Initial QSfera import

Server/vendor/go-micro.dev/v4/debug/trace/trace.go

@@ -0,0 +1,82 @@
+// Package trace provides an interface for distributed tracing
+package trace
+
+import (
+	"context"
+	"time"
+
+	"go-micro.dev/v4/metadata"
+	"go-micro.dev/v4/transport/headers"
+)
+
+var (
+	// DefaultTracer is the default tracer.
+	DefaultTracer = NewTracer()
+)
+
+// Tracer is an interface for distributed tracing.
+type Tracer interface {
+	// Start a trace
+	Start(ctx context.Context, name string) (context.Context, *Span)
+	// Finish the trace
+	Finish(*Span) error
+	// Read the traces
+	Read(...ReadOption) ([]*Span, error)
+}
+
+// SpanType describe the nature of the trace span.
+type SpanType int
+
+const (
+	// SpanTypeRequestInbound is a span created when serving a request.
+	SpanTypeRequestInbound SpanType = iota
+	// SpanTypeRequestOutbound is a span created when making a service call.
+	SpanTypeRequestOutbound
+)
+
+// Span is used to record an entry.
+type Span struct {
+	// Start time
+	Started time.Time
+	// associated data
+	Metadata map[string]string
+	// Id of the trace
+	Trace string
+	// name of the span
+	Name string
+	// id of the span
+	Id string
+	// parent span id
+	Parent string
+	// Duration in nano seconds
+	Duration time.Duration
+	// Type
+	Type SpanType
+}
+
+// FromContext returns a span from context.
+func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFound bool) {
+	traceID, traceOk := metadata.Get(ctx, headers.TraceIDKey)
+	microID, microOk := metadata.Get(ctx, headers.ID)
+
+	if !traceOk && !microOk {
+		isFound = false
+		return
+	}
+
+	if !traceOk {
+		traceID = microID
+	}
+
+	parentSpanID, ok := metadata.Get(ctx, headers.SpanID)
+
+	return traceID, parentSpanID, ok
+}
+
+// ToContext saves the trace and span ids in the context.
+func ToContext(ctx context.Context, traceID, parentSpanID string) context.Context {
+	return metadata.MergeContext(ctx, map[string]string{
+		headers.TraceIDKey: traceID,
+		headers.SpanID:     parentSpanID,
+	}, true)
+}