Initial QSfera import
This commit is contained in:
Курнат Андрей
+309
@@ -0,0 +1,309 @@
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// Copyright 2023 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package parse
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import (
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"fmt"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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const (
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eof rune = -1
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)
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func isReserved(r rune) bool {
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return unicode.IsSpace(r) || strings.ContainsRune("{}!=~,\\\"'`", r)
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}
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// expectedError is returned when the next rune does not match what is expected.
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type expectedError struct {
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position
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input string
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expected string
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}
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func (e expectedError) Error() string {
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if e.offsetEnd >= len(e.input) {
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return fmt.Sprintf("%d:%d: unexpected end of input, expected one of '%s'",
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e.columnStart,
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e.columnEnd,
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e.expected,
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)
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}
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return fmt.Sprintf("%d:%d: %s: expected one of '%s'",
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e.columnStart,
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e.columnEnd,
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e.input[e.offsetStart:e.offsetEnd],
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e.expected,
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)
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}
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// invalidInputError is returned when the next rune in the input does not match
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// the grammar of Prometheus-like matchers.
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type invalidInputError struct {
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position
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input string
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}
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func (e invalidInputError) Error() string {
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return fmt.Sprintf("%d:%d: %s: invalid input",
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e.columnStart,
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e.columnEnd,
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e.input[e.offsetStart:e.offsetEnd],
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)
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}
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// unterminatedError is returned when text in quotes does not have a closing quote.
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type unterminatedError struct {
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position
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input string
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quote rune
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}
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func (e unterminatedError) Error() string {
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return fmt.Sprintf("%d:%d: %s: missing end %c",
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e.columnStart,
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e.columnEnd,
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e.input[e.offsetStart:e.offsetEnd],
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e.quote,
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)
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}
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// lexer scans a sequence of tokens that match the grammar of Prometheus-like
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// matchers. A token is emitted for each call to scan() which returns the
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// next token in the input or an error if the input does not conform to the
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// grammar. A token can be one of a number of kinds and corresponds to a
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// subslice of the input. Once the input has been consumed successive calls to
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// scan() return a tokenEOF token.
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type lexer struct {
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input string
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err error
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start int // The offset of the current token.
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pos int // The position of the cursor in the input.
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width int // The width of the last rune.
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column int // The column offset of the current token.
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cols int // The number of columns (runes) decoded from the input.
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}
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// Scans the next token in the input or an error if the input does not
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// conform to the grammar. Once the input has been consumed successive
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// calls scan() return a tokenEOF token.
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func (l *lexer) scan() (token, error) {
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t := token{}
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// Do not attempt to emit more tokens if the input is invalid.
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if l.err != nil {
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return t, l.err
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}
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// Iterate over each rune in the input and either emit a token or an error.
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for r := l.next(); r != eof; r = l.next() {
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switch {
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case r == '{':
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t = l.emit(tokenOpenBrace)
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return t, l.err
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case r == '}':
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t = l.emit(tokenCloseBrace)
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return t, l.err
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case r == ',':
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t = l.emit(tokenComma)
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return t, l.err
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case r == '=' || r == '!':
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l.rewind()
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t, l.err = l.scanOperator()
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return t, l.err
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case r == '"':
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l.rewind()
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t, l.err = l.scanQuoted()
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return t, l.err
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case !isReserved(r):
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l.rewind()
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t, l.err = l.scanUnquoted()
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return t, l.err
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case unicode.IsSpace(r):
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l.skip()
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default:
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l.err = invalidInputError{
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position: l.position(),
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input: l.input,
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}
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return t, l.err
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}
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}
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return t, l.err
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}
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func (l *lexer) scanOperator() (token, error) {
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// If the first rune is an '!' then it must be followed with either an
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// '=' or '~' to not match a string or regex.
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if l.accept("!") {
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if l.accept("=") {
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return l.emit(tokenNotEquals), nil
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}
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if l.accept("~") {
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return l.emit(tokenNotMatches), nil
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}
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return token{}, expectedError{
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position: l.position(),
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input: l.input,
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expected: "=~",
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}
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}
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// If the first rune is an '=' then it can be followed with an optional
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// '~' to match a regex.
