skrrytch / camel-and-rabbitmq-issue

Example project to demonstrate different behaviour of camel-rabbitmq and cammel-spring-rabbitmq

This example project is intended to show the different behaviour of the components

• camel-rabbitmq (deprecated, removed in camel 4.x)
• camel-spring-rabbitmq

Configuring RabbitMQ

The sample application uses localhost:5672 to connect to the RabbitMQ broker. This can be configured in the application.properties file.

The login information is the default guest/guest account, which can be configured in the application.properties file as well.

How to run

The sample requires a RabbitMQ broker to be running.

You can for example easily start RabbitMQ via Docker

docker run -it -p 5672:5672 --hostname my-rabbit --name some-rabbit rabbitmq:3

Then you can run this example using

mvn spring-boot:run

Description of my issue

This example project is intended to show the different behaviour of the components camel-rabbitmq (deprecated, removed in camel 4.x) and camel-spring-rabbitmq:

There are two route builders:

1. CamelRabbitRouteBuilder, uses Camel component camel-rabbitmq
2. CamelSpringRabbitRouteBuilder, uses Camel component camel-spring-rabbitmq

Both route builders define two routes:

• The first route sends a text message to a RabbitMQ exchange
• The other route receives that message from RabbitMQ and simulates an error (exception).
• The exception handling defines a retry every 3 seconds for this test.

Test procedure

Run the application, so you can see an output of the retry for both, like this:

SpringRabbit REDELIVERY: Message from 2024-05-07T14:43:41.954489120+02:00[Europe/Berlin]
Camel-Rabbit REDELIVERY: Message from 2024-05-07T14:41:33.463028488+02:00[Europe/Berlin]
SpringRabbit REDELIVERY: Message from 2024-05-07T14:43:41.954489120+02:00[Europe/Berlin]
Camel-Rabbit REDELIVERY: Message from 2024-05-07T14:41:33.463028488+02:00[Europe/Berlin]
...

Use jconsole (or similar) to call the Camel JMX routine stop() on both receive routes while they perform a retry.

Observation

1. With 'camel-rabbit' the route is terminated after a timeout, and the retry is interrupted (java.lang.InterruptedException: sleep interrupted), and the message is back in the RabbitMQ ready for the next delivery (when the route is restarted)
2. With 'camel-spring-rabbitmq' the route is also terminated after a timeout, but the retry continues.

Our scenario in a more complex project

We absolutely need a way to interrupt a retry in progress by stopping the route.

Use cases:

• maintenance
• possibility to stop the retry, remove the message from the queue and then restart.