I have a project where I set a timeout of 5 seconds (getRabbitTemplate (). SetReplyTimeout (5000)) and I use the sendAndReceive method to send the messages:getXbidRabbitTemplate ()
SendAndReceive (exchange, routingkey, msg).
Today there was an error in the connection
(ShutdownSignalException)
but there has not been a TimeOut in two shipments.
The first shipment occurred at 09-04-2019 07: 25: 33.980; and the second at 09-04-2019 07: 25: 36.902;
I have not received an answer (or any error) and shortly after the connection error has jumped (at 09-04-2019 07: 25: 52.939)
Other times, we have detected a TimeOut error, and the only configuration change is that we have removed the retryTemplate from the RabbitTemplate configuration.
This is how we detect the TimeOut:
getRabbitTemplate().setReplyTimeout(5000);
mResponse = getRabbitTemplate().sendAndReceive(exchange, routingkey, msg);
if(mResponse == null)
{
// TIMEOUT
}
I expected that if no answer is obtained in those 5 seconds, I would enter the TIMEOUT part. Is it possible that if the connection is dropped and the message does not reach the server, that TIMEOUT will not occur?
The timeout has nothing to do with any rabbit communication, the calling thread simply calls get(timeout, TimeUnitMilliseconds) on a future. When the reply is receieved (on another thread), it completes the future and the get() returns that result. If no reply is received, the get() times out.
I don't see any way that the thread can never time out.
Related
I'm trying to ensure single worker session/window at a time.
In order to achieve this I have added a parameter closeExistingSessions to the createWorker and it's disconnecting (websocket) the other workerClient as expected.
Just wondering if there is a way to know the disconnect reason using this disconnected event listener so that I can show a relevant message to the end user.
const worker = new Twilio.TaskRouter.Worker(WORKER_TOKEN);
worker.on("disconnected", function(<ANY_ERROR_CODE_OR_SOMETHING_HERE?!>) {
console.log("Websocket has disconnected");
});
We are getting the reason (The reason the Worker websocket disconnected) as parameter to the disconnected callback.
const worker = new Twilio.TaskRouter.Worker(WORKER_TOKEN);
worker.on("disconnected", function(reason) {
console.log(reason.message);
});
And the reason for disconnecting due to existing sessions is 'Websocket disconnected due to new connection being registered'
Hope Twilio will keep their docs up to date
when I try to test to connect to my broker and publish it keeps connecting but then failing to stay connected an publish a test. does anyone see a problem in my code?
import paho.mqtt.client as mqtt
import time
broker = "*************"
port = ****
def on_log(client, userdata, level, buf):
print(buf)
def on_connect(client,usedata,flags,rc):
if rc == 0:
client.connected_flag=True ##set flag
print("client is connected")
global connected
else:
print("connection failed")
client.loop_stop()
def on_disconnect(client, userdata, rc):
print("client disconnected ok")
def on_publish(client, userdata, mid):
print("In on_pub callback mid= ", mid)
mqtt.Client.connected_flag=False #create flag in class
client = mqtt.Client("MyClient-01") #create new instance
client.on_log=on_log
client.on_connect=on_connect
client.on_disconnect=on_disconnect
client.on_publish=on_publish
client.connect(broker,port) #establish connection
client.loop_start()
while not client.connected_flag:
print("in wait loop")
time.sleep(1)
time.sleep(3)
print("publishing")
#client.loop()
ret=client.publish("house/bulb1","Test message 0",0)
time.sleep(3)
#client.loop()
ret=client.publish("house/bulb1","Test message 1",1)
time.sleep(3)
#client.loop()
ret=client.publish("house/bulb1","Test message 2",2)
time.sleep(3)
client.loop_stop()
client.disconnect()
and I get this log:
Sending CONNECT (u0, p0, wr0, wq0, wf0, c1, k60) client_id=b'MyClient-01'
in wait loop
Received CONNACK (0, 5)
connection failed
client disconnected ok
in wait loop
in wait loop
in wait loop
in wait loop
in wait loop
in wait loop
in wait loop
It just stays in the loop to try and connect , broker is found with an ip and port should be the correct one.
