VictoriaMetrics/lib/protoparser/prometheus/parser.go
Aliaksandr Valialkin f3e89754a9 lib/promscrape: reduce CPU usage for common case when calculating scrape_series_added metric
Also reduce CPU usage when applying `series_limit` to scrape targets with constant set of metrics.

The main idea is to perform the calculations on scrape_series_added and series_limit
only if the set of metrics exposed by the target has been changed.
Scrape targets rarely change the set of exposed metrics,
so this optimization should reduce CPU usage in general case.
2021-09-12 12:53:14 +03:00

578 lines
13 KiB
Go

package prometheus
import (
"fmt"
"strconv"
"strings"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/metrics"
"github.com/valyala/fastjson/fastfloat"
)
// Rows contains parsed Prometheus rows.
type Rows struct {
Rows []Row
tagsPool []Tag
}
// Reset resets rs.
func (rs *Rows) Reset() {
// Reset items, so they can be GC'ed
for i := range rs.Rows {
rs.Rows[i].reset()
}
rs.Rows = rs.Rows[:0]
for i := range rs.tagsPool {
rs.tagsPool[i].reset()
}
rs.tagsPool = rs.tagsPool[:0]
}
// Unmarshal unmarshals Prometheus exposition text rows from s.
//
// See https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
//
// s shouldn't be modified while rs is in use.
func (rs *Rows) Unmarshal(s string) {
rs.UnmarshalWithErrLogger(s, stdErrLogger)
}
func stdErrLogger(s string) {
logger.ErrorfSkipframes(1, "%s", s)
}
// UnmarshalWithErrLogger unmarshal Prometheus exposition text rows from s.
//
// It calls errLogger for logging parsing errors.
//
// s shouldn't be modified while rs is in use.
func (rs *Rows) UnmarshalWithErrLogger(s string, errLogger func(s string)) {
noEscapes := strings.IndexByte(s, '\\') < 0
rs.Rows, rs.tagsPool = unmarshalRows(rs.Rows[:0], s, rs.tagsPool[:0], noEscapes, errLogger)
}
// Row is a single Prometheus row.
type Row struct {
Metric string
Tags []Tag
Value float64
Timestamp int64
}
func (r *Row) reset() {
r.Metric = ""
r.Tags = nil
r.Value = 0
r.Timestamp = 0
}
func skipTrailingComment(s string) string {
n := strings.IndexByte(s, '#')
if n < 0 {
return s
}
return s[:n]
}
func skipLeadingWhitespace(s string) string {
// Prometheus treats ' ' and '\t' as whitespace
// according to https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
for len(s) > 0 && (s[0] == ' ' || s[0] == '\t') {
s = s[1:]
}
return s
}
func skipTrailingWhitespace(s string) string {
// Prometheus treats ' ' and '\t' as whitespace
// according to https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-details
for len(s) > 0 && (s[len(s)-1] == ' ' || s[len(s)-1] == '\t') {
s = s[:len(s)-1]
}
return s
}
func nextWhitespace(s string) int {
n := strings.IndexByte(s, ' ')
if n < 0 {
return strings.IndexByte(s, '\t')
}
n1 := strings.IndexByte(s, '\t')
if n1 < 0 || n1 > n {
return n
}
return n1
}
func (r *Row) unmarshal(s string, tagsPool []Tag, noEscapes bool) ([]Tag, error) {
r.reset()
s = skipLeadingWhitespace(s)
n := strings.IndexByte(s, '{')
if n >= 0 {
// Tags found. Parse them.
r.Metric = skipTrailingWhitespace(s[:n])
s = s[n+1:]
tagsStart := len(tagsPool)
var err error
s, tagsPool, err = unmarshalTags(tagsPool, s, noEscapes)
if err != nil {
return tagsPool, fmt.Errorf("cannot unmarshal tags: %w", err)
}
if len(s) > 0 && s[0] == ' ' {
// Fast path - skip whitespace.
