Bugfix: OTLP exporters should not percent decode the key when parsing HEADERS env vars

[zhihali]

Bugfix #5623

As stated in the issue, we need to avoid parsing the key and instead implement a validation check for it. I've added some unit tests to verify this fix.

However, I noticed a comment at the top of this file:

// Code created by gotmpl. DO NOT MODIFY.
// source: internal/shared/otlp/envconfig/envconfig.go.tmpl

It seems that internal/shared/otlp/envconfig/envconfig.go.tmpl is the source template for this file. Since this template matches exporters/otlp/otlptrace/otlptracegrpc/internal/envconfig/envconfig.go, I updated the template to maintain consistency. I’m not entirely sure if this approach is correct, so please confirm if this is the right course of action.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.5%. Comparing base (083d03e) to head (74361cd).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #5705     +/-   ##
=======================================
- Coverage   84.5%   84.5%   -0.1%     
=======================================
  Files        272     272             
  Lines      22554   22614     +60     
=======================================
+ Hits       19069   19117     +48     
- Misses      3151    3159      +8     
- Partials     334     338      +4     

see 4 files with indirect coverage changes

[dmathieu]

We need to do the same for otlplog.

opentelemetry-go/exporters/otlp/otlplog/otlploghttp/config.go

Lines 551 to 556 in 772d3d7

	escKey, e := url.PathUnescape(rawKey)
	if e != nil {
	err = errors.Join(err, fmt.Errorf("invalid header key: %s", rawKey))
	continue
	}
	key := strings.TrimSpace(escKey)

[zhihali]

Hi @dmathieu, Thanks for the review. I'm thinking should I create a new PR for this?

just thinking this change and some tests added could make this PR too long

We need to do the same for otlplog.

opentelemetry-go/exporters/otlp/otlplog/otlploghttp/config.go

Lines 551 to 556 in 772d3d7

	escKey, e := url.PathUnescape(rawKey)
	if e != nil {
	err = errors.Join(err, fmt.Errorf("invalid header key: %s", rawKey))
	continue
	}
	key := strings.TrimSpace(escKey)

[dmathieu]

Sure, that can happen in another PR. Can you leave a comment in the original issue then, so we don't forget?

[zhihali]

ok, I have created an issue to track it and comment in original issue and will submit an PR soon. thanks! Any other comments for this PR?