Imported github.com/ardanlabs/service as base example project

example-project/vendor/github.com/openzipkin/zipkin-go/model/span.go

@@ -0,0 +1,124 @@
+package model
+
+import (
+	"encoding/json"
+	"errors"
+	"time"
+)
+
+// unmarshal errors
+var (
+	ErrValidTraceIDRequired  = errors.New("valid traceId required")
+	ErrValidIDRequired       = errors.New("valid span id required")
+	ErrValidDurationRequired = errors.New("valid duration required")
+)
+
+// SpanContext holds the context of a Span.
+type SpanContext struct {
+	TraceID  TraceID `json:"traceId"`
+	ID       ID      `json:"id"`
+	ParentID *ID     `json:"parentId,omitempty"`
+	Debug    bool    `json:"debug,omitempty"`
+	Sampled  *bool   `json:"-"`
+	Err      error   `json:"-"`
+}
+
+// SpanModel structure.
+//
+// If using this library to instrument your application you will not need to
+// directly access or modify this representation. The SpanModel is exported for
+// use cases involving 3rd party Go instrumentation libraries desiring to
+// export data to a Zipkin server using the Zipkin V2 Span model.
+type SpanModel struct {
+	SpanContext
+	Name           string            `json:"name,omitempty"`
+	Kind           Kind              `json:"kind,omitempty"`
+	Timestamp      time.Time         `json:"timestamp,omitempty"`
+	Duration       time.Duration     `json:"duration,omitempty"`
+	Shared         bool              `json:"shared,omitempty"`
+	LocalEndpoint  *Endpoint         `json:"localEndpoint,omitempty"`
+	RemoteEndpoint *Endpoint         `json:"remoteEndpoint,omitempty"`
+	Annotations    []Annotation      `json:"annotations,omitempty"`
+	Tags           map[string]string `json:"tags,omitempty"`
+}
+
+// MarshalJSON exports our Model into the correct format for the Zipkin V2 API.
+func (s SpanModel) MarshalJSON() ([]byte, error) {
+	type Alias SpanModel
+
+	var timestamp int64
+	if !s.Timestamp.IsZero() {
+		if s.Timestamp.Unix() < 1 {
+			// Zipkin does not allow Timestamps before Unix epoch
+			return nil, ErrValidTimestampRequired
+		}
+		timestamp = s.Timestamp.Round(time.Microsecond).UnixNano() / 1e3
+	}
+
+	if s.Duration < time.Microsecond {
+		if s.Duration < 0 {
+			// negative duration is not allowed and signals a timing logic error
+			return nil, ErrValidDurationRequired
+		} else if s.Duration > 0 {
+			// sub microsecond durations are reported as 1 microsecond
+			s.Duration = 1 * time.Microsecond
+		}
+	} else {
+		// Duration will be rounded to nearest microsecond representation.
+		//
+		// NOTE: Duration.Round() is not available in Go 1.8 which we still support.
+		// To handle microsecond resolution rounding we'll add 500 nanoseconds to
+		// the duration. When truncated to microseconds in the call to marshal, it
+		// will be naturally rounded. See TestSpanDurationRounding in span_test.go
+		s.Duration += 500 * time.Nanosecond
+	}
+
+	if s.LocalEndpoint.Empty() {
+		s.LocalEndpoint = nil
+	}
+
+	if s.RemoteEndpoint.Empty() {
+		s.RemoteEndpoint = nil
+	}
+
+	return json.Marshal(&struct {
+		Timestamp int64 `json:"timestamp,omitempty"`
+		Duration  int64 `json:"duration,omitempty"`
+		Alias
+	}{
+		Timestamp: timestamp,
+		Duration:  s.Duration.Nanoseconds() / 1e3,
+		Alias:     (Alias)(s),
+	})
+}
+
+// UnmarshalJSON imports our Model from a Zipkin V2 API compatible span
+// representation.
+func (s *SpanModel) UnmarshalJSON(b []byte) error {
+	type Alias SpanModel
+	span := &struct {
+		TimeStamp uint64 `json:"timestamp,omitempty"`
+		Duration  uint64 `json:"duration,omitempty"`
+		*Alias
+	}{
+		Alias: (*Alias)(s),
+	}
+	if err := json.Unmarshal(b, &span); err != nil {
+		return err
+	}
+	if s.ID < 1 {
+		return ErrValidIDRequired
+	}
+	if span.TimeStamp > 0 {
+		s.Timestamp = time.Unix(0, int64(span.TimeStamp)*1e3)
+	}
+	s.Duration = time.Duration(span.Duration*1e3) * time.Nanosecond
+	if s.LocalEndpoint.Empty() {
+		s.LocalEndpoint = nil
+	}
+
+	if s.RemoteEndpoint.Empty() {
+		s.RemoteEndpoint = nil
+	}
+	return nil
+}