s = s[1:]
}
tags := tagsPool[tagsStart:]
r.Tags = tags[:len(tags):len(tags)]
} else {
// Tags weren't found. Search for value after whitespace
n = nextWhitespace(s)
if n < 0 {
return tagsPool, fmt.Errorf("missing value")
}
r.Metric = s[:n]
s = s[n+1:]
}
if len(r.Metric) == 0 {
return tagsPool, fmt.Errorf("metric cannot be empty")
}
s = skipLeadingWhitespace(s)
s = skipTrailingComment(s)
if len(s) == 0 {
return tagsPool, fmt.Errorf("value cannot be empty")
}
n = nextWhitespace(s)
if n < 0 {
// There is no timestamp.
v, err := fastfloat.Parse(s)
if err != nil {
return tagsPool, fmt.Errorf("cannot parse value %q: %w", s, err)
}
r.Value = v
return tagsPool, nil
}
// There is a timestamp.
v, err := fastfloat.Parse(s[:n])
if err != nil {
return tagsPool, fmt.Errorf("cannot parse value %q: %w", s[:n], err)
}
r.Value = v
s = skipLeadingWhitespace(s[n+1:])
if len(s) == 0 {
// There is no timestamp - just a whitespace after the value.
return tagsPool, nil
}
// There are some whitespaces after timestamp
s = skipTrailingWhitespace(s)
ts, err := fastfloat.Parse(s)
if err != nil {
return tagsPool, fmt.Errorf("cannot parse timestamp %q: %w", s, err)
}
if ts >= -1<<31 && ts < 1<<31 {
// This looks like OpenMetrics timestamp in Unix seconds.
// Convert it to milliseconds.
//
// See https://github.com/OpenObservability/OpenMetrics/blob/master/specification/OpenMetrics.md#timestamps
ts *= 1000
}
r.Timestamp = int64(ts)
return tagsPool, nil
}
var rowsReadScrape = metrics.NewCounter(`vm_protoparser_rows_read_total{type="promscrape"}`)
func unmarshalRows(dst []Row, s string, tagsPool []Tag, noEscapes bool, errLogger func(s string)) ([]Row, []Tag) {
dstLen := len(dst)
for len(s) > 0 {
n := strings.IndexByte(s, '\n')
if n < 0 {
// The last line.
dst, tagsPool = unmarshalRow(dst, s, tagsPool, noEscapes, errLogger)
break
}
dst, tagsPool = unmarshalRow(dst, s[:n], tagsPool, noEscapes, errLogger)
s = s[n+1:]
}
rowsReadScrape.Add(len(dst) - dstLen)
return dst, tagsPool
}
func unmarshalRow(dst []Row, s string, tagsPool []Tag, noEscapes bool, errLogger func(s string)) ([]Row, []Tag) {
if len(s) > 0 && s[len(s)-1] == '\r' {
s = s[:len(s)-1]
}
s = skipLeadingWhitespace(s)
if len(s) == 0 {
// Skip empty line
return dst, tagsPool
}
if s[0] == '#' {
// Skip comment
return dst, tagsPool
}
if cap(dst) > len(dst) {
dst = dst[:len(dst)+1]
} else {
dst = append(dst, Row{})
}
r := &dst[len(dst)-1]
var err error
tagsPool, err = r.unmarshal(s, tagsPool, noEscapes)
if err != nil {
dst = dst[:len(dst)-1]
msg := fmt.Sprintf("cannot unmarshal Prometheus line %q: %s", s, err)
errLogger(msg)
invalidLines.Inc()
}
return dst, tagsPool
}
var invalidLines = metrics.NewCounter(`vm_rows_invalid_total{type="prometheus"}`)
func unmarshalTags(dst []Tag, s string, noEscapes bool) (string, []Tag, error) {
for {
s = skipLeadingWhitespace(s)
if len(s) > 0 && s[0] == '}' {
// End of tags found.
