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PromQL: Add position metadata to the AST (#6615)

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Signed-off-by: Tobias Guggenmos <tguggenm@redhat.com>
Co-authored-by: Julius Volz <julius.volz@gmail.com>
This commit is contained in:
Tobias Guggenmos 2020-01-14 17:12:15 +01:00 committed by Brian Brazil
parent e12e5ecc8f
commit 0c8e9ef09e
7 changed files with 1390 additions and 443 deletions
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101
promql/ast.go
View file

@ -39,6 +39,9 @@ type Node interface {
// String representation of the node that returns the given node when parsed
// as part of a valid query.
String() string
// PositionRange returns the position of the AST Node in the query string.
PositionRange() PositionRange
}
// Statement is a generic interface for all statements.
@ -84,6 +87,7 @@ type AggregateExpr struct {
Param Expr // Parameter used by some aggregators.
Grouping []string // The labels by which to group the Vector.
Without bool // Whether to drop the given labels rather than keep them.
PosRange PositionRange
}
// BinaryExpr represents a binary expression between two child expressions.
@ -103,12 +107,16 @@ type BinaryExpr struct {
type Call struct {
Func *Function // The function that was called.
Args Expressions // Arguments used in the call.
PosRange PositionRange
}
// MatrixSelector represents a Matrix selection.
type MatrixSelector struct {
VectorSelector *VectorSelector
Range time.Duration
EndPos Pos
}
// SubqueryExpr represents a subquery.
@ -117,22 +125,28 @@ type SubqueryExpr struct {
Range time.Duration
Offset time.Duration
Step time.Duration
EndPos Pos
}
// NumberLiteral represents a number.
type NumberLiteral struct {
Val float64
PosRange PositionRange
}
// ParenExpr wraps an expression so it cannot be disassembled as a consequence
// of operator precedence.
type ParenExpr struct {
Expr Expr
Expr Expr
PosRange PositionRange
}
// StringLiteral represents a string.
type StringLiteral struct {
Val string
Val string
PosRange PositionRange
}
// UnaryExpr represents a unary operation on another expression.
@ -140,6 +154,8 @@ type StringLiteral struct {
type UnaryExpr struct {
Op ItemType
Expr Expr
StartPos Pos
}
// VectorSelector represents a Vector selection.
@ -151,6 +167,8 @@ type VectorSelector struct {
// The unexpanded seriesSet populated at query preparation time.
unexpandedSeriesSet storage.SeriesSet
series []storage.Series
PosRange PositionRange
}
func (e *AggregateExpr) Type() ValueType { return ValueTypeVector }
@ -319,3 +337,82 @@ func Children(node Node) []Node {
panic(errors.Errorf("promql.Children: unhandled node type %T", node))
}
}
// PositionRange describes a position in the input string of the parser.
type PositionRange struct {
Start Pos
End Pos
}
// mergeRanges is a helper function to merge the PositionRanges of two Nodes.
// Note that the arguments must be in the same order as they
// occur in the input string.
func mergeRanges(first Node, last Node) PositionRange {
return PositionRange{
Start: first.PositionRange().Start,
End: last.PositionRange().End,
}
}
// Item implements the Node interface.
// This makes it possible to call mergeRanges on them.
func (i *Item) PositionRange() PositionRange {
return PositionRange{
Start: i.Pos,
End: i.Pos + Pos(len(i.Val)),
}
}
func (e *AggregateExpr) PositionRange() PositionRange {
return e.PosRange
}
func (e *BinaryExpr) PositionRange() PositionRange {
return mergeRanges(e.LHS, e.RHS)
}
func (e *Call) PositionRange() PositionRange {
return e.PosRange
}
func (e *EvalStmt) PositionRange() PositionRange {
return e.Expr.PositionRange()
}
func (e Expressions) PositionRange() PositionRange {
if len(e) == 0 {
// Position undefined.
return PositionRange{
Start: -1,
End: -1,
}
} else {
return mergeRanges(e[0], e[len(e)-1])
}
}
func (e *MatrixSelector) PositionRange() PositionRange {
return PositionRange{
Start: e.VectorSelector.PositionRange().Start,
End: e.EndPos,
}
}
func (e *SubqueryExpr) PositionRange() PositionRange {
return PositionRange{
Start: e.Expr.PositionRange().Start,
End: e.EndPos,
}
}
func (e *NumberLiteral) PositionRange() PositionRange {
return e.PosRange
}
func (e *ParenExpr) PositionRange() PositionRange {
return e.PosRange
}
func (e *StringLiteral) PositionRange() PositionRange {
return e.PosRange
}
func (e *UnaryExpr) PositionRange() PositionRange {
return PositionRange{
Start: e.StartPos,
End: e.Expr.PositionRange().End,
}
}
func (e *VectorSelector) PositionRange() PositionRange {
return e.PosRange
}

