122 lines
3.2 KiB
Go
122 lines
3.2 KiB
Go
// Copyright 2015 Prometheus Team
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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 types
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import (
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"encoding/json"
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"fmt"
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"regexp"
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"strings"
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"github.com/prometheus/common/model"
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)
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// Matcher defines a matching rule for the value of a given label.
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type Matcher struct {
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Name model.LabelName
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Value string
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isRegex bool
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regex *regexp.Regexp
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}
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func (m *Matcher) String() string {
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if m.isRegex {
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return fmt.Sprintf("<RegexMatcher %s:%q>", m.Name, m.Value)
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}
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return fmt.Sprintf("<Matcher %s:%q>", m.Name, m.Value)
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}
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// MarshalJSON implements json.Marshaler.
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func (m *Matcher) MarshalJSON() ([]byte, error) {
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v := struct {
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Name model.LabelName `json:"name"`
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Value string `json:"value"`
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IsRegex bool `json:"isRegex"`
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}{
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Name: m.Name,
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Value: m.Value,
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IsRegex: m.isRegex,
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}
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return json.Marshal(&v)
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}
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// IsRegex returns true of the matcher compares against a regular expression.
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func (m *Matcher) IsRegex() bool {
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return m.isRegex
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}
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// Match checks whether the label of the matcher has the specified
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// matching value.
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func (m *Matcher) Match(lset model.LabelSet) bool {
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// Unset labels are treated as unset labels globally. Thus, if a
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// label is not set we retrieve the empty label which is correct
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// for the comparison below.
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v := lset[m.Name]
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if m.isRegex {
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return m.regex.MatchString(string(v))
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}
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return string(v) == m.Value
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}
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// NewMatcher returns a new matcher that compares against equality of
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// the given value.
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func NewMatcher(name model.LabelName, value string) *Matcher {
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return &Matcher{
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Name: name,
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Value: value,
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}
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}
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// NewRegexMatcher returns a new matcher that treats value as a regular
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// expression which is used for matching.
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func NewRegexMatcher(name model.LabelName, re *regexp.Regexp) *Matcher {
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value := strings.TrimSuffix(strings.TrimPrefix(re.String(), "^(?:"), ")$")
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if len(re.String())-len(value) != 6 {
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// Any non-anchored regexp is a bug.
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panic(fmt.Errorf("regexp %q not properly anchored", re))
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}
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return &Matcher{
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Name: name,
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Value: value,
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isRegex: true,
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regex: re,
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}
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}
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// Matchers provides the Match and Fingerprint methods for a slice of Matchers.
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type Matchers []*Matcher
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// Match checks whether all matchers are fulfilled against the given label set.
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func (ms Matchers) Match(lset model.LabelSet) bool {
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for _, m := range ms {
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if !m.Match(lset) {
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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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// Fingerprint returns a quasi-unique fingerprint for the matchers.
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func (ms Matchers) Fingerprint() model.Fingerprint {
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lset := make(model.LabelSet, 3*len(ms))
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for _, m := range ms {
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lset[model.LabelName(fmt.Sprintf("%s-%s-%v", m.Name, m.Value, m.isRegex))] = ""
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}
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return lset.Fingerprint()
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}
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