return s[1:], dst, nil
}
n := strings.IndexByte(s, '=')
if n < 0 {
return s, dst, fmt.Errorf("missing value for tag %q", s)
}
key := skipTrailingWhitespace(s[:n])
s = skipLeadingWhitespace(s[n+1:])
if len(s) == 0 || s[0] != '"' {
return s, dst, fmt.Errorf("expecting quoted value for tag %q; got %q", key, s)
}
value := s[1:]
if noEscapes {
// Fast path - the line has no escape chars
n = strings.IndexByte(value, '"')
if n < 0 {
return s, dst, fmt.Errorf("missing closing quote for tag value %q", s)
}
s = value[n+1:]
value = value[:n]
} else {
// Slow path - the line contains escape chars
n = findClosingQuote(s)
if n < 0 {
return s, dst, fmt.Errorf("missing closing quote for tag value %q", s)
}
value = unescapeValue(s[1:n])
s = s[n+1:]
}
if len(key) > 0 {
// Allow empty values (len(value)==0) - see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/453
if cap(dst) > len(dst) {
dst = dst[:len(dst)+1]
} else {
dst = append(dst, Tag{})
}
tag := &dst[len(dst)-1]
tag.Key = key
tag.Value = value
}
s = skipLeadingWhitespace(s)
if len(s) > 0 && s[0] == '}' {
// End of tags found.
return s[1:], dst, nil
}
if len(s) == 0 || s[0] != ',' {
return s, dst, fmt.Errorf("missing comma after tag %s=%q", key, value)
}
s = s[1:]
}
}
// Tag is a Prometheus tag.
type Tag struct {
Key string
Value string
}
func (t *Tag) reset() {
t.Key = ""
t.Value = ""
}
func findClosingQuote(s string) int {
if len(s) == 0 || s[0] != '"' {
return -1
}
off := 1
s = s[1:]
for {
n := strings.IndexByte(s, '"')
if n < 0 {
return -1
}
if prevBackslashesCount(s[:n])%2 == 0 {
return off + n
}
off += n + 1
s = s[n+1:]
}
}
func unescapeValue(s string) string {
n := strings.IndexByte(s, '\\')
if n < 0 {
// Fast path - nothing to unescape
return s
}
b := make([]byte, 0, len(s))
for {
b = append(b, s[:n]...)
s = s[n+1:]
if len(s) == 0 {
b = append(b, '\\')
break
}
// label_value can be any sequence of UTF-8 characters, but the backslash (\), double-quote ("),
// and line feed (\n) characters have to be escaped as \\, \", and \n, respectively.
// See https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md
switch s[0] {
case '\\':
b = append(b, '\\')
case '"':
b = append(b, '"')
case 'n':
b = append(b, '\n')
default:
b = append(b, '\\', s[0])
}
s = s[1:]
n = strings.IndexByte(s, '\\')
if n < 0 {
b = append(b, s...)
break
}
}
return string(b)
}
func prevBackslashesCount(s string) int {
n := 0
for len(s) > 0 && s[len(s)-1] == '\\' {
n++
s = s[:len(s)-1]
}
return n
}
// GetRowsDiff returns rows from s1, which are missing in s2.
//
// The returned rows have default value 0 and have no timestamps.
func GetRowsDiff(s1, s2 string) string {
var r1, r2 Rows
r1.Unmarshal(s1)
r2.Unmarshal(s2)
rows1 := r1.Rows
rows2 := r2.Rows
m := make(map[string]bool, len(rows2))
for i := range rows2 {
r := &rows2[i]
key := marshalMetricNameWithTags(r)
m[key] = true
}
var diff []byte
for i := range rows1 {
r := &rows1[i]
key := marshalMetricNameWithTags(r)
if !m[key] {
diff = append(diff, key...)
diff = append(diff, " 0\n"...)
}
}
return string(diff)
}
func marshalMetricNameWithTags(r *Row) string {
if len(r.Tags) == 0 {
return r.Metric
}
var b []byte
b = append(b, r.Metric...)
b = append(b, '{')
for i, t := range r.Tags {
b = append(b, t.Key...)
b = append(b, '=')
b = strconv.AppendQuote(b, t.Value)
if i+1 < len(r.Tags) {
b = append(b, ',')
}
}
b = append(b, '}')
return string(b)
}
// AreIdenticalSeriesFast returns true if s1 and s2 contains identical Prometheus series with possible different values.
