prometheus/rules/lexer.l

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/* Copyright 2013 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 rules
import (
"fmt"
"strconv"
"strings"
clientmodel "github.com/prometheus/client_golang/model"
)
// Lex is called by the parser generated by "go tool yacc" to obtain each
// token. The method is opened before the matching rules block and closed at
// the end of the file.
func (lexer *RulesLexer) Lex(lval *yySymType) int {
// Internal lexer states.
const (
S_INITIAL = iota
S_COMMENTS
)
// 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
}
c := lexer.current
currentState := 0
if lexer.empty {
c, lexer.empty = lexer.getChar(), false
}
%}
D [0-9]
L [a-zA-Z_]
M [a-zA-Z_:]
U [smhdwy]
FLOAT ({D}*\.?{D}+|{D}+\.?{D}*){EXPONENT}?|[+-]?[iI][nN][fF]|[nN][aA][nN]
EXPONENT [eE][-+]?[0-9]+
STR \"(\\.|[^\\"])*\"|\'(\\.|[^\\'])*\'
%x S_COMMENTS
%yyc c
%yyn c = lexer.getChar()
%yyt currentState
%%
lexer.buf = lexer.buf[:0] // The code before the first rule executed before every scan cycle (rule #0 / state 0 action)
"/*" currentState = S_COMMENTS
<S_COMMENTS>"*/" currentState = S_INITIAL
<S_COMMENTS>.|\n /* ignore chars within multi-line comments */
\/\/[^\r\n]*\n /* gobble up one-line comments */
ALERT|alert return ALERT
IF|if return IF
FOR|for return FOR
WITH|with return WITH
SUMMARY|summary return SUMMARY
DESCRIPTION|description return DESCRIPTION
PERMANENT|permanent return PERMANENT
BY|by return GROUP_OP
ON|on return MATCH_OP
GROUP_LEFT|GROUP_RIGHT lval.str = lexer.token(); return MATCH_MOD
group_left|group_right lval.str = strings.ToUpper(lexer.token()); return MATCH_MOD
KEEPING_EXTRA|keeping_extra return KEEPING_EXTRA
Implement offset operator. This allows changing the time offset for individual instant and range vectors in a query. For example, this returns the value of `foo` 5 minutes in the past relative to the current query evaluation time: foo offset 5m Note that the `offset` modifier always needs to follow the selector immediately. I.e. the following would be correct: sum(foo offset 5m) // GOOD. While the following would be *incorrect*: sum(foo) offset 5m // INVALID. The same works for range vectors. This returns the 5-minutes-rate that `foo` had a week ago: rate(foo[5m] offset 1w) This change touches the following components: * Lexer/parser: additions to correctly parse the new `offset`/`OFFSET` keyword. * AST: vector and matrix nodes now have an additional `offset` field. This is used during their evaluation to adjust query and result times appropriately. * Query analyzer: now works on separate sets of ranges and instants per offset. Isolating different offsets from each other completely in this way keeps the preloading code relatively simple. No storage engine changes were needed by this change. The rules tests have been changed to not probe the internal implementation details of the query analyzer anymore (how many instants and ranges have been preloaded). This would also become too cumbersome to test with the new model, and measuring the result of the query should be sufficient. This fixes https://github.com/prometheus/prometheus/issues/529 This fixed https://github.com/prometheus/promdash/issues/201
2015-02-18 01:30:41 +00:00
OFFSET|offset return OFFSET
AVG|SUM|MAX|MIN|COUNT|STDVAR|STDDEV lval.str = lexer.token(); return AGGR_OP
avg|sum|max|min|count|stdvar|stddev lval.str = strings.ToUpper(lexer.token()); return AGGR_OP
\<|>|AND|OR|and|or lval.str = strings.ToUpper(lexer.token()); return CMP_OP
==|!=|>=|<=|=~|!~ lval.str = lexer.token(); return CMP_OP
[+\-] lval.str = lexer.token(); return ADDITIVE_OP
[*/%] lval.str = lexer.token(); return MULT_OP
{FLOAT} num, err := strconv.ParseFloat(lexer.token(), 64);
if (err != nil && err.(*strconv.NumError).Err == strconv.ErrSyntax) {
panic("Invalid float")
}
lval.num = clientmodel.SampleValue(num)
return NUMBER
{D}+{U} lval.str = lexer.token(); return DURATION
{L}({L}|{D})* lval.str = lexer.token(); return IDENTIFIER
{M}({M}|{D})* lval.str = lexer.token(); return METRICNAME
{STR} lval.str = lexer.token()[1:len(lexer.token()) - 1]; return STRING
[{}\[\]()=,] return int(lexer.buf[0])
[\t\n\r ] /* gobble up any whitespace */
%%
lexer.empty = true
return int(c)
}