RabbitMQ data lost on crash - node.js

I'm using RabbitMQ to store and retrieve data. I referred this article. I have set the durable flag to true and the noAck flag to false (i need to store the messages on the queue even after consuming).
I created these scenarios:
I updated stock data 3 times with consumers off state (inactive). Then I activated the consumer.It consumed all the three messages from the queue. [Works good.]
Now I again produced three messages (consumer inactive again) then I turned off the rabbitmq server. When I restarted the server and activated the consumer. It doesn't seem to be consuming the data (are the messages that were on the queue has been lost?)
Consumer :
connection.createChannel(function (error1, channel) {
if (error1) {
throw error1;
}
var queue = "updateStock2";
channel.assertQueue(queue, {
durable: true,
});
console.log(
" [*] Waiting for stockData messages in %s. To exit press CTRL+C",
queue
);
channel.consume(
queue,
function (data) {
stock = JSON.parse(data.content.toString());
console.log(" [x] Received Stock:", stock.name + " : " + stock.value);
},
{
noAck: false,
}
);
Producer :
connection.createChannel(function (error1, channel) {
if (error1) {
throw error1;
}
var queue = "updateStock2";
channel.assertQueue(queue, {
durable: true,
});
channel.sendToQueue(queue, Buffer.from(data));
console.log(" [x] Sent %s", data);
});
setTimeout(function () {
connection.close();
//process.exit(0);
}, 500);});
Aren't they persistent? If the server crashes all the messages in the queue are gone forever?
How to retrieve data that were in the queue when the server crashes?
Thanks in advance.

Why your messages have lost?
Regret to say, you did not declare {persistent: true} when you send message.Check https://www.rabbitmq.com/tutorials/tutorial-two-javascript.html, so you should use channel.sendToQueue(queue, Buffer.from(msg), {persistent: true});
Aren't they persistent?
Durable queues will be recovered on node boot, including messages in them published as persistent. Messages published as transient will be discarded during recovery, even if they were stored in durable queues.
Which middleware maybe better for you?
If you want a middleware which can persist messages even if consumed by consumers, you maybe need kafka

Related

Can I filter an Azure ServiceBusService using node.js SDK?

I have millions of messages in a queue and the first ten million or so are irrelevant. Each message has a sequential ActionId so ideally anything < 10000000 I can just ignore or better yet delete from the queue. What I have so far:
let azure = require("azure");
function processMessage(sb, message) {
// Deserialize the JSON body into an object representing the ActionRecorded event
var actionRecorded = JSON.parse(message.body);
console.log(`processing id: ${actionRecorded.ActionId} from ${actionRecorded.ActionTaken.ActionTakenDate}`);
if (actionRecorded.ActionId < 10000000) {
// When done, delete the message from the queue
console.log(`Deleting message: ${message.brokerProperties.MessageId} with ActionId: ${actionRecorded.ActionId}`);
sb.deleteMessage(message, function(deleteError, response) {
if (deleteError) {
console.log("Error deleting message: " + message.brokerProperties.MessageId);
}
});
}
// immediately check for another message
checkForMessages(sb);
}
function checkForMessages(sb) {
// Checking for messages
sb.receiveQueueMessage("my-queue-name", { isPeekLock: true }, function(receiveError, message) {
if (receiveError && receiveError === "No messages to receive") {
console.log("No messages left in queue");
return;
} else if (receiveError) {
console.log("Receive error: " + receiveError);
} else {
processMessage(sb, message);
}
});
}
let connectionString = "Endpoint=sb://<myhub>.servicebus.windows.net/;SharedAccessKeyName=KEYNAME;SharedAccessKey=[mykey]"
let serviceBusService = azure.createServiceBusService(connectionString);
checkForMessages(serviceBusService);
I've tried looking at the docs for withFilter but it doesn't seem like that applies to queues.
I don't have access to create or modify the underlying queue aside from the operations mentioned above since the queue is provided by a client.
Can I either
Filter my results that I get from the queue
speed up the queue processing somehow?
Filter my results that I get from the queue
As you found, filters as a feature are only applicable to Topics & Subscriptions.
speed up the queue processing somehow
If you were to use the #azure/service-bus package which is the newer, faster library to work with Service Bus, you could receive the messages in ReceiveAndDelete mode until you reach the message with ActionId 9999999, close that receiver and then create a new receiver in PeekLock mode. For more on these receive modes, see https://learn.microsoft.com/en-us/azure/service-bus-messaging/message-transfers-locks-settlement#settling-receive-operations