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if l.accept("=") {
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if l.accept("~") {
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return l.emit(tokenMatches), nil
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}
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return l.emit(tokenEquals), nil
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}
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return token{}, expectedError{
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position: l.position(),
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input: l.input,
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expected: "!=",
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}
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}
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func (l *lexer) scanQuoted() (token, error) {
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if err := l.expect("\""); err != nil {
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return token{}, err
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}
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var isEscaped bool
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for r := l.next(); r != eof; r = l.next() {
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if isEscaped {
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isEscaped = false
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} else if r == '\\' {
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isEscaped = true
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} else if r == '"' {
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l.rewind()
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break
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}
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}
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if err := l.expect("\""); err != nil {
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return token{}, unterminatedError{
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position: l.position(),
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input: l.input,
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quote: '"',
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}
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}
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return l.emit(tokenQuoted), nil
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}
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func (l *lexer) scanUnquoted() (token, error) {
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for r := l.next(); r != eof; r = l.next() {
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if isReserved(r) {
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l.rewind()
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break
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}
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}
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return l.emit(tokenUnquoted), nil
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}
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// peek the next token in the input or an error if the input does not
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// conform to the grammar. Once the input has been consumed successive
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// calls peek() return a tokenEOF token.
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func (l *lexer) peek() (token, error) {
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start := l.start
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pos := l.pos
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width := l.width
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column := l.column
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cols := l.cols
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// Do not reset l.err because we can return it on the next call to scan().
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defer func() {
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l.start = start
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l.pos = pos
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l.width = width
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l.column = column
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l.cols = cols
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}()
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return l.scan()
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}
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// position returns the position of the last emitted token.
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func (l *lexer) position() position {
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return position{
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offsetStart: l.start,
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offsetEnd: l.pos,
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columnStart: l.column,
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columnEnd: l.cols,
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}
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}
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// accept consumes the next if its one of the valid runes.
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// It returns true if the next rune was accepted, otherwise false.
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func (l *lexer) accept(valid string) bool {
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if strings.ContainsRune(valid, l.next()) {
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return true
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}
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l.rewind()
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return false
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}
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// expect consumes the next rune if its one of the valid runes.
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// It returns nil if the next rune is valid, otherwise an expectedError
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// error.
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func (l *lexer) expect(valid string) error {
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if strings.ContainsRune(valid, l.next()) {
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return nil
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}
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l.rewind()
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return expectedError{
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position: l.position(),
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input: l.input,
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expected: valid,
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}
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}
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// emits returns the scanned input as a token.
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func (l *lexer) emit(kind tokenKind) token {
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t := token{
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kind: kind,
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value: l.input[l.start:l.pos],
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position: l.position(),
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}
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l.start = l.pos
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l.column = l.cols
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return t
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}
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// next returns the next rune in the input or eof.
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func (l *lexer) next() rune {
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if l.pos >= len(l.input) {
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l.width = 0
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return eof
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}
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r, width := utf8.DecodeRuneInString(l.input[l.pos:])
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l.width = width
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l.pos += width
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l.cols++
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return r
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}
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// rewind the last rune in the input. It should not be called more than once
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// between consecutive calls of next.
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func (l *lexer) rewind() {
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l.pos -= l.width
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// When the next rune in the input is eof the width is zero. This check
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// prevents cols from being decremented when the next rune being accepted
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// is instead eof.
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if l.width > 0 {
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l.cols--
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}
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}
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// skip the scanned input between start and pos.
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func (l *lexer) skip() {
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l.start = l.pos
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l.column = l.cols
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}
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+308
@@ -0,0 +1,308 @@
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// Copyright 2023 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
|
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package parse
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import (
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"errors"
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"fmt"
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"os"
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"runtime/debug"
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"github.com/prometheus/alertmanager/pkg/labels"
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)
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var (
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errEOF = errors.New("end of input")
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errExpectedEOF = errors.New("expected end of input")
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errNoOpenBrace = errors.New("expected opening brace")
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errNoCloseBrace = errors.New("expected close brace")
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errNoLabelName = errors.New("expected label name")
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errNoLabelValue = errors.New("expected label value")
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errNoOperator = errors.New("expected an operator such as '=', '!=', '=~' or '!~'")
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errExpectedComma = errors.New("expected a comma")
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errExpectedCommaOrCloseBrace = errors.New("expected a comma or close brace")
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errExpectedMatcherOrCloseBrace = errors.New("expected a matcher or close brace after comma")
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)
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// Matchers parses one or more matchers in the input string. It returns an error
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// if the input is invalid.
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func Matchers(input string) (matchers labels.Matchers, err error) {
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defer func() {
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if r := recover(); r != nil {
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fmt.Fprintf(os.Stderr, "parser panic: %s, %s", r, debug.Stack())
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err = errors.New("parser panic: this should never happen, check stderr for the stack trace")
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}
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}()
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p := parser{lexer: lexer{input: input}}
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return p.parse()
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}
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// Matcher parses the matcher in the input string. It returns an error
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// if the input is invalid or contains two or more matchers.
