// Copyright 2017, OpenCensus Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package internal
import (
"strings"
"unicode"
)
const labelKeySizeLimit = 100
// Sanitize returns a string that is trunacated to 100 characters if it's too
// long, and replaces non-alphanumeric characters to underscores.
func Sanitize(s string) string {
if len(s) == 0 {
return s
}
if len(s) > labelKeySizeLimit {
s = s[:labelKeySizeLimit]
}
s = strings.Map(sanitizeRune, s)
if unicode.IsDigit(rune(s[0])) {
s = "key_" + s
}
if s[0] == '_' {
s = "key" + s
}
return s
}
// converts anything that is not a letter or digit to an underscore
func sanitizeRune(r rune) rune {
if unicode.IsLetter(r) || unicode.IsDigit(r) {
return r
}
// Everything else turns into an underscore
return '_'
}