I used RabbitMQ to distribute messages between components of a distributed grading service that I wrote in Kotlin and deployed on Kubernetes.
My experiences were pretty mixed. Overall I found it to be more difficult than I would have wanted to get simple things to work. Part of this seems to be a problem with the Java library, which is not great. For example, IIRC you have to be really careful not to create the same queue twice, even with identical configurations, since the second time something blows up. At the end of the day just a simple fan-out configuration ends up involving a lot of somewhat-intricate code. It definitely does not Just Work (TM).
And then there was the bizarre hangs that I would experience during testing. I set up a Docker Compose configuration so that I could test the various parts of the system independently. It included one container running RabbitMQ to simulate the cluster we have running on our cloud.
Usually tests ran fine. But then, from time to time, the client would just hang trying to send a message through RabbitMQ. Unfortunately, again, the code you need to just run a basic configuration using RabbitMQ is complex enough that at first I was pretty sure that I had done something wrong. But after a few hours of increasing frustration I finally broke down and discovered that a simple test case that just sent a single message using code torn right out of the docs would hang. Forever. (Or, long enough that I gave up waiting.)
After a lot of digging I found the culprit. RabbitMQ will just take its ball and go home if the broker doesn't have enough disk space. Given that I use Docker heavily for a lot of projects, the amount available to new containers would vary a lot depending on what other data sets I had loaded or how recently I had run docker system prune.
I filed an issue about this, asking to have a better error message displayed when an attempt to send a message was made. The response was: there's already an error message, printed during startup. You didn't see it? No. I must have missed it among the hundreds of other lines of output that RabbitMQ spews when it starts.
Overall my favorite part of this story is that RabbitMQ chooses to start but refuse to send messages when low on disk space, when just crashing would be much more useful and make it much easier to pinpoint what was going on.
Anyway, I'm in the market for a simpler alternative that's Kotlin friendly.
My experiences were pretty mixed. Overall I found it to be more difficult than I would have wanted to get simple things to work. Part of this seems to be a problem with the Java library, which is not great. For example, IIRC you have to be really careful not to create the same queue twice, even with identical configurations, since the second time something blows up. At the end of the day just a simple fan-out configuration ends up involving a lot of somewhat-intricate code. It definitely does not Just Work (TM).
And then there was the bizarre hangs that I would experience during testing. I set up a Docker Compose configuration so that I could test the various parts of the system independently. It included one container running RabbitMQ to simulate the cluster we have running on our cloud.
Usually tests ran fine. But then, from time to time, the client would just hang trying to send a message through RabbitMQ. Unfortunately, again, the code you need to just run a basic configuration using RabbitMQ is complex enough that at first I was pretty sure that I had done something wrong. But after a few hours of increasing frustration I finally broke down and discovered that a simple test case that just sent a single message using code torn right out of the docs would hang. Forever. (Or, long enough that I gave up waiting.)
After a lot of digging I found the culprit. RabbitMQ will just take its ball and go home if the broker doesn't have enough disk space. Given that I use Docker heavily for a lot of projects, the amount available to new containers would vary a lot depending on what other data sets I had loaded or how recently I had run docker system prune.
I filed an issue about this, asking to have a better error message displayed when an attempt to send a message was made. The response was: there's already an error message, printed during startup. You didn't see it? No. I must have missed it among the hundreds of other lines of output that RabbitMQ spews when it starts.
Overall my favorite part of this story is that RabbitMQ chooses to start but refuse to send messages when low on disk space, when just crashing would be much more useful and make it much easier to pinpoint what was going on.
Anyway, I'm in the market for a simpler alternative that's Kotlin friendly.