Add BearerTokenFunc to support dynamic bearer token authentication
for OTLP gRPC exporters. Tokens are injected via gRPC PerRPCCredentials
on each export request.
- Add BearerTokenFunc type and Config field in tracerconfig
- Implement bearerCredentials (gRPC) and bearerRoundTripper (HTTP)
- Wire bearer auth into all three gRPC exporter creation functions
- Add token verification before flushing buffered logs
- Fix race condition in buffering exporter initialization
Note: HTTP exporters don't support dynamic bearer tokens due to
OpenTelemetry SDK limitations (no WithHTTPClient option). Use gRPC
protocol for dynamic tokens.
Ask Bjørn Hansen
fc3617b7d8