crowdsec/pkg/leakybucket/uniq.go
Thibault "bui" Koechlin dbb420f79e
local api (#482)
Co-authored-by: AlteredCoder
Co-authored-by: erenJag
2020-11-30 10:37:17 +01:00

68 lines
2 KiB
Go

package leakybucket
import (
"github.com/antonmedv/expr"
"github.com/antonmedv/expr/vm"
"github.com/crowdsecurity/crowdsec/pkg/exprhelpers"
"github.com/crowdsecurity/crowdsec/pkg/types"
)
// Uniq creates three new functions that share the same initialisation and the same scope.
// They are triggered respectively:
// on pour
// on overflow
// on leak
type Uniq struct {
DistinctCompiled *vm.Program
}
func (u *Uniq) OnBucketPour(bucketFactory *BucketFactory) func(types.Event, *Leaky) *types.Event {
return func(msg types.Event, leaky *Leaky) *types.Event {
element, err := getElement(msg, u.DistinctCompiled)
if err != nil {
leaky.logger.Errorf("Uniq filter exec failed : %v", err)
return &msg
}
leaky.logger.Tracef("Uniq '%s' -> '%s'", bucketFactory.Distinct, element)
for _, evt := range leaky.Queue.GetQueue() {
if val, err := getElement(evt, u.DistinctCompiled); err == nil && val == element {
leaky.logger.Debugf("Uniq(%s) : ko, discard event", element)
return nil
}
if err != nil {
leaky.logger.Errorf("Uniq filter exec failed : %v", err)
}
}
leaky.logger.Debugf("Uniq(%s) : ok", element)
return &msg
}
}
func (u *Uniq) OnBucketOverflow(bucketFactory *BucketFactory) func(*Leaky, types.RuntimeAlert, *Queue) (types.RuntimeAlert, *Queue) {
return func(leaky *Leaky, alert types.RuntimeAlert, queue *Queue) (types.RuntimeAlert, *Queue) {
return alert, queue
}
}
func (u *Uniq) OnBucketInit(bucketFactory *BucketFactory) error {
var err error
u.DistinctCompiled, err = expr.Compile(bucketFactory.Distinct, expr.Env(exprhelpers.GetExprEnv(map[string]interface{}{"evt": &types.Event{}})))
return err
}
// getElement computes a string from an event and a filter
func getElement(msg types.Event, cFilter *vm.Program) (string, error) {
el, err := expr.Run(cFilter, exprhelpers.GetExprEnv(map[string]interface{}{"evt": &msg}))
if err != nil {
return "", err
}
element, ok := el.(string)
if !ok {
return "", err
}
return element, nil
}