prometheus/promql/parse.go

1100 lines
27 KiB
Go

// Copyright 2015 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 promql
import (
"fmt"
"math"
"os"
"runtime"
"sort"
"strconv"
"strings"
"time"
"github.com/pkg/errors"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/value"
"github.com/prometheus/prometheus/util/strutil"
)
type parser struct {
lex *Lexer
token Item
peeking bool
inject Item
injecting bool
switchSymbols []ItemType
generatedParserResult interface{}
}
// ParseErr wraps a parsing error with line and position context.
// If the parsing input was a single line, line will be 0 and omitted
// from the error string.
type ParseErr struct {
Line, Pos int
Err error
}
func (e *ParseErr) Error() string {
return fmt.Sprintf("%d:%d: parse error: %s", e.Line+1, e.Pos, e.Err)
}
// ParseExpr returns the expression parsed from the input.
func ParseExpr(input string) (Expr, error) {
p := newParser(input)
expr, err := p.parseExpr()
if err != nil {
return nil, err
}
err = p.typecheck(expr)
return expr, err
}
// ParseMetric parses the input into a metric
func ParseMetric(input string) (m labels.Labels, err error) {
p := newParser(input)
defer p.recover(&err)
m = p.metric()
if p.peek().Typ != EOF {
p.errorf("could not parse remaining input %.15q...", p.lex.input[p.lex.lastPos:])
}
return m, nil
}
// ParseMetricSelector parses the provided textual metric selector into a list of
// label matchers.
func ParseMetricSelector(input string) (m []*labels.Matcher, err error) {
p := newParser(input)
defer p.recover(&err)
name := ""
if t := p.peek().Typ; t == METRIC_IDENTIFIER || t == IDENTIFIER {
name = p.next().Val
}
vs := p.VectorSelector(name)
if p.peek().Typ != EOF {
p.errorf("could not parse remaining input %.15q...", p.lex.input[p.lex.lastPos:])
}
return vs.LabelMatchers, nil
}
// newParser returns a new parser.
func newParser(input string) *parser {
p := &parser{
lex: Lex(input),
}
return p
}
// parseExpr parses a single expression from the input.
func (p *parser) parseExpr() (expr Expr, err error) {
defer p.recover(&err)
for p.peek().Typ != EOF {
if expr != nil {
p.errorf("could not parse remaining input %.15q...", p.lex.input[p.lex.lastPos:])
}
expr = p.expr()
}
if expr == nil {
p.errorf("no expression found in input")
}
return
}
// sequenceValue is an omittable value in a sequence of time series values.
type sequenceValue struct {
value float64
omitted bool
}
func (v sequenceValue) String() string {
if v.omitted {
return "_"
}
return fmt.Sprintf("%f", v.value)
}
// parseSeriesDesc parses the description of a time series.
func parseSeriesDesc(input string) (labels.Labels, []sequenceValue, error) {
p := newParser(input)
p.lex.seriesDesc = true
return p.parseSeriesDesc()
}
// parseSeriesDesc parses a description of a time series into its metric and value sequence.
func (p *parser) parseSeriesDesc() (m labels.Labels, vals []sequenceValue, err error) {
defer p.recover(&err)
m = p.metric()
const ctx = "series values"
for {
for p.peek().Typ == SPACE {
p.next()
}
if p.peek().Typ == EOF {
break
}
// Extract blanks.
if p.peek().Typ == BLANK {
p.next()
times := uint64(1)
if p.peek().Typ == TIMES {
p.next()
times, err = strconv.ParseUint(p.expect(NUMBER, ctx).Val, 10, 64)
if err != nil {
p.errorf("invalid repetition in %s: %s", ctx, err)
}
}
for i := uint64(0); i < times; i++ {
vals = append(vals, sequenceValue{omitted: true})
}
// This is to ensure that there is a space between this and the next number.
