[bitnami/cassandra] Add possibility to update cassandra.yaml from the environment variables

[dpavlov-smartling]

@CeliaGMqrz This is the same PR as https://github.com/bitnami/containers/pull/55278 I didn't realize how to properly solve conflict without dropping original commits, so, created this new pull request. Sorry for the inconvenience.

Description of the change Changes allow updating cassandra.yaml configuration file from environment variables using the same syntax as already used for CASSANDRA_CFG_ENV_, etc.

Benefits Currently, you can update only a few, pre-configured parameters of cassandra.yaml. For example, I needed to set parameterinternode_compression to all, but that can't be done via an environment variable. So, instead of adding a single environment variable for this particular parameter, I added the possibility to update multiple parameters via environment variables.

Possible drawbacks TBD

Applicable issues TBD

Additional information Current limitations:

can't update commented parameters in cassandra.yaml. This is because the internal function replace_in_file uses regex that requires a match from the beginning of the string can't update nested yaml parameters. The reason is the same as for the previous limitation

[dpavlov-smartling]

Hello @juan131 ,

This is the same approach that this docker image uses to update other 3 files - https://github.com/bitnami/containers/blob/d0d2c7b39108535b1cc3c75fe2f6c253c7463412/bitnami/cassandra/README.md?plain=1#L239C1-L241C121 So, my pool request uses this as an example and that is why it was implemented in that way. And no, mounting the whole cassandra.yaml file isn't easier. To do this you need to generate cassandra.yaml file and cover all the cases, which docker image already covers like updated hostname, seeds, SSL configuration, etc. In my particular case I needed only to change 1 option and updating the Environment variable is much easier than generating and mounting the whole cassandra.yaml Hope this clarifies things and helps speed up the merging of the PR Thanks,

[juan131]

Hi @dpavlov-smartling

Thanks for the details. I think this is good-to-have feature but we should find a solution for nested config properties before accepting it. Once we have it, I think we're ready to accept it.

[dpavlov-smartling]

Hello @juan131 ,

I am sorry for the confusion. It does update nested parameters. I used your image default function to update yaml parameters cassandra_yaml_set. You can find its code here - https://github.com/bitnami/containers/blob/7766faad45aa1beff1910417b06985d3edc29f54/bitnami/cassandra/4.0/debian-12/rootfs/opt/bitnami/scripts/libcassandra.sh#L29C1-L40C2 It is used all around in the image, including for the updating nested parameters.

Thanks

[dpavlov-smartling]

Removed warning about nested parameters from the readme file. @juan131 I hope this helps. Thanks,

[juan131]

Thanks so much!

@dpavlov-smartling could you add a small example in the README about how to use this new way to adapt the configuration? It'd be nice if you could in the example the use of env. vars to customize nested properties.

[dpavlov-smartling]

@juan131 I have updated readme file with examples.

[juan131]

Hi @dpavlov-smartling

Thanks so much for your contribution! Please expect a new image to be released within the next 24 hours including your changes.

[juan131]

Hi @dpavlov-smartling

New images (4.0.12-debian-12-r8 and 4.1.4-debian-12-r4) have been released including your changes.