The MQTT specification may be some of the clearest documentation I've ever had the pleasure to read, porbably because it is so simple. For version 3.1.1 and the CONNACK message you can find it here:
http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718033
You configured the library to log and got this message printed:
Received CONNACK (0, 5)
CONNACK is your message type (response to your CONNECT message). 0 and 5 refer to the Conneck Acknowledge Flags and Connect Return code variables from the CONNACK variable header. 0 means that this is the beginning of a new session and 5 means that you are not authorized, as you figured out.
Fixed with adding username and password arguments and adding
client.username_pw_set(user,password=password)
The documentation for mqtt.client:connect() states that the last arg is a "callback function for when the connection could not be established".
I have a case where mqtt.client:connect() succeeds, so the "not established" callback is not called (correct behavior). But, later, when my mqtt broker goes down, the "not established" callback function gets unexpectedly activated.
I have the following code:
function handle_mqtt_error (client, reason)
print("mqtt connect failed, reason = "..reason..". Trying again shortly.")
tmr.create():alarm(10 * 1000, tmr.ALARM_SINGLE, do_mqtt_connect)
end
function do_mqtt_connect ()
print("connecting---")
m:connect(MQTT_HOST, MQTT_PORT, 1, function(client)
print("mqtt connected")
client:publish("topic/status", "online", 1, 1)
end,
handle_mqtt_error
)
print("returning---")
end
-- init mqtt client
m = mqtt.Client(MQTT_CLIENT_ID, 120, MQTT_USER, MQTT_PASS)
-- connect to mqtt
print("Starting Test")
do_mqtt_connect()
I see the output from the test begin, as expected, with:
Starting Test
connecting---
returning---
mqtt connected
At this point, I kill my mqtt broker, and I unexpectedly see:
mqtt connect failed, reason = -5. Trying again shortly.
connecting---
returning---
mqtt connect failed, reason = -5. Trying again shortly.
connecting---
returning---
And, happily, but unexpectedly, when I restart my broker, I see:
mqtt connected
So, it appears that handle_mqtt_error() is not only called "when the connection could not be established". It appears that it also be called if mqtt.client:connect() successfully establishes a connection, then the connection is later broken.
======= New Information =======
I downloaded the "dev" tree and used the Docker image to build the firmware. Within mqtt.c, I enabled NODE_DBG. The interesting lines are:
enter mqtt_socket_reconnected.
mqtt connect failed, reason = -5. Trying again shortly.
enter mqtt_socket_disconnected.
leave mqtt_socket_disconnected.
leave mqtt_socket_reconnected.
The "mqtt connect failed..." message is printed by handle_mqtt_error(), which is my "connect failed" callback.
Here's my theory. When my test starts, do_mqtt_connect() calls mqtt_socket_connect(), which does this:
espconn_regist_reconcb(pesp_conn, mqtt_socket_reconnected);
This sets reconnect_callback (in app/lwip/app/espconn.c). Later, after my broker goes down and comes back up, espconn_tcp_reconnect() is called (in app/lwip/app/espconn_tcp.c). It calls the reconnect_callback, which is mqtt_socket_reconnected(), which calls handle_mqtt_error().
So, I think the end result doesn't match the documentation, but it works out okay for me. If the behavior did match the documentation, I would just add some Lua code to handle the "offline" event, and try to reestablish the mqtt connection. I just thought someone might be interested if the behavior doesn't match the documentation.
My application only listens to a certain queue, the producer is the 3rd party application. I receive the messages but sometimes based on some logic I need to send fail message to the producer so that the message is resend to my listener again until I decide to consume it and acknowledge it. My current implementation of this process is just throwing some custom exception. But this is not a clean solution, therefore can any one help me to send FAIL to producer without throwing exception.