High performance on Nodejs RabbitMQ server

I'm building an analysis system with a million users online in the same time. I use RabbitMQ such as message broker to reduce capacity for server
Here is my diagram
My system include 3 components.
Publisher server : ( Producer )
This system was built on nodejs. The purpose of this system to publish the messages into queue
RabbitMQ queue : This system stored the messages that publisher server sent to. After that, one connect is opened to send message from queue for subscriber server.
Subscriber server ( Consumer ) : This system receive the messages from queue
Publisher server source code
var amqp = require('amqplib/callback_api');
amqp.connect("amqp://localhost", function(error, connect) {
if (error) {
return callback(-1, null);
} else {
connect.createChannel(function(error, channel) {
if (error) {
return callback(-3, null);
} else {
var q = 'logs';
var msg = data; // object
// convert msg object to buffer
var new_msg = Buffer.from(JSON.stringify(msg), 'binary');
channel.assertExchange(q, 'fanout', { durable: false });
channel.publish(q, 'message_queues', new Buffer(new_msg));
console.log(" [x] Sent %s", new_msg);
return callback(null, msg);
}
});
}
});
create exclusively exchange "message_queues" with "fanout" to send
broadcast to all consumer
Subscriber server source code
var amqp = require('amqplib/callback_api');
amqp.connect("amqp://localhost", function(error, connect) {
if (error) {
console.log('111');
} else {
connect.createChannel(function(error, channel) {
if (error) {
console.log('1');
} else {
var ex = 'logs';
channel.assertExchange(ex, 'fanout', { durable: false });
channel.assertQueue('message_queues', { exclusive: true }, function(err, q) {
if (err) {
console.log('123');
} else {
console.log(" [*] Waiting for messages in %s. To exit press CTRL+C", q.queue);
channel.bindQueue(q.queue, ex, 'message_queues');
channel.consume(q.queue, function(msg) {
console.log(" [x] %s", msg.content.toString());
}, { noAck: true });
}
});
}
});
}
});
receive messge from "message_queues" exchange
When I implement send a message. The system work well, however I tried benchmark test performance of this system (with ~ 1000 users sent request per second ) then the system has some issue. The system seem as overload / buffer overflow ( or some thing don't work well ).
I just only read about rabbitmq 2 days ago. I know its tutorials is basic example, so I need help to build systems in real world than .. Any
solution & suggestion
Hope that my question make a sense
Your question is general. Probably you should provide more details to help to identify the bottleneck and help you out.
So, first of all I think you should check the rabbit mq - whether its a bottleneck or not.
There are many things that can go wrong:
The number of consumers that can consume the message is too low (I assume you use a pool of consumers)
The network is too slow
The queues and messages are replicated between too many nodes of Rabbit MQ and go do disk (its possible to use rabbit mq like this)
The consumer can't really handle a message and it gets constantly re-queued
So, in general during your tests you should check rabbit mq and see what happens there.
The message once arrives into queue is in Ready State once this happens, it will be there till one of consumers connected to queue won't attempt to take the the message for handling
When one of consumers (rabbit does round-robin between them) picks the message for processing it's state will turn to Unacknowledged
if consumer fails to handle the message, it will be re-queued by rabbit so that another consumer would have a chance to handle the message.
Of course, if consumer handles the message successfully, the message disappears from rabbit mq server.
Assuming you've installed rabbit mq web ui (I highly recommend it especially for beginners) - you can visually see what happens in your queue - you'll see how many messages are in ready state, and how many are unacknowledged.
This will help to identify a bottleneck.
For example - if you see that only one message is usually in unacknowledged state, this can mean that the consumer can't handle the message and sends it back to rabbit. On the other hand new messages always arrive from producer, so the number of ready messages will increase very fast
It also can point on the fact that you use only one consumer that can handle only one message at a time. So you can consider paralleling here, by running many consumers in different threads or even clustering your application (in rabbit consumers can reside in different machines)
Hope this helps in general, of course, as I've said before if you have more specific questions - please provide more information about what exactly happens during the test

