prometheus/pkg/textparse/openmetricsparse.go

478 lines
12 KiB
Go

// Copyright 2018 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.
//go:generate go get -u modernc.org/golex
//go:generate golex -o=openmetricslex.l.go openmetricslex.l
package textparse
import (
"bytes"
"fmt"
"io"
"math"
"sort"
"strings"
"unicode/utf8"
"github.com/pkg/errors"
"github.com/prometheus/prometheus/pkg/exemplar"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/value"
)
var allowedSuffixes = [][]byte{[]byte("_total"), []byte("_bucket")}
type openMetricsLexer struct {
b []byte
i int
start int
err error
state int
}
// buf returns the buffer of the current token.
func (l *openMetricsLexer) buf() []byte {
return l.b[l.start:l.i]
}
func (l *openMetricsLexer) cur() byte {
if l.i < len(l.b) {
return l.b[l.i]
}
return byte(' ')
}
// next advances the openMetricsLexer to the next character.
func (l *openMetricsLexer) next() byte {
l.i++
if l.i >= len(l.b) {
l.err = io.EOF
return byte(tEOF)
}
// Lex struggles with null bytes. If we are in a label value or help string, where
// they are allowed, consume them here immediately.
for l.b[l.i] == 0 && (l.state == sLValue || l.state == sMeta2 || l.state == sComment) {
l.i++
if l.i >= len(l.b) {
l.err = io.EOF
return byte(tEOF)
}
}
return l.b[l.i]
}
func (l *openMetricsLexer) Error(es string) {
l.err = errors.New(es)
}
// OpenMetricsParser parses samples from a byte slice of samples in the official
// OpenMetrics text exposition format.
// This is based on the working draft https://docs.google.com/document/u/1/d/1KwV0mAXwwbvvifBvDKH_LU1YjyXE_wxCkHNoCGq1GX0/edit
type OpenMetricsParser struct {
l *openMetricsLexer
series []byte
text []byte
mtype MetricType
val float64
ts int64
hasTS bool
start int
offsets []int
eOffsets []int
exemplar []byte
exemplarVal float64
exemplarTs int64
hasExemplarTs bool
}
// NewOpenMetricsParser returns a new parser of the byte slice.
func NewOpenMetricsParser(b []byte) Parser {
return &OpenMetricsParser{l: &openMetricsLexer{b: b}}
}
// Series returns the bytes of the series, the timestamp if set, and the value
// of the current sample.
func (p *OpenMetricsParser) Series() ([]byte, *int64, float64) {
if p.hasTS {
ts := p.ts
return p.series, &ts, p.val
}
return p.series, nil, p.val
}
// Help returns the metric name and help text in the current entry.
// Must only be called after Next returned a help entry.
// The returned byte slices become invalid after the next call to Next.
func (p *OpenMetricsParser) Help() ([]byte, []byte) {
m := p.l.b[p.offsets[0]:p.offsets[1]]
// Replacer causes allocations. Replace only when necessary.
if strings.IndexByte(yoloString(p.text), byte('\\')) >= 0 {
// OpenMetrics always uses the Prometheus format label value escaping.
return m, []byte(lvalReplacer.Replace(string(p.text)))
}
return m, p.text
}
// Type returns the metric name and type in the current entry.
// Must only be called after Next returned a type entry.
// The returned byte slices become invalid after the next call to Next.
func (p *OpenMetricsParser) Type() ([]byte, MetricType) {
return p.l.b[p.offsets[0]:p.offsets[1]], p.mtype
}
// Unit returns the metric name and unit in the current entry.
// Must only be called after Next returned a unit entry.
// The returned byte slices become invalid after the next call to Next.
func (p *OpenMetricsParser) Unit() ([]byte, []byte) {
// The Prometheus format does not have units.
return p.l.b[p.offsets[0]:p.offsets[1]], p.text
}
// Comment returns the text of the current comment.
// Must only be called after Next returned a comment entry.
// The returned byte slice becomes invalid after the next call to Next.
func (p *OpenMetricsParser) Comment() []byte {
return p.text
}
// Metric writes the labels of the current sample into the passed labels.