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func Matcher(input string) (*labels.Matcher, error) {
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m, err := Matchers(input)
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if err != nil {
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return nil, err
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}
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switch len(m) {
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case 1:
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return m[0], nil
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case 0:
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return nil, fmt.Errorf("no matchers")
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default:
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return nil, fmt.Errorf("expected 1 matcher, found %d", len(m))
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}
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}
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// parseFunc is state in the finite state automata.
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type parseFunc func(l *lexer) (parseFunc, error)
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// parser reads the sequence of tokens from the lexer and returns either a
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// series of matchers or an error. It works as a finite state automata, where
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// each state in the automata is a parseFunc. The finite state automata can move
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// from one state to another by returning the next parseFunc. It terminates when
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// a parseFunc returns nil as the next parseFunc, if the lexer attempts to scan
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// input that does not match the expected grammar, or if the tokens returned from
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// the lexer cannot be parsed into a complete series of matchers.
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type parser struct {
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matchers labels.Matchers
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// Tracks if the input starts with an open brace and if we should expect to
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// parse a close brace at the end of the input.
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hasOpenBrace bool
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lexer lexer
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}
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func (p *parser) parse() (labels.Matchers, error) {
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var (
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err error
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fn = p.parseOpenBrace
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l = &p.lexer
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)
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for {
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||||
if fn, err = fn(l); err != nil {
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return nil, err
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} else if fn == nil {
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break
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}
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}
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return p.matchers, nil
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}
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func (p *parser) parseOpenBrace(l *lexer) (parseFunc, error) {
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var (
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hasCloseBrace bool
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err error
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)
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// Can start with an optional open brace.
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p.hasOpenBrace, err = p.accept(l, tokenOpenBrace)
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||||
if err != nil {
|
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if errors.Is(err, errEOF) {
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return p.parseEOF, nil
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}
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return nil, err
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}
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||||
// If the next token is a close brace there are no matchers in the input.
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hasCloseBrace, err = p.acceptPeek(l, tokenCloseBrace)
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if err != nil {
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// If there is no more input after the open brace then parse the close brace
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// so the error message contains ErrNoCloseBrace.
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||||
if errors.Is(err, errEOF) {
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return p.parseCloseBrace, nil
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||||
}
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||||
return nil, err
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||||
}
|
||||
if hasCloseBrace {
|
||||
return p.parseCloseBrace, nil
|
||||
}
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return p.parseMatcher, nil
|
||||
}
|
||||
|
||||
func (p *parser) parseCloseBrace(l *lexer) (parseFunc, error) {
|
||||
if p.hasOpenBrace {
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// If there was an open brace there must be a matching close brace.
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||||
if _, err := p.expect(l, tokenCloseBrace); err != nil {
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||||
return nil, fmt.Errorf("0:%d: %w: %w", l.position().columnEnd, err, errNoCloseBrace)
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||||
}
|
||||
} else {
|
||||
// If there was no open brace there must not be a close brace either.
|
||||
if _, err := p.expect(l, tokenCloseBrace); err == nil {
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||||
return nil, fmt.Errorf("0:%d: }: %w", l.position().columnEnd, errNoOpenBrace)
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||||
}
|
||||
}
|
||||
return p.parseEOF, nil
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||||
}
|
||||
|
||||
func (p *parser) parseMatcher(l *lexer) (parseFunc, error) {
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||||
var (
|
||||
err error
|
||||
t token
|
||||
matchName, matchValue string
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||||
matchTy labels.MatchType
|
||||
)
|
||||
// The first token should be the label name.
|
||||
if t, err = p.expect(l, tokenQuoted, tokenUnquoted); err != nil {
|
||||
return nil, fmt.Errorf("%w: %w", err, errNoLabelName)
|
||||
}
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||||
matchName, err = t.unquote()
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("%d:%d: %s: invalid input", t.columnStart, t.columnEnd, t.value)
|
||||
}
|
||||
// The next token should be the operator.
|
||||
if t, err = p.expect(l, tokenEquals, tokenNotEquals, tokenMatches, tokenNotMatches); err != nil {
|
||||
return nil, fmt.Errorf("%w: %w", err, errNoOperator)
|
||||
}
|
||||
switch t.kind {
|
||||
case tokenEquals:
|
||||
matchTy = labels.MatchEqual
|
||||
case tokenNotEquals:
|
||||
matchTy = labels.MatchNotEqual
|
||||
case tokenMatches:
|
||||
matchTy = labels.MatchRegexp
|
||||
case tokenNotMatches:
|
||||
matchTy = labels.MatchNotRegexp
|
||||
default:
|
||||
panic(fmt.Sprintf("bad operator %s", t))
|
||||
}
|
||||
// The next token should be the match value. Like the match name, this too
|
||||
// can be either double-quoted UTF-8 or unquoted UTF-8 without reserved characters.
