agilite-core/src/service-pool-manager.ts

A NodeJS module that provides reusable backend functionality to the Agilit-e environment

'use strict'

import Async from 'async'
import ServicePool from 'service-pool'

let pool: any = null
let tempPool = {}

// Create Queue Manager for Service Pool
const queue = Async.queue((params, callback) => {
  _getExtended(params, callback)
})
queue.drain(() => {})

// NATIVE FUNTIONS
const get = (params) => {
  // console.log('--START: Service Pool Manager - Running Get')

  if (!pool) {
    pool = new ServicePool(params.servicePoolConfig)
  }

  return new Promise((resolve, reject) => {
    const service = pool.get(params.id)

    if (service) {
      delete tempPool[params.id]
      // console.log('Pool Entry exists for - ' + params.id)
      resolve(service)
    } else {
      // console.log('Queuing request to create new Service Pool for - ' + params.id)
      queue.push(params, (err, service2) => {
        if (err) {
          reject(err)
        } else {
          resolve(service2)
        }
      })
    }
  })
}

const reset = () => {
  pool.reset()
  tempPool = {}
}

const destroy = (id) => {
  if (pool) {
    pool.destroy(id)
  }
  delete tempPool[id]
}

// PRIVATE FUNTIONS
const _getExtended = async (params, callback) => {
  let service = pool.get(params.id)

  if (service) {
    delete tempPool[params.id]
    // console.log('Pool Entry exists for - ' + params.id)
    callback(null, service)
  } else {
    // console.log('Pool Entry doesn\'t exist for - ' + params.id + '. Checking if we are allowed to create one')
    if (tempPool[params.id]) {
      // console.log('Someone else is trying to create the same request. Wait and try again for - ' + params.id)
      setTimeout(() => {
        _getExtended(params, callback)
      }, 10)
    } else {
      // console.log('No one\'s creating request. We can create for - ' + params.id)
      tempPool[params.id] = true
      service = await pool.add(params.servicePoolObject)
      callback(null, service)
    }
  }
}

export default {
  get,
  reset,
  destroy
}