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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
// Validate checks whether all names and values in the label set
// are valid.
func (ls LabelSet) Validate() error {
for ln, lv := range ls {
if !ln.IsValid() {
return fmt.Errorf("invalid name %q", ln)
}
if !lv.IsValid() {
return fmt.Errorf("invalid value %q", lv)
}
}
return nil
}
// Equal returns true iff both label sets have exactly the same key/value pairs.
func (ls LabelSet) Equal(o LabelSet) bool {
if len(ls) != len(o) {
return false
}
for ln, lv := range ls {
olv, ok := o[ln]
if !ok {
return false
}
if olv != lv {
return false
}
}
return true
}
// Before compares the metrics, using the following criteria:
//
// If m has fewer labels than o, it is before o. If it has more, it is not.
//
// If the number of labels is the same, the superset of all label names is
// sorted alphanumerically. The first differing label pair found in that order
// determines the outcome: If the label does not exist at all in m, then m is
// before o, and vice versa. Otherwise the label value is compared
// alphanumerically.
//
// If m and o are equal, the method returns false.
func (ls LabelSet) Before(o LabelSet) bool {
if len(ls) < len(o) {
return true
}
if len(ls) > len(o) {
return false
}
lns := make(LabelNames, 0, len(ls)+len(o))
for ln := range ls {
lns = append(lns, ln)
}
for ln := range o {
lns = append(lns, ln)
}
// It's probably not worth it to de-dup lns.
sort.Sort(lns)
for _, ln := range lns {
mlv, ok := ls[ln]
if !ok {
return true
}
olv, ok := o[ln]
if !ok {
return false
}
if mlv < olv {
return true
}
if mlv > olv {
return false
}
}
return false
}
// Clone returns a copy of the label set.
func (ls LabelSet) Clone() LabelSet {
lsn := make(LabelSet, len(ls))
for ln, lv := range ls {
lsn[ln] = lv
}
return lsn
}
// 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 {
lstrs := make([]string, 0, len(l))
for l, v := range l {
lstrs = append(lstrs, fmt.Sprintf("%s=%q", l, v))
}
sort.Strings(lstrs)
return fmt.Sprintf("{%s}", strings.Join(lstrs, ", "))
}
// Fingerprint returns the LabelSet's fingerprint.
func (ls LabelSet) Fingerprint() Fingerprint {
return labelSetToFingerprint(ls)
}
// FastFingerprint returns the LabelSet's Fingerprint calculated by a faster hashing
// algorithm, which is, however, more susceptible to hash collisions.
func (ls LabelSet) FastFingerprint() Fingerprint {
return labelSetToFastFingerprint(ls)
}
// 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 !ln.IsValid() {
return fmt.Errorf("%q is not a valid label name", ln)
}
}
*l = LabelSet(m)
return nil
}
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