mirror of
https://github.com/prometheus/prometheus
synced 2024-12-26 08:33:06 +00:00
ea54751431
This repository moved from matttproud/prometheus to prometheus/prometheus, and all import paths need to be updated.
123 lines
3.1 KiB
Go
123 lines
3.1 KiB
Go
package rules
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"github.com/prometheus/prometheus/rules/ast"
|
|
"io"
|
|
"os"
|
|
"strings"
|
|
)
|
|
|
|
// NOTE: This parser is non-reentrant due to its dependence on global state.
|
|
|
|
// GoLex sadly needs these global variables for storing temporary token/parsing information.
|
|
var yylval *yySymType // For storing extra token information, like the contents of a string.
|
|
var yyline int // Line number within the current file or buffer.
|
|
var yypos int // Character position within the current line.
|
|
|
|
type RulesLexer struct {
|
|
errors []string // Errors encountered during parsing.
|
|
startToken int // Dummy token to simulate multiple start symbols (see below).
|
|
parsedRules []*Rule // Parsed full rules.
|
|
parsedExpr ast.Node // Parsed single expression.
|
|
}
|
|
|
|
func (lexer *RulesLexer) Lex(lval *yySymType) int {
|
|
yylval = lval
|
|
|
|
// We simulate multiple start symbols for closely-related grammars via dummy tokens. See
|
|
// http://www.gnu.org/software/bison/manual/html_node/Multiple-start_002dsymbols.html
|
|
// Reason: we want to be able to parse lists of named rules as well as single expressions.
|
|
if lexer.startToken != 0 {
|
|
startToken := lexer.startToken
|
|
lexer.startToken = 0
|
|
return startToken
|
|
}
|
|
|
|
tokenType := yylex()
|
|
return tokenType
|
|
}
|
|
|
|
func (lexer *RulesLexer) Error(errorStr string) {
|
|
err := fmt.Sprintf("Error parsing rules at line %v, char %v: %v", yyline, yypos, errorStr)
|
|
lexer.errors = append(lexer.errors, err)
|
|
}
|
|
|
|
func LoadFromReader(rulesReader io.Reader, singleExpr bool) (interface{}, error) {
|
|
yyin = rulesReader
|
|
yypos = 1
|
|
yyline = 1
|
|
yydata = ""
|
|
yytext = ""
|
|
|
|
lexer := &RulesLexer{
|
|
startToken: START_RULES,
|
|
}
|
|
|
|
if singleExpr {
|
|
lexer.startToken = START_EXPRESSION
|
|
}
|
|
|
|
ret := yyParse(lexer)
|
|
if ret != 0 && len(lexer.errors) == 0 {
|
|
lexer.Error("Unknown parser error")
|
|
}
|
|
|
|
if len(lexer.errors) > 0 {
|
|
err := errors.New(strings.Join(lexer.errors, "\n"))
|
|
return nil, err
|
|
}
|
|
|
|
if singleExpr {
|
|
return lexer.parsedExpr, nil
|
|
} else {
|
|
return lexer.parsedRules, nil
|
|
}
|
|
panic("")
|
|
}
|
|
|
|
func LoadRulesFromReader(rulesReader io.Reader) ([]*Rule, error) {
|
|
expr, err := LoadFromReader(rulesReader, false)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return expr.([]*Rule), err
|
|
}
|
|
|
|
func LoadRulesFromString(rulesString string) ([]*Rule, error) {
|
|
rulesReader := strings.NewReader(rulesString)
|
|
return LoadRulesFromReader(rulesReader)
|
|
}
|
|
|
|
func LoadRulesFromFile(fileName string) ([]*Rule, error) {
|
|
rulesReader, err := os.Open(fileName)
|
|
defer rulesReader.Close()
|
|
if err != nil {
|
|
return []*Rule{}, err
|
|
}
|
|
return LoadRulesFromReader(rulesReader)
|
|
}
|
|
|
|
func LoadExprFromReader(exprReader io.Reader) (ast.Node, error) {
|
|
expr, err := LoadFromReader(exprReader, true)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return expr.(ast.Node), err
|
|
}
|
|
|
|
func LoadExprFromString(exprString string) (ast.Node, error) {
|
|
exprReader := strings.NewReader(exprString)
|
|
return LoadExprFromReader(exprReader)
|
|
}
|
|
|
|
func LoadExprFromFile(fileName string) (ast.Node, error) {
|
|
exprReader, err := os.Open(fileName)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer exprReader.Close()
|
|
return LoadExprFromReader(exprReader)
|
|
}
|