7
promql/engine.go
View file

@ -406,6 +406,13 @@ type testStmt func(context.Context) error
func (testStmt) String() string { return "test statement" }
func (testStmt) stmt() {}
func (testStmt) PositionRange() PositionRange {
return PositionRange{
Start: -1,
End: -1,
}
}
func (ng *Engine) newTestQuery(f func(context.Context) error) Query {
qry := &query{
q: "test statement",

84
promql/generated_parser.y
View file

@ -36,7 +36,6 @@ import (
series []sequenceValue
uint uint64
float float64
string string
duration time.Duration
}
@ -127,7 +126,7 @@ START_METRIC_SELECTOR
// Type definitions for grammar rules.
%type <matchers> label_match_list label_matchers
%type <matchers> label_match_list
%type <matcher> label_matcher
%type <item> aggregate_op grouping_label match_op maybe_label metric_identifier unary_op
@ -138,8 +137,7 @@ START_METRIC_SELECTOR
%type <series> series_item series_values
%type <uint> uint
%type <float> number series_value signed_number
%type <node> aggregate_expr aggregate_modifier bin_modifier binary_expr bool_modifier expr function_call function_call_args function_call_body group_modifiers matrix_selector number_literal offset_expr on_or_ignoring paren_expr string_literal subquery_expr unary_expr vector_selector
%type <string> string
%type <node> aggregate_expr aggregate_modifier bin_modifier binary_expr bool_modifier expr function_call function_call_args function_call_body group_modifiers label_matchers matrix_selector number_literal offset_expr on_or_ignoring paren_expr string_literal subquery_expr unary_expr vector_selector
%type <duration> duration maybe_duration
%start start
@ -333,6 +331,10 @@ function_call : IDENTIFIER function_call_body
$$ = &Call{
Func: fn,
Args: $2.(Expressions),
PosRange: PositionRange{
Start: $1.Pos,
End: yylex.(*parser).lastClosing,
},
}
}
;
@ -354,7 +356,7 @@ function_call_args: function_call_args COMMA expr
*/
paren_expr : LEFT_PAREN expr RIGHT_PAREN
{ $$ = &ParenExpr{Expr: $2.(Expr)} }
{ $$ = &ParenExpr{Expr: $2.(Expr), PosRange: mergeRanges(&$1, &$3)} }
;
/*
@ -386,6 +388,7 @@ matrix_selector : expr LEFT_BRACKET duration RIGHT_BRACKET
$$ = &MatrixSelector{
VectorSelector: vs,
Range: $3,
EndPos: yylex.(*parser).lastClosing,
}
}
;
@ -396,6 +399,8 @@ subquery_expr : expr LEFT_BRACKET duration COLON maybe_duration RIGHT_BRACKET
Expr: $1.(Expr),
Range: $3,
Step: $5,
EndPos: $6.Pos + 1,
}
}
| expr LEFT_BRACKET duration COLON duration error
@ -420,9 +425,10 @@ unary_expr :
if $1.Typ == SUB {
nl.Val *= -1
}
nl.PosRange.Start = $1.Pos
$$ = nl
} else {
$$ = &UnaryExpr{Op: $1.Typ, Expr: $2.(Expr)}
$$ = &UnaryExpr{Op: $1.Typ, Expr: $2.(Expr), StartPos: $1.Pos}
}
}
;
@ -432,20 +438,52 @@ unary_expr :
*/
vector_selector: metric_identifier label_matchers
{ $$ = yylex.(*parser).newVectorSelector($1.Val, $2) }
{
vs := $2.(*VectorSelector)
vs.PosRange = mergeRanges(&$1, vs)
vs.Name = $1.Val
yylex.(*parser).assembleVectorSelector(vs)
$$ = vs
}
| metric_identifier
{ $$ = yylex.(*parser).newVectorSelector($1.Val, nil) }
{
vs := &VectorSelector{
Name: $1.Val,
LabelMatchers: []*labels.Matcher{},
PosRange: $1.PositionRange(),
}
yylex.(*parser).assembleVectorSelector(vs)
$$ = vs
}
| label_matchers
{ $$ = yylex.(*parser).newVectorSelector("", $1) }
{
vs := $1.(*VectorSelector)
yylex.(*parser).assembleVectorSelector(vs)
$$ = vs
}
;
label_matchers : LEFT_BRACE label_match_list RIGHT_BRACE
{ $$ = $2 }
{
$$ = &VectorSelector{
LabelMatchers: $2,
PosRange: mergeRanges(&$1, &$3),
}
}
| LEFT_BRACE label_match_list COMMA RIGHT_BRACE
{ $$ = $2 }
{
$$ = &VectorSelector{
LabelMatchers: $2,
PosRange: mergeRanges(&$1, &$4),
}
}
| LEFT_BRACE RIGHT_BRACE
{ $$ = []*labels.Matcher{} }
{
$$ = &VectorSelector{
LabelMatchers: []*labels.Matcher{},
PosRange: mergeRanges(&$1, &$2),
}
}
;
label_match_list: label_match_list COMMA label_matcher
@ -590,7 +628,14 @@ match_op : EQL | NEQ | EQL_REGEX | NEQ_REGEX ;
* Literals.
*/
number_literal : number { $$ = &NumberLiteral{$1}} ;
number_literal : NUMBER
{
$$ = &NumberLiteral{
Val: yylex.(*parser).number($1.Val),
PosRange: $1.PositionRange(),
}
}
;
number : NUMBER { $$ = yylex.(*parser).number($1.Val) } ;
@ -619,9 +664,14 @@ duration : DURATION
;
string_literal : string { $$ = &StringLiteral{$1}} ;
string : STRING { $$ = yylex.(*parser).unquoteString($1.Val) } ;
string_literal : STRING
{
$$ = &StringLiteral{
Val: yylex.(*parser).unquoteString($1.Val),
PosRange: $1.PositionRange(),
}
}
;
/*
* Wrappers for optional arguments.

