behaviour
• Scheduler extends p-queue, so interface is the same essentially with some additions
• constructor opts should include PouchDB property (will be copied to instance)

const PouchDB = require 'pouchdb'
const Scheduler = require('@nhz.io/pouch-db-job-scheduler')
const replicate = require('@nhz.io/pouch-db-replication-job')

class MyScheduler extends Scheduler {
  /* ... */
}

const scheduler = new MyScheduler({ PouchDB, concurrency: 1 })

scheduler.addAll([ replicate({}, 'http://foo', 'foo'), replicate({}, 'foo', 'bar'), /* ... */ ])

/* ... */

Literate Source

Import

PQueue = require 'p-queue'

Scheduler

class Scheduler extends PQueue

  constructor: (opts) ->
    super opts

    @PouchDB = opts?.PouchDB or PouchDB

  add: (run, args...) -> super (@prepare run, args...)

Prepare job for run (Binding cleanup upon completion/fail)

  prepare: (run) -> () =>

    job = run { @PouchDB }

    job.then () => @cleanup job

    job.catch => @cleanup job

    job

Need to call stop on any pouchdb job to unbind listeners

  cleanup: (job) ->

    job.stop()

    null

Exports

module.exports = Scheduler

Tests

test = require 'tape-async'

PouchDB = require 'pouchdb-memory'
PQueue = require 'p-queue'

replicate = require '@nhz.io/pouch-db-replication-job'

mkdb = (i, n = 0) ->

  db = new PouchDB "db-#{ i }"

  await db.put { _id: "doc-#{ i + 1 }" } for i in [0...n]

  db

Base Scheduler test

test 'Scheduler', (t) ->

  rand = Math.random().toString().slice(3)

  scheduler = new Scheduler ({ concurrency: 1 })

  source = await mkdb 1 + rand, 2

  target = await mkdb 5 + rand

  jobs = for i in [1..4] then replicate {}, "db-#{ i + rand }", await mkdb i + 1 + rand

  await scheduler.addAll jobs

  t.deepEqual await source.allDocs(), await target.allDocs()

Version 0.1.3

License MIT