// This is especially required if the next number is negative.
if t := p.expectOneOf(SPACE, EOF, ctx).Typ; t == EOF {
break
}
continue
}
// Extract values.
sign := 1.0
if t := p.peek().Typ; t == SUB || t == ADD {
if p.next().Typ == SUB {
sign = -1
}
}
var k float64
if t := p.peek().Typ; t == NUMBER {
k = sign * p.number(p.expect(NUMBER, ctx).Val)
} else if t == IDENTIFIER && p.peek().Val == "stale" {
p.next()
k = math.Float64frombits(value.StaleNaN)
} else {
p.errorf("expected number or 'stale' in %s but got %s (value: %s)", ctx, t.desc(), p.peek())
}
vals = append(vals, sequenceValue{
value: k,
})
// If there are no offset repetitions specified, proceed with the next value.
if t := p.peek(); t.Typ == SPACE {
// This ensures there is a space between every value.
continue
} else if t.Typ == EOF {
break
} else if t.Typ != ADD && t.Typ != SUB {
p.errorf("expected next value or relative expansion in %s but got %s (value: %s)", ctx, t.desc(), p.peek())
}
// Expand the repeated offsets into values.
sign = 1.0
if p.next().Typ == SUB {
sign = -1.0
}
offset := sign * p.number(p.expect(NUMBER, ctx).Val)
p.expect(TIMES, ctx)
times, err := strconv.ParseUint(p.expect(NUMBER, ctx).Val, 10, 64)
if err != nil {
p.errorf("invalid repetition in %s: %s", ctx, err)
}
for i := uint64(0); i < times; i++ {
k += offset
vals = append(vals, sequenceValue{
value: k,
})
}
// This is to ensure that there is a space between this expanding notation
// and the next number. This is especially required if the next number
// is negative.
if t := p.expectOneOf(SPACE, EOF, ctx).Typ; t == EOF {
break
}
}
return m, vals, nil
}
// typecheck checks correct typing of the parsed statements or expression.
func (p *parser) typecheck(node Node) (err error) {
defer p.recover(&err)
p.checkType(node)
return nil
}
// next returns the next token.
func (p *parser) next() Item {
if !p.peeking {
t := p.lex.NextItem()
// Skip comments.
for t.Typ == COMMENT {
t = p.lex.NextItem()
}
p.token = t
}
p.peeking = false
if p.token.Typ == ERROR {
p.errorf("%s", p.token.Val)
}
return p.token
}
// peek returns but does not consume the next token.
func (p *parser) peek() Item {
if p.peeking {
return p.token
}
p.peeking = true
t := p.lex.NextItem()
// Skip comments.
for t.Typ == COMMENT {
t = p.lex.NextItem()
}
p.token = t
return p.token
}
// backup backs the input stream up one token.
func (p *parser) backup() {
p.peeking = true
}
// errorf formats the error and terminates processing.
func (p *parser) errorf(format string, args ...interface{}) {
p.error(errors.Errorf(format, args...))
}
// error terminates processing.
func (p *parser) error(err error) {
perr := &ParseErr{
Line: p.lex.lineNumber(),
Pos: p.lex.linePosition(),
Err: err,
}
if strings.Count(strings.TrimSpace(p.lex.input), "\n") == 0 {
perr.Line = 0
}
panic(perr)
}
// expect consumes the next token and guarantees it has the required type.
func (p *parser) expect(exp ItemType, context string) Item {
token := p.next()
if token.Typ != exp {
p.errorf("unexpected %s in %s, expected %s", token.desc(), context, exp.desc())
}
return token
}
// expectOneOf consumes the next token and guarantees it has one of the required types.
func (p *parser) expectOneOf(exp1, exp2 ItemType, context string) Item {
token := p.next()
if token.Typ != exp1 && token.Typ != exp2 {
p.errorf("unexpected %s in %s, expected %s or %s", token.desc(), context, exp1.desc(), exp2.desc())
}
return token
}
var errUnexpected = errors.New("unexpected error")
// recover is the handler that turns panics into returns from the top level of Parse.
func (p *parser) recover(errp *error) {
e := recover()
if _, ok := e.(runtime.Error); ok {
// Print the stack trace but do not inhibit the running application.
buf := make([]byte, 64<<10)
buf = buf[:runtime.Stack(buf, false)]
fmt.Fprintf(os.Stderr, "parser panic: %v\n%s", e, buf)
*errp = errUnexpected
} else if e != nil {
*errp = e.(error)
}
p.lex.close()
}
// Lex is expected by the yyLexer interface of the yacc generated parser.
