Node/EVM: Add GetLatestBlocks API (#4274)

* Node/EVM: Add GetLatestBlocks API

* Code review rework

node/pkg/adminrpc/adminserver_test.go

@@ -72,6 +72,10 @@ func (m mockEVMConnector) SubscribeForBlocks(ctx context.Context, errC chan erro
 	panic("unimplemented")
 }
 
+func (e mockEVMConnector) GetLatest(ctx context.Context) (latest, finalized, safe uint64, err error) {
+	panic("unimplemented")
+}
+
 func (m mockEVMConnector) RawCallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error {
 	panic("unimplemented")
 }

node/pkg/watchers/evm/ccq_backfill.go

@@ -74,7 +74,7 @@ func (w *Watcher) ccqBackfillStart(ctx context.Context, errC chan error) {
 // ccqBackfillInit determines the maximum batch size to be used for backfilling the cache. It also loads the initial batch of timestamps.
 func (w *Watcher) ccqBackfillInit(ctx context.Context) error {
 	// Get the latest block so we can use that as the starting point in our cache.
-	latestBlock, err := connectors.GetLatestBlock(ctx, w.ccqLogger, w.ethConn)
+	latestBlock, err := connectors.GetLatestBlock(ctx, w.ethConn)
 	if err != nil {
 		return fmt.Errorf("failed to look up latest block: %w", err)
 	}

node/pkg/watchers/evm/connectors/batch_poller.go

@@ -135,6 +135,32 @@ func (b *BatchPollConnector) SubscribeForBlocks(ctx context.Context, errC chan e
 	return headerSubscription, nil
 }
 
+func (b *BatchPollConnector) GetLatest(ctx context.Context) (latest, finalized, safe uint64, err error) {
+	block, err := GetBlockByFinality(ctx, b.Connector, Latest)
+	if err != nil {
+		return 0, 0, 0, fmt.Errorf("failed to get latest block: %w", err)
+	}
+	latest = block.Number.Uint64()
+
+	block, err = GetBlockByFinality(ctx, b.Connector, Finalized)
+	if err != nil {
+		return 0, 0, 0, fmt.Errorf("failed to get finalized block: %w", err)
+	}
+	finalized = block.Number.Uint64()
+
+	if b.generateSafe {
+		safe = finalized
+	} else {
+		block, err = GetBlockByFinality(ctx, b.Connector, Safe)
+		if err != nil {
+			return 0, 0, 0, fmt.Errorf("failed to get safe block: %w", err)
+		}
+		safe = block.Number.Uint64()
+	}
+
+	return
+}
+
 // pollBlocks polls for the latest blocks (finalized, safe and latest), compares them to the last ones, and publishes any new ones.
 // In the case of an error, it returns the last blocks that were passed in, otherwise it returns the new blocks.
 func (b *BatchPollConnector) pollBlocks(ctx context.Context, sink chan<- *NewBlock, prevBlocks Blocks) (Blocks, error) {

node/pkg/watchers/evm/connectors/batch_poller_test.go

@@ -91,6 +91,10 @@ func (e *mockConnectorForBatchPoller) SubscribeForBlocks(ctx context.Context, er
 	return e.sub, fmt.Errorf("not implemented")
 }
 
+func (e *mockConnectorForBatchPoller) GetLatest(ctx context.Context) (latest, finalized, safe uint64, err error) {
+	return e.prevLatest, e.prevFinalized, e.prevSafe, nil
+}
+
 func (e *mockConnectorForBatchPoller) RawCallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error {
 	panic("method not implemented by mockConnectorForBatchPoller")
 }

node/pkg/watchers/evm/connectors/block_utils.go

@@ -0,0 +1,49 @@
+package connectors
+
+import (
+	"context"
+	"fmt"
+	"math/big"
+	"time"
+)
+
+func GetLatestBlock(ctx context.Context, conn Connector) (*NewBlock, error) {
+	return GetBlockByFinality(ctx, conn, Latest)
+}
+
+func GetBlockByFinality(ctx context.Context, conn Connector, blockFinality FinalityLevel) (*NewBlock, error) {
+	return GetBlock(ctx, conn, blockFinality.String(), blockFinality)
+}
+
+func GetBlockByNumberUint64(ctx context.Context, conn Connector, blockNum uint64, blockFinality FinalityLevel) (*NewBlock, error) {
+	return GetBlock(ctx, conn, "0x"+fmt.Sprintf("%x", blockNum), blockFinality)
+}
+
+func GetBlock(ctx context.Context, conn Connector, str string, blockFinality FinalityLevel) (*NewBlock, error) {
+	timeout, cancel := context.WithTimeout(ctx, 15*time.Second)
+	defer cancel()
+
+	var m BlockMarshaller
+	err := conn.RawCallContext(timeout, &m, "eth_getBlockByNumber", str, false)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get block for %s: %w", str, err)
+	}
+	if m.Number == nil {
+		return nil, fmt.Errorf("failed to unmarshal block for %s: Number is nil", str)
+	}
+	n := big.Int(*m.Number)
+
+	var l1bn *big.Int
+	if m.L1BlockNumber != nil {
+		bn := big.Int(*m.L1BlockNumber)
+		l1bn = &bn
+	}
+
+	return &NewBlock{
+		Number:        &n,
+		Time:          uint64(m.Time),
+		Hash:          m.Hash,
+		L1BlockNumber: l1bn,
+		Finality:      blockFinality,
+	}, nil
+}

node/pkg/watchers/evm/connectors/common.go

@@ -56,6 +56,7 @@ type Connector interface {
 	TimeOfBlockByHash(ctx context.Context, hash common.Hash) (uint64, error)
 	ParseLogMessagePublished(log types.Log) (*ethabi.AbiLogMessagePublished, error)
 	SubscribeForBlocks(ctx context.Context, errC chan error, sink chan<- *NewBlock) (ethereum.Subscription, error)
+	GetLatest(ctx context.Context) (latest, finalized, safe uint64, err error)
 	RawCallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error
 	RawBatchCallContext(ctx context.Context, b []rpc.BatchElem) error
 	Client() *ethClient.Client

node/pkg/watchers/evm/connectors/ethereum.go

@@ -101,6 +101,10 @@ func (e *EthereumBaseConnector) SubscribeForBlocks(ctx context.Context, errC cha
 	panic("not implemented")
 }
 
+func (e *EthereumBaseConnector) GetLatest(ctx context.Context) (latest, finalized, safe uint64, err error) {
+	panic("not implemented")
+}
+
 func (e *EthereumBaseConnector) RawCallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error {
 	return e.rawClient.CallContext(ctx, result, method, args...)
 }