statsd_exporter/mapper.go
Katharina Dankert 7e86bcaa92 Avoid panic from compiling user supplied regex
If an invalid regex is supplied mustCompile would panic during
configuration reload. Return an error instead that can be handled.
2018-02-22 23:50:25 +01:00

178 lines
4.9 KiB
Go

// Copyright 2013 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 main
import (
"fmt"
"io/ioutil"
"regexp"
"strings"
"sync"
"github.com/prometheus/client_golang/prometheus"
yaml "gopkg.in/yaml.v2"
)
var (
statsdMetricRE = `[a-zA-Z_](-?[a-zA-Z0-9_])+`
templateReplaceRE = `(\$\{?\d+\}?)`
metricLineRE = regexp.MustCompile(`^(\*\.|` + statsdMetricRE + `\.)+(\*|` + statsdMetricRE + `)$`)
metricNameRE = regexp.MustCompile(`^([a-zA-Z_]|` + templateReplaceRE + `)([a-zA-Z0-9_]|` + templateReplaceRE + `)*$`)
labelNameRE = regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_]+$`)
)
type mapperConfigDefaults struct {
TimerType timerType `yaml:"timer_type"`
Buckets []float64 `yaml:"buckets"`
MatchType matchType `yaml:"match_type"`
}
type metricMapper struct {
Defaults mapperConfigDefaults `yaml:"defaults"`
Mappings []metricMapping `yaml:"mappings"`
mutex sync.Mutex
}
type metricMapping struct {
Match string `yaml:"match"`
Name string `yaml:"name"`
regex *regexp.Regexp
Labels prometheus.Labels `yaml:"labels"`
TimerType timerType `yaml:"timer_type"`
Buckets []float64 `yaml:"buckets"`
MatchType matchType `yaml:"match_type"`
HelpText string `yaml:"help"`
Action actionType `yaml:"action"`
}
func (m *metricMapper) initFromYAMLString(fileContents string) error {
var n metricMapper
if err := yaml.Unmarshal([]byte(fileContents), &n); err != nil {
return err
}
if n.Defaults.Buckets == nil || len(n.Defaults.Buckets) == 0 {
n.Defaults.Buckets = prometheus.DefBuckets
}
if n.Defaults.MatchType == matchTypeDefault {
n.Defaults.MatchType = matchTypeGlob
}
for i := range n.Mappings {
currentMapping := &n.Mappings[i]
// check that label is correct
for k := range currentMapping.Labels {
if !labelNameRE.MatchString(k) {
return fmt.Errorf("invalid label key: %s", k)
}
}
if currentMapping.Name == "" {
return fmt.Errorf("line %d: metric mapping didn't set a metric name", i)
}
if !metricNameRE.MatchString(currentMapping.Name) {
return fmt.Errorf("metric name '%s' doesn't match regex '%s'", currentMapping.Name, metricNameRE)
}
if currentMapping.MatchType == "" {
currentMapping.MatchType = n.Defaults.MatchType
}
if currentMapping.Action == "" {
currentMapping.Action = actionTypeMap
}
if currentMapping.MatchType == matchTypeGlob {
if !metricLineRE.MatchString(currentMapping.Match) {
return fmt.Errorf("invalid match: %s", currentMapping.Match)
}
// Translate the glob-style metric match line into a proper regex that we
// can use to match metrics later on.
metricRe := strings.Replace(currentMapping.Match, ".", "\\.", -1)
metricRe = strings.Replace(metricRe, "*", "([^.]*)", -1)
if regex, err := regexp.Compile("^" + metricRe + "$"); err != nil {
return fmt.Errorf("invalid match %s. cannot compile regex in mapping: %v", currentMapping.Match, err)
} else {
currentMapping.regex = regex
}
} else {
if regex, err := regexp.Compile(currentMapping.Match); err != nil {
return fmt.Errorf("invalid regex %s in mapping: %v", currentMapping.Match, err)
} else {
currentMapping.regex = regex
}
}
if currentMapping.TimerType == "" {
currentMapping.TimerType = n.Defaults.TimerType
}
if currentMapping.Buckets == nil || len(currentMapping.Buckets) == 0 {
currentMapping.Buckets = n.Defaults.Buckets
}
}
m.mutex.Lock()
defer m.mutex.Unlock()
m.Defaults = n.Defaults
m.Mappings = n.Mappings
mappingsCount.Set(float64(len(n.Mappings)))
return nil
}
func (m *metricMapper) initFromFile(fileName string) error {
mappingStr, err := ioutil.ReadFile(fileName)
if err != nil {
return err
}
return m.initFromYAMLString(string(mappingStr))
}
func (m *metricMapper) getMapping(statsdMetric string) (*metricMapping, prometheus.Labels, bool) {
m.mutex.Lock()
defer m.mutex.Unlock()
for _, mapping := range m.Mappings {
matches := mapping.regex.FindStringSubmatchIndex(statsdMetric)
if len(matches) == 0 {
continue
}
mapping.Name = string(mapping.regex.ExpandString(
[]byte{},
mapping.Name,
statsdMetric,
matches,
))
labels := prometheus.Labels{}
for label, valueExpr := range mapping.Labels {
value := mapping.regex.ExpandString([]byte{}, valueExpr, statsdMetric, matches)
labels[label] = string(value)
}
return &mapping, labels, true
}
return nil, nil, false
}