// It writes the next Item provided by the lexer to the provided pointer address.
// Comments are skipped.
//
// The yyLexer interface is currently implemented by the parser to allow
// the generated and non-generated parts to work together with regards to lookahead
// and error handling.
//
// For more information, see https://godoc.org/golang.org/x/tools/cmd/goyacc.
func (p *parser) Lex(lval *yySymType) int {
if p.injecting {
lval.item = p.inject
p.injecting = false
} else {
lval.item = p.next()
}
typ := lval.item.Typ
for _, t := range p.switchSymbols {
if t == typ {
p.InjectItem(0)
}
}
return int(typ)
}
// Error is expected by the yyLexer interface of the yacc generated parser.
//
// It is a no-op since the parsers error routines are triggered
// by mechanisms that allow more fine grained control
// For more information, see https://godoc.org/golang.org/x/tools/cmd/goyacc.
func (p *parser) Error(e string) {
}
// InjectItem allows injecting a single Item at the beginning of the token stream
// consumed by the generated parser.
// This allows having multiple start symbols as described in
// https://www.gnu.org/software/bison/manual/html_node/Multiple-start_002dsymbols.html .
// Only the Lex function used by the generated parser is affected by this injected Item.
// Trying to inject when a previously injected Item has not yet been consumed will panic.
// Only Item types that are supposed to be used as start symbols are allowed as an argument.
func (p *parser) InjectItem(typ ItemType) {
if p.injecting {
panic("cannot inject multiple Items into the token stream")
}
if typ != 0 && (typ <= startSymbolsStart || typ >= startSymbolsEnd) {
panic("cannot inject symbol that isn't start symbol")
}
p.inject = Item{Typ: typ}
p.injecting = true
}
// expr parses any expression.
func (p *parser) expr() Expr {
// Parse the starting expression.
expr := p.unaryExpr()
// Loop through the operations and construct a binary operation tree based
// on the operators' precedence.
for {
// If the next token is not an operator the expression is done.
op := p.peek().Typ
if !op.isOperator() {
// Check for subquery.
if op == LEFT_BRACKET {
expr = p.subqueryOrRangeSelector(expr, false)
if s, ok := expr.(*SubqueryExpr); ok {
// Parse optional offset.
if p.peek().Typ == OFFSET {
offset := p.offset()
s.Offset = offset
}
}
}
return expr
}
p.next() // Consume operator.
// Parse optional operator matching options. Its validity
// is checked in the type-checking stage.
vecMatching := &VectorMatching{
Card: CardOneToOne,
}
if op.isSetOperator() {
vecMatching.Card = CardManyToMany
}
returnBool := false
// Parse bool modifier.
if p.peek().Typ == BOOL {
if !op.isComparisonOperator() {
p.errorf("bool modifier can only be used on comparison operators")
}
p.next()
returnBool = true
}
// Parse ON/IGNORING clause.
if p.peek().Typ == ON || p.peek().Typ == IGNORING {
if p.peek().Typ == ON {
vecMatching.On = true
}
p.next()
vecMatching.MatchingLabels = p.labels()
// Parse grouping.
if t := p.peek().Typ; t == GROUP_LEFT || t == GROUP_RIGHT {
p.next()
if t == GROUP_LEFT {
vecMatching.Card = CardManyToOne
} else {
vecMatching.Card = CardOneToMany
}
if p.peek().Typ == LEFT_PAREN {
vecMatching.Include = p.labels()
}
}
}
for _, ln := range vecMatching.MatchingLabels {
for _, ln2 := range vecMatching.Include {
if ln == ln2 && vecMatching.On {
p.errorf("label %q must not occur in ON and GROUP clause at once", ln)
}
}
}
// Parse the next operand.
rhs := p.unaryExpr()
// Assign the new root based on the precedence of the LHS and RHS operators.
