add missing file

node/impl/full/beacon.go

@@ -0,0 +1,35 @@
+package full
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/filecoin-project/lotus/chain/beacon"
+	"github.com/filecoin-project/lotus/chain/types"
+	"github.com/filecoin-project/specs-actors/actors/abi"
+	"go.uber.org/fx"
+)
+
+type BeaconAPI struct {
+	fx.In
+
+	Beacon beacon.RandomBeacon
+}
+
+func (a *BeaconAPI) BeaconGetEntry(ctx context.Context, epoch abi.ChainEpoch) (*types.BeaconEntry, error) {
+	rr := a.Beacon.MaxBeaconRoundForEpoch(epoch, types.BeaconEntry{})
+	e := a.Beacon.Entry(ctx, rr)
+
+	select {
+	case be, ok := <-e:
+		if !ok {
+			return nil, fmt.Errorf("beacon get returned no value")
+		}
+		if be.Err != nil {
+			return nil, be.Err
+		}
+		return &be.Entry, nil
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}