redis parser: avoid string conversions and reduce allocations on hot path

[rafaelroquetto]

Reduce unnecessary allocations and string conversions in the Redis
detection pipeline:

• parseRedisRequest now takes []byte instead of string, eliminating
  the buffer-to-string copy at both TCP call sites
  (string(requestBuffer.UnsafeView())). The Go Redis uprobe path also
  drops the string(event.Buf[:]) wrapper.

• split.Iterator is made generic (Iterator[T string | []byte]) with
  two typed constructors: NewStringIterator and NewBytesIterator. The
  bytes variant is used by parseRedisRequest to iterate lines without
  any intermediate allocation. All existing string call sites are updated
  to NewStringIterator.

• redisErrorCodes [...]string replaced with a redisErrors struct array
  pairing each []byte prefix with its pre-trimmed string code,
  eliminating the per-iteration []byte(code) conversion in
  getRedisError. Description is now trimmed before string conversion
  (string(bytes.Trim(...))), reducing the size of the allocation.

• getRedisDB replaces strings.ToUpper with strings.EqualFold for
  the SELECT/QUIT check, avoiding an allocation for the uppercased copy.

Checklist

• If this enhances / fixes / changes a core feature, I have updated the features documentation

[codecov]

Codecov Report

❌ Patch coverage is 88.57143% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 43.99%. Comparing base (db77da0) to head (7a34330).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/ebpf/common/redis_detect_transform.go	87.50%	1 Missing and 1 partial ⚠️
pkg/ebpf/common/tcp_detect_transform.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1481      +/-   ##
==========================================
+ Coverage   43.98%   43.99%   +0.01%     
==========================================
  Files         313      313              
  Lines       34353    34354       +1     
==========================================
+ Hits        15110    15115       +5     
+ Misses      18260    18255       -5     
- Partials      983      984       +1     

Flag	Coverage Δ
integration-test	21.47% <0.00%> (-0.01%)	⬇️
integration-test-arm	0.00% <0.00%> (ø)
integration-test-vm-x86_64-5.15.152	?
integration-test-vm-x86_64-6.10.6	?
k8s-integration-test	2.30% <0.00%> (+<0.01%)	⬆️
oats-test	0.00% <0.00%> (ø)
unittests	45.01% <88.57%> (+<0.01%)	⬆️

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[Copilot]

Pull request overview

This PR optimizes the Redis detection/parsing hot path by reducing allocations and avoiding unnecessary string conversions, while extending the internal split iterator to support both string and []byte inputs.

Changes:

• Updated Redis request parsing to operate on []byte end-to-end (TCP and Go uprobe paths), avoiding buffer-to-string copies.
• Refactored split.Iterator into a generic iterator with NewStringIterator and NewBytesIterator, and updated all call sites accordingly.
• Optimized Redis error extraction and DB selection logic to reduce per-iteration conversions/allocations.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pkg/internal/split/splititerator.go	Makes Iterator generic over string/[]byte and adds typed constructors.
pkg/internal/split/splititerator_test.go	Updates string iterator tests and adds coverage for the new bytes iterator.
pkg/export/attributes/env.go	Switches env var parsing to NewStringIterator.
pkg/ebpf/common/http/sqlpp.go	Switches SQL++ parsing helpers to NewStringIterator.
pkg/ebpf/common/tcp_detect_transform.go	Removes request/response string(...) conversions when parsing Redis frames.
pkg/ebpf/common/redis_detect_transform.go	Updates Redis parsing to consume []byte, refactors error-prefix handling, and removes ToUpper allocation.
pkg/ebpf/common/redis_detect_transform_test.go	Updates Redis parsing tests to pass []byte inputs.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

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Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated no new comments.

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[mariomac]

🚀