expr = p.balance(expr, op, rhs, vecMatching, returnBool)
}
}
func (p *parser) balance(lhs Expr, op ItemType, rhs Expr, vecMatching *VectorMatching, returnBool bool) *BinaryExpr {
if lhsBE, ok := lhs.(*BinaryExpr); ok {
precd := lhsBE.Op.precedence() - op.precedence()
if (precd < 0) || (precd == 0 && op.isRightAssociative()) {
balanced := p.balance(lhsBE.RHS, op, rhs, vecMatching, returnBool)
if lhsBE.Op.isComparisonOperator() && !lhsBE.ReturnBool && balanced.Type() == ValueTypeScalar && lhsBE.LHS.Type() == ValueTypeScalar {
p.errorf("comparisons between scalars must use BOOL modifier")
}
return &BinaryExpr{
Op: lhsBE.Op,
LHS: lhsBE.LHS,
RHS: balanced,
VectorMatching: lhsBE.VectorMatching,
ReturnBool: lhsBE.ReturnBool,
}
}
}
if op.isComparisonOperator() && !returnBool && rhs.Type() == ValueTypeScalar && lhs.Type() == ValueTypeScalar {
p.errorf("comparisons between scalars must use BOOL modifier")
}
return &BinaryExpr{
Op: op,
LHS: lhs,
RHS: rhs,
VectorMatching: vecMatching,
ReturnBool: returnBool,
}
}
// unaryExpr parses a unary expression.
//
// <Vector_selector> | <Matrix_selector> | (+|-) <number_literal> | '(' <expr> ')'
//
func (p *parser) unaryExpr() Expr {
switch t := p.peek(); t.Typ {
case ADD, SUB:
p.next()
e := p.unaryExpr()
// Simplify unary expressions for number literals.
if nl, ok := e.(*NumberLiteral); ok {
if t.Typ == SUB {
nl.Val *= -1
}
return nl
}
return &UnaryExpr{Op: t.Typ, Expr: e}
case LEFT_PAREN:
p.next()
e := p.expr()
p.expect(RIGHT_PAREN, "paren expression")
return &ParenExpr{Expr: e}
}
e := p.primaryExpr()
// Expression might be followed by a range selector.
if p.peek().Typ == LEFT_BRACKET {
e = p.subqueryOrRangeSelector(e, true)
}
// Parse optional offset.
if p.peek().Typ == OFFSET {
offset := p.offset()
switch s := e.(type) {
case *VectorSelector:
s.Offset = offset
case *MatrixSelector:
s.Offset = offset
case *SubqueryExpr:
s.Offset = offset
default:
p.errorf("offset modifier must be preceded by an instant or range selector, but follows a %T instead", e)
}
}
return e
}
// subqueryOrRangeSelector parses a Subquery based on given Expr (or)
// a Matrix (a.k.a. range) selector based on a given Vector selector.
//
// <Vector_selector> '[' <duration> ']' | <Vector_selector> '[' <duration> ':' [<duration>] ']'
//
func (p *parser) subqueryOrRangeSelector(expr Expr, checkRange bool) Expr {
ctx := "subquery selector"
if checkRange {
ctx = "range/subquery selector"
}
p.next()
var erange time.Duration
var err error
erangeStr := p.expect(DURATION, ctx).Val
erange, err = parseDuration(erangeStr)
if err != nil {
p.error(err)
}
var itm Item
if checkRange {
itm = p.expectOneOf(RIGHT_BRACKET, COLON, ctx)
if itm.Typ == RIGHT_BRACKET {
// Range selector.
vs, ok := expr.(*VectorSelector)
if !ok {
p.errorf("range specification must be preceded by a metric selector, but follows a %T instead", expr)
}
return &MatrixSelector{
Name: vs.Name,
LabelMatchers: vs.LabelMatchers,
Range: erange,
}
}
} else {
itm = p.expect(COLON, ctx)
}
// Subquery.
var estep time.Duration
itm = p.expectOneOf(RIGHT_BRACKET, DURATION, ctx)
if itm.Typ == DURATION {
estepStr := itm.Val
estep, err = parseDuration(estepStr)
if err != nil {
p.error(err)
}
p.expect(RIGHT_BRACKET, ctx)
}
return &SubqueryExpr{
Expr: expr,
Range: erange,
Step: estep,
}
}
// number parses a number.
func (p *parser) number(val string) float64 {
n, err := strconv.ParseInt(val, 0, 64)
f := float64(n)
if err != nil {
f, err = strconv.ParseFloat(val, 64)
}
if err != nil {
p.errorf("error parsing number: %s", err)
}
return f
}
// primaryExpr parses a primary expression.