624
promql/generated_parser.y.go
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1
promql/lex.go
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@ -213,6 +213,7 @@ const eof = -1
type stateFn func(*Lexer) stateFn
// Pos is the position in a string.
// Negative numbers indicate undefined positions.
type Pos int
// Lexer holds the state of the scanner.

44
promql/parse.go
View file

@ -41,6 +41,10 @@ type parser struct {
inject ItemType
injecting bool
// Everytime an Item is lexed that could be the end
// of certain expressions its end position is stored here.
lastClosing Pos
yyParser yyParserImpl
generatedParserResult interface{}
@ -229,13 +233,15 @@ func (p *parser) Lex(lval *yySymType) int {
}
}
if typ == ERROR {
p.errorf("%s", lval.item.Val)
}
switch typ {
if typ == EOF {
case ERROR:
p.errorf("%s", lval.item.Val)
case EOF:
lval.item.Typ = EOF
p.InjectItem(0)
case RIGHT_BRACE, RIGHT_PAREN, RIGHT_BRACKET, DURATION:
p.lastClosing = lval.item.Pos + Pos(len(lval.item.Val))
}
return int(typ)
@ -298,29 +304,26 @@ func (p *parser) newBinaryExpression(lhs Node, op Item, modifiers Node, rhs Node
return ret
}
func (p *parser) newVectorSelector(name string, labelMatchers []*labels.Matcher) *VectorSelector {
ret := &VectorSelector{LabelMatchers: labelMatchers}
func (p *parser) assembleVectorSelector(vs *VectorSelector) {
if vs.Name != "" {
if name != "" {
ret.Name = name
for _, m := range ret.LabelMatchers {
for _, m := range vs.LabelMatchers {
if m.Name == labels.MetricName {
p.errorf("metric name must not be set twice: %q or %q", name, m.Value)
p.errorf("metric name must not be set twice: %q or %q", vs.Name, m.Value)
}
}
nameMatcher, err := labels.NewMatcher(labels.MatchEqual, labels.MetricName, name)
nameMatcher, err := labels.NewMatcher(labels.MatchEqual, labels.MetricName, vs.Name)
if err != nil {
panic(err) // Must not happen with labels.MatchEqual
}
ret.LabelMatchers = append(ret.LabelMatchers, nameMatcher)
vs.LabelMatchers = append(vs.LabelMatchers, nameMatcher)
}
// A Vector selector must contain at least one non-empty matcher to prevent
// implicit selection of all metrics (e.g. by a typo).
notEmpty := false
for _, lm := range ret.LabelMatchers {
for _, lm := range vs.LabelMatchers {
if !lm.Matches("") {
notEmpty = true
break
@ -329,8 +332,6 @@ func (p *parser) newVectorSelector(name string, labelMatchers []*labels.Matcher)
if !notEmpty {
p.errorf("vector selector must contain at least one non-empty matcher")
}
return ret
}
func (p *parser) newAggregateExpr(op Item, modifier Node, args Node) (ret *AggregateExpr) {
@ -364,6 +365,11 @@ func (p *parser) newAggregateExpr(op Item, modifier Node, args Node) (ret *Aggre
ret.Expr = arguments[desiredArgs-1]
ret.PosRange = PositionRange{
Start: op.Pos,
End: p.lastClosing,
}
return ret
}
@ -578,14 +584,18 @@ func (p *parser) newLabelMatcher(label Item, operator Item, value Item) *labels.
func (p *parser) addOffset(e Node, offset time.Duration) {
var offsetp *time.Duration
var endPosp *Pos
switch s := e.(type) {
case *VectorSelector:
offsetp = &s.Offset
endPosp = &s.PosRange.End
case *MatrixSelector:
offsetp = &s.VectorSelector.Offset
endPosp = &s.EndPos
case *SubqueryExpr:
offsetp = &s.Offset
endPosp = &s.EndPos
default:
p.errorf("offset modifier must be preceded by an instant or range selector, but follows a %T instead", e)
return
@ -598,4 +608,6 @@ func (p *parser) addOffset(e Node, offset time.Duration) {
*offsetp = offset
}
*endPosp = p.lastClosing
}

972
promql/parse_test.go
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