// It returns the string from which the metric was parsed.
func (p *OpenMetricsParser) Metric(l *labels.Labels) string {
// Allocate the full immutable string immediately, so we just
// have to create references on it below.
s := string(p.series)
*l = append(*l, labels.Label{
Name: labels.MetricName,
Value: s[:p.offsets[0]-p.start],
})
for i := 1; i < len(p.offsets); i += 4 {
a := p.offsets[i] - p.start
b := p.offsets[i+1] - p.start
c := p.offsets[i+2] - p.start
d := p.offsets[i+3] - p.start
// Replacer causes allocations. Replace only when necessary.
if strings.IndexByte(s[c:d], byte('\\')) >= 0 {
*l = append(*l, labels.Label{Name: s[a:b], Value: lvalReplacer.Replace(s[c:d])})
continue
}
*l = append(*l, labels.Label{Name: s[a:b], Value: s[c:d]})
}
// Sort labels. We can skip the first entry since the metric name is
// already at the right place.
sort.Sort((*l)[1:])
return s
}
// Exemplar writes the exemplar of the current sample into the passed
// exemplar. It returns the whether an exemplar exists.
func (p *OpenMetricsParser) Exemplar(e *exemplar.Exemplar) bool {
if len(p.exemplar) == 0 {
return false
}
// Allocate the full immutable string immediately, so we just
// have to create references on it below.
s := string(p.exemplar)
e.Value = p.exemplarVal
if p.hasExemplarTs {
e.HasTs = true
e.Ts = p.exemplarTs
}
for i := 0; i < len(p.eOffsets); i += 4 {
a := p.eOffsets[i] - p.start
b := p.eOffsets[i+1] - p.start
c := p.eOffsets[i+2] - p.start
d := p.eOffsets[i+3] - p.start
e.Labels = append(e.Labels, labels.Label{Name: s[a:b], Value: s[c:d]})
}
// Sort the labels.
sort.Sort(e.Labels)
return true
}
// nextToken returns the next token from the openMetricsLexer.
func (p *OpenMetricsParser) nextToken() token {
tok := p.l.Lex()
return tok
}
// Next advances the parser to the next sample. It returns false if no
// more samples were read or an error occurred.
func (p *OpenMetricsParser) Next() (Entry, error) {
var err error
p.start = p.l.i
p.offsets = p.offsets[:0]
p.eOffsets = p.eOffsets[:0]
p.exemplar = p.exemplar[:0]
p.exemplarVal = 0
p.hasExemplarTs = false
switch t := p.nextToken(); t {
case tEofWord:
if t := p.nextToken(); t != tEOF {
return EntryInvalid, errors.New("unexpected data after # EOF")
}
return EntryInvalid, io.EOF
case tEOF:
return EntryInvalid, io.EOF
case tHelp, tType, tUnit:
switch t := p.nextToken(); t {
case tMName:
p.offsets = append(p.offsets, p.l.start, p.l.i)
default:
return EntryInvalid, parseError("expected metric name after HELP", t)
}
switch t := p.nextToken(); t {
case tText:
if len(p.l.buf()) > 1 {
p.text = p.l.buf()[1 : len(p.l.buf())-1]
} else {
p.text = []byte{}
}
default:
return EntryInvalid, parseError("expected text in HELP", t)
}
switch t {
case tType:
switch s := yoloString(p.text); s {
case "counter":
p.mtype = MetricTypeCounter
case "gauge":
p.mtype = MetricTypeGauge
case "histogram":
p.mtype = MetricTypeHistogram
case "gaugehistogram":
p.mtype = MetricTypeGaugeHistogram
case "summary":
p.mtype = MetricTypeSummary
case "info":
p.mtype = MetricTypeInfo
case "stateset":
p.mtype = MetricTypeStateset
case "unknown":
p.mtype = MetricTypeUnknown
default:
return EntryInvalid, errors.Errorf("invalid metric type %q", s)
}
case tHelp:
if !utf8.Valid(p.text) {
return EntryInvalid, errors.New("help text is not a valid utf8 string")
}
}
switch t {
case tHelp:
return EntryHelp, nil
case tType:
return EntryType, nil
case tUnit:
m := yoloString(p.l.b[p.offsets[0]:p.offsets[1]])
u := yoloString(p.text)
if len(u) > 0 {
if !strings.HasSuffix(m, u) || len(m) < len(u)+1 || p.l.b[p.offsets[1]-len(u)-1] != '_' {
return EntryInvalid, errors.Errorf("unit not a suffix of metric %q", m)
}
}
return EntryUnit, nil
}
case tMName:
p.offsets = append(p.offsets, p.l.i)
p.series = p.l.b[p.start:p.l.i]
t2 := p.nextToken()
if t2 == tBraceOpen {
offsets, err := p.parseLVals()
if err != nil {
return EntryInvalid, err
}
p.offsets = append(p.offsets, offsets...)
