113 lines
2.6 KiB
Go
113 lines
2.6 KiB
Go
// Copyright 2017 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 labels
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import (
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"fmt"
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"regexp"
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)
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// MatchType is an enum for label matching types.
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type MatchType int
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// Possible MatchTypes.
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const (
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MatchEqual MatchType = iota
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MatchNotEqual
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MatchRegexp
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MatchNotRegexp
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)
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func (m MatchType) String() string {
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typeToStr := map[MatchType]string{
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MatchEqual: "=",
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MatchNotEqual: "!=",
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MatchRegexp: "=~",
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MatchNotRegexp: "!~",
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}
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if str, ok := typeToStr[m]; ok {
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return str
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}
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panic("unknown match type")
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}
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// Matcher models the matching of a label.
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type Matcher struct {
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Type MatchType
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Name string
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Value string
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re *regexp.Regexp
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}
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// NewMatcher returns a matcher object.
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func NewMatcher(t MatchType, n, v string) (*Matcher, error) {
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m := &Matcher{
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Type: t,
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Name: n,
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Value: v,
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}
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if t == MatchRegexp || t == MatchNotRegexp {
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re, err := regexp.Compile("^(?:" + v + ")$")
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if err != nil {
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return nil, err
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}
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m.re = re
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}
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return m, nil
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}
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// MustNewMatcher panics on error - only for use in tests!
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func MustNewMatcher(mt MatchType, name, val string) *Matcher {
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m, err := NewMatcher(mt, name, val)
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if err != nil {
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panic(err)
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}
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return m
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}
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func (m *Matcher) String() string {
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return fmt.Sprintf("%s%s%q", m.Name, m.Type, m.Value)
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}
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// Matches returns whether the matcher matches the given string value.
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func (m *Matcher) Matches(s string) bool {
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switch m.Type {
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case MatchEqual:
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return s == m.Value
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case MatchNotEqual:
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return s != m.Value
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case MatchRegexp:
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return m.re.MatchString(s)
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case MatchNotRegexp:
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return !m.re.MatchString(s)
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}
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panic("labels.Matcher.Matches: invalid match type")
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}
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// Inverse returns a matcher that matches the opposite.
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func (m *Matcher) Inverse() (*Matcher, error) {
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switch m.Type {
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case MatchEqual:
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return NewMatcher(MatchNotEqual, m.Name, m.Value)
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case MatchNotEqual:
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return NewMatcher(MatchEqual, m.Name, m.Value)
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case MatchRegexp:
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return NewMatcher(MatchNotRegexp, m.Name, m.Value)
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case MatchNotRegexp:
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return NewMatcher(MatchRegexp, m.Name, m.Value)
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}
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panic("labels.Matcher.Matches: invalid match type")
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}
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