//
// <metric_name> | <function_call> | <Vector_aggregation> | <literal>
//
func (p *parser) primaryExpr() Expr {
switch t := p.next(); {
case t.Typ == NUMBER:
f := p.number(t.Val)
return &NumberLiteral{f}
case t.Typ == STRING:
return &StringLiteral{p.unquoteString(t.Val)}
case t.Typ == LEFT_BRACE:
// Metric selector without metric name.
p.backup()
return p.VectorSelector("")
case t.Typ == IDENTIFIER:
// Check for function call.
if p.peek().Typ == LEFT_PAREN {
return p.call(t.Val)
}
fallthrough // Else metric selector.
case t.Typ == METRIC_IDENTIFIER:
return p.VectorSelector(t.Val)
case t.Typ.isAggregator():
p.backup()
return p.aggrExpr()
default:
p.errorf("no valid expression found")
}
return nil
}
// labels parses a list of labelnames.
//
// '(' <label_name>, ... ')'
//
func (p *parser) labels() []string {
const ctx = "grouping opts"
p.expect(LEFT_PAREN, ctx)
labels := []string{}
if p.peek().Typ != RIGHT_PAREN {
for {
id := p.next()
if !isLabel(id.Val) {
p.errorf("unexpected %s in %s, expected label", id.desc(), ctx)
}
labels = append(labels, id.Val)
if p.peek().Typ != COMMA {
break
}
p.next()
}
}
p.expect(RIGHT_PAREN, ctx)
return labels
}
// aggrExpr parses an aggregation expression.
//
// <aggr_op> (<Vector_expr>) [by|without <labels>]
// <aggr_op> [by|without <labels>] (<Vector_expr>)
//
func (p *parser) aggrExpr() *AggregateExpr {
const ctx = "aggregation"
agop := p.next()
if !agop.Typ.isAggregator() {
p.errorf("expected aggregation operator but got %s", agop)
}
var grouping []string
var without bool
modifiersFirst := false
if t := p.peek().Typ; t == BY || t == WITHOUT {
if t == WITHOUT {
without = true
}
p.next()
grouping = p.labels()
modifiersFirst = true
}
p.expect(LEFT_PAREN, ctx)
var param Expr
if agop.Typ.isAggregatorWithParam() {
param = p.expr()
p.expect(COMMA, ctx)
}
e := p.expr()
p.expect(RIGHT_PAREN, ctx)
if !modifiersFirst {
if t := p.peek().Typ; t == BY || t == WITHOUT {
if len(grouping) > 0 {
p.errorf("aggregation must only contain one grouping clause")
}
if t == WITHOUT {
without = true
}
p.next()
grouping = p.labels()
}
}
return &AggregateExpr{
Op: agop.Typ,
Expr: e,
Param: param,
Grouping: grouping,
Without: without,
}
}
// call parses a function call.
//
// <func_name> '(' [ <arg_expr>, ...] ')'
//
func (p *parser) call(name string) *Call {
const ctx = "function call"
fn, exist := getFunction(name)
if !exist {
p.errorf("unknown function with name %q", name)
}
p.expect(LEFT_PAREN, ctx)
// Might be call without args.
if p.peek().Typ == RIGHT_PAREN {
p.next() // Consume.
return &Call{fn, nil}
}
var args []Expr
for {
e := p.expr()
args = append(args, e)
// Terminate if no more arguments.
if p.peek().Typ != COMMA {
break
}
p.next()
}
// Call must be closed.
p.expect(RIGHT_PAREN, ctx)
return &Call{Func: fn, Args: args}
}
// labelSet parses a set of label matchers
//
// '{' [ <labelname> '=' <match_string>, ... ] '}'
//
func (p *parser) labelSet() labels.Labels {
return p.parseGenerated(START_LABEL_SET, []ItemType{RIGHT_BRACE, EOF}).(labels.Labels)
}
// metric parses a metric.
