fix: Improved logging for OTLP Tonic Exporter

[cijothomas]

Improved logging

1. Interceptor failures are logged separately from export failures. Built-in interceptor simply adds Metadata, and has no scope of failure, so if this fails, it indicates user has added custom interceptors which is failing.
2. Log individual fields in the OTLP exporter, and then return Result contains just the minimal info about failure as OTLP's own log already has sufficient information, and no need to duplicate it by upstream component like batchexportprocessor/readers.

Related to #3021

[codecov]

Codecov Report

❌ Patch coverage is 0% with 38 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.0%. Comparing base (0462369) to head (ee0d2bc).

Files with missing lines	Patch %	Lines
opentelemetry-otlp/src/exporter/tonic/metrics.rs	0.0%	14 Missing ⚠️
opentelemetry-otlp/src/exporter/tonic/logs.rs	0.0%	12 Missing ⚠️
opentelemetry-otlp/src/exporter/tonic/trace.rs	0.0%	12 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3108     +/-   ##
=======================================
- Coverage   80.1%   80.0%   -0.1%     
=======================================
  Files        126     126             
  Lines      21957   21981     +24     
=======================================
  Hits       17603   17603             
- Misses      4354    4378     +24     

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[Copilot]

Pull Request Overview

This PR improves logging for OTLP Tonic Exporter by separating interceptor failures from export failures and providing more detailed error information while simplifying error messages passed upstream.

• Separates interceptor failure logging from export failure logging to better identify custom interceptor issues
• Enhances debug logging to include individual gRPC error fields (code, message, details) instead of formatting the entire error object
• Simplifies error messages returned to upstream components while maintaining detailed logging

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 12 comments.

File	Description
opentelemetry-otlp/src/exporter/tonic/trace.rs	Updates trace exporter with improved interceptor and export error logging
opentelemetry-otlp/src/exporter/tonic/metrics.rs	Updates metrics exporter with improved interceptor and export error logging
opentelemetry-otlp/src/exporter/tonic/logs.rs	Updates logs exporter with improved interceptor and export error logging

[Copilot]

Using format!("{:?}", e.code()) is unnecessary since e.code() already returns a displayable type. Consider using grpc_code = %e.code() or grpc_code = e.code() directly to avoid the formatting overhead.

Suggested change

	grpc_code = format!("{:?}", e.code()),
	grpc_code = e.code(),

[Copilot]

Using format!("{:?}", e.details()) is unnecessary since e.details() should be directly displayable. Consider using grpc_details = %e.details() or similar to avoid the formatting overhead.

Suggested change

	grpc_details = format!("{:?}", e.details())
	grpc_details = e.details()

[Copilot]

Using format!("{:?}", e.code()) is unnecessary since e.code() already returns a displayable type. Consider using grpc_code = %e.code() or grpc_code = e.code() directly to avoid the formatting overhead.

Suggested change

	grpc_code = format!("{:?}", e.code()),
	grpc_code = e.code(),

[Copilot]

Using format!("{:?}", e.details()) is unnecessary since e.details() should be directly displayable. Consider using grpc_details = %e.details() or similar to avoid the formatting overhead.

Suggested change

	grpc_details = format!("{:?}", e.details())
	grpc_details = e.details()

[Copilot]

Using format!("{:?}", e.code()) is unnecessary since e.code() already returns a displayable type. Consider using grpc_code = %e.code() or grpc_code = e.code() directly to avoid the formatting overhead.

Suggested change

	grpc_code = format!("{:?}", e.code()),
	grpc_code = e.code(),

[Copilot]

Using format!("{:?}", e.details()) is unnecessary since e.details() should be directly displayable. Consider using grpc_details = %e.details() or similar to avoid the formatting overhead.

Suggested change

	grpc_details = format!("{:?}", e.details())
	grpc_details = e.details()

[Copilot]

Using format!("{:?}", e.code()) is unnecessary since e.code() already returns a displayable type. Consider using grpc_code = %e.code() or grpc_code = e.code() directly to avoid the formatting overhead.

Suggested change

	grpc_code = format!("{:?}", e.code()),
	grpc_code = e.code(),

[Copilot]

Using format!("{:?}", e.details()) is unnecessary since e.details() should be directly displayable. Consider using grpc_details = %e.details() or similar to avoid the formatting overhead.

Suggested change

	grpc_details = format!("{:?}", e.details())
	grpc_details = %e.details()

[Copilot]

Using format!("{:?}", e.code()) is unnecessary since e.code() already returns a displayable type. Consider using grpc_code = %e.code() or grpc_code = e.code() directly to avoid the formatting overhead.

Suggested change

	grpc_code = format!("{:?}", e.code()),
	grpc_code = e.code(),

[Copilot]

Using format!("{:?}", e.details()) is unnecessary since e.details() should be directly displayable. Consider using grpc_details = %e.details() or similar to avoid the formatting overhead.

Suggested change

	grpc_details = format!("{:?}", e.details())
	grpc_details = e.details()