How to control commit of a consumed kafka message using kafka-node

I'm using Node with kafka for the first time, using kafka-node. Consuming a message requires calling an external API, which might even take a second to response. I wish to overcome sudden failures of my consumer, in a way that if a consumer fails, another consumer that will consume that will replace it will receive the same message that its work was not completed.
I'm using kafka 0.10 and trying to use ConsumerGroup.
I thought of setting autoCommit: false in options, and committing the message only once its work has been completed (as I previously done with some Java code some time ago).
However, I can't seem to be sure how should I correctly commit the message only once it is done. How should I commit it?
Another worry I have is that it seems, because of the callbacks, that the next message is being read before the previous one had finished. And I'm afraid that if message x+2 have finished before message x+1, then the offset will be set at x+2, thus in case of failure x+1 will never be re-executed.
Here is basically what I did so far:
var options = {
host: connectionString,
groupId: consumerGroupName,
id: clientId,
autoCommit: false
};
var kafka = require("kafka-node");
var ConsumerGroup = kafka.ConsumerGroup;
var consumerGroup = new ConsumerGroup(options, topic);
consumerGroup.on('connect', function() {
console.log("Consuming Kafka %s, topic=%s", JSON.stringify(options), topic);
});
consumerGroup.on('message', function(message) {
console.log('%s read msg Topic="%s" Partition=%s Offset=%d', this.client.clientId, message.topic, message.partition, message.offset);
console.log(message.value);
doSomeStuff(function() {
// HOW TO COMMIT????
consumerGroup.commit(function(err, data) {
console.log("------ Message done and committed ------");
});
});
});
consumerGroup.on('error', function(err) {
console.log("Error in consumer: " + err);
close();
});
process.once('SIGINT', function () {
close();
});
var close = function() {
// SHOULD SEND 'TRUE' TO CLOSE ???
consumerGroup.close(true, function(error) {
if (error) {
console.log("Consuming closed with error", error);
} else {
console.log("Consuming closed");
}
});
};
One thing you can do here is to have a retry mechanism for every message you process.
You can consult my answer on this thread:
https://stackoverflow.com/a/44328233/2439404
I consume messages from Kafka using kafka-consumer, batch them together using async/cargo and put them in async/queue (in-memory queue). The queue takes a worker function as an arguement to which I am passing a async/retryable.
For your problem, you can just use retryable to do processing on your messages.
https://caolan.github.io/async/docs.html#retryable
This may solve your problem.

NodeJS + RabbitMQ - How to limit the number of messages a receiver processes

I am using the amqplib node module and following the hello world send/receive tutorial.
https://github.com/squaremo/amqp.node/tree/master/examples/tutorials
My receivers/workers take that message and perform a CPU intensive task in the background, so I can only process about 5 messages at once.
What is the best way to control the number of messages that are being accepted by the receiver.
Code sample:
var amqp = require('amqplib');
amqp.connect('amqp://localhost').then(function(conn) {
process.once('SIGINT', function() { conn.close(); });
return conn.createChannel().then(function(ch) {
var ok = ch.assertQueue('hello', {durable: false});
ok = ok.then(function(_qok) {
return ch.consume('hello', function(msg) {
console.log(" [x] Received '%s'", msg.content.toString());
}, {noAck: true});
});
return ok.then(function(_consumeOk) {
console.log(' [*] Waiting for messages. To exit press CTRL+C');
});
});
}).then(null, console.warn);
You need to set the Quality Of Service on the model. Here is how you would do that in C#
var _model = rabbitConnection.CreateModel();
// Configure the Quality of service for the model. Below is how what each setting means.
// BasicQos(0="Dont send me a new message untill I’ve finshed", _fetchSize = "Send me N messages at a time", false ="Apply to this Model only")
_model.BasicQos(0, _fetchSize, false);
The QOS works with the Ack process. So until you Ack a message, it will only send you N (_fetchSize) at a time. I think you'll have to set noAck: false in your code to get this working.
Good luck!

