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ast.go
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ast.go
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package logql
import (
"bytes"
"fmt"
"regexp"
"github.com/grafana/loki/pkg/iter"
"github.com/prometheus/prometheus/pkg/labels"
)
// Filter is a line filter sent to a querier to filter out log line.
type Filter func([]byte) bool
// QuerierFunc implements Querier.
type QuerierFunc func([]*labels.Matcher, Filter) (iter.EntryIterator, error)
// Query implements Querier.
func (q QuerierFunc) Query(ms []*labels.Matcher, entryFilter Filter) (iter.EntryIterator, error) {
return q(ms, entryFilter)
}
// Querier allows a LogQL expression to fetch an EntryIterator for a
// set of matchers.
type Querier interface {
Query([]*labels.Matcher, Filter) (iter.EntryIterator, error)
}
// Expr is a LogQL expression.
type Expr interface {
Eval(Querier) (iter.EntryIterator, error)
Matchers() []*labels.Matcher
}
type matchersExpr struct {
matchers []*labels.Matcher
}
func (e *matchersExpr) Eval(q Querier) (iter.EntryIterator, error) {
return q.Query(e.matchers, nil)
}
func (e *matchersExpr) Matchers() []*labels.Matcher {
return e.matchers
}
type filterExpr struct {
left Expr
ty labels.MatchType
match string
}
func (e *filterExpr) Matchers() []*labels.Matcher {
return e.left.Matchers()
}
// NewFilterExpr wraps an existing Expr with a next filter expression.
func NewFilterExpr(left Expr, ty labels.MatchType, match string) Expr {
return &filterExpr{
left: left,
ty: ty,
match: match,
}
}
func (e *filterExpr) filter() (func([]byte) bool, error) {
var f func([]byte) bool
switch e.ty {
case labels.MatchRegexp:
re, err := regexp.Compile(e.match)
if err != nil {
return nil, err
}
f = re.Match
case labels.MatchNotRegexp:
re, err := regexp.Compile(e.match)
if err != nil {
return nil, err
}
f = func(line []byte) bool {
return !re.Match(line)
}
case labels.MatchEqual:
f = func(line []byte) bool {
return bytes.Contains(line, []byte(e.match))
}
case labels.MatchNotEqual:
f = func(line []byte) bool {
return !bytes.Contains(line, []byte(e.match))
}
default:
return nil, fmt.Errorf("unknow matcher: %v", e.match)
}
next, ok := e.left.(*filterExpr)
if ok {
nextFilter, err := next.filter()
if err != nil {
return nil, err
}
return func(line []byte) bool {
return nextFilter(line) && f(line)
}, nil
}
return f, nil
}
func (e *filterExpr) Eval(q Querier) (iter.EntryIterator, error) {
f, err := e.filter()
if err != nil {
return nil, err
}
next, err := q.Query(e.left.Matchers(), f)
if err != nil {
return nil, err
}
return next, nil
}
func mustNewMatcher(t labels.MatchType, n, v string) *labels.Matcher {
m, err := labels.NewMatcher(t, n, v)
if err != nil {
panic(err)
}
return m
}