Restrict template name when putting index template

[spinscale]

Storing an index template named * will result in the in ability to
delete it. Also that naming is really confusing.

Reviewers Note: I pretty much like the logic in MetaDataCreateIndexService.validateIndexOrAliasName that we could probably use for templates as well. I just added the smallest fix to prevent the above behaviour.

This change breaks BWC, but I still think it's worth getting in (in master), as this happens due to user mistakes. See https://discuss.elastic.co/t/template-with-asterisk-name/224452

[elasticmachine]

Pinging @elastic/es-search (:Search/Mapping)

[cbuescher]

Hi @spinscale, I took a look and the asterisk behaviour looks really trappy indeed, especially for deletion.

I pretty much like the logic in MetaDataCreateIndexService.validateIndexOrAliasName

There seems to be naming conventions for template names already, (see MetadataIndexTemplateService#validate()), so I would probably look into adding an additional case there.

Unfortunately most of the rules checked there look pretty much undocumented, maybe you could also add a few lines to the docs in terms of documentation?

Another more general issue I'm curious about wrt to this PR: poking around I found that in the course of the work for "Index Templates v2" (#53101) we are adding other code paths to putting index templates. I wonder if validation of names is or will be also included there, currently it doesn't seem to be. Maybe @martijnvg or somebody else from @elastic/es-core-infra can comment on this aspect? Also they might have an opinion about the breaking nature of an additional restriction in naming rules.

[elasticmachine]

Pinging @elastic/es-core-features (:Core/Features/Indices APIs)

[cbuescher]

@andreidan thanks for correcting the assigned team, I would mostly like to get an opinion on where to best put the proposed validation (dissallow asterisks) on template names. Currently most of the restrictions are checked in MetadataIndexTemplateService#validate(), we can add it there but I also want to check what's planned in terms of validation for template names for v2. Maybe reusing the current logic there makes sense, otherwise we can track that in a separate issue and move forward here?

[dakrone]

Maybe reusing the current logic there makes sense, otherwise we can track that in a separate issue and move forward here?

Yes, re-using the logic would be best. I'll add this as a todo for the meta issue #53101

[dakrone]

I opened #56170 to address this in a generic way for v1 and v2 templates.

[cbuescher]

@spinscale with #56170 open which should adress your issue, I hope you don't mind if I close this.