implement event handling

Author: imcaizheng

app.js

@@ -10,6 +10,7 @@ const cors = require('cors')
 const HttpStatus = require('http-status-codes')
 const interceptor = require('express-interceptor')
 const logger = require('./src/common/logger')
+const eventHandlers = require('./src/eventHandlers')
 
 // setup express app
 const app = express()
@@ -91,6 +92,7 @@ app.use((err, req, res, next) => {
 
 const server = app.listen(app.get('port'), () => {
   logger.info({ component: 'app', message: `Express server listening on port ${app.get('port')}` })
+  eventHandlers.init()
 })
 
 if (process.env.NODE_ENV === 'test') {

docs/swagger.yaml

@@ -575,8 +575,8 @@ paths:
           required: false
           schema:
             type: string
-            enum: ['open', 'selected', 'shortlist', 'rejected']
-          description: The user id.
+            enum: ['open', 'selected', 'shortlist', 'rejected', 'cancelled']
+          description: The job candidate status.
       responses:
         '200':
           description: OK
@@ -1686,8 +1686,8 @@ components:
           description: "The user id."
         status:
           type: string
-          enum: ['open', 'selected', 'shortlist', 'rejected']
-          description: "The job status."
+          enum: ['open', 'selected', 'shortlist', 'rejected', 'cancelled']
+          description: "The job candidate status."
         createdAt:
           type: string
           format: date-time
@@ -1722,7 +1722,7 @@ components:
       properties:
         status:
           type: string
-          enum: ['open', 'selected', 'shortlist', 'rejected']
+          enum: ['open', 'selected', 'shortlist', 'rejected', 'cancelled']
     JobPatchRequestBody:
       properties:
         status:
@@ -2130,8 +2130,8 @@ components:
                 description: 'The link for the resume that can be downloaded'
               status:
                 type: string
-                enum: ['open', 'selected', 'shortlist', 'rejected']
-                description: "The job status."
+                enum: ['open', 'selected', 'shortlist', 'rejected', 'cancelled']
+                description: "The job candidate status."
               skills: 
                   type: array
                   items:

src/bootstrap.js

@@ -8,7 +8,7 @@ Joi.perPage = () => Joi.number().integer().min(1).default(20)
 Joi.rateType = () => Joi.string().valid('hourly', 'daily', 'weekly', 'monthly')
 Joi.jobStatus = () => Joi.string().valid('sourcing', 'in-review', 'assigned', 'closed', 'cancelled')
 Joi.workload = () => Joi.string().valid('full-time', 'fractional')
-Joi.jobCandidateStatus = () => Joi.string().valid('open', 'selected', 'shortlist', 'rejected')
+Joi.jobCandidateStatus = () => Joi.string().valid('open', 'selected', 'shortlist', 'rejected', 'cancelled')
 
 function buildServices (dir) {
   const files = fs.readdirSync(dir)

src/common/eventDispatcher.js

@@ -0,0 +1,33 @@
+/*
+ * Implement an event dispatcher that handles events synchronously.
+ */
+
+const handlers = []
+
+/**
+ * Handle event.
+ *
+ * @param {String} topic the topic name
+ * @param {Object} payload the message payload
+ * @returns {undefined}
+ */
+async function handleEvent (topic, payload) {
+  for (const handler of handlers) {
+    await handler.handleEvent(topic, payload)
+  }
+}
+
+/**
+ * Register to the dispatcher.
+ *
+ * @param {Object} handler the handler containing the `handleEvent` function
+ * @returns {undefined}
+ */
+function register (handler) {
+  handlers.push(handler)
+}
+
+module.exports = {
+  handleEvent,
+  register
+}

src/common/helper.js

@@ -12,6 +12,7 @@ const elasticsearch = require('@elastic/elasticsearch')
 const errors = require('../common/errors')
 const logger = require('./logger')
 const models = require('../models')
+const eventDispatcher = require('./eventDispatcher')
 const busApi = require('@topcoder-platform/topcoder-bus-api-wrapper')
 
 const localLogger = {
@@ -313,6 +314,7 @@ async function postEvent (topic, payload) {
     payload
   }
   await client.postEvent(message)
+  await eventDispatcher.handleEvent(topic, payload)
 }
 
