prometheus/pkg/labels/matcher.go
Julius Volz 33c1171b9c Don't add anchoring to exported Value matcher field
Instead, just make the anchoring part of the internal regex. This helps because
some users will want to read back the `Value` field and expect it to be the
same as the input value (e.g. some tests in Cortex), or use the value in
another context which is already expected to add its own anchoring, leading to
superfluous double anchoring (such as when we translate matchers into remote
read request matchers).
2017-10-10 10:10:21 -07:00

89 lines
1.9 KiB
Go

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