add tracing and refactor some api pkgs

internal/tracing/span.go

@@ -0,0 +1,89 @@
+package tracing
+
+import (
+	"fmt"
+	"strconv"
+
+	"go.opencensus.io/trace"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+type Span struct {
+	span       *trace.Span
+	attributes []trace.Attribute
+}
+
+func CreateSpan(span *trace.Span) *Span {
+	return &Span{span: span, attributes: []trace.Attribute{}}
+}
+
+func (s *Span) End() {
+	if s.span == nil {
+		return
+	}
+	s.span.AddAttributes(s.attributes...)
+	s.span.End()
+}
+
+func (s *Span) EndWithError(err error) {
+	s.SetStatusByError(err)
+	s.End()
+}
+
+func (s *Span) SetStatusByError(err error) {
+	if s.span == nil {
+		return
+	}
+	s.span.SetStatus(statusFromError(err))
+}
+
+func statusFromError(err error) trace.Status {
+	if statusErr, ok := status.FromError(err); ok {
+		return trace.Status{Code: int32(statusErr.Code()), Message: statusErr.Message()}
+	}
+	return trace.Status{Code: int32(codes.Unknown), Message: "Unknown"}
+}
+
+// AddAnnotation creates an annotation. The annotation will not be added to the tracing use Annotate(msg) afterwards
+func (s *Span) AddAnnotation(key string, value interface{}) *Span {
+	attribute, err := toTraceAttribute(key, value)
+	if err != nil {
+		return s
+	}
+	s.attributes = append(s.attributes, attribute)
+	return s
+}
+
+// Annotate creates an annotation in tracing. Before added annotations will be set
+func (s *Span) Annotate(message string) *Span {
+	if s.span == nil {
+		return s
+	}
+	s.span.Annotate(s.attributes, message)
+	s.attributes = []trace.Attribute{}
+	return s
+}
+
+func (s *Span) Annotatef(format string, addiations ...interface{}) *Span {
+	s.Annotate(fmt.Sprintf(format, addiations...))
+	return s
+}
+
+func toTraceAttribute(key string, value interface{}) (attr trace.Attribute, err error) {
+	switch value := value.(type) {
+	case bool:
+		return trace.BoolAttribute(key, value), nil
+	case string:
+		return trace.StringAttribute(key, value), nil
+	}
+	if valueInt, err := convertToInt64(value); err == nil {
+		return trace.Int64Attribute(key, valueInt), nil
+	}
+	return attr, status.Error(codes.InvalidArgument, "Attribute is not of type bool, string or int64")
+}
+
+func convertToInt64(value interface{}) (int64, error) {
+	valueString := fmt.Sprintf("%v", value)
+	return strconv.ParseInt(valueString, 10, 64)
+}