cubefs

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// Copyright 2013 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package model
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import (
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	"fmt"
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	"regexp"
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	"sort"
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	"strings"
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)
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var (
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	// MetricNameRE is a regular expression matching valid metric
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	// names. Note that the IsValidMetricName function performs the same
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	// check but faster than a match with this regular expression.
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	MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`)
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)
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// A Metric is similar to a LabelSet, but the key difference is that a Metric is
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// a singleton and refers to one and only one stream of samples.
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type Metric LabelSet
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// Equal compares the metrics.
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func (m Metric) Equal(o Metric) bool {
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	return LabelSet(m).Equal(LabelSet(o))
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}
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// Before compares the metrics' underlying label sets.
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func (m Metric) Before(o Metric) bool {
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	return LabelSet(m).Before(LabelSet(o))
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}
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// Clone returns a copy of the Metric.
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func (m Metric) Clone() Metric {
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	clone := make(Metric, len(m))
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	for k, v := range m {
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		clone[k] = v
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	}
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	return clone
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}
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func (m Metric) String() string {
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	metricName, hasName := m[MetricNameLabel]
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	numLabels := len(m) - 1
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	if !hasName {
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		numLabels = len(m)
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	}
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	labelStrings := make([]string, 0, numLabels)
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	for label, value := range m {
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		if label != MetricNameLabel {
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			labelStrings = append(labelStrings, fmt.Sprintf("%s=%q", label, value))
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		}
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	}
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	switch numLabels {
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	case 0:
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		if hasName {
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			return string(metricName)
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		}
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		return "{}"
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	default:
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		sort.Strings(labelStrings)
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		return fmt.Sprintf("%s{%s}", metricName, strings.Join(labelStrings, ", "))
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	}
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}
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// Fingerprint returns a Metric's Fingerprint.
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func (m Metric) Fingerprint() Fingerprint {
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	return LabelSet(m).Fingerprint()
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}
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// FastFingerprint returns a Metric's Fingerprint calculated by a faster hashing
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// algorithm, which is, however, more susceptible to hash collisions.
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func (m Metric) FastFingerprint() Fingerprint {
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	return LabelSet(m).FastFingerprint()
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}
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// IsValidMetricName returns true iff name matches the pattern of MetricNameRE.
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// This function, however, does not use MetricNameRE for the check but a much
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// faster hardcoded implementation.
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func IsValidMetricName(n LabelValue) bool {
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	if len(n) == 0 {
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		return false
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	}
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	for i, b := range n {
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		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) {
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			return false
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		}
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	}
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	return true
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}
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