op-program: Implement caching for the L2 oracle.

op-program/client/l2/cache.go

+package l2
+
+import (
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+type CachingOracle struct {
+	oracle Oracle
+	blocks map[common.Hash]*types.Block
+	nodes  map[common.Hash][]byte
+	codes  map[common.Hash][]byte
+}
+
+func NewCachingOracle(oracle Oracle) *CachingOracle {
+	return &CachingOracle{
+		oracle: oracle,
+		blocks: make(map[common.Hash]*types.Block),
+		nodes:  make(map[common.Hash][]byte),
+		codes:  make(map[common.Hash][]byte),
+	}
+}
+
+func (o CachingOracle) NodeByHash(nodeHash common.Hash) []byte {
+	node, ok := o.nodes[nodeHash]
+	if ok {
+		return node
+	}
+	node = o.oracle.NodeByHash(nodeHash)
+	o.nodes[nodeHash] = node
+	return node
+}
+
+func (o CachingOracle) CodeByHash(codeHash common.Hash) []byte {
+	code, ok := o.codes[codeHash]
+	if ok {
+		return code
+	}
+	code = o.oracle.CodeByHash(codeHash)
+	o.codes[codeHash] = code
+	return code
+}
+
+func (o CachingOracle) BlockByHash(blockHash common.Hash) *types.Block {
+	block, ok := o.blocks[blockHash]
+	if ok {
+		return block
+	}
+	block = o.oracle.BlockByHash(blockHash)
+	o.blocks[blockHash] = block
+	return block
+}

op-program/client/l2/cache_test.go

+package l2
+
+import (
+	"math/rand"
+	"testing"
+
+	"github.com/ethereum-optimism/optimism/op-node/testutils"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/require"
+)
+
+// Should be an Oracle implementation
+var _ Oracle = (*CachingOracle)(nil)
+
+func TestBlockByHash(t *testing.T) {
+	stub, _ := newStubOracle(t)
+	oracle := NewCachingOracle(stub)
+
+	rng := rand.New(rand.NewSource(1))
+	block, _ := testutils.RandomBlock(rng, 1)
+
+	// Initial call retrieves from the stub
+	stub.blocks[block.Hash()] = block
+	actual := oracle.BlockByHash(block.Hash())
+	require.Equal(t, block, actual)
+
+	// Later calls should retrieve from cache
+	delete(stub.blocks, block.Hash())
+	actual = oracle.BlockByHash(block.Hash())
+	require.Equal(t, block, actual)
+}
+
+func TestNodeByHash(t *testing.T) {
+	stub, stateStub := newStubOracle(t)
+	oracle := NewCachingOracle(stub)
+
+	node := []byte{12, 3, 4}
+	hash := common.Hash{0xaa}
+
+	// Initial call retrieves from the stub
+	stateStub.data[hash] = node
+	actual := oracle.NodeByHash(hash)
+	require.Equal(t, node, actual)
+
+	// Later calls should retrieve from cache
+	delete(stateStub.data, hash)
+	actual = oracle.NodeByHash(hash)
+	require.Equal(t, node, actual)
+}
+
+func TestCodeByHash(t *testing.T) {
+	stub, stateStub := newStubOracle(t)
+	oracle := NewCachingOracle(stub)
+
+	node := []byte{12, 3, 4}
+	hash := common.Hash{0xaa}
+
+	// Initial call retrieves from the stub
+	stateStub.code[hash] = node
+	actual := oracle.CodeByHash(hash)
+	require.Equal(t, node, actual)
+
+	// Later calls should retrieve from cache
+	delete(stateStub.code, hash)
+	actual = oracle.CodeByHash(hash)
+	require.Equal(t, node, actual)
+}

op-program/client/l2/db_test.go

@@ -194,51 +194,3 @@ func assertStateDataAvailable(t *testing.T, db ethdb.KeyValueStore, l2Genesis *c
 	require.Nil(t, statedb.GetCode(unknownAccount), "unset account code")
 	require.Equal(t, common.Hash{}, statedb.GetCodeHash(unknownAccount), "unset account code hash")
 }
-
-func newStubStateOracle(t *testing.T) *stubStateOracle {
-	return &stubStateOracle{
-		t:    t,
-		data: make(map[common.Hash][]byte),
-		code: make(map[common.Hash][]byte),
-	}
-}
-
-type stubStateOracle struct {
-	t    *testing.T
-	data map[common.Hash][]byte
-	code map[common.Hash][]byte
-}
-
-func (o *stubStateOracle) NodeByHash(nodeHash common.Hash) []byte {
-	data, ok := o.data[nodeHash]
-	if !ok {
-		o.t.Fatalf("no value for node %v", nodeHash)
-	}
-	return data
-}
-
-func (o *stubStateOracle) CodeByHash(hash common.Hash) []byte {
-	data, ok := o.code[hash]
-	if !ok {
-		o.t.Fatalf("no value for code %v", hash)
-	}
-	return data
-}
-
-// kvStateOracle loads data from a source ethdb.KeyValueStore
-type kvStateOracle struct {
-	t      *testing.T
-	source ethdb.KeyValueStore
-}
-
-func (o *kvStateOracle) NodeByHash(nodeHash common.Hash) []byte {
-	val, err := o.source.Get(nodeHash.Bytes())
-	if err != nil {
-		o.t.Fatalf("error retrieving node %v: %v", nodeHash, err)
-	}
-	return val
-}
-
-func (o *kvStateOracle) CodeByHash(hash common.Hash) []byte {
-	return rawdb.ReadCode(o.source, hash)
-}

op-program/client/l2/engine_backend_test.go

@@ -14,7 +14,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
-	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/stretchr/testify/require"
@@ -168,7 +167,7 @@ func setupOracle(t *testing.T, blockCount int, headBlockNumber int) (*params.Cha
 	genesisBlock := l2Genesis.MustCommit(db)
 	blocks, _ := core.GenerateChain(chainCfg, genesisBlock, consensus, db, blockCount, func(i int, gen *core.BlockGen) {})
 	blocks = append([]*types.Block{genesisBlock}, blocks...)
-	oracle := newStubBlockOracle(t, blocks[:headBlockNumber+1], db)
+	oracle := newStubOracleWithBlocks(t, blocks[:headBlockNumber+1], db)
 	return chainCfg, blocks, oracle
 }
 
