Fix go regression in json.Number unmarshalling (#312)

dashboards.go

@@ -114,8 +114,8 @@ type Yaxis struct {
 func (y *Yaxis) UnmarshalJSON(data []byte) error {
 	type Alias Yaxis
 	wrapper := &struct {
-		Min *json.Number `json:"min,omitempty"`
-		Max *json.Number `json:"max,omitempty"`
+		Min *interface{} `json:"min,omitempty"`
+		Max *interface{} `json:"max,omitempty"`
 		*Alias
 	}{
 		Alias: (*Alias)(y),
@@ -125,31 +125,20 @@ func (y *Yaxis) UnmarshalJSON(data []byte) error {
 		return err
 	}
 
-	if wrapper.Min != nil {
-		if *wrapper.Min == "auto" {
-			y.AutoMin = true
-			y.Min = nil
-		} else {
-			f, err := wrapper.Min.Float64()
-			if err != nil {
-				return err
-			}
-			y.Min = &f
-		}
+	val, auto, err := GetFloatFromInterface(wrapper.Min)
+	if err != nil {
+		return fmt.Errorf(`faild parsing value for Yaxis.min: %s`, err.Error())
 	}
+	y.AutoMin = auto
+	y.Min = val
 
-	if wrapper.Max != nil {
-		if *wrapper.Max == "auto" {
-			y.AutoMax = true
-			y.Max = nil
-		} else {
-			f, err := wrapper.Max.Float64()
-			if err != nil {
-				return err
-			}
-			y.Max = &f
-		}
+	val, auto, err = GetFloatFromInterface(wrapper.Max)
+	if err != nil {
+		return fmt.Errorf(`faild parsing value for Yaxis.max: %s`, err.Error())
 	}
+	y.AutoMax = auto
+	y.Max = val
+
 	return nil
 }
 

helper_test.go

@@ -128,3 +128,51 @@ func TestHelperGetStringId(t *testing.T) {
 	assert.NotNil(t, err)
 	assert.Contains(t, err.Error(), "unsupported id type")
 }
+
+func TestGetFloatFromInterface(t *testing.T) {
+	var input interface{}
+
+	input = nil
+	val, auto, err := datadog.GetFloatFromInterface(nil)
+	assert.Nil(t, err)
+	assert.Equal(t, false, auto)
+	assert.Nil(t, val)
+
+	input = 0.0
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.Nil(t, err)
+	assert.Equal(t, false, auto)
+	assert.Equal(t, 0.0, *val)
+
+	input = 12.3
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.Nil(t, err)
+	assert.Equal(t, false, auto)
+	assert.Equal(t, 12.3, *val)
+
+	input = 123
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.Nil(t, err)
+	assert.Equal(t, false, auto)
+	assert.Equal(t, 123.0, *val)
+
+	input = int64(1234567890123456789.0)
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.Nil(t, err)
+	assert.Equal(t, false, auto)
+	assert.Equal(t, 1234567890123456789.0, *val)
+
+	input = "auto"
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.Nil(t, err)
+	assert.Equal(t, true, auto)
+	assert.Nil(t, val)
+
+	input = "wrong!"
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.NotNil(t, err)
+
+	input = false
+	val, auto, err = datadog.GetFloatFromInterface(&input)
+	assert.NotNil(t, err)
+}

helpers.go

@@ -11,6 +11,7 @@ package datadog
 import (
 	"encoding/json"
 	"errors"
+	"fmt"
 	"math"
 	"strconv"
 )
@@ -122,3 +123,43 @@ func GetStringId(id interface{}) (string, error) {
 		return "", errors.New("unsupported id type")
 	}
 }
+
+func GetFloatFromInterface(intf *interface{}) (*float64, bool, error) {
+	var result *float64
+	var auto bool
+
+	if intf != nil {
+		val := *intf
+		switch tp := val.(type) {
+		case float32:
+			fv := float64(val.(float32))
+			result = &fv
+		case float64:
+			fv := val.(float64)
+			result = &fv
+		case int:
+			fv := float64(val.(int))
+			result = &fv
+		case int32:
+			fv := float64(val.(int32))
+			result = &fv
+		case int64:
+			fv := float64(val.(int64))
+			result = &fv
+		case string:
+			fv := val.(string)
+			if fv == "auto" {
+				auto = true
+			} else {
+				f, err := strconv.ParseFloat(fv, 64)
+				if err != nil {
+					return nil, false, err
+				}
+				result = &f
+			}
+		default:
+			return nil, false, fmt.Errorf(`bad type "%v" for Yaxis.min, expected "auto" or a number`, tp)
+		}
+	}
+	return result, auto, nil
+}