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