prometheus/vendor/github.com/digitalocean/godo/strings.go

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package godo
import (
"bytes"
"fmt"
"io"
"reflect"
"strings"
)
var timestampType = reflect.TypeOf(Timestamp{})
type ResourceWithURN interface {
URN() string
}
// ToURN converts the resource type and ID to a valid DO API URN.
func ToURN(resourceType string, id interface{}) string {
return fmt.Sprintf("%s:%s:%v", "do", strings.ToLower(resourceType), id)
}
// Stringify attempts to create a string representation of DigitalOcean types
func Stringify(message interface{}) string {
var buf bytes.Buffer
v := reflect.ValueOf(message)
stringifyValue(&buf, v)
return buf.String()
}
// stringifyValue was graciously cargoculted from the goprotubuf library
func stringifyValue(w io.Writer, val reflect.Value) {
if val.Kind() == reflect.Ptr && val.IsNil() {
_, _ = w.Write([]byte("<nil>"))
return
}
v := reflect.Indirect(val)
switch v.Kind() {
case reflect.String:
fmt.Fprintf(w, `"%s"`, v)
case reflect.Slice:
stringifySlice(w, v)
return
case reflect.Struct:
stringifyStruct(w, v)
default:
if v.CanInterface() {
fmt.Fprint(w, v.Interface())
}
}
}
func stringifySlice(w io.Writer, v reflect.Value) {
_, _ = w.Write([]byte{'['})
for i := 0; i < v.Len(); i++ {
if i > 0 {
_, _ = w.Write([]byte{' '})
}
stringifyValue(w, v.Index(i))
}
_, _ = w.Write([]byte{']'})
}
func stringifyStruct(w io.Writer, v reflect.Value) {
if v.Type().Name() != "" {
_, _ = w.Write([]byte(v.Type().String()))
}
// special handling of Timestamp values
if v.Type() == timestampType {
fmt.Fprintf(w, "{%s}", v.Interface())
return
}
_, _ = w.Write([]byte{'{'})
var sep bool
for i := 0; i < v.NumField(); i++ {
fv := v.Field(i)
if fv.Kind() == reflect.Ptr && fv.IsNil() {
continue
}
if fv.Kind() == reflect.Slice && fv.IsNil() {
continue
}
if sep {
_, _ = w.Write([]byte(", "))
} else {
sep = true
}
_, _ = w.Write([]byte(v.Type().Field(i).Name))
_, _ = w.Write([]byte{':'})
stringifyValue(w, fv)
}
_, _ = w.Write([]byte{'}'})
}