Update ssl.session_cache.enabled to be session_cache.value

[ezelkow1]

Fixes #11901

[maskit]

I thought the implementation should be changed instead because the documentation is what users see and new users who didn't use ATS 9 would be required to update their settings. But, unfortunately, convert2yaml.py disagrees.

trafficserver/tools/records/convert2yaml.py

Lines 48 to 49 in dc59c4c

	'proxy.config.ssl.origin_session_cache': 'proxy.config.ssl.origin_session_cache.enabled',
	'proxy.config.ssl.session_cache': 'proxy.config.ssl.session_cache.value',

I think the best way is to support the both names (.value and .enabled) for now, and introduce new name (.mode) to address the inconsistency between session_cache and origin_session_cache.

[ezelkow1]

yea I did notice that the upgrading to 10 doc does mention some of these. So there is a reference there for previous users:
https://docs.trafficserver.apache.org/en/10.0.x/release-notes/upgrading.en.html

Also having the old one there is apparently required for the upgrading document to be buildable? This seems like an odd dependency on an old name:

Warning, treated as error:
/home/jenkins/workspace/Github_Builds/docs/src/doc/release-notes/upgrading.en.rst:175:No definition found for configuration variable 'proxy.config.ssl.session_cache.enabled'

[bryancall]

It looks like there are other configuration options named proxy..enabled and this is the only one with proxy..value. It would be great if this was consistent with other settings. @maskit suggested supporting both configuration option names for now. I would lean towards this as a solution too.

[brbzull0]

There was a reason why we have value and enabled.

In this case Implementation seems fine, at least it follows what was the logic when this fields were renamed:

Naming Changes:

All these renamed records are subject to the following reasoning:

If a value is meant to be used as a toggle on/off, I’ve used the name enabled.
If a value is meant to be used as an enumeration, I’ve used the name value

So proxy.config.ssl.origin_session_cache.enabled and proxy.config.ssl.session_cache.value were renamed based on the above, but documentation wasn't properly updated.

I do agree that mode is more appropriate than value, but seems late to make this ammend.

upgrading.en.rst needs to be updated too.

[maskit]

We can introduce mode later if we want. Sooner would be better but I think 10.1 is reasonable (and we should deprecate the current ones). For now, we should address the inconsistency between the documentation and the implementation.

If we support the both names (for this particular setting), which one wins if the both enabled and value exist on a config file and have different values? Should it be an error?