//
// This function is optimized for speed.
func AreIdenticalSeriesFast(s1, s2 string) bool {
for {
if len(s1) == 0 {
// The last byte on the line reached.
return len(s2) == 0
}
if len(s2) == 0 {
// The last byte on s2 reached, while s1 has non-empty contents.
return false
}
// Extract the next pair of lines from s1 and s2.
var x1, x2 string
n1 := strings.IndexByte(s1, '\n')
if n1 < 0 {
x1 = s1
s1 = ""
} else {
x1 = s1[:n1]
s1 = s1[n1+1:]
}
if n := strings.IndexByte(x1, '#'); n >= 0 {
// Drop comment.
x1 = x1[:n]
}
n2 := strings.IndexByte(s2, '\n')
if n2 < 0 {
if n1 >= 0 {
return false
}
x2 = s2
s2 = ""
} else {
if n1 < 0 {
return false
}
x2 = s2[:n2]
s2 = s2[n2+1:]
}
if n := strings.IndexByte(x2, '#'); n >= 0 {
// Drop comment.
x2 = x2[:n]
}
// Skip whitespaces in front of lines
for len(x1) > 0 && x1[0] == ' ' {
if len(x2) == 0 || x2[0] != ' ' {
return false
}
x1 = x1[1:]
x2 = x2[1:]
}
if len(x1) == 0 {
// The last byte on x1 reached.
if len(x2) != 0 {
return false
}
continue
}
if len(x2) == 0 {
// The last byte on x2 reached, while x1 has non-empty contents.
return false
}
// Compare metric names
n := strings.IndexByte(x1, ' ')
if n < 0 {
// Invalid Prometheus line - it must contain at least a single space between metric name and value
return false
}
n++
if n > len(x2) || x1[:n] != x2[:n] {
// Metric names mismatch
return false
}
x1 = x1[n:]
x2 = x2[n:]
// The space could belong to metric name in the following cases:
// foo {bar="baz"} 1
// foo{ bar="baz"} 2
// foo{bar="baz", aa="b"} 3
// foo{bar="b az"} 4
// foo 5
// Continue comparing the remaining parts until space or newline.
for {
n1 := strings.IndexByte(x1, ' ')
if n1 < 0 {
// Fast path.
// Treat x1 as a value.
// Skip values at x1 and x2.
n2 := strings.IndexByte(x2, ' ')
if n2 >= 0 {
// x2 contains additional parts.
return false
}
break
}
n1++
// Slow path.
// The x1[:n1] can be either a part of metric name or a value if timestamp is present:
// foo 12 34
if isNumeric(x1[:n1-1]) {
// Skip numeric part (most likely a value before timestamp) in x1 and x2
n2 := strings.IndexByte(x2, ' ')
if n2 < 0 {
// x2 contains less parts than x1
return false
}
n2++
if !isNumeric(x2[:n2-1]) {
// x1 contains numeric part, while x2 contains non-numeric part
return false
}
x1 = x1[n1:]
x2 = x2[n2:]
} else {
// The non-numeric part from x1 must match the corresponding part from x2.
if n1 > len(x2) || x1[:n1] != x2[:n1] {
// Parts mismatch
return false
}
x1 = x1[n1:]
x2 = x2[n1:]
}
}
}
}
func isNumeric(s string) bool {
for i := 0; i < len(s); i++ {
if numericChars[s[i]] {
continue
}
if i == 0 && s == "NaN" || s == "nan" || s == "Inf" || s == "inf" {
return true
}
if i == 1 && (s[0] == '-' || s[0] == '+') && (s[1:] == "Inf" || s[1:] == "inf") {
return true
}
return false
}
return true
}
var numericChars = [256]bool{
'0': true,
'1': true,
'2': true,
'3': true,
'4': true,
'5': true,
'6': true,
'7': true,
'8': true,
'9': true,
'-': true,
'+': true,
'e': true,
'E': true,
'.': true,
}