RabbitMQ / AMQP: single queue, multiple consumers for same message?

I am just starting to use RabbitMQ and AMQP in general.
I have a queue of messages
I have multiple consumers, which I would like to do different things with the same message.
Most of the RabbitMQ documentation seems to be focused on round-robin, ie where a single message is consumed by a single consumer, with the load being spread between each consumer. This is indeed the behavior I witness.
An example: the producer has a single queue, and send messages every 2 sec:
var amqp = require('amqp');
var connection = amqp.createConnection({ host: "localhost", port: 5672 });
var count = 1;
connection.on('ready', function () {
var sendMessage = function(connection, queue_name, payload) {
var encoded_payload = JSON.stringify(payload);
connection.publish(queue_name, encoded_payload);
}
setInterval( function() {
var test_message = 'TEST '+count
sendMessage(connection, "my_queue_name", test_message)
count += 1;
}, 2000)
})
And here's a consumer:
var amqp = require('amqp');
var connection = amqp.createConnection({ host: "localhost", port: 5672 });
connection.on('ready', function () {
connection.queue("my_queue_name", function(queue){
queue.bind('#');
queue.subscribe(function (message) {
var encoded_payload = unescape(message.data)
var payload = JSON.parse(encoded_payload)
console.log('Recieved a message:')
console.log(payload)
})
})
})
If I start the consumer twice, I can see that each consumer is consuming alternate messages in round-robin behavior. Eg, I'll see messages 1, 3, 5 in one terminal, 2, 4, 6 in the other.
My question is:
Can I have each consumer receive the same messages? Ie, both consumers get message 1, 2, 3, 4, 5, 6? What is this called in AMQP/RabbitMQ speak? How is it normally configured?
Is this commonly done? Should I just have the exchange route the message into two separate queues, with a single consumer, instead?
Can I have each consumer receive the same messages? Ie, both consumers get message 1, 2, 3, 4, 5, 6? What is this called in AMQP/RabbitMQ speak? How is it normally configured?
No, not if the consumers are on the same queue. From RabbitMQ's AMQP Concepts guide:
it is important to understand that, in AMQP 0-9-1, messages are load balanced between consumers.
This seems to imply that round-robin behavior within a queue is a given, and not configurable. Ie, separate queues are required in order to have the same message ID be handled by multiple consumers.
Is this commonly done? Should I just have the exchange route the message into two separate queues, with a single consumer, instead?
No it's not, single queue/multiple consumers with each consumer handling the same message ID isn't possible. Having the exchange route the message onto into two separate queues is indeed better.
As I don't require too complex routing, a fanout exchange will handle this nicely. I didn't focus too much on Exchanges earlier as node-amqp has the concept of a 'default exchange' allowing you to publish messages to a connection directly, however most AMQP messages are published to a specific exchange.
Here's my fanout exchange, both sending and receiving:
var amqp = require('amqp');
var connection = amqp.createConnection({ host: "localhost", port: 5672 });
var count = 1;
connection.on('ready', function () {
connection.exchange("my_exchange", options={type:'fanout'}, function(exchange) {
var sendMessage = function(exchange, payload) {
console.log('about to publish')
var encoded_payload = JSON.stringify(payload);
exchange.publish('', encoded_payload, {})
}
// Recieve messages
connection.queue("my_queue_name", function(queue){
console.log('Created queue')
queue.bind(exchange, '');
queue.subscribe(function (message) {
console.log('subscribed to queue')
var encoded_payload = unescape(message.data)
var payload = JSON.parse(encoded_payload)
console.log('Recieved a message:')
console.log(payload)
})
})
setInterval( function() {
var test_message = 'TEST '+count
sendMessage(exchange, test_message)
count += 1;
}, 2000)
})
})
