feat: add passive option to queueFsm

allows for checkQueue instead of assertQueue when clients have restricted permissions

fixes issue #183

spec/behavior/queue.spec.js

@@ -0,0 +1,56 @@
+require('../setup.js');
+var ampqQueue = require('../../src/amqp/queue');
+
+describe('AMQP Queue', function () {
+  let amqpChannelMock, options, topology, serializers;
+
+  beforeEach(() => {
+    amqpChannelMock = {
+      ack: sinon.stub().callsFake(() => Promise.resolve()),
+      nack: sinon.stub().callsFake(() => Promise.resolve()),
+      checkQueue: sinon.stub().callsFake(() => Promise.resolve()),
+      assertQueue: sinon.stub().callsFake(() => Promise.resolve())
+    };
+
+    options = {
+      uniqueName: 'one-unique-name-coming-up'
+    };
+
+    topology = {
+      connection: {
+        getChannel: sinon.stub().callsFake(() => Promise.resolve(amqpChannelMock))
+      }
+    };
+
+    serializers = sinon.stub();
+  });
+
+  describe('when executing "define"', () => {
+    describe('when options.passive is not set', () => {
+      it('calls assertQueue', function () {
+        return ampqQueue(options, topology, serializers)
+          .then((instance) => {
+            return instance.define();
+          })
+          .then(() => {
+            amqpChannelMock.checkQueue.calledOnce.should.equal(false);
+            amqpChannelMock.assertQueue.calledOnce.should.equal(true);
+          });
+      });
+    });
+
+    describe('when options.passive is true', function () {
+      it('calls checkQueue instead of assertQueue', async () => {
+        options.passive = true;
+        return ampqQueue(options, topology, serializers)
+          .then((instance) => {
+            return instance.define();
+          })
+          .then(() => {
+            amqpChannelMock.checkQueue.calledOnce.should.equal(true);
+            amqpChannelMock.assertQueue.calledOnce.should.equal(false);
+          });
+      });
+    });
+  });
+});

spec/integration/addPassiveQueue.spec.js

@@ -0,0 +1,48 @@
+require('../setup');
+const rabbit = require('../../src/index.js');
+
+describe('Adding Queues', function () {
+  describe('with a connection', function () {
+    describe('when the queue does not already exist', function () {
+      it('should error on addQueue in passive mode', function () {
+        return rabbit.configure({
+          connection: {
+            name: 'temp'
+          }
+        }).then(() => {
+          return rabbit.addQueue('no-queue-here', { passive: true }, 'temp')
+            .then(
+              () => { throw new Error('Should not have succeeded in the checkQueue call'); },
+              (err) => {
+                err.toString().should.contain("Failed to create queue 'no-queue-here' on connection 'temp' with 'Error: Operation failed: QueueDeclare; 404 (NOT-FOUND)");
+              });
+        });
+      });
+    });
+
+    describe('when the queue does exist', function () {
+      const existingQueueName = 'totes-exists-already';
+      it('should NOT error on addQueue when in passive mode', function () {
+        return rabbit.configure({
+          connection: {
+            name: 'temp'
+          },
+          queues: [
+            { name: existingQueueName, connection: 'temp' }
+          ]
+        }).then(() => {
+          return rabbit.addQueue(existingQueueName, { passive: true }, 'temp');
+        });
+      });
+
+      afterEach(function () {
+        return rabbit.deleteQueue(existingQueueName, 'temp');
+      });
+    });
+
+    afterEach(function () {
+      rabbit.reset();
+      return rabbit.shutdown('temp');
+    });
+  });
+});

src/amqp/queue.js

@@ -45,16 +45,24 @@ function define (channel, options, subscriber, connectionName) {
     deadletter: 'deadLetterExchange',
     deadLetter: 'deadLetterExchange',
     deadLetterRoutingKey: 'deadLetterRoutingKey'
-  }, 'subscribe', 'limit', 'noBatch', 'unique');
+  }, 'subscribe', 'limit', 'noBatch', 'unique', 'passive');
   topLog.info("Declaring queue '%s' on connection '%s' with the options: %s",
     options.uniqueName, connectionName, JSON.stringify(options));
-  return channel.assertQueue(options.uniqueName, valid)
-    .then(function (q) {
-      if (options.limit) {
-        channel.prefetch(options.limit);
-      }
-      return q;
-    });
+
+  let queuePromise;
+
+  if (options.passive) {
+    queuePromise = channel.checkQueue(options.uniqueName);
+  } else {
+    queuePromise = channel.assertQueue(options.uniqueName, valid);
+  }
+
+  return queuePromise.then(function (q) {
+    if (options.limit) {
+      channel.prefetch(options.limit);
+    }
+    return q;
+  });
 }
 
 function finalize (channel, messages) {

src/queueFsm.js

@@ -29,6 +29,7 @@ var Factory = function (options, connection, topology, serializers, queueFn) {
   var Fsm = machina.Fsm.extend({
     name: options.name,
     uniqueName: options.uniqueName,
+    passive: options.passive,
     responseSubscriptions: {},
     signalSubscription: undefined,
     subscribed: false,