 /**
@@ -589,6 +591,15 @@ async function ensureUserById (userId) {
   }
 }
 
+/**
+ * Generate M2M auth user.
+ *
+ * @returns {Object} the M2M auth user
+ */
+function getAuditM2Muser () {
+  return { isMachine: true, userId: config.m2m.M2M_AUDIT_USER_ID, handle: config.m2m.M2M_AUDIT_HANDLE }
+}
+
 module.exports = {
   checkIfExists,
   autoWrapExpress,
@@ -615,5 +626,6 @@ module.exports = {
   getSkillById,
   getUserSkill,
   ensureJobById,
-  ensureUserById
+  ensureUserById,
+  getAuditM2Muser
 }

src/eventHandlers/JobEventHandler.js

@@ -0,0 +1,86 @@
+/*
+ * Handle events for Job.
+ */
+
+const { Op } = require('sequelize')
+const models = require('../models')
+const logger = require('../common/logger')
+const helper = require('../common/helper')
+const JobCandidateService = require('../services/JobCandidateService')
+const ResourceBookingService = require('../services/ResourceBookingService')
+
+/**
+ * Cancel all related resource bookings and all related candidates when a job is cancelled.
+ *
+ * @param {Object} payload the event payload
+ * @returns {undefined}
+ */
+async function cancelJob (payload) {
+  if (payload.status !== 'cancelled') {
+    logger.info({
+      component: 'JobEventHandler',
+      context: 'cancelJob',
+      message: `not interested job - status: ${payload.status}`
+    })
+    return
+  }
+  // pull data from db instead of directly extract data from the payload
+  // since the payload may not contain all fields when it is from partically update operation.
+  const job = await models.Job.findById(payload.id)
+  const candidates = await models.JobCandidate.findAll({
+    where: {
+      jobId: job.id,
+      status: {
+        [Op.not]: 'cancelled'
+      },
+      deletedAt: null
+    }
+  })
+  const resourceBookings = await models.ResourceBooking.findAll({
+    where: {
+      projectId: job.projectId,
+      status: {
+        [Op.not]: 'cancelled'
+      },
+      deletedAt: null
+    }
+  })
+  await Promise.all([
+    ...candidates.map(candidate => JobCandidateService.partiallyUpdateJobCandidate(
+      helper.getAuditM2Muser(),
+      candidate.id,
+      { status: 'cancelled' }
+    ).then(result => {
+      logger.info({
+        component: 'JobEventHandler',
+        context: 'cancelJob',
+        message: `id: ${result.id} candidate got cancelled.`
+      })
+    })),
+    ...resourceBookings.map(resource => ResourceBookingService.partiallyUpdateResourceBooking(
+      helper.getAuditM2Muser(),
+      resource.id,
+      { status: 'cancelled' }
+    ).then(result => {
+      logger.info({
+        component: 'JobEventHandler',
+        context: 'cancelJob',
+        message: `id: ${result.id} resource booking got cancelled.`
+      })
+    }))
+  ])
+}
+
+/**
+ * Process job update event.
+ *
+ * @param {Object} payload the event payload
+ * @returns {undefined}
+ */
+async function processUpdate (payload) {
+  await cancelJob(payload)
+}
+
+module.exports = {
+  processUpdate
+}