//
// <label_set>
// <metric_identifier> [<label_set>]
//
func (p *parser) metric() labels.Labels {
name := ""
var m labels.Labels
t := p.peek().Typ
if t == IDENTIFIER || t == METRIC_IDENTIFIER {
name = p.next().Val
t = p.peek().Typ
}
if t != LEFT_BRACE && name == "" {
p.errorf("missing metric name or metric selector")
}
if t == LEFT_BRACE {
m = p.labelSet()
}
if name != "" {
m = append(m, labels.Label{Name: labels.MetricName, Value: name})
sort.Sort(m)
}
return m
}
// offset parses an offset modifier.
//
// offset <duration>
//
func (p *parser) offset() time.Duration {
const ctx = "offset"
p.next()
offi := p.expect(DURATION, ctx)
offset, err := parseDuration(offi.Val)
if err != nil {
p.error(err)
}
return offset
}
// VectorSelector parses a new (instant) vector selector.
//
// <metric_identifier> [<label_matchers>]
// [<metric_identifier>] <label_matchers>
//
func (p *parser) VectorSelector(name string) *VectorSelector {
ret := &VectorSelector{
Name: name,
}
// Parse label matching if any.
if t := p.peek(); t.Typ == LEFT_BRACE {
p.generatedParserResult = ret
p.parseGenerated(START_LABELS, []ItemType{RIGHT_BRACE, EOF})
}
// Metric name must not be set in the label matchers and before at the same time.
if name != "" {
for _, m := range ret.LabelMatchers {
if m.Name == labels.MetricName {
p.errorf("metric name must not be set twice: %q or %q", name, m.Value)
}
}
// Set name label matching.
m, err := labels.NewMatcher(labels.MatchEqual, labels.MetricName, name)
if err != nil {
panic(err) // Must not happen with metric.Equal.
}
ret.LabelMatchers = append(ret.LabelMatchers, m)
}
if len(ret.LabelMatchers) == 0 {
p.errorf("vector selector must contain label matchers or metric name")
}
// 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 {
if !lm.Matches("") {
notEmpty = true
break
}
}
if !notEmpty {
p.errorf("vector selector must contain at least one non-empty matcher")
}
return ret
}
// expectType checks the type of the node and raises an error if it
// is not of the expected type.
func (p *parser) expectType(node Node, want ValueType, context string) {
t := p.checkType(node)
if t != want {
p.errorf("expected type %s in %s, got %s", documentedType(want), context, documentedType(t))
}
}
// check the types of the children of each node and raise an error
// if they do not form a valid node.
//
// Some of these checks are redundant as the parsing stage does not allow
// them, but the costs are small and might reveal errors when making changes.
func (p *parser) checkType(node Node) (typ ValueType) {
// For expressions the type is determined by their Type function.
// Lists do not have a type but are not invalid either.
switch n := node.(type) {
case Expressions:
typ = ValueTypeNone
case Expr:
typ = n.Type()
default:
p.errorf("unknown node type: %T", node)
}
// Recursively check correct typing for child nodes and raise
// errors in case of bad typing.
switch n := node.(type) {
case *EvalStmt:
ty := p.checkType(n.Expr)
if ty == ValueTypeNone {
p.errorf("evaluation statement must have a valid expression type but got %s", documentedType(ty))
}
case Expressions:
for _, e := range n {
ty := p.checkType(e)
if ty == ValueTypeNone {
p.errorf("expression must have a valid expression type but got %s", documentedType(ty))
}
}
case *AggregateExpr:
if !n.Op.isAggregator() {
p.errorf("aggregation operator expected in aggregation expression but got %q", n.Op)
}
p.expectType(n.Expr, ValueTypeVector, "aggregation expression")
if n.Op == TOPK || n.Op == BOTTOMK || n.Op == QUANTILE {
p.expectType(n.Param, ValueTypeScalar, "aggregation parameter")
}
if n.Op == COUNT_VALUES {
p.expectType(n.Param, ValueTypeString, "aggregation parameter")
}
case *BinaryExpr:
lt := p.checkType(n.LHS)
rt := p.checkType(n.RHS)
if !n.Op.isOperator() {
p.errorf("binary expression does not support operator %q", n.Op)
}
if (lt != ValueTypeScalar && lt != ValueTypeVector) || (rt != ValueTypeScalar && rt != ValueTypeVector) {
p.errorf("binary expression must contain only scalar and instant vector types")
}
if (lt != ValueTypeVector || rt != ValueTypeVector) && n.VectorMatching != nil {
if len(n.VectorMatching.MatchingLabels) > 0 {
p.errorf("vector matching only allowed between instant vectors")
}
n.VectorMatching = nil
} else {
// Both operands are Vectors.
