Infrastructure

Cross-cutting infrastructure that supports both the controller and router: structured logging with trace correlation, declarative configuration binding, and gRPC service communication.

Logging architecture

Logging is context-based: log.With(ctx, fields...) accumulates structured fields that propagate through the call chain. All log functions take context as the first argument: log.Info(ctx, "message", fields...).

Type-safe attribute keys

Attribute keys are defined in internal/key/. Each key provides both .Slog() and .Otel() methods, ensuring consistent naming across logs and traces. This eliminates string duplication and typos when the same attribute appears in both systems.

Log-trace correlation

Error-level log records automatically include trace_id and span_id when a span exists in context. Errors are also recorded on the active span via span.SetStatus(codes.Error), enabling bidirectional navigation between logs and traces.

Configuration system

The internal/config/ package provides declarative flag binding via struct tags.

Supported tags

Resolution order

1. CLI flags (highest priority)
2. Environment variables (--my-flag becomes SKIPPER_MY_FLAG)

Supported types: scalars, slices, durations, URLs, maps, and any type implementing encoding.TextUnmarshaler.

gRPC communication

The controller exposes a gRPC service on port 50051 (default). Routers connect using DNS-based service discovery with round-robin load balancing (dns:///service:port).

Retry policies

All retries trigger only on the UNAVAILABLE status code. Every RPC is instrumented with OpenTelemetry.