prometheus/rules/parser.y
Julius Volz 0712d738d1 Allow alternative "by"-clause position in grammar.
In addition to the existing by-clause syntax:

  sum(<expression>) by (<labels>) [keeping_extra]

...this allows the following new syntax:

  sum by (<labels>) [keeping_extra] (<expression>)

Both orderings may be used in a single expression. It is up to the users
to establish guidelines around their usage.

Change-Id: Iba10c9cc5fb6ac62edfcf246d281473e82467992
2014-11-25 17:09:04 +01:00

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// Copyright 2013 Prometheus Team
// 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 (
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/prometheus/rules/ast"
"github.com/prometheus/prometheus/storage/metric"
)
%}
%union {
num clientmodel.SampleValue
str string
ruleNode ast.Node
ruleNodeSlice []ast.Node
boolean bool
labelNameSlice clientmodel.LabelNames
labelSet clientmodel.LabelSet
labelMatcher *metric.LabelMatcher
labelMatchers metric.LabelMatchers
}
/* 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.
*/
%token START_RULES START_EXPRESSION
%token <str> IDENTIFIER STRING DURATION METRICNAME
%token <num> NUMBER
%token PERMANENT GROUP_OP KEEPING_EXTRA
%token <str> AGGR_OP CMP_OP ADDITIVE_OP MULT_OP
%token ALERT IF FOR WITH SUMMARY DESCRIPTION
%type <ruleNodeSlice> func_arg_list
%type <labelNameSlice> label_list grouping_opts
%type <labelSet> label_assign label_assign_list rule_labels
%type <labelMatcher> label_match
%type <labelMatchers> label_match_list label_matches
%type <ruleNode> rule_expr func_arg
%type <boolean> qualifier extra_labels_opts
%type <str> for_duration metric_name label_match_type
%right '='
%left CMP_OP
%left ADDITIVE_OP
%left MULT_OP
%start start
%%
start : START_RULES rules_stat_list
| START_EXPRESSION saved_rule_expr
;
rules_stat_list : /* empty */
| rules_stat_list rules_stat
;
saved_rule_expr : rule_expr
{ yylex.(*RulesLexer).parsedExpr = $1 }
;
rules_stat : qualifier metric_name rule_labels '=' rule_expr
{
rule, err := CreateRecordingRule($2, $3, $5, $1)
if err != nil { yylex.Error(err.Error()); return 1 }
yylex.(*RulesLexer).parsedRules = append(yylex.(*RulesLexer).parsedRules, rule)
}
| ALERT IDENTIFIER IF rule_expr for_duration WITH rule_labels SUMMARY STRING DESCRIPTION STRING
{
rule, err := CreateAlertingRule($2, $4, $5, $7, $9, $11)
if err != nil { yylex.Error(err.Error()); return 1 }
yylex.(*RulesLexer).parsedRules = append(yylex.(*RulesLexer).parsedRules, rule)
}
;
for_duration : /* empty */
{ $$ = "0s" }
| FOR DURATION
{ $$ = $2 }
;
qualifier : /* empty */
{ $$ = false }
| PERMANENT
{ $$ = true }
;
metric_name : METRICNAME
{ $$ = $1 }
| IDENTIFIER
{ $$ = $1 }
;
rule_labels : /* empty */
{ $$ = clientmodel.LabelSet{} }
| '{' label_assign_list '}'
{ $$ = $2 }
| '{' '}'
{ $$ = clientmodel.LabelSet{} }
label_assign_list : label_assign
{ $$ = $1 }
| label_assign_list ',' label_assign
{ for k, v := range $3 { $$[k] = v } }
;
label_assign : IDENTIFIER '=' STRING
{ $$ = clientmodel.LabelSet{ clientmodel.LabelName($1): clientmodel.LabelValue($3) } }
;
label_matches : /* empty */
{ $$ = metric.LabelMatchers{} }
| '{' '}'
{ $$ = metric.LabelMatchers{} }
| '{' label_match_list '}'
{ $$ = $2 }
;
label_match_list : label_match
{ $$ = metric.LabelMatchers{$1} }
| label_match_list ',' label_match
{ $$ = append($$, $3) }
;
label_match : IDENTIFIER label_match_type STRING
{
var err error
$$, err = newLabelMatcher($2, clientmodel.LabelName($1), clientmodel.LabelValue($3))
if err != nil { yylex.Error(err.Error()); return 1 }
}
;
label_match_type : '='
{ $$ = "=" }
| CMP_OP
{ $$ = $1 }
;
rule_expr : '(' rule_expr ')'
{ $$ = $2 }
| '{' label_match_list '}'
{ $$ = ast.NewVectorSelector($2) }
| metric_name label_matches
{
var err error
m, err := metric.NewLabelMatcher(metric.Equal, clientmodel.MetricNameLabel, clientmodel.LabelValue($1))
if err != nil { yylex.Error(err.Error()); return 1 }
$2 = append($2, m)
$$ = ast.NewVectorSelector($2)
}
| IDENTIFIER '(' func_arg_list ')'
{
var err error
$$, err = NewFunctionCall($1, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| IDENTIFIER '(' ')'
{
var err error
$$, err = NewFunctionCall($1, []ast.Node{})
if err != nil { yylex.Error(err.Error()); return 1 }
}
| rule_expr '[' DURATION ']'
{
var err error
$$, err = NewMatrixSelector($1, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| AGGR_OP '(' rule_expr ')' grouping_opts extra_labels_opts
{
var err error
$$, err = NewVectorAggregation($1, $3, $5, $6)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| AGGR_OP grouping_opts extra_labels_opts '(' rule_expr ')'
{
var err error
$$, err = NewVectorAggregation($1, $5, $2, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
/* Yacc can only attach associativity to terminals, so we
* have to list all operators here. */
| rule_expr ADDITIVE_OP rule_expr
{
var err error
$$, err = NewArithExpr($2, $1, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| rule_expr MULT_OP rule_expr
{
var err error
$$, err = NewArithExpr($2, $1, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| rule_expr CMP_OP rule_expr
{
var err error
$$, err = NewArithExpr($2, $1, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| NUMBER
{ $$ = ast.NewScalarLiteral($1)}
;
extra_labels_opts :
{ $$ = false }
| KEEPING_EXTRA
{ $$ = true }
;
grouping_opts :
{ $$ = clientmodel.LabelNames{} }
| GROUP_OP '(' label_list ')'
{ $$ = $3 }
;
label_list : IDENTIFIER
{ $$ = clientmodel.LabelNames{clientmodel.LabelName($1)} }
| label_list ',' IDENTIFIER
{ $$ = append($$, clientmodel.LabelName($3)) }
;
func_arg_list : func_arg
{ $$ = []ast.Node{$1} }
| func_arg_list ',' func_arg
{ $$ = append($$, $3) }
;
func_arg : rule_expr
{ $$ = $1 }
| STRING
{ $$ = ast.NewStringLiteral($1) }
;
%%