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 stackdriver

import (
	
	
)

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 ( string) string {
	if len() == 0 {
		return 
	}
	if len() > labelKeySizeLimit {
		 = [:labelKeySizeLimit]
	}
	 = strings.Map(sanitizeRune, )
	if unicode.IsDigit(rune([0])) {
		 = "key_" + 
	}
	if [0] == '_' {
		 = "key" + 
	}
	return 
}
converts anything that is not a letter or digit to an underscore
func ( rune) rune {
	if unicode.IsLetter() || unicode.IsDigit() {
		return
Everything else turns into an underscore
	return '_'