Merge pull request #6235 from oasisprotocol/peternose/feature/stateless-client

go/consensus/cometbft: Add stateless client node

Author: peternose

.changelog/6235.breaking.md

@@ -0,0 +1,6 @@
+go/consensus/cometbft: Switch to Protobuf encoding for block metadata
+
+Block metadata now uses Protobuf encoding for the block header and the last
+commit. This change addresses an issue with CBOR encoding, which stripped
+milliseconds from timestamps, preventing light clients from verifying
+them.

.changelog/6235.feature.md

@@ -0,0 +1,15 @@
+go/consensus/cometbft: Add stateless client node
+
+A stateless client node can now be started using the following configuration.
+To ensure compatibility, all provider nodes specified must be running
+the latest version of Oasis Core.
+
+```yaml
+mode: client-stateless
+# ... sections not relevant are omitted ...
+consensus:
+    providers:
+        - <node-address-1>
+        - <node-address-2>
+        # Add more node addresses as needed
+```

go/consensus/cometbft/abci/system.go

@@ -6,13 +6,13 @@ import (
 	"fmt"
 
 	"github.com/cometbft/cometbft/abci/types"
-	cmtmerkle "github.com/cometbft/cometbft/crypto/merkle"
 
 	"github.com/oasisprotocol/oasis-core/go/common/cbor"
 	consensus "github.com/oasisprotocol/oasis-core/go/consensus/api"
 	"github.com/oasisprotocol/oasis-core/go/consensus/api/transaction"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/api"
 	cmtcrypto "github.com/oasisprotocol/oasis-core/go/consensus/cometbft/crypto"
+	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/crypto/merkle"
 )
 
 // prepareSystemTxs prepares a list of system transactions to be included in a proposed block in
@@ -154,5 +154,5 @@ func (mux *abciMux) computeProvableEventsRoot() ([]byte, error) {
 	for i, pe := range provable {
 		provableEvents[i] = cbor.Marshal(pe.ProvableRepresentation())
 	}
-	return cmtmerkle.HashFromByteSlices(provableEvents), nil
+	return merkle.RootHash(provableEvents), nil
 }

go/consensus/cometbft/api/api.go

@@ -160,18 +160,25 @@ func QueryForApp(eventApp string) cmtpubsub.Query {
 // BlockMeta is the CometBFT-specific per-block metadata.
 type BlockMeta struct {
 	// Header is the CometBFT block header.
-	Header *cmttypes.Header `json:"header"`
+	Header []byte `json:"header"`
 	// LastCommit is the CometBFT last commit info.
-	LastCommit *cmttypes.Commit `json:"last_commit"`
+	LastCommit []byte `json:"last_commit"`
 }
 
 // NewBlock creates a new consensus.Block from a CometBFT block.
-func NewBlock(blk *cmttypes.Block) *consensus.Block {
+func NewBlock(blk *cmttypes.Block) (*consensus.Block, error) {
+	header, err := blk.Header.ToProto().Marshal()
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal header: %w", err)
+	}
+	lastCommit, err := blk.LastCommit.ToProto().Marshal()
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal last commit: %w", err)
+	}
 	meta := BlockMeta{
-		Header:     &blk.Header,
-		LastCommit: blk.LastCommit,
+		Header:     header,
+		LastCommit: lastCommit,
 	}
-	rawMeta := cbor.Marshal(meta)
 
 	var stateRoot hash.Hash
 	switch blk.Header.AppHash {
@@ -194,8 +201,8 @@ func NewBlock(blk *cmttypes.Block) *consensus.Block {
 			Hash:    stateRoot,
 		},
 		Size: uint64(blk.Size()),
-		Meta: rawMeta,
-	}
+		Meta: cbor.Marshal(meta),
+	}, nil
 }
 
 // BlockResults are CometBFT-specific consensus block results.

go/consensus/cometbft/cometbft.go

@@ -2,13 +2,20 @@ package cometbft
 
 import (
 	"context"
+	"encoding/hex"
+	"fmt"
+
+	cmtlight "github.com/cometbft/cometbft/light"
+	cmttypes "github.com/cometbft/cometbft/types"
 
 	"github.com/oasisprotocol/oasis-core/go/common/identity"
 	"github.com/oasisprotocol/oasis-core/go/config"
 	consensusAPI "github.com/oasisprotocol/oasis-core/go/consensus/api"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/api"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/full"
 	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/light"
+	"github.com/oasisprotocol/oasis-core/go/consensus/cometbft/stateless"
+	"github.com/oasisprotocol/oasis-core/go/consensus/pricediscovery"
 	genesisAPI "github.com/oasisprotocol/oasis-core/go/genesis/api"
 	p2pAPI "github.com/oasisprotocol/oasis-core/go/p2p/api"
 	"github.com/oasisprotocol/oasis-core/go/p2p/rpc"
@@ -30,7 +37,163 @@ func New(
 		return nil, err
 	}
 
