Send trigger at each block

Author: jannikluhn

rolling-shutter/keyperimpl/gnosis/keyper.go

@@ -69,6 +69,8 @@ func (kpr *Keyper) Start(ctx context.Context, runner service.Runner) error {
 		return errors.Wrap(err, "can't instantiate keyper core")
 	}
 
+	triggerer := NewDecryptionTriggerer(kpr.config.Gnosis, decrTrigChan)
+
 	kpr.chainSyncClient, err = chainsync.NewClient(
 		ctx,
 		chainsync.WithClientURL(kpr.config.Gnosis.EthereumURL),
@@ -82,7 +84,7 @@ func (kpr *Keyper) Start(ctx context.Context, runner service.Runner) error {
 		return err
 	}
 
-	return runner.StartService(kpr.core, kpr.chainSyncClient)
+	return runner.StartService(kpr.core, triggerer, kpr.chainSyncClient)
 }
 
 func (kpr *Keyper) newBlock(_ context.Context, ev *syncevent.LatestBlock) error {

rolling-shutter/keyperimpl/gnosis/trigger.go

@@ -0,0 +1,80 @@
+package gnosis
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/rs/zerolog/log"
+
+	"github.com/shutter-network/rolling-shutter/rolling-shutter/keyper/epochkghandler"
+	"github.com/shutter-network/rolling-shutter/rolling-shutter/medley/broker"
+	"github.com/shutter-network/rolling-shutter/rolling-shutter/medley/configuration"
+	"github.com/shutter-network/rolling-shutter/rolling-shutter/medley/identitypreimage"
+	"github.com/shutter-network/rolling-shutter/rolling-shutter/medley/service"
+)
+
+type DecryptionTriggerer struct {
+	config                   *configuration.EthnodeConfig
+	decryptionTriggerChannel chan *broker.Event[*epochkghandler.DecryptionTrigger]
+}
+
+func NewDecryptionTriggerer(
+	config *configuration.EthnodeConfig,
+	decryptionTriggerChannel chan *broker.Event[*epochkghandler.DecryptionTrigger],
+) *DecryptionTriggerer {
+	return &DecryptionTriggerer{
+		config:                   config,
+		decryptionTriggerChannel: decryptionTriggerChannel,
+	}
+}
+
+func (t *DecryptionTriggerer) Start(ctx context.Context, runner service.Runner) error {
+	client, err := ethclient.DialContext(ctx, t.config.EthereumURL)
+	if err != nil {
+		return err
+	}
+	runner.Go(func() error {
+		headers := make(chan *types.Header)
+		headSubscription, err := client.SubscribeNewHead(ctx, headers)
+		if err != nil {
+			return err
+		}
+
+		for {
+			select {
+			case err := <-headSubscription.Err():
+				return err
+			case header := <-headers:
+				err := t.handleNewHead(ctx, header)
+				if err != nil {
+					return err
+				}
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+		}
+	})
+	return nil
+}
+
+func (t *DecryptionTriggerer) handleNewHead(_ context.Context, header *types.Header) error {
+	log.Debug().Uint64("block-number", header.Number.Uint64()).Msg("handling new head")
+
+	// create some random identities for testing
+	maxNumIdentityPreimages := uint64(2)
+	numIdentityPreimages := header.Number.Uint64()%maxNumIdentityPreimages + 1
+	identityPreimages := []identitypreimage.IdentityPreimage{}
+	for i := 0; i < int(numIdentityPreimages); i++ {
+		n := header.Number.Uint64()*maxNumIdentityPreimages + uint64(i)
+		identityPreimage := identitypreimage.Uint64ToIdentityPreimage(n)
+		identityPreimages = append(identityPreimages, identityPreimage)
+	}
+	trigger := epochkghandler.DecryptionTrigger{
+		BlockNumber:       header.Number.Uint64(),
+		IdentityPreimages: identityPreimages,
+	}
+	event := broker.NewEvent(&trigger)
+	t.decryptionTriggerChannel <- event
+	return nil
+}