prometheus/pkg/textparse/openmetricsparse.go
zhulongcheng 970ef41bb6 Fix exported function comments (#6002)
Signed-off-by: zhulongcheng <zhulongcheng.dev@gmail.com>
2019-09-10 14:45:09 +01:00

350 lines
9.4 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 (
"io"
"math"
"sort"
"strings"
"unicode/utf8"
"github.com/pkg/errors"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/value"
)
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
}
// 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 {
return p.series, &p.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
}
// 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]
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, parseError("unexpected end of data", t)
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 {
if err := p.parseLVals(); err != nil {
return EntryInvalid, err
}
p.series = p.l.b[p.start:p.l.i]
t2 = p.nextToken()
}
if t2 != tValue {
return EntryInvalid, parseError("expected value after metric", t)
}
if p.val, err = parseFloat(yoloString(p.l.buf()[1:])); err != nil {
return EntryInvalid, err
}
// Ensure canonical NaN value.
if math.IsNaN(p.val) {
p.val = math.Float64frombits(value.NormalNaN)
}
p.hasTS = false
switch p.nextToken() {
case tLinebreak:
break
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)
if t2 := p.nextToken(); t2 != tLinebreak {
return EntryInvalid, parseError("expected next entry after timestamp", t)
}
default:
return EntryInvalid, parseError("expected timestamp or new record", t)
}
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) parseLVals() error {
first := true
for {
t := p.nextToken()
switch t {
case tBraceClose:
return nil
case tComma:
if first {
return parseError("expected label name or left brace", t)
}
t = p.nextToken()
if t != tLName {
return parseError("expected label name", t)
}
case tLName:
if !first {
return parseError("expected comma", t)
}
default:
if first {
return parseError("expected label name or left brace", t)
}
return parseError("expected comma or left brace", t)
}
first = false
// t is now a label name.
p.offsets = append(p.offsets, p.l.start, p.l.i)
if t := p.nextToken(); t != tEqual {
return parseError("expected equal", t)
}
if t := p.nextToken(); t != tLValue {
return parseError("expected label value", t)
}
if !utf8.Valid(p.l.buf()) {
return errors.New("invalid UTF-8 label value")
}
// The openMetricsLexer ensures the value string is quoted. Strip first
// and last character.
p.offsets = append(p.offsets, p.l.start+1, p.l.i-1)
}
}