alertmanager/matcher/compat/parse.go

206 lines
8.5 KiB
Go

// Copyright 2023 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 compat
import (
"fmt"
"log/slog"
"reflect"
"strings"
"unicode/utf8"
"github.com/prometheus/common/model"
"github.com/prometheus/common/promslog"
"github.com/prometheus/alertmanager/featurecontrol"
"github.com/prometheus/alertmanager/matcher/parse"
"github.com/prometheus/alertmanager/pkg/labels"
)
var (
isValidLabelName = isValidClassicLabelName(promslog.NewNopLogger())
parseMatcher = ClassicMatcherParser(promslog.NewNopLogger())
parseMatchers = ClassicMatchersParser(promslog.NewNopLogger())
)
// IsValidLabelName returns true if the string is a valid label name.
func IsValidLabelName(name model.LabelName) bool {
return isValidLabelName(name)
}
type ParseMatcher func(input, origin string) (*labels.Matcher, error)
type ParseMatchers func(input, origin string) (labels.Matchers, error)
// Matcher parses the matcher in the input string. It returns an error
// if the input is invalid or contains two or more matchers.
func Matcher(input, origin string) (*labels.Matcher, error) {
return parseMatcher(input, origin)
}
// Matchers parses one or more matchers in the input string. It returns
// an error if the input is invalid.
func Matchers(input, origin string) (labels.Matchers, error) {
return parseMatchers(input, origin)
}
// InitFromFlags initializes the compat package from the flagger.
func InitFromFlags(l *slog.Logger, f featurecontrol.Flagger) {
if f.ClassicMode() {
isValidLabelName = isValidClassicLabelName(l)
parseMatcher = ClassicMatcherParser(l)
parseMatchers = ClassicMatchersParser(l)
} else if f.UTF8StrictMode() {
isValidLabelName = isValidUTF8LabelName(l)
parseMatcher = UTF8MatcherParser(l)
parseMatchers = UTF8MatchersParser(l)
} else {
isValidLabelName = isValidUTF8LabelName(l)
parseMatcher = FallbackMatcherParser(l)
parseMatchers = FallbackMatchersParser(l)
}
}
// ClassicMatcherParser uses the pkg/labels parser to parse the matcher in
// the input string.
func ClassicMatcherParser(l *slog.Logger) ParseMatcher {
return func(input, origin string) (matcher *labels.Matcher, err error) {
l.Debug("Parsing with classic matchers parser", "input", input, "origin", origin)
return labels.ParseMatcher(input)
}
}
// ClassicMatchersParser uses the pkg/labels parser to parse zero or more
// matchers in the input string. It returns an error if the input is invalid.
func ClassicMatchersParser(l *slog.Logger) ParseMatchers {
return func(input, origin string) (matchers labels.Matchers, err error) {
l.Debug("Parsing with classic matchers parser", "input", input, "origin", origin)
return labels.ParseMatchers(input)
}
}
// UTF8MatcherParser uses the new matcher/parse parser to parse the matcher
// in the input string. If this fails it does not revert to the pkg/labels parser.
func UTF8MatcherParser(l *slog.Logger) ParseMatcher {
return func(input, origin string) (matcher *labels.Matcher, err error) {
l.Debug("Parsing with UTF-8 matchers parser", "input", input, "origin", origin)
if strings.HasPrefix(input, "{") || strings.HasSuffix(input, "}") {
return nil, fmt.Errorf("unexpected open or close brace: %s", input)
}
return parse.Matcher(input)
}
}
// UTF8MatchersParser uses the new matcher/parse parser to parse zero or more
// matchers in the input string. If this fails it does not revert to the
// pkg/labels parser.
func UTF8MatchersParser(l *slog.Logger) ParseMatchers {
return func(input, origin string) (matchers labels.Matchers, err error) {
l.Debug("Parsing with UTF-8 matchers parser", "input", input, "origin", origin)
return parse.Matchers(input)
}
}
// FallbackMatcherParser uses the new matcher/parse parser to parse zero or more
// matchers in the string. If this fails it reverts to the pkg/labels parser and
// emits a warning log line.
