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