My JMS Listener Factory settings:
#Bean
public DefaultJmsListenerContainerFactory jmsListenerContainerFactoryForQexpress(SQSErrorHandler errorHandler) {
SQSConnectionFactory connectionFactory = SQSConnectionFactory.builder()
.withRegion(RegionUtils.getRegion(StaticSystemConstants.getQexpressSqsRegion()))
.withAWSCredentialsProvider(new ClasspathPropertiesFileCredentialsProvider(StaticSystemConstants.getQexpressSqsCredentials()))
.build();
DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
factory.setConnectionFactory(connectionFactory);
factory.setDestinationResolver(new DynamicDestinationResolver());
factory.setConcurrency("3-10");
factory.setSessionAcknowledgeMode(Session.CLIENT_ACKNOWLEDGE);
factory.setErrorHandler(errorHandler);
return factory;
}
My Listener Settings:
#JmsListener(destination = StaticSystemConstants.QUEXPRESS_ORDER_STATUS_QUEUE, containerFactory = "jmsListenerContainerFactoryForQexpress")
public void receiveQExpressOrderStatusQueue(String text) throws JSONException {
LOG.debug("Consumed QExpress status {}", text);
//here i need to decide either acknowlege or fail
...
if (success) {
updateStatus();
} else {
//todo I need to replace this with explicit FAIL message
throw new CustomException("Not right time to update status");
}
}
Please, share your experience on this. Thank you!
SQS -- internally speaking -- is fully asynchronous and completely decouples the producer from the consumer.
Once the producer successfully hands off a message to SQS and receives the message-id in response, the producer only knows that SQS has received and committed the message to its internal storage and that the message will be delivered to a consumer at least once.¹ There is no further feedback to the producer.
A consumer can "snooze" a message for later retry by simply not deleting it (see setSessionAcknowledgeMode docs) or by actively resetting the visibility timeout on the message instead of deleting it, which triggers SQS to leave the message in the in flight status until the timer expires, at which point it will again deliver the message for the consumer to retry.
Note, too, that a single SQS queue can have multiple producers and/or multiple consumers, as long as all the producers ask for and consumers provide identical services, but there is no intrinsic concept of which consumer or which producer. There is no consumer-to-producer backwards communication channel, and no mechanism for a producer to inquire about the status of an earlier message -- the design assumption is that once SQS has received a message, it will be delivered,² so no such mechanism should be needed.
¹at least once. Unless the queue is a FIFO queue, SQS will typically deliver the message exactly once, but there is not an absolute guarantee that the message will not be delivered more than once. Because SQS is a massive, distributed system that stores redundant copies of messages, it is possible in some edge case conditions for messages to be delivered more than once. FIFO queues avoid this possibility by leveraging stronger internal consistency guarantees, at a cost of reduced throughput of 300 TPS.
²it will be delivered assuming of course that you actually have a consumer running. SQS does not block the producer, and will allow you to enqueue an unbounded number of messages waiting for a consumer to arrive. It accepts messages from producers regardless of whether there are currently any consumers listening. The messages are held until consumed or until the MessageRetentionPeriod (default 4 days, max 14 days) timer expires for each message, whichever comes first.
I have created on replyQ and done biniding with one direct exchange.
Created the message by setting replyto property to "replyQ"
And sending the message on rabbit to the other service.
The service at other end getting the message and sending reply on given replyTo queue.
and now I am trying to read from a replyQ queue using
template.receiveAndConvert(replyQueue));
But getting null response and i can see the message in the replyQ.
That is the service is able to send the reply but am not able to read it from the given queue
Please help what is going wrong.
template.receiveAndConvert() is sync, blocked for some time one time function, where default timeout is:
private static final long DEFAULT_REPLY_TIMEOUT = 5000;
Maybe this one is your problem.
Consider to switch to ListenerContainer for continuous queue polling.
Another option is RabbitTemplate.sendAndReceive(), but yeah, with fixed reply queue you still get deal with ListenerContainer. See Spring AMQP Reference Manual for more info.
I don't know if this could help anyone, but I found out that declaring the expected Object as a parameter of a method listener did the work
#RabbitListener(queues = QUEUE_PRODUCT_NEW)
public void onNewProductListener(ProductDTO productDTO) {
// messagingTemplate.receiveAndConvert(QUEUE_PRODUCT_NEW) this returns null
log.info("A new product was created {}", productDTO);
}