func FallbackMatcherParser(l *slog.Logger) ParseMatcher {
return func(input, origin string) (matcher *labels.Matcher, err error) {
l.Debug("Parsing with UTF-8 matchers parser, with fallback to classic matchers parser", "input", input, "origin", origin)
if strings.HasPrefix(input, "{") || strings.HasSuffix(input, "}") {
return nil, fmt.Errorf("unexpected open or close brace: %s", input)
}
// Parse the input in both parsers to look for disagreement and incompatible
// inputs.
nMatcher, nErr := parse.Matcher(input)
cMatcher, cErr := labels.ParseMatcher(input)
if nErr != nil {
// If the input is invalid in both parsers, return the error.
if cErr != nil {
return nil, cErr
}
// The input is valid in the pkg/labels parser, but not the matcher/parse
// parser. This means the input is not forwards compatible.
suggestion := cMatcher.String()
l.Warn("Alertmanager is moving to a new parser for labels and matchers, and this input is incompatible. Alertmanager has instead parsed the input using the classic matchers parser as a fallback. To make this input compatible with the UTF-8 matchers parser please make sure all regular expressions and values are double-quoted. If you are still seeing this message please open an issue.", "input", input, "origin", origin, "err", nErr, "suggestion", suggestion)
return cMatcher, nil
}
// If the input is valid in both parsers, but produces different results,
// then there is disagreement.
if nErr == nil && cErr == nil && !reflect.DeepEqual(nMatcher, cMatcher) {
l.Warn("Matchers input has disagreement", "input", input, "origin", origin)
return cMatcher, nil
}
return nMatcher, nil
}
}
// FallbackMatchersParser uses the new matcher/parse parser to parse the
// matcher in the input string. If this fails it falls back to the pkg/labels
// parser and emits a warning log line.
func FallbackMatchersParser(l *slog.Logger) ParseMatchers {
return func(input, origin string) (matchers labels.Matchers, err error) {
l.Debug("Parsing with UTF-8 matchers parser, with fallback to classic matchers parser", "input", input, "origin", origin)
// Parse the input in both parsers to look for disagreement and incompatible
// inputs.
nMatchers, nErr := parse.Matchers(input)
cMatchers, cErr := labels.ParseMatchers(input)
if nErr != nil {
// If the input is invalid in both parsers, return the error.
if cErr != nil {
return nil, cErr
}
// The input is valid in the pkg/labels parser, but not the matcher/parse
// parser. This means the input is not forwards compatible.
var sb strings.Builder
for i, n := range cMatchers {
sb.WriteString(n.String())
if i < len(cMatchers)-1 {
sb.WriteRune(',')
}
}
suggestion := sb.String()
// The input is valid in the pkg/labels parser, but not the
// new matcher/parse parser.
l.Warn("Alertmanager is moving to a new parser for labels and matchers, and this input is incompatible. Alertmanager has instead parsed the input using the classic matchers parser as a fallback. To make this input compatible with the UTF-8 matchers parser please make sure all regular expressions and values are double-quoted. If you are still seeing this message please open an issue.", "input", input, "origin", origin, "err", nErr, "suggestion", suggestion)
return cMatchers, nil
}
// If the input is valid in both parsers, but produces different results,
// then there is disagreement. We need to compare to labels.Matchers(cMatchers)
// as cMatchers is a []*labels.Matcher not labels.Matchers.
if nErr == nil && cErr == nil && !reflect.DeepEqual(nMatchers, labels.Matchers(cMatchers)) {
l.Warn("Matchers input has disagreement", "input", input, "origin", origin)
return cMatchers, nil
}
return nMatchers, nil
}
}
// isValidClassicLabelName returns true if the string is a valid classic label name.
func isValidClassicLabelName(_ *slog.Logger) func(model.LabelName) bool {
return func(name model.LabelName) bool {
return name.IsValid()
}
}
// isValidUTF8LabelName returns true if the string is a valid UTF-8 label name.
func isValidUTF8LabelName(_ *slog.Logger) func(model.LabelName) bool {
return func(name model.LabelName) bool {
if len(name) == 0 {
return false
}
return utf8.ValidString(string(name))
}
}