|
||||
if t, err = p.expect(l, tokenUnquoted, tokenQuoted); err != nil {
|
||||
return nil, fmt.Errorf("%w: %w", err, errNoLabelValue)
|
||||
}
|
||||
matchValue, err = t.unquote()
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("%d:%d: %s: invalid input", t.columnStart, t.columnEnd, t.value)
|
||||
}
|
||||
m, err := labels.NewMatcher(matchTy, matchName, matchValue)
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("failed to create matcher: %w", err)
|
||||
}
|
||||
p.matchers = append(p.matchers, m)
|
||||
return p.parseEndOfMatcher, nil
|
||||
}
|
||||
|
||||
func (p *parser) parseEndOfMatcher(l *lexer) (parseFunc, error) {
|
||||
t, err := p.expectPeek(l, tokenComma, tokenCloseBrace)
|
||||
if err != nil {
|
||||
if errors.Is(err, errEOF) {
|
||||
// If this is the end of input we still need to check if the optional
|
||||
// open brace has a matching close brace.
|
||||
return p.parseCloseBrace, nil
|
||||
}
|
||||
return nil, fmt.Errorf("%w: %w", err, errExpectedCommaOrCloseBrace)
|
||||
}
|
||||
switch t.kind {
|
||||
case tokenComma:
|
||||
return p.parseComma, nil
|
||||
case tokenCloseBrace:
|
||||
return p.parseCloseBrace, nil
|
||||
default:
|
||||
panic(fmt.Sprintf("bad token %s", t))
|
||||
}
|
||||
}
|
||||
|
||||
func (p *parser) parseComma(l *lexer) (parseFunc, error) {
|
||||
if _, err := p.expect(l, tokenComma); err != nil {
|
||||
return nil, fmt.Errorf("%w: %w", err, errExpectedComma)
|
||||
}
|
||||
// The token after the comma can be another matcher, a close brace or end of input.
|
||||
t, err := p.expectPeek(l, tokenCloseBrace, tokenUnquoted, tokenQuoted)
|
||||
if err != nil {
|
||||
if errors.Is(err, errEOF) {
|
||||
// If this is the end of input we still need to check if the optional
|
||||
// open brace has a matching close brace.
|
||||
return p.parseCloseBrace, nil
|
||||
}
|
||||
return nil, fmt.Errorf("%w: %w", err, errExpectedMatcherOrCloseBrace)
|
||||
}
|
||||
if t.kind == tokenCloseBrace {
|
||||
return p.parseCloseBrace, nil
|
||||
}
|
||||
return p.parseMatcher, nil
|
||||
}
|
||||
|
||||
func (p *parser) parseEOF(l *lexer) (parseFunc, error) {
|
||||
t, err := l.scan()
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("%w: %w", err, errExpectedEOF)
|
||||
}
|
||||
if !t.isEOF() {
|
||||
return nil, fmt.Errorf("%d:%d: %s: %w", t.columnStart, t.columnEnd, t.value, errExpectedEOF)
|
||||
}
|
||||
return nil, nil
|
||||
}
|
||||
|
||||
// nolint:godot
|
||||
// accept returns true if the next token is one of the specified kinds,
|
||||
// otherwise false. If the token is accepted it is consumed. tokenEOF is
|
||||
// not an accepted kind and instead accept returns ErrEOF if there is no
|
||||
// more input.
|
||||
func (p *parser) accept(l *lexer, kinds ...tokenKind) (ok bool, err error) {
|
||||
ok, err = p.acceptPeek(l, kinds...)
|
||||
if ok {
|
||||
if _, err = l.scan(); err != nil {
|
||||
panic("failed to scan peeked token")
|
||||
}
|
||||
}
|
||||
return ok, err
|
||||
}
|
||||
|
||||
// nolint:godot
|
||||
// acceptPeek returns true if the next token is one of the specified kinds,
|
||||
// otherwise false. However, unlike accept, acceptPeek does not consume accepted
|
||||
// tokens. tokenEOF is not an accepted kind and instead accept returns ErrEOF
|
||||
// if there is no more input.
