Ken Liao created AMQ-9592:
-----------------------------
Summary: Incorrect MQTTv3.1.1 behaviour: QoS2 messages were
delivered to unintended consumers
Key: AMQ-9592
URL: https://issues.apache.org/jira/browse/AMQ-9592
Project: ActiveMQ Classic
Issue Type: Bug
Components: MQTT
Affects Versions: 6.1.3, 5.18.5
Reporter: Ken Liao
To replicate:
- Run a subscriber with QOS2 to a topic with client ID say "1"and stop it
- Publish 5 messages to the topic, do not consume these yet.
- Run another subscriber with QOS2 to the topic with a different client ID say
"2'.
- This subscriber with different cliend ID receives 5 messages that were
intended for the clientID "1". However, this does not mean that client ID "1"
will not receive the 5 messages when it comes back online. I noticed that
client ID "1" also received the 5 message.
Now that both clientID 1 and 2 received messages, subscribing a new clientID
doesn't receive these message. However, if we send 5 message again to the topic
and do not consume it for all clientIDs, it would delivered to any new
subscription.
For new client Id broker must create new session, so messages sent after client
1 disconnected should route to client 1 only since client 2 because it was
connected after those 5 messages were sent (hence the new session of client 2
shouldn't contain old messages).
Here are sample codes to reproduce:
The producer Python script
```
import paho.mqtt.client as mqttClient
import time
import ssl
Connected = False
broker_address= "localhost"
port = 1883
user = "admin"
password = "admin"
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to broker")
global Connected #Use global variable
Connected = True #Signal connection
else:
print("Connection failed")
client = mqttClient.Client(client_id="producer",transport="tcp") #
client.username_pw_set(user, password=password) #set username and password
client.on_connect=on_connect
# client.tls_set_context(context=context)
client.connect(broker_address, port=port)
client.loop_start()
i=0
while True:
time.sleep(1)
i=i+1
client.publish("test/data", "This is my test msg 123.",2,False)
print("Sent"+str(i))
```
The consumer Python script
```
import paho.mqtt.client as mqttClient
import time
import ssl
Connected = False
broker_address= "localhost"
port = 1883
user = "admin"
password = "admin"
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to broker")
global Connected #Use global variable
Connected = True #Signal connection
print(flags)
client.subscribe("test/data",2)
else:
print("Connection failed")
def on_message(client, userdata, msg):
print(msg.topic+" "+str(msg.payload))
client = mqttClient.Client(client_id="id2",transport="tcp",clean_session=False)
#
client.username_pw_set(user, password=password) #set username and password
client.on_connect=on_connect
client.on_message=on_message
# client.tls_set_context(context=context)
client.connect(broker_address, port=port)
client.loop_start()
while Connected != True:
time.sleep(0.1)
time.sleep(1000)
```
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
For further information, visit: https://activemq.apache.org/contact