The last couple of answers are almost correct - I have tons of apps that generate messages that need to end up with different consumers so the process is very simple.
If you want multiple consumers to the same message, do the following procedure.
Create multiple queues, one for each app that is to receive the message, in each queue properties, "bind" a routing tag with the amq.direct exchange. Change you publishing app to send to amq.direct and use the routing-tag (not a queue). AMQP will then copy the message into each queue with the same binding. Works like a charm :)
Example: Lets say I have a JSON string I generate, I publish it to the "amq.direct" exchange using the routing tag "new-sales-order", I have a queue for my order_printer app that prints order, I have a queue for my billing system that will send a copy of the order and invoice the client and I have a web archive system where I archive orders for historic/compliance reasons and I have a client web interface where orders are tracked as other info comes in about an order.
So my queues are: order_printer, order_billing, order_archive and order_tracking
All have the binding tag "new-sales-order" bound to them, all 4 will get the JSON data.
This is an ideal way to send data without the publishing app knowing or caring about the receiving apps.
Just read the rabbitmq tutorial. You publish message to exchange, not to queue; it is then routed to appropriate queues. In your case, you should bind separate queue for each consumer. That way, they can consume messages completely independently.
Yes each consumer can receive the same messages. have a look at
http://www.rabbitmq.com/tutorials/tutorial-three-python.html
http://www.rabbitmq.com/tutorials/tutorial-four-python.html
http://www.rabbitmq.com/tutorials/tutorial-five-python.html
for different ways to route messages. I know they are for python and java but its good to understand the principles, decide what you are doing and then find how to do it in JS. Its sounds like you want to do a simple fanout (tutorial 3), which sends the messages to all queues connected to the exchange.
The difference with what you are doing and what you want to do is basically that you are going to set up and exchange or type fanout. Fanout excahnges send all messages to all connected queues. Each queue will have a consumer that will have access to all the messages separately.
Yes this is commonly done, it is one of the features of AMPQ.
The send pattern is a one-to-one relationship. If you want to "send" to more than one receiver you should be using the pub/sub pattern. See http://www.rabbitmq.com/tutorials/tutorial-three-python.html for more details.
RabbitMQ / AMQP: single queue, multiple consumers for same message and page refresh.
rabbit.on('ready', function () { });
sockjs_chat.on('connection', function (conn) {
conn.on('data', function (message) {
try {
var obj = JSON.parse(message.replace(/\r/g, '').replace(/\n/g, ''));
if (obj.header == "register") {
// Connect to RabbitMQ
try {
conn.exchange = rabbit.exchange(exchange, { type: 'topic',
autoDelete: false,
durable: false,
exclusive: false,
confirm: true
});
conn.q = rabbit.queue('my-queue-'+obj.agentID, {
durable: false,
autoDelete: false,
exclusive: false
}, function () {
conn.channel = 'my-queue-'+obj.agentID;
conn.q.bind(conn.exchange, conn.channel);
conn.q.subscribe(function (message) {
console.log("[MSG] ---> " + JSON.stringify(message));
conn.write(JSON.stringify(message) + "\n");
}).addCallback(function(ok) {
ctag[conn.channel] = ok.consumerTag; });
});
} catch (err) {
console.log("Could not create connection to RabbitMQ. \nStack trace -->" + err.stack);
}
} else if (obj.header == "typing") {
var reply = {
type: 'chatMsg',
msg: utils.escp(obj.msga),
visitorNick: obj.channel,
customField1: '',
time: utils.getDateTime(),
channel: obj.channel
};
conn.exchange.publish('my-queue-'+obj.agentID, reply);
}
} catch (err) {
console.log("ERROR ----> " + err.stack);
}
});
// When the visitor closes or reloads a page we need to unbind from RabbitMQ?
conn.on('close', function () {
