client_golang/model/labelset.go

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// Copyright 2013 The Prometheus 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 model
import (
"encoding/json"
"fmt"
"sort"
"strings"
)
// A LabelSet is a collection of LabelName and LabelValue pairs. The LabelSet
// may be fully-qualified down to the point where it may resolve to a single
// Metric in the data store or not. All operations that occur within the realm
// of a LabelSet can emit a vector of Metric entities to which the LabelSet may
// match.
type LabelSet map[LabelName]LabelValue
// Merge is a helper function to non-destructively merge two label sets.
func (l LabelSet) Merge(other LabelSet) LabelSet {
result := make(LabelSet, len(l))
for k, v := range l {
result[k] = v
}
for k, v := range other {
result[k] = v
}
return result
}
func (l LabelSet) String() string {
labelStrings := make([]string, 0, len(l))
for label, value := range l {
labelStrings = append(labelStrings, fmt.Sprintf("%s=%q", label, value))
}
switch len(labelStrings) {
case 0:
return ""
default:
sort.Strings(labelStrings)
return fmt.Sprintf("{%s}", strings.Join(labelStrings, ", "))
}
}
// MergeFromMetric merges Metric into this LabelSet.
func (l LabelSet) MergeFromMetric(m Metric) {
for k, v := range m {
l[k] = v
}
}
// UnmarshalJSON implements the json.Unmarshaler interface.
func (l *LabelSet) UnmarshalJSON(b []byte) error {
var m map[LabelName]LabelValue
if err := json.Unmarshal(b, &m); err != nil {
return err
}
// encoding/json only unmarshals maps of the form map[string]T. It treats
// LabelName as a string and does not call its UnmarshalJSON method.
// Thus, we have to replicate the behavior here.
for ln := range m {
if !LabelNameRE.MatchString(string(ln)) {
return fmt.Errorf("%q is not a valid label name", ln)
}
}
*l = LabelSet(m)
return nil
}