prometheus/rules/parser.y

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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 "fmt"
import "github.com/prometheus/prometheus/model"
import "github.com/prometheus/prometheus/rules/ast"
%}
%union {
num model.SampleValue
str string
ruleNode ast.Node
ruleNodeSlice []ast.Node
boolean bool
labelNameSlice []model.LabelName
labelSet model.LabelSet
}
/* 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
%token <num> NUMBER
%token PERMANENT GROUP_OP
%token <str> AGGR_OP CMP_OP ADDITIVE_OP MULT_OP
%type <ruleNodeSlice> func_arg_list
%type <labelNameSlice> label_list grouping_opts
%type <labelSet> label_assign label_assign_list rule_labels
%type <ruleNode> rule_expr func_arg
%type <boolean> qualifier
%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 IDENTIFIER rule_labels '=' rule_expr
{
rule, err := CreateRule($2, $3, $5, $1)
if err != nil { yylex.Error(err.Error()); return 1 }
yylex.(*RulesLexer).parsedRules = append(yylex.(*RulesLexer).parsedRules, rule)
}
;
qualifier : /* empty */
{ $$ = false }
| PERMANENT
{ $$ = true }
;
rule_labels : /* empty */
{ $$ = model.LabelSet{} }
| '{' label_assign_list '}'
{ $$ = $2 }
| '{' '}'
{ $$ = model.LabelSet{} }
label_assign_list : label_assign
{ $$ = $1 }
| label_assign_list ',' label_assign
{ for k, v := range $3 { $$[k] = v } }
;
label_assign : IDENTIFIER '=' STRING
{ $$ = model.LabelSet{ model.LabelName($1): model.LabelValue($3) } }
;
rule_expr : '(' rule_expr ')'
{ $$ = $2 }
| IDENTIFIER rule_labels
{ $2["name"] = model.LabelValue($1); $$ = ast.NewVectorLiteral($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
$$, err = NewMatrix($1, $3)
if err != nil { yylex.Error(err.Error()); return 1 }
}
| AGGR_OP '(' rule_expr ')' grouping_opts
{
var err error
$$, err = NewVectorAggregation($1, $3, $5)
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)}
;
grouping_opts :
{ $$ = []model.LabelName{} }
| GROUP_OP '(' label_list ')'
{ $$ = $3 }
;
label_list : IDENTIFIER
{ $$ = []model.LabelName{model.LabelName($1)} }
| label_list ',' IDENTIFIER
{ $$ = append($$, model.LabelName($3)) }
;
func_arg_list : func_arg
{ $$ = []ast.Node{$1} }
| func_arg_list ',' func_arg
{ $$ = append($$, $3) }
;
func_arg : rule_expr
{ $$ = $1 }
| STRING
{ $$ = ast.NewStringLiteral($1) }
;
%%