if n.Op.isSetOperator() {
if n.VectorMatching.Card == CardOneToMany || n.VectorMatching.Card == CardManyToOne {
p.errorf("no grouping allowed for %q operation", n.Op)
}
if n.VectorMatching.Card != CardManyToMany {
p.errorf("set operations must always be many-to-many")
}
}
}
if (lt == ValueTypeScalar || rt == ValueTypeScalar) && n.Op.isSetOperator() {
p.errorf("set operator %q not allowed in binary scalar expression", n.Op)
}
case *Call:
nargs := len(n.Func.ArgTypes)
if n.Func.Variadic == 0 {
if nargs != len(n.Args) {
p.errorf("expected %d argument(s) in call to %q, got %d", nargs, n.Func.Name, len(n.Args))
}
} else {
na := nargs - 1
if na > len(n.Args) {
p.errorf("expected at least %d argument(s) in call to %q, got %d", na, n.Func.Name, len(n.Args))
} else if nargsmax := na + n.Func.Variadic; n.Func.Variadic > 0 && nargsmax < len(n.Args) {
p.errorf("expected at most %d argument(s) in call to %q, got %d", nargsmax, n.Func.Name, len(n.Args))
}
}
for i, arg := range n.Args {
if i >= len(n.Func.ArgTypes) {
i = len(n.Func.ArgTypes) - 1
}
p.expectType(arg, n.Func.ArgTypes[i], fmt.Sprintf("call to function %q", n.Func.Name))
}
case *ParenExpr:
p.checkType(n.Expr)
case *UnaryExpr:
if n.Op != ADD && n.Op != SUB {
p.errorf("only + and - operators allowed for unary expressions")
}
if t := p.checkType(n.Expr); t != ValueTypeScalar && t != ValueTypeVector {
p.errorf("unary expression only allowed on expressions of type scalar or instant vector, got %q", documentedType(t))
}
case *SubqueryExpr:
ty := p.checkType(n.Expr)
if ty != ValueTypeVector {
p.errorf("subquery is only allowed on instant vector, got %s in %q instead", ty, n.String())
}
case *NumberLiteral, *MatrixSelector, *StringLiteral, *VectorSelector:
// Nothing to do for terminals.
default:
p.errorf("unknown node type: %T", node)
}
return
}
func (p *parser) unquoteString(s string) string {
unquoted, err := strutil.Unquote(s)
if err != nil {
p.errorf("error unquoting string %q: %s", s, err)
}
return unquoted
}
func parseDuration(ds string) (time.Duration, error) {
dur, err := model.ParseDuration(ds)
if err != nil {
return 0, err
}
if dur == 0 {
return 0, errors.New("duration must be greater than 0")
}
return time.Duration(dur), nil
}
// parseGenerated invokes the yacc generated parser.
// The generated parser gets the provided startSymbol injected into
// the lexer stream, based on which grammar will be used.
//
// The generated parser will consume the lexer Stream until one of the
// tokens listed in switchSymbols is encountered. switchSymbols
// should at least contain EOF
func (p *parser) parseGenerated(startSymbol ItemType, switchSymbols []ItemType) interface{} {
p.InjectItem(startSymbol)
p.switchSymbols = switchSymbols
yyParse(p)
return p.generatedParserResult
}
func (p *parser) newLabelMatcher(label Item, operator Item, value Item) *labels.Matcher {
op := operator.Typ
val := p.unquoteString(value.Val)
// Map the Item to the respective match type.
var matchType labels.MatchType
switch op {
case EQL:
matchType = labels.MatchEqual
case NEQ:
matchType = labels.MatchNotEqual
case EQL_REGEX:
matchType = labels.MatchRegexp
case NEQ_REGEX:
matchType = labels.MatchNotRegexp
default:
// This should never happen, since the error should have been chaught
// by the generated parser.
panic("invalid operator")
}
m, err := labels.NewMatcher(matchType, label.Val, val)
if err != nil {
p.error(err)
}
return m
}