Unable to "Peek" messages from an Azure Service Bus Queue using AMQP and Node

Question

I'm trying to "Peek" messages from an Azure Service Bus queue using nodeamqp10 library but unfortunately I am not able to do so.

Here's the code I am using:

const AMQPClient = require('amqp10/lib').Client,
Policy = require('amqp10/lib').Policy;

const protocol = 'amqps';
const keyName = 'MyPolicy';
const sasKey = 'My SAS Key'
const serviceBusHost = 'account.servicebus.windows.net';
const uri = protocol + '://' + encodeURIComponent(keyName) + ':' + encodeURIComponent(sasKey) + '@' + serviceBusHost;
const queueName = 'queue-name';
const policy = Policy.ServiceBusQueue;
policy.receiverLink.attach.rcvSettleMode = 1;
var client = new AMQPClient(policy);
client.connect(uri)
.then(function () {
    return Promise.all([
        client.createReceiver(queueName),
        client.createSender(queueName)
    ]);
})
.spread(function(receiver, sender) {
    sender.on('errorReceived', function (tx_err) { console.warn('===> TX ERROR: ', tx_err); });
    receiver.on('errorReceived', function (rx_err) { console.warn('===> RX ERROR: ', rx_err); });
    receiver.on('message', function(message) {
        console.log('Received message');
        console.log(message);
        console.log('------------------------------------');
        messages.push(message);
    });
    var messageOptions = {
      'applicationProperties': {
        'operation': 'com.microsoft:peek-message'
      }
    };
    return sender.send({}, messageOptions);
})
.error(function (e) {
    console.warn('connection error: ', e);
});

Few things are happening with this code that I am not able to comprehend:

1. The code above fetches the messages but it is fetching them in Peek/Lock mode i.e. every time I run the code, the delivery count of messages is increasing by one which is not what I am looking for.
2. The code above inserts a message in a queue every time it is run. I only want to fetch the messages from the queue and not insert any new message.

I have gone through the documentation here, and based on this I am specifying operation as com.microsoft:peek-message in applicationProperties which should only allow peeking at messages and not peeking and locking them.

Can anyone please tell me what am I doing wrong here?

Answer 1

In order to receive the messages without locks, set receiver-settle-mode property to settle on disposition while creating the receiver.

Answering your second question, you have created a sender for your queue, which sends the message when it is compiled. To stop it from sending message, just remove the sender and related code.

Answer 2

I think releasing the message will solve the problem:

receiver.release(message);

......

 receiver.on('message', function(message) {
        console.log('Received message');
        console.log(message);
        console.log('------------------------------------');
        messages.push(message);

        receiver.release(message);  

 });
.......

Apparently, I could achieve this with messageOptions as well. Currently, it seems malformed.

var messageOptions = {'applicationProperties': {'operation': 'com.microsoft:peek-message'}};

applicationProperties is not matching with any available configuration property, and so it is being added in "Custom Properties" of the message.

The following seems to work just fine:

var messageOptions = {'operation': 'com.microsoft:peek-message'};

Please let me know if that helps, thanks.