p.series = p.l.b[p.start:p.l.i]
t2 = p.nextToken()
}
p.val, err = p.getFloatValue(t2, "metric")
if err != nil {
return EntryInvalid, err
}
p.hasTS = false
switch t2 := p.nextToken(); t2 {
case tEOF:
return EntryInvalid, io.EOF
case tLinebreak:
break
case tComment:
if err := p.parseComment(); err != nil {
return EntryInvalid, err
}
case tTimestamp:
p.hasTS = true
var ts float64
// A float is enough to hold what we need for millisecond resolution.
if ts, err = parseFloat(yoloString(p.l.buf()[1:])); err != nil {
return EntryInvalid, err
}
p.ts = int64(ts * 1000)
switch t3 := p.nextToken(); t3 {
case tLinebreak:
case tComment:
if err := p.parseComment(); err != nil {
return EntryInvalid, err
}
default:
return EntryInvalid, parseError("expected next entry after timestamp", t3)
}
default:
return EntryInvalid, parseError("expected timestamp or # symbol", t2)
}
return EntrySeries, nil
default:
err = errors.Errorf("%q %q is not a valid start token", t, string(p.l.cur()))
}
return EntryInvalid, err
}
func (p *OpenMetricsParser) parseComment() error {
// Validate the name of the metric. It must have _total or _bucket as
// suffix for exemplars to be supported.
if err := p.validateNameForExemplar(p.series[:p.offsets[0]-p.start]); err != nil {
return err
}
// Parse the labels.
offsets, err := p.parseLVals()
if err != nil {
return err
}
p.eOffsets = append(p.eOffsets, offsets...)
p.exemplar = p.l.b[p.start:p.l.i]
// Get the value.
p.exemplarVal, err = p.getFloatValue(p.nextToken(), "exemplar labels")
if err != nil {
return err
}
// Read the optional timestamp.
p.hasExemplarTs = false
switch t2 := p.nextToken(); t2 {
case tEOF:
return io.EOF
case tLinebreak:
break
case tTimestamp:
p.hasExemplarTs = true
var ts float64
// A float is enough to hold what we need for millisecond resolution.
if ts, err = parseFloat(yoloString(p.l.buf()[1:])); err != nil {
return err
}
p.exemplarTs = int64(ts * 1000)
switch t3 := p.nextToken(); t3 {
case tLinebreak:
default:
return parseError("expected next entry after exemplar timestamp", t3)
}
default:
return parseError("expected timestamp or comment", t2)
}
return nil
}
func (p *OpenMetricsParser) parseLVals() ([]int, error) {
var offsets []int
first := true
for {
t := p.nextToken()
switch t {
case tBraceClose:
return offsets, nil
case tComma:
if first {
return nil, parseError("expected label name or left brace", t)
}
t = p.nextToken()
if t != tLName {
return nil, parseError("expected label name", t)
}
case tLName:
if !first {
return nil, parseError("expected comma", t)
}
default:
if first {
return nil, parseError("expected label name or left brace", t)
}
return nil, parseError("expected comma or left brace", t)
}
first = false
// t is now a label name.
offsets = append(offsets, p.l.start, p.l.i)
if t := p.nextToken(); t != tEqual {
return nil, parseError("expected equal", t)
}
if t := p.nextToken(); t != tLValue {
return nil, parseError("expected label value", t)
}
if !utf8.Valid(p.l.buf()) {
return nil, errors.New("invalid UTF-8 label value")
}
// The openMetricsLexer ensures the value string is quoted. Strip first
// and last character.
offsets = append(offsets, p.l.start+1, p.l.i-1)
}
}
func (p *OpenMetricsParser) getFloatValue(t token, after string) (float64, error) {
if t != tValue {
return 0, parseError(fmt.Sprintf("expected value after %v", after), t)
}
val, err := parseFloat(yoloString(p.l.buf()[1:]))
if err != nil {
return 0, err
}
// Ensure canonical NaN value.
if math.IsNaN(p.exemplarVal) {
val = math.Float64frombits(value.NormalNaN)
}
return val, nil
}
func (p *OpenMetricsParser) validateNameForExemplar(name []byte) error {
for _, suffix := range allowedSuffixes {
if bytes.HasSuffix(name, suffix) {
return nil
}
}
return fmt.Errorf("metric name %v does not support exemplars", string(name))
}