Add BearerTokenFunc to support dynamic bearer token authentication
for OTLP exporters. Tokens are injected per-request via gRPC
PerRPCCredentials and HTTP custom RoundTripper.
- Add BearerTokenFunc type and Config field in tracerconfig
- Implement bearerCredentials (gRPC) and bearerRoundTripper (HTTP)
- Wire bearer auth into all exporter creation functions
- Add getHTTPClient helper for DRY HTTP client configuration
- Upgrade OpenTelemetry SDK to v1.39.0 for WithHTTPClient support
- Create new metrics/ package for OpenTelemetry-native metrics with OTLP export
- Refactor OTLP configuration to internal/tracerconfig/ to eliminate code duplication
- Add consistent retry configuration across all HTTP OTLP exporters
- Add configuration validation and improved error messages
- Include test coverage for all new functionality
- Make OpenTelemetry metrics dependencies explicit in go.mod
Designed for new applications requiring structured metrics export to
observability backends via OTLP protocol.
Add buffering exporter to queue OTLP logs until tracing is configured.
Support TLS configuration for OpenTelemetry log export with client
certificate authentication. Improve logfmt formatting and tracing setup.
