1// Copyright 2013 The Prometheus Authors 2// Licensed under the Apache License, Version 2.0 (the "License"); 3// you may not use this file except in compliance with the License. 4// You may obtain a copy of the License at 5// 6// http://www.apache.org/licenses/LICENSE-2.0 7// 8// Unless required by applicable law or agreed to in writing, software 9// distributed under the License is distributed on an "AS IS" BASIS, 10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 11// See the License for the specific language governing permissions and 12// limitations under the License. 13 14package model 15 16import ( 17 "fmt" 18 "regexp" 19 "sort" 20 "strings" 21) 22 23var ( 24 separator = []byte{0} 25 // MetricNameRE is a regular expression matching valid metric 26 // names. Note that the IsValidMetricName function performs the same 27 // check but faster than a match with this regular expression. 28 MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`) 29) 30 31// A Metric is similar to a LabelSet, but the key difference is that a Metric is 32// a singleton and refers to one and only one stream of samples. 33type Metric LabelSet 34 35// Equal compares the metrics. 36func (m Metric) Equal(o Metric) bool { 37 return LabelSet(m).Equal(LabelSet(o)) 38} 39 40// Before compares the metrics' underlying label sets. 41func (m Metric) Before(o Metric) bool { 42 return LabelSet(m).Before(LabelSet(o)) 43} 44 45// Clone returns a copy of the Metric. 46func (m Metric) Clone() Metric { 47 clone := make(Metric, len(m)) 48 for k, v := range m { 49 clone[k] = v 50 } 51 return clone 52} 53 54func (m Metric) String() string { 55 metricName, hasName := m[MetricNameLabel] 56 numLabels := len(m) - 1 57 if !hasName { 58 numLabels = len(m) 59 } 60 labelStrings := make([]string, 0, numLabels) 61 for label, value := range m { 62 if label != MetricNameLabel { 63 labelStrings = append(labelStrings, fmt.Sprintf("%s=%q", label, value)) 64 } 65 } 66 67 switch numLabels { 68 case 0: 69 if hasName { 70 return string(metricName) 71 } 72 return "{}" 73 default: 74 sort.Strings(labelStrings) 75 return fmt.Sprintf("%s{%s}", metricName, strings.Join(labelStrings, ", ")) 76 } 77} 78 79// Fingerprint returns a Metric's Fingerprint. 80func (m Metric) Fingerprint() Fingerprint { 81 return LabelSet(m).Fingerprint() 82} 83 84// FastFingerprint returns a Metric's Fingerprint calculated by a faster hashing 85// algorithm, which is, however, more susceptible to hash collisions. 86func (m Metric) FastFingerprint() Fingerprint { 87 return LabelSet(m).FastFingerprint() 88} 89 90// IsValidMetricName returns true iff name matches the pattern of MetricNameRE. 91// This function, however, does not use MetricNameRE for the check but a much 92// faster hardcoded implementation. 93func IsValidMetricName(n LabelValue) bool { 94 if len(n) == 0 { 95 return false 96 } 97 for i, b := range n { 98 if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) { 99 return false 100 } 101 } 102 return true 103} 104