try {
// Close the socket
conn.close();
// Close RabbitMQ
conn.q.unsubscribe(ctag[conn.channel]);
} catch (er) {
console.log(":::::::: EXCEPTION SOCKJS (ON-CLOSE) ::::::::>>>>>>> " + er.stack);
}
});
});
As I assess your case is:
I have a queue of messages (your source for receiving messages, lets name it q111)
I have multiple consumers, which I would like to do different things with the same message.
Your problem here is while 3 messages are received by this queue, message 1 is consumed by a consumer A, other consumers B and C consumes message 2 and 3. Where as you are in need of a setup where rabbitmq passes on the same copies of all these three messages(1,2,3) to all three connected consumers (A,B,C) simultaneously.
While many configurations can be made to achieve this, a simple way is to use the following two step concept:
Use a dynamic rabbitmq-shovel to pickup messages from the desired queue(q111) and publish to a fanout exchange (exchange exclusively created and dedicated for this purpose).
Now re-configure your consumers A,B & C (who were listening to queue(q111)) to listen from this Fanout exchange directly using a exclusive & anonymous queue for each consumer.
Note: While using this concept don't consume directly from the source queue(q111), as messages already consumed wont be shovelled to your Fanout exchange.
If you think this does not satisfies your exact requirement... feel free to post your suggestions :-)
I think you should check sending your messages using the fan-out exchanger. That way you willl receiving the same message for differents consumers, under the table RabbitMQ is creating differents queues for each one of this new consumers/subscribers.
This is the link for see the tutorial example in javascript
https://www.rabbitmq.com/tutorials/tutorial-one-javascript.html
To get the behavior you want, simply have each consumer consume from its own queue. You'll have to use a non-direct exchange type (topic, header, fanout) in order to get the message to all of the queues at once.
If you happen to be using the amqplib library as I am, they have a handy example of an implementation of the Publish/Subscribe RabbitMQ tutorial which you might find handy.
There is one interesting option in this scenario I haven`t found in answers here.
You can Nack messages with "requeue" feature in one consumer to process them in another.
Generally speaking it is not a right way, but maybe it will be good enough for someone.
https://www.rabbitmq.com/nack.html
And beware of loops (when all concumers nack+requeue message)!
Fan out was clearly what you wanted. fanout
read rabbitMQ tutorial:
https://www.rabbitmq.com/tutorials/tutorial-three-javascript.html
here's my example:
Publisher.js:
amqp.connect('amqp://<user>:<pass>#<host>:<port>', async (error0, connection) => {
if (error0) {
throw error0;
}
console.log('RabbitMQ connected')
try {
// Create exchange for queues
channel = await connection.createChannel()
await channel.assertExchange(process.env.EXCHANGE_NAME, 'fanout', { durable: false });
await channel.publish(process.env.EXCHANGE_NAME, '', Buffer.from('msg'))
} catch(error) {
console.error(error)
}
})
Subscriber.js:
amqp.connect('amqp://<user>:<pass>#<host>:<port>', async (error0, connection) => {
if (error0) {
throw error0;
}
console.log('RabbitMQ connected')
try {
// Create/Bind a consumer queue for an exchange broker
channel = await connection.createChannel()
await channel.assertExchange(process.env.EXCHANGE_NAME, 'fanout', { durable: false });
const queue = await channel.assertQueue('', {exclusive: true})
channel.bindQueue(queue.queue, process.env.EXCHANGE_NAME, '')
console.log(" [*] Waiting for messages in %s. To exit press CTRL+C");
channel.consume('', consumeMessage, {noAck: true});
} catch(error) {
console.error(error)
}
});
here is an example i found in the internet. maybe can also help.
https://www.codota.com/code/javascript/functions/amqplib/Channel/assertExchange
You just need to assign different groups to the consumers.

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