feat: add DataToPoint

Author: sranka

api/write.go

@@ -6,6 +6,8 @@ package api
 
 import (
 	"context"
+	"fmt"
+	"reflect"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -266,3 +268,79 @@ func (w *WriteAPIImpl) WritePoint(point *write.Point) {
 func buffer(lines []string) string {
 	return strings.Join(lines, "")
 }
+
+// DataToPoint converts custom point structures into a Point.
+// Each visible field of the point on input must be annotated with
+// 'lp' prefix and values measurement,tag, field or timestamp.
+// Valid point must contain measurement and at least one field.
+//
+// A field with timestamp must be of a type time.Time
+//
+//	 type TemperatureSensor struct {
+//		  Measurement string `lp:"measurement"`
+//		  Sensor string `lp:"tag,sensor"`
+//		  ID string `lp:"tag,device_id"`
+//		  Temp float64 `lp:"field,temperature"`
+//		  Hum int	`lp:"field,humidity"`
+//		  Time time.Time `lp:"timestamp,temperature"`
+//		  Description string `lp:"-"`
+//	 }
+func DataToPoint(x interface{}) (*write.Point, error) {
+	if err := checkContainerType(x, false, "point"); err != nil {
+		return nil, err
+	}
+	t := reflect.TypeOf(x)
+	v := reflect.ValueOf(x)
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+		v = v.Elem()
+	}
+	fields := reflect.VisibleFields(t)
+
+	var measurement string = ""
+	var lpTags = make(map[string]string)
+	var lpFields = make(map[string]interface{})
+	var lpTime time.Time
+
+	for _, f := range fields {
+		name := f.Name
+		if tag, ok := f.Tag.Lookup("lp"); ok {
+			if tag == "-" {
+				continue
+			}
+			parts := strings.Split(tag, ",")
+			if len(parts) > 2 {
+				return nil, fmt.Errorf("multiple tag attributes are not supported")
+			}
+			typ := parts[0]
+			if len(parts) == 2 {
+				name = parts[1]
+			}
+			switch typ {
+			case "measurement":
+				if measurement != "" {
+					return nil, fmt.Errorf("multiple measurement fields")
+				}
+				measurement = v.FieldByIndex(f.Index).String()
+			case "tag":
+				lpTags[name] = v.FieldByIndex(f.Index).String()
+			case "field":
+				lpFields[name] = v.FieldByIndex(f.Index).Interface()
+			case "timestamp":
+				if f.Type != timeType {
+					return nil, fmt.Errorf("cannot use field '%s' as a timestamp", f.Name)
+				}
+				lpTime = v.FieldByIndex(f.Index).Interface().(time.Time)
+			default:
+				return nil, fmt.Errorf("invalid tag %s", typ)
+			}
+		}
+	}
+	if measurement == "" {
+		return nil, fmt.Errorf("no struct field with tag 'measurement'")
+	}
+	if len(lpFields) == 0 {
+		return nil, fmt.Errorf("no struct field with tag 'field'")
+	}
+	return write.NewPoint(measurement, lpTags, lpFields, lpTime), nil
+}

api/write/point.go

@@ -84,6 +84,12 @@ func (m *Point) Name() string {
 	return m.measurement
 }
 
+// Name returns the name of measurement of a point.
+func (m *Point) SetName(name string) *Point {
+	m.measurement = name
+	return m
+}
+
 // NewPointWithMeasurement creates a empty Point
 // Use AddTag and AddField to fill point with data
 func NewPointWithMeasurement(measurement string) *Point {