Introduce trace verbosity config and produce less spans by default

pkg/middlewares/observability/observability.go

@@ -3,6 +3,7 @@ package observability
 import (
 	"context"
 	"fmt"
+	"net/http"
 
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/trace"
@@ -10,8 +11,58 @@ import (
 
 type contextKey int
 
-// DisableMetricsKey is a context key used to disable the metrics.
-const DisableMetricsKey contextKey = iota
+const observabilityKey contextKey = iota
+
+type Observability struct {
+	AccessLogsEnabled      bool
+	MetricsEnabled         bool
+	SemConvMetricsEnabled  bool
+	TracingEnabled         bool
+	DetailedTracingEnabled bool
+}
+
+// WithObservabilityHandler sets the observability state in the context for the next handler.
+// This is also used for testing purposes to control whether access logs are enabled or not.
+func WithObservabilityHandler(next http.Handler, obs Observability) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		next.ServeHTTP(rw, req.WithContext(WithObservability(req.Context(), obs)))
+	})
+}
+
+// WithObservability injects the observability state into the context.
+func WithObservability(ctx context.Context, obs Observability) context.Context {
+	return context.WithValue(ctx, observabilityKey, obs)
+}
+
+// AccessLogsEnabled returns whether access-logs are enabled.
+func AccessLogsEnabled(ctx context.Context) bool {
+	obs, ok := ctx.Value(observabilityKey).(Observability)
+	return ok && obs.AccessLogsEnabled
+}
+
+// MetricsEnabled returns whether metrics are enabled.
+func MetricsEnabled(ctx context.Context) bool {
+	obs, ok := ctx.Value(observabilityKey).(Observability)
+	return ok && obs.MetricsEnabled
+}
+
+// SemConvMetricsEnabled returns whether metrics are enabled.
+func SemConvMetricsEnabled(ctx context.Context) bool {
+	obs, ok := ctx.Value(observabilityKey).(Observability)
+	return ok && obs.SemConvMetricsEnabled
+}
+
+// TracingEnabled returns whether tracing is enabled.
+func TracingEnabled(ctx context.Context) bool {
+	obs, ok := ctx.Value(observabilityKey).(Observability)
+	return ok && obs.TracingEnabled
+}
+
+// DetailedTracingEnabled returns whether detailed tracing is enabled.
+func DetailedTracingEnabled(ctx context.Context) bool {
+	obs, ok := ctx.Value(observabilityKey).(Observability)
+	return ok && obs.DetailedTracingEnabled
+}
 
 // SetStatusErrorf flags the span as in error and log an event.
 func SetStatusErrorf(ctx context.Context, format string, args ...interface{}) {