statsd_exporter/mapper.go

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// 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"
"path/filepath"
"regexp"
"strings"
"sync"
"github.com/prometheus/client_golang/prometheus"
yaml "gopkg.in/yaml.v2"
)
var (
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identifierRE = `[a-zA-Z_][a-zA-Z0-9_]+`
statsdMetricRE = `[a-zA-Z_](-?[a-zA-Z0-9_])+`
metricLineRE = regexp.MustCompile(`^(\*\.|` + statsdMetricRE + `\.)+(\*|` + statsdMetricRE + `)$`)
labelLineRE = regexp.MustCompile(`^(` + identifierRE + `)\s*=\s*"(.*)"$`)
metricNameRE = regexp.MustCompile(`^` + identifierRE + `$`)
)
type mapperConfigDefaults struct {
TimerType timerType `yaml:"timer_type"`
Buckets []float64 `yaml:"buckets"`
}
type metricMapper struct {
Defaults mapperConfigDefaults `yaml:"defaults"`
Mappings []metricMapping `yaml:"mappings"`
mutex sync.Mutex
}
type metricMapping struct {
Match string `yaml:"match"`
regex *regexp.Regexp
Labels prometheus.Labels `yaml:"labels"`
TimerType timerType `yaml:"timer_type"`
Buckets []float64 `yaml:"buckets"`
}
type configLoadStates int
const (
SEARCHING configLoadStates = iota
METRIC_DEFINITION
)
func (m *metricMapper) initFromString(fileContents string) error {
lines := strings.Split(fileContents, "\n")
numLines := len(lines)
state := SEARCHING
parsedMappings := []metricMapping{}
currentMapping := metricMapping{Labels: prometheus.Labels{}}
for i, line := range lines {
line = strings.TrimSpace(line)
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// skip comments
if strings.HasPrefix(line, "#") {
continue
}
switch state {
case SEARCHING:
if line == "" {
continue
}
if !metricLineRE.MatchString(line) {
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return fmt.Errorf("line %d: expected metric match line, got: %s", i, line)
}
// Translate the glob-style metric match line into a proper regex that we
// can use to match metrics later on.
metricRe := strings.Replace(line, ".", "\\.", -1)
metricRe = strings.Replace(metricRe, "*", "([^.]+)", -1)
currentMapping.regex = regexp.MustCompile("^" + metricRe + "$")
state = METRIC_DEFINITION
case METRIC_DEFINITION:
if (i == numLines-1) && (line != "") {
return fmt.Errorf("Line %d: missing terminating newline", i)
}
if line == "" {
if len(currentMapping.Labels) == 0 {
return fmt.Errorf("Line %d: metric mapping didn't set any labels", i)
}
if _, ok := currentMapping.Labels["name"]; !ok {
return fmt.Errorf("Line %d: metric mapping didn't set a metric name", i)
}
parsedMappings = append(parsedMappings, currentMapping)
state = SEARCHING
currentMapping = metricMapping{Labels: prometheus.Labels{}}
continue
}
if err := m.updateMapping(line, i, &currentMapping); err != nil {
return err
}
default:
panic("illegal state")
}
}
m.mutex.Lock()
defer m.mutex.Unlock()
m.Mappings = parsedMappings
mappingsCount.Set(float64(len(parsedMappings)))
return nil
}
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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
}
for i := range n.Mappings {
currentMapping := &n.Mappings[i]
if !metricLineRE.MatchString(currentMapping.Match) {
return fmt.Errorf("invalid match: %s", currentMapping.Match)
}
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// Check that label is correct.
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for k, v := range currentMapping.Labels {
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if !metricNameRE.MatchString(k) {
return fmt.Errorf("invalid label key: %s", k)
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}
if k == "name" && !metricNameRE.MatchString(v) {
return fmt.Errorf("metric name '%s' doesn't match regex '%s'", v, metricNameRE)
}
}
if _, ok := currentMapping.Labels["name"]; !ok {
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return fmt.Errorf("line %d: metric mapping didn't set a metric name", i)
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}
// 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)
currentMapping.regex = regexp.MustCompile("^" + metricRe + "$")
if currentMapping.TimerType == "" {
currentMapping.TimerType = n.Defaults.TimerType
}
if currentMapping.Buckets == nil || len(currentMapping.Buckets) == 0 {
currentMapping.Buckets = n.Defaults.Buckets
}
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}
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
}
switch strings.ToLower(filepath.Ext(fileName)) {
case ".yaml", ".yml":
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return m.initFromYAMLString(string(mappingStr))
default:
return m.initFromString(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
}
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
}
func (m *metricMapper) updateMapping(line string, i int, mapping *metricMapping) error {
matches := labelLineRE.FindStringSubmatch(line)
if len(matches) != 3 {
return fmt.Errorf("Line %d: expected label mapping line, got: %s", i, line)
}
label, value := matches[1], matches[2]
if label == "name" && !metricNameRE.MatchString(value) {
return fmt.Errorf("Line %d: metric name '%s' doesn't match regex '%s'", i, value, metricNameRE)
}
(*mapping).Labels[label] = value
return nil
}