fix: setup consumer and producer methods early

* Create method after setting up queue model.

* Setup queues after app boot event.

* log the request to queue before its been initialised

* code cleanup

Author: rahulbile

lib/index.js

@@ -19,21 +19,23 @@ module.exports = function loopbackComponentMq(app, config) {
   // Independent of app boot, add model and ACL
   setupModel(app)
 
+  // Get a reference to the created model and set up the topology
+  const Queue = app.models.Queue
+
+  RabbitTopology.setupTopology(Queue)
+
   // Wait the app to be booted
   app.once('booted', () => {
 
-    // Get a reference to the created model
-    const Queue = app.models.Queue
-
     // Get a reference to the configured datasource
     const dsName = _.get(app, 'settings.loopback-component-mq.options.dataSource', 'rabbit')
     const ds = app.dataSources[dsName]
     const dsOptions = _.get(ds, 'settings.options')
 
-    // If we have a datasource, wire up Rabbit and set up the topology
+    // If we have a datasource, wire up Rabbit and setup Queues
     if (ds && dsOptions) {
       Queue.rabbit = new Rabbit(dsOptions)
-      RabbitTopology.setupTopology(Queue)
+      RabbitTopology.setupQueues(Queue)
     }
 
   })

lib/rabbit-topology.js

@@ -12,6 +12,16 @@ module.exports = function rabbitTopology() {
     msqQueue = QueueModel.rabbit.exchange.queue({ name, durable: true })
   }
 
+  function setupQueues(Model) {
+    QueueModel = Model
+
+    // Loop through all the defined queues
+    _.forEach(QueueModel.topology, (handlers, queue) => {
+      // Setup the actual queue on RabbitMQ
+      setupQueue(queue)
+    })
+  }
+
   function setupQueueConsumer(app, queue, definition) {
     debug('setupQueueConsumer')
     const modelName = definition.model
@@ -31,7 +41,10 @@ module.exports = function rabbitTopology() {
     }
 
     // Start consuming the queue
-    msqQueue.consume(Method)
+    if (msqQueue) {
+      msqQueue.consume(Method)
+    }
+
 
     debug('setupQueueConsumer: queue: %s, model: %s, method: %s', queue, modelName, methodName)
   }
@@ -49,7 +62,12 @@ module.exports = function rabbitTopology() {
 
     Model[methodName] = function queueProducer(params) {
       debug(`${modelName}.${methodName}(%o)`, params)
-      QueueModel.rabbit.exchange.publish(params, { key: queue })
+      if (QueueModel.rabbit && QueueModel.rabbit.exchange) {
+        QueueModel.rabbit.exchange.publish(params, { key: queue })
+      }
+      else {
+        debug('setupQueueProducer: queue %s is not yet initialised', queue)
+      }
     }
   }
 
@@ -59,9 +77,6 @@ module.exports = function rabbitTopology() {
     // Loop through all the defined queues
     _.forEach(QueueModel.topology, (handlers, queue) => {
 
-      // Setup the actual queue on RabbitMQ
-      setupQueue(queue)
-
       // Setup the consumer of this queue
       if (handlers.consumer) {
         setupQueueConsumer(QueueModel.app, queue, handlers.consumer)
@@ -77,6 +92,7 @@ module.exports = function rabbitTopology() {
 
   return {
     setupQueue,
+    setupQueues,
     setupTopology,
     setupQueueProducer,
     setupQueueConsumer,