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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 (
"fmt"
"regexp"
"sort"
"strings"
)
var (
separator = []byte{0}
// MetricNameRE is a regular expression matching valid metric
// names. Note that the IsValidMetricName function performs the same
// check but faster than a match with this regular expression.
MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`)
)
// A Metric is similar to a LabelSet, but the key difference is that a Metric is
// a singleton and refers to one and only one stream of samples.
type Metric LabelSet
// Equal compares the metrics.
func (m Metric) Equal(o Metric) bool {
return LabelSet(m).Equal(LabelSet(o))
}
// Before compares the metrics' underlying label sets.
func (m Metric) Before(o Metric) bool {
return LabelSet(m).Before(LabelSet(o))
}
// Clone returns a copy of the Metric.
func (m Metric) Clone() Metric {
clone := make(Metric, len(m))
for k, v := range m {
clone[k] = v
}
return clone
}
func (m Metric) String() string {
metricName, hasName := m[MetricNameLabel]
numLabels := len(m) - 1
if !hasName {
numLabels = len(m)
}
labelStrings := make([]string, 0, numLabels)
for label, value := range m {
if label != MetricNameLabel {
labelStrings = append(labelStrings, fmt.Sprintf("%s=%q", label, value))
}
}
switch numLabels {
case 0:
if hasName {
return string(metricName)
}
return "{}"
default:
sort.Strings(labelStrings)
return fmt.Sprintf("%s{%s}", metricName, strings.Join(labelStrings, ", "))
}
}
// Fingerprint returns a Metric's Fingerprint.
func (m Metric) Fingerprint() Fingerprint {
return LabelSet(m).Fingerprint()
}
// FastFingerprint returns a Metric's Fingerprint calculated by a faster hashing
// algorithm, which is, however, more susceptible to hash collisions.
func (m Metric) FastFingerprint() Fingerprint {
return LabelSet(m).FastFingerprint()
}
// IsValidMetricName returns true iff name matches the pattern of MetricNameRE.
// This function, however, does not use MetricNameRE for the check but a much
// faster hardcoded implementation.
func IsValidMetricName(n LabelValue) bool {
if len(n) == 0 {
return false
}
for i, b := range n {
if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) {
return false
}
}
return true
}
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