recheck best known tipset after waiting for random beacon entry to become available

api/api_full.go

@@ -107,6 +107,14 @@ type FullNode interface {
 	// ChainExport returns a stream of bytes with CAR dump of chain data.
 	ChainExport(context.Context, types.TipSetKey) (<-chan []byte, error)
 
+	// MethodGroup: Beacon
+	// The Beacon method group contains methods for interacting with the random beacon (DRAND)
+
+	// BeaconGetEntry returns the beacon entry for the given filecoin epoch. If
+	// the entry has not yet been produced, the call will block until the entry
+	// becomes available
+	BeaconGetEntry(ctx context.Context, epoch abi.ChainEpoch) (*types.BeaconEntry, error)
+
 	// GasEstimateGasLimit estimates gas used by the message and returns it.
 	// It fails if message fails to execute.
 	GasEstimateGasLimit(context.Context, *types.Message, types.TipSetKey) (int64, error)

api/apistruct/struct.go

@@ -85,6 +85,8 @@ type FullNodeStruct struct {
 		ChainGetPath           func(context.Context, types.TipSetKey, types.TipSetKey) ([]*api.HeadChange, error)                                 `perm:"read"`
 		ChainExport            func(context.Context, types.TipSetKey) (<-chan []byte, error)                                                      `perm:"read"`
 
+		BeaconGetEntry func(ctx context.Context, epoch abi.ChainEpoch) (*types.BeaconEntry, error) `perm:"read"`
+
 		GasEstimateGasPrice func(context.Context, uint64, address.Address, int64, types.TipSetKey) (types.BigInt, error) `perm:"read"`
 		GasEstimateGasLimit func(context.Context, *types.Message, types.TipSetKey) (int64, error)                        `perm:"read"`
 
@@ -598,6 +600,10 @@ func (c *FullNodeStruct) ChainExport(ctx context.Context, tsk types.TipSetKey) (
 	return c.Internal.ChainExport(ctx, tsk)
 }
 
+func (c *FullNodeStruct) BeaconGetEntry(ctx context.Context, epoch abi.ChainEpoch) (*types.BeaconEntry, error) {
+	return c.Internal.BeaconGetEntry(ctx, epoch)
+}
+
 func (c *FullNodeStruct) SyncState(ctx context.Context) (*api.SyncState, error) {
 	return c.Internal.SyncState(ctx)
 }

miner/miner.go

@@ -147,6 +147,11 @@ func (m *Miner) mine(ctx context.Context) {
 		default:
 		}
 
+		var base *MiningBase
+		var onDone func(bool, error)
+		var injectNulls abi.ChainEpoch
+
+		for {
 			prebase, err := m.GetBestMiningCandidate(ctx)
 			if err != nil {
 				log.Errorf("failed to get best mining candidate: %s", err)
@@ -154,18 +159,27 @@ func (m *Miner) mine(ctx context.Context) {
 				continue
 			}
 
+			if base != nil && base.TipSet.Height() == prebase.TipSet.Height() && base.NullRounds == prebase.NullRounds {
+				break
+			}
+
 			// Wait until propagation delay period after block we plan to mine on
-		onDone, injectNulls, err := m.waitFunc(ctx, prebase.TipSet.MinTimestamp())
+			onDone, injectNulls, err = m.waitFunc(ctx, prebase.TipSet.MinTimestamp())
 			if err != nil {
 				log.Error(err)
 				continue
 			}
 
-		base, err := m.GetBestMiningCandidate(ctx)
+			// just wait for the beacon entry to become available before we select our final mining base
+			_, err = m.api.BeaconGetEntry(ctx, prebase.TipSet.Height()+prebase.NullRounds+1)
 			if err != nil {
-			log.Errorf("failed to get best mining candidate: %s", err)
+				log.Errorf("failed getting beacon entry: %s", err)
 				continue
 			}
+
+			base = prebase
+		}
+
 		if base.TipSet.Equals(lastBase.TipSet) && lastBase.NullRounds == base.NullRounds {
 			log.Warnf("BestMiningCandidate from the previous round: %s (nulls:%d)", lastBase.TipSet.Cids(), lastBase.NullRounds)
 			m.niceSleep(time.Duration(build.BlockDelaySecs) * time.Second)