Unable to “Peek” messages from an Azure Service Bu

问题:

This question already has an answer here:

• Getting “amqp:internal-error” when peeking messages from Azure Service Bus Queue using AMQP, rhea and Node 1 answer

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?

回答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.

回答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.