@@ -195,30 +194,6 @@ func createBlock(t *testing.T, chain *OracleBackedL2Chain) *types.Block {
 	return blocks[0]
 }
 
-type stubBlockOracle struct {
-	blocks map[common.Hash]*types.Block
-	kvStateOracle
-}
-
-func newStubBlockOracle(t *testing.T, chain []*types.Block, db ethdb.Database) *stubBlockOracle {
-	blocks := make(map[common.Hash]*types.Block, len(chain))
-	for _, block := range chain {
-		blocks[block.Hash()] = block
-	}
-	return &stubBlockOracle{
-		blocks:        blocks,
-		kvStateOracle: kvStateOracle{t: t, source: db},
-	}
-}
-
-func (o stubBlockOracle) BlockByHash(blockHash common.Hash) *types.Block {
-	block, ok := o.blocks[blockHash]
-	if !ok {
-		o.t.Fatalf("requested unknown block %s", blockHash)
-	}
-	return block
-}
-
 func TestEngineAPITests(t *testing.T) {
 	test.RunEngineAPITests(t, func(t *testing.T) engineapi.EngineBackend {
 		_, chain := setupOracleBackedChain(t, 0)

op-program/client/l2/stub_oracle_test.go

+package l2
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethdb"
+)
+
+type stubBlockOracle struct {
+	t      *testing.T
+	blocks map[common.Hash]*types.Block
+	StateOracle
+}
+
+func newStubOracle(t *testing.T) (*stubBlockOracle, *stubStateOracle) {
+	stateOracle := newStubStateOracle(t)
+	blockOracle := stubBlockOracle{
+		t:           t,
+		blocks:      make(map[common.Hash]*types.Block),
+		StateOracle: stateOracle,
+	}
+	return &blockOracle, stateOracle
+}
+
+func newStubOracleWithBlocks(t *testing.T, chain []*types.Block, db ethdb.Database) *stubBlockOracle {
+	blocks := make(map[common.Hash]*types.Block, len(chain))
+	for _, block := range chain {
+		blocks[block.Hash()] = block
+	}
+	return &stubBlockOracle{
+		blocks:      blocks,
+		StateOracle: &kvStateOracle{t: t, source: db},
+	}
+}
+
+func (o stubBlockOracle) BlockByHash(blockHash common.Hash) *types.Block {
+	block, ok := o.blocks[blockHash]
+	if !ok {
+		o.t.Fatalf("requested unknown block %s", blockHash)
+	}
+	return block
+}
+
+// kvStateOracle loads data from a source ethdb.KeyValueStore
+type kvStateOracle struct {
+	t      *testing.T
+	source ethdb.KeyValueStore
+}
+
+func (o *kvStateOracle) NodeByHash(nodeHash common.Hash) []byte {
+	val, err := o.source.Get(nodeHash.Bytes())
+	if err != nil {
+		o.t.Fatalf("error retrieving node %v: %v", nodeHash, err)
+	}
+	return val
+}
+
+func (o *kvStateOracle) CodeByHash(hash common.Hash) []byte {
+	return rawdb.ReadCode(o.source, hash)
+}
+
+func newStubStateOracle(t *testing.T) *stubStateOracle {
+	return &stubStateOracle{
+		t:    t,
+		data: make(map[common.Hash][]byte),
+		code: make(map[common.Hash][]byte),
+	}
+}
+
+// Stub StateOracle implementation that reads from simple maps
+type stubStateOracle struct {
+	t    *testing.T
+	data map[common.Hash][]byte
+	code map[common.Hash][]byte
+}
+
+func (o *stubStateOracle) NodeByHash(nodeHash common.Hash) []byte {
+	data, ok := o.data[nodeHash]
+	if !ok {
+		o.t.Fatalf("no value for node %v", nodeHash)
+	}
+	return data
+}
+
+func (o *stubStateOracle) CodeByHash(hash common.Hash) []byte {
+	data, ok := o.code[hash]
+	if !ok {
+		o.t.Fatalf("no value for code %v", hash)
+	}
+	return data
+}

op-program/host/l2/l2.go

@@ -19,10 +19,11 @@ func NewFetchingEngine(ctx context.Context, logger log.Logger, cfg *config.Confi
 	if err != nil {
 		return nil, err
 	}
-	oracle, err := NewFetchingL2Oracle(ctx, logger, cfg.L2URL, cfg.L2Head)
+	fetcher, err := NewFetchingL2Oracle(ctx, logger, cfg.L2URL, cfg.L2Head)
 	if err != nil {
 		return nil, fmt.Errorf("connect l2 oracle: %w", err)
 	}
+	oracle := cll2.NewCachingOracle(fetcher)
 
 	engineBackend, err := cll2.NewOracleBackedL2Chain(logger, oracle, genesis, cfg.L2Head)
 	if err != nil {