src/eventHandlers/ResourceBookingEventHandler.js

@@ -0,0 +1,105 @@
+/*
+ * Handle events for ResourceBooking.
+ */
+
+const { Op } = require('sequelize')
+const models = require('../models')
+const logger = require('../common/logger')
+const helper = require('../common/helper')
+const JobService = require('../services/JobService')
+const JobCandidateService = require('../services/JobCandidateService')
+
+/**
+ * When ResourceBooking's status is changed to `assigned`
+ * the corresponding JobCandidate record (with the same userId and jobId)
+ * should be updated with status `selected`
+ *
+ * @param {String} jobId the job id
+ * @param {String} userId the user id
+ * @returns {undefined}
+ */
+async function selectJobCandidate (jobId, userId) {
+  const candidates = await models.JobCandidate.findAll({
+    where: {
+      jobId,
+      userId,
+      status: {
+        [Op.not]: 'selected'
+      },
+      deletedAt: null
+    }
+  })
+  await Promise.all(candidates.map(candidate => JobCandidateService.partiallyUpdateJobCandidate(
+    helper.getAuditM2Muser(),
+    candidate.id,
+    { status: 'selected' }
+  ).then(result => {
+    logger.info({
+      component: 'ResourceBookingEventHandler',
+      context: 'selectJobCandidate',
+      message: `id: ${result.id} candidate got selected.`
+    })
+  })))
+}
+
+/**
+ * Update the status of the Job to assigned when it positions requirement is fullfilled.
+ *
+ * @param {Object} job the job data
+ * @returns {undefined}
+ */
+async function assignJob (job) {
+  if (job.status === 'assigned') {
+    logger.info({
+      component: 'ResourceBookingEventHandler',
+      context: 'assignJob',
+      message: `job with projectId ${job.projectId} is already assigned`
+    })
+    return
+  }
+  const resourceBookings = await models.ResourceBooking.findAll({
+    where: {
+      status: 'assigned',
+      deletedAt: null
+    }
+  })
+  logger.debug({
+    component: 'ResourceBookingEventHandler',
+    context: 'assignJob',
+    message: `the number of assigned resource bookings is ${resourceBookings.length} - the numPositions of the job is ${job.numPositions}`
+  })
+  if (job.numPositions === resourceBookings.length) {
+    await JobService.partiallyUpdateJob(helper.getAuditM2Muser(), job.id, { status: 'assigned' })
+    logger.info({ component: 'ResourceBookingEventHandler', context: 'assignJob', message: `job with projectId ${job.projectId} is assigned` })
+  }
+}
+
+/**
+ * Process resource booking update event.
+ *
+ * @param {Object} payload the event payload
+ * @returns {undefined}
+ */
+async function processUpdate (payload) {
+  if (payload.status !== 'assigned') {
+    logger.info({
+      component: 'ResourceBookingEventHandler',
+      context: 'selectJobCandidate',
+      message: `not interested resource booking - status: ${payload.status}`
+    })
+    return
+  }
+  const resourceBooking = await models.ResourceBooking.findById(payload.id)
+  const job = await models.Job.findOne({
+    where: {
+      projectId: resourceBooking.projectId,
+      deletedAt: null
+    }
+  })
+  await selectJobCandidate(job.id, resourceBooking.userId)
+  await assignJob(job)
+}
+
+module.exports = {
+  processUpdate
+}

src/eventHandlers/index.js

@@ -0,0 +1,52 @@
+/*
+ * The entry of event handlers.
+ */
+
+const config = require('config')
+const eventDispatcher = require('../common/eventDispatcher')
+const JobEventHandler = require('./JobEventHandler')
+const ResourceBookingEventHandler = require('./ResourceBookingEventHandler')
+const logger = require('../common/logger')
+
+const TopicOperationMapping = {
+  [config.TAAS_JOB_UPDATE_TOPIC]: JobEventHandler.processUpdate,
+  [config.TAAS_RESOURCE_BOOKING_UPDATE_TOPIC]: ResourceBookingEventHandler.processUpdate
+}
+
+/**
+ * Handle event.
+ *
+ * @param {String} topic the topic name
+ * @param {Object} payload the message payload
+ * @returns {undefined}
+ */
+async function handleEvent (topic, payload) {
+  if (!TopicOperationMapping[topic]) {
+    logger.info({ component: 'eventHanders', context: 'handleEvent', message: `not interested event - topic: ${topic}` })
+    return
+  }
+  logger.debug({ component: 'eventHanders', context: 'handleEvent', message: `handling event - topic: ${topic} - payload: ${JSON.stringify(payload)}` })
+  try {
+    await TopicOperationMapping[topic](payload)
+  } catch (err) {
+    logger.error({ component: 'eventHanders', context: 'handleEvent', message: 'failed to handle event' })
+    // throw error so that it can be handled by the app
+    throw err
+  }
+  logger.info({ component: 'eventHanders', context: 'handleEvent', message: 'event successfully handled' })
+}
+
+/**
+ * Attach the handlers to the event dispatcher.
+ *
+ * @returns {undefined}
+ */
+function init () {
+  eventDispatcher.register({
+    handleEvent
+  })
+}
+
+module.exports = {
+  init
+}