Revert "Revert "Fix: Force usage of case-sensitive keys in configurations (#6876)" (#6988)"

[gbbr]

This reverts commit 80cabdd.

Closes #7002

[codecov]

Codecov Report

Base: 90.36% // Head: 89.88% // Decreases project coverage by -0.48% ⚠️

Coverage data is based on head (77b4981) compared to base (1af31a0).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7021      +/-   ##
==========================================
- Coverage   90.36%   89.88%   -0.48%     
==========================================
  Files         243      245       +2     
  Lines       14598    14724     +126     
==========================================
+ Hits        13191    13235      +44     
- Misses       1138     1219      +81     
- Partials      269      270       +1     

Impacted Files	Coverage Δ
confmap/confmap.go	90.12% <100.00%> (+0.18%)	⬆️
featuregate/registry.go	70.65% <0.00%> (-13.56%)	⬇️
service/graph.go	71.42% <0.00%> (-8.58%)	⬇️
service/nodes.go	4.49% <0.00%> (-8.41%)	⬇️
pdata/plog/plogotlp/grpc.go	73.33% <0.00%> (-5.24%)	⬇️
pdata/ptrace/ptraceotlp/grpc.go	73.33% <0.00%> (-5.24%)	⬇️
pdata/pmetric/pmetricotlp/grpc.go	73.33% <0.00%> (-5.24%)	⬇️
service/service.go	66.14% <0.00%> (-1.36%)	⬇️
otelcol/config.go	96.38% <0.00%> (ø)
service/zpages.go	64.00% <0.00%> (ø)
... and 12 more

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[bogdandrutu]

Some things that I have in mind and will like answers/someone to think about:

• We have a test helper for configs that disallow uppercase, see https://github.com/open-telemetry/opentelemetry-collector/blob/main/component/componenttest/configtest.go#L34. Please consider to come with a fix there as well if needed.
• By default because fields need to be public they are uppercase. In case of not having a "mapstructure" tag they will be uppercased in the config, is that expected? Do we want to be lowercase by default if no tag?

[gbbr]

@rapphil I think you may want to jump in here considering you have opened to original PR.

[rapphil]

@bogdandrutu
Based on https://github.com/open-telemetry/opentelemetry-collector/blob/main/component/componenttest/configtest.go#L34 can we say that we only support case sensitive configurations with with lowercase keys? (otherwise why would we enforce the tags to be lowercase?)

So answering your questions:

We have a test helper for configs that disallow uppercase, see https://github.com/open-telemetry/opentelemetry-collector/blob/main/component/componenttest/configtest.go#L34. Please consider to come with a fix there as well if needed.

We don't need to fix anything as this check function is enforcing case-sensitive tags in the config structs, so it aligns with the validation that will happen in mapstructrure when the configuration is Unmarshalled into a struct.

By default because fields need to be public they are uppercase. In case of not having a "mapstructure" tag they will be uppercased in the config, is that expected? Do we want to be lowercase by default if no tag?

This will only happen if a config is not validated using the CheckConfigStruct function. yes, we should check this case.

[bogdandrutu]

@gbbr you need to also remove the wrong comment from IsSet

[gbbr]

Thanks for flagging that Bogdan, done.