client_golang/model/signature.go

70 lines
1.7 KiB
Go

// Copyright 2014 Prometheus Team
// 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 model
import (
"hash/fnv"
"sort"
)
// cache the signature of an empty label set.
var emptyLabelSignature = fnv.New64a().Sum64()
// LabelsToSignature provides a way of building a unique signature
// (i.e., fingerprint) for a given label set sequence.
func LabelsToSignature(labels map[string]string) uint64 {
if len(labels) == 0 {
return emptyLabelSignature
}
names := make([]string, 0, len(labels))
for name := range labels {
names = append(names, name)
}
sort.Strings(names)
hasher := fnv.New64a()
for _, name := range names {
hasher.Write([]byte(name))
hasher.Write([]byte(labels[name]))
}
return hasher.Sum64()
}
// LabelValuesToSignature provides a way of building a unique signature
// (i.e., fingerprint) for a given set of label's values.
func LabelValuesToSignature(labels map[string]string) uint64 {
if len(labels) == 0 {
return emptyLabelSignature
}
names := make([]string, 0, len(labels))
for name := range labels {
names = append(names, name)
}
sort.Strings(names)
hasher := fnv.New64a()
for _, name := range names {
hasher.Write([]byte(labels[name]))
}
return hasher.Sum64()
}