RABBITMQ_LOGS=- prevents logging to other sources altogether

[lukebakken]

https://groups.google.com/g/rabbitmq-users/c/j1AY7lBWI6c/m/kUMOb5wnAwAJ

When you run RabbitMQ from an official docker image, the following env variable is set:

RABBITMQ_LOGS=-

This is what prevents the logging exchange from starting, even though that exchange is defined in the configuration file. I can reproduce the behavior outside of Docker if I run RabbitMQ like this:

RABBITMQ_LOGS=- RABBITMQ_ALLOW_INPUT=true RABBITMQ_CONFIG_FILE="/home/lbakken/development/lukebakken/rabbitmq-users-j1AY7lBWI6c/rabbitmq.conf" ./sbin/rabbitmq-server

As a workaround, you can build an image with a custom entrypoint that unsets the RABBITMQ_LOGS env variable. I have updated this repo with just that workaround and it DOES fix the issue:

https://github.com/lukebakken/rabbitmq-users-j1AY7lBWI6c/blob/main/Dockerfile

After reading the source code, it looks like setting the RABBITMQ_LOG env var may be a better solution for Docker, but I can't seem to figure out the right syntax to enable both the console log and exchange log.

https://github.com/rabbitmq/rabbitmq-server/blob/master/deps/rabbit/src/rabbit_prelaunch_logging.erl#L1094

The above suggests the following should work:

RABBITMQ_LOG='console=debug,+color,exchange=debug'

But it does not enable the exchange logger. In addition, I don't see how the parsing could work since commas are used to delineate per-logger configuration as well as the overall loggers themselves. This form makes more sense:

RABBITMQ_LOG='console=debug,+color:exchange=debug'

@dumbbell we should discuss.

[michaelklishin]

Those who use rabbitmq.conf settings should have none of these problems.

[lukebakken]

@michaelklishin unfortunately the env vars take precedence.

[dumbbell]

Environment variables in general are meant to override any configuration files to allow one to quickly run RabbitMQ with a different setting without touching those configuration files. So yes, setting RABBITMQ_LOGS=... is expected to override the configuration file. In other words, RABBITMQ_LOGS and RABBITMQ_LOG are only useful when starting RabbitMQ to try or debug things. They are not designed to configure RabbitMQ in production.

RABBITMQ_LOG syntax is a list of the following elements, separated by commas:

• $level (debug to emergency)
• $category=$level, where $category is something like "prelaunch", "channel", "mirroring", ...
• $modifier, where $modifier is "+color", "-color", "+json", "-json", ...

In particular, exchange or console are not categories.

To enable the exchange logging output, you should be able to set RABBITMQ_LOGS=exchange:.

Update: I fixed the line above: it was RABBITMQ_LOG=exchange: instead of RABBITMQ_LOGS=exchange:.

[dumbbell]

To me, the following is a bug in the docker image:

When you run RabbitMQ from an official docker image, the following env variable is set:

RABBITMQ_LOGS=-

[lukebakken]

How does RABBITMQ_LOG=exchange: fit into the syntax you described? I'd like to document that variable better.

It sounds like we need to change how the Docker image configures logging. I'll open a related issue in that repo.

[dumbbell]

Sorry, I meant RABBITMQ_LOGS=exchange: in my previous comment. I fixed it.

[michaelklishin]

My point is that environment variables should never be used for what can be configured in rabbitmq.conf. We have been telling this to the Docker image community for a few years now. Here is one obvious example of how some things cannot be reasonably well expressed in a single string.

So I agree that an unconditional RABBITMQ_LOGS=- in the image is an issue that must be addressed there.

[dumbbell]

RabbitMQ now supports several configuration files. On Unix, it will load all files found in $SYS_PREFIX/etc/rabbitmq/conf.d by default.

It should be easy for people packaging RabbitMQ to write their default values in $SYS_PREFIX/etc/rabbitmq/conf.d/00-default.conf for instance. Then users can add their own configuration snippets in additional files in that directory.

[lukebakken]

I like it @dumbbell. I'll open an issue and PR for the docker image, and will get to documenting these vars a bit better on the website.

Have a great weekend!

[lukebakken]

docker-library/rabbitmq#555

Test procedure:

https://github.com/lukebakken/test-docker-library-rabbitmq-gh-554

[jeremy-evidos]

Hello,

Looks like omitting RABBITMQ_LOGS=- from the Dockerfile seems to break JSON logging set with RABBITMQ_LOG=+json. When adding RABBITMQ_LOGS=- again JSON logging starts working again. If there is a configuration option for enabling JSON logging I can add to /etc/rabbitmq/conf.d/ I'd prefer that but it seems only the environment variable was extended according to #2861.

Best,

Jeremy

[michaelklishin]

log.file.formatter = json

[michaelklishin]

So apparently there are both log.file.formatter = json and log.console.formatter = json, and neither is documented.

[jeremy-evidos]

Thanks! Adding log.console.formatter = json did the trick.

[lukebakken]

Fixed by the following:

docker-library/rabbitmq#555
https://github.com/rabbitmq/tanzu/issues/7
https://github.com/rabbitmq/tanzu/pull/8
https://github.com/rabbitmq/bitnami-docker-vmware-tanzu-rabbitmq/pull/2