|
||||
func (p *parser) acceptPeek(l *lexer, kinds ...tokenKind) (bool, error) {
|
||||
t, err := l.peek()
|
||||
if err != nil {
|
||||
return false, err
|
||||
}
|
||||
if t.isEOF() {
|
||||
return false, errEOF
|
||||
}
|
||||
return t.isOneOf(kinds...), nil
|
||||
}
|
||||
|
||||
// nolint:godot
|
||||
// expect returns the next token if it is one of the specified kinds, otherwise
|
||||
// it returns an error. If the token is expected it is consumed. tokenEOF is not
|
||||
// an accepted kind and instead expect returns ErrEOF if there is no more input.
|
||||
func (p *parser) expect(l *lexer, kind ...tokenKind) (token, error) {
|
||||
t, err := p.expectPeek(l, kind...)
|
||||
if err != nil {
|
||||
return t, err
|
||||
}
|
||||
if _, err = l.scan(); err != nil {
|
||||
panic("failed to scan peeked token")
|
||||
}
|
||||
return t, nil
|
||||
}
|
||||
|
||||
// nolint:godot
|
||||
// expect returns the next token if it is one of the specified kinds, otherwise
|
||||
// it returns an error. However, unlike expect, expectPeek does not consume tokens.
|
||||
// tokenEOF is not an accepted kind and instead expect returns ErrEOF if there is no
|
||||
// more input.
|
||||
func (p *parser) expectPeek(l *lexer, kind ...tokenKind) (token, error) {
|
||||
t, err := l.peek()
|
||||
if err != nil {
|
||||
return t, err
|
||||
}
|
||||
if t.isEOF() {
|
||||
return t, errEOF
|
||||
}
|
||||
if !t.isOneOf(kind...) {
|
||||
return t, fmt.Errorf("%d:%d: unexpected %s", t.columnStart, t.columnEnd, t.value)
|
||||
}
|
||||
return t, nil
|
||||
}
|
||||
+104
@@ -0,0 +1,104 @@
|
||||
// Copyright 2023 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 parse
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"slices"
|
||||
"strconv"
|
||||
"unicode/utf8"
|
||||
)
|
||||
|
||||
type tokenKind int
|
||||
|
||||
const (
|
||||
tokenEOF tokenKind = iota
|
||||
tokenOpenBrace
|
||||
tokenCloseBrace
|
||||
tokenComma
|
||||
tokenEquals
|
||||
tokenNotEquals
|
||||
tokenMatches
|
||||
tokenNotMatches
|
||||
tokenQuoted
|
||||
tokenUnquoted
|
||||
)
|
||||
|
||||
func (k tokenKind) String() string {
|
||||
switch k {
|
||||
case tokenOpenBrace:
|
||||
return "OpenBrace"
|
||||
case tokenCloseBrace:
|
||||
return "CloseBrace"
|
||||
case tokenComma:
|
||||
return "Comma"
|
||||
case tokenEquals:
|
||||
return "Equals"
|
||||
case tokenNotEquals:
|
||||
return "NotEquals"
|
||||
case tokenMatches:
|
||||
return "Matches"
|
||||
case tokenNotMatches:
|
||||
return "NotMatches"
|
||||
case tokenQuoted:
|
||||
return "Quoted"
|
||||
case tokenUnquoted:
|
||||
return "Unquoted"
|
||||
default:
|
||||
return "EOF"
|
||||
}
|
||||
}
|
||||
|
||||
type token struct {
|
||||
kind tokenKind
|
||||
value string
|
||||
position
|
||||
}
|
||||
|
||||
// isEOF returns true if the token is an end of file token.
|
||||
func (t token) isEOF() bool {
|
||||
return t.kind == tokenEOF
|
||||
}
|
||||
|
||||
// isOneOf returns true if the token is one of the specified kinds.
|
||||
func (t token) isOneOf(kinds ...tokenKind) bool {
|
||||
return slices.Contains(kinds, t.kind)
|
||||
}
|
||||
|
||||
// unquote the value in token. If unquoted returns it unmodified.
|
||||
func (t token) unquote() (string, error) {
|
||||
if t.kind == tokenQuoted {
|
||||
unquoted, err := strconv.Unquote(t.value)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
if !utf8.ValidString(unquoted) {
|
||||
return "", errors.New("quoted string contains invalid UTF-8 code points")
|
||||
}
|
||||
return unquoted, nil
|
||||
}
|
||||
return t.value, nil
|
||||
}
|
||||
|
||||
func (t token) String() string {
|
||||
return fmt.Sprintf("(%s) '%s'", t.kind, t.value)
|
||||
}
|
||||
|
||||
type position struct {
|
||||
offsetStart int // The start position in the input.
|
||||
offsetEnd int // The end position in the input.
|
||||
columnStart int // The column number.
|
||||
columnEnd int // The end of the column.
|
||||
}
|
||||
Reference in New Issue
Block a user