-	commonCfg := full.CommonConfig{
+	switch config.GlobalConfig.Mode {
+	case config.ModeArchive:
+		node, err := createArchiveNode(ctx, dataDir, identity, genesis, doc, genesisDoc)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create archive node: %w", err)
+		}
+		return node, nil
+	case config.ModeStatelessClient:
+		node, err := createStatelessNode(ctx, genesis, doc, genesisDoc, p2p)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create stateless node: %w", err)
+		}
+		return node, nil
+	default:
+		node, err := createFullNode(ctx, dataDir, identity, genesis, doc, genesisDoc, upgrader, p2p)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create full node: %w", err)
+		}
+		return node, nil
+	}
+}
+
+func createArchiveNode(
+	ctx context.Context,
+	dataDir string,
+	identity *identity.Identity,
+	genesis genesisAPI.Provider,
+	doc *genesisAPI.Document,
+	genesisDoc *cmttypes.GenesisDoc,
+) (consensusAPI.Service, error) {
+	cfg := full.ArchiveConfig{
+		CommonConfig: createCommonConfig(dataDir, identity, genesis, doc, genesisDoc),
+	}
+
+	return full.NewArchive(ctx, cfg)
+}
+
+func createFullNode(
+	ctx context.Context,
+	dataDir string,
+	identity *identity.Identity,
+	genesis genesisAPI.Provider,
+	doc *genesisAPI.Document,
+	genesisDoc *cmttypes.GenesisDoc,
+	upgrader upgradeAPI.Backend,
+	p2p p2pAPI.Service,
+) (consensusAPI.Service, error) {
+	cfg := full.Config{
+		CommonConfig:       createCommonConfig(dataDir, identity, genesis, doc, genesisDoc),
+		TimeoutCommit:      doc.Consensus.Parameters.TimeoutCommit,
+		EmptyBlockInterval: doc.Consensus.Parameters.EmptyBlockInterval,
+		SkipTimeoutCommit:  doc.Consensus.Parameters.SkipTimeoutCommit,
+		Upgrader:           upgrader,
+	}
+
+	return full.New(ctx, p2p, cfg)
+}
+
+func createStatelessNode(
+	ctx context.Context,
+	genesis genesisAPI.Provider,
+	doc *genesisAPI.Document,
+	genesisDoc *cmttypes.GenesisDoc,
+	p2p p2pAPI.Service,
+) (consensusAPI.Service, error) {
+	provider, err := createProvider()
+	if err != nil {
+		return nil, fmt.Errorf("failed to create provider: %w", err)
+	}
+
+	lightClient, err := createLightClient(ctx, genesisDoc, doc, p2p)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create light client: %w", err)
+	}
+
+	services, err := createStatelessServices(doc, genesis, genesisDoc, provider, lightClient)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create stateless client: %w", err)
+	}
+
+	submitter, err := createSubmissionManager(ctx, services)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create submission manager: %w", err)
+	}
+
+	return stateless.NewService(services, submitter)
+}
+
+func createStatelessServices(
+	doc *genesisAPI.Document,
+	genesis genesisAPI.Provider,
+	genesisDoc *cmttypes.GenesisDoc,
+	provider *consensusAPI.Client,
+	lightClient *light.Client,
+) (*stateless.Services, error) {
+	cfg := stateless.Config{
+		ChainID:       doc.ChainID,
+		ChainContext:  doc.ChainContext(),
+		Genesis:       genesis,
+		GenesisDoc:    genesisDoc,
+		GenesisHeight: doc.Height,
+		BaseEpoch:     doc.Beacon.Base,
+		BaseHeight:    doc.Height,
+	}
+
+	return stateless.NewServices(provider, lightClient, cfg)
+}
+
+func createProvider() (*consensusAPI.Client, error) {
+	addresses := config.GlobalConfig.Consensus.Providers
+	if len(addresses) == 0 {
+		return nil, fmt.Errorf("no providers configured")
+	}
+
+	return stateless.NewProvider(addresses[0])
+}
+
+func createLightClient(
+	ctx context.Context,
+	genesisDoc *cmttypes.GenesisDoc,
+	doc *genesisAPI.Document,
+	p2p p2pAPI.Service,
+) (*light.Client, error) {
+	hash, err := hex.DecodeString(config.GlobalConfig.Consensus.LightClient.Trust.Hash)
+	if err != nil {
+		return nil, fmt.Errorf("failed to decode trust hash: %w", err)
+	}
+
+	cfg := light.Config{
+		GenesisDocument: genesisDoc,
+		TrustOptions: cmtlight.TrustOptions{
+			Period: config.GlobalConfig.Consensus.LightClient.Trust.Period,
+			Height: int64(config.GlobalConfig.Consensus.LightClient.Trust.Height),
+			Hash:   hash,
+		},
+	}
+
+	return light.NewClient(ctx, doc.ChainContext(), p2p, cfg)
+}
+
+func createSubmissionManager(ctx context.Context, services consensusAPI.Services) (consensusAPI.SubmissionManager, error) {
+	pd, err := pricediscovery.New(ctx, services.Core(), config.GlobalConfig.Consensus.Submission.GasPrice)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create price discovery: %w", err)
+	}
+
+	return consensusAPI.NewSubmissionManager(services, pd, config.GlobalConfig.Consensus.Submission.MaxFee), nil
+}
+
+func createCommonConfig(
+	dataDir string,
+	identity *identity.Identity,
+	genesis genesisAPI.Provider,
+	doc *genesisAPI.Document,
+	genesisDoc *cmttypes.GenesisDoc,
+) full.CommonConfig {
+	return full.CommonConfig{
 		DataDir:            dataDir,
 		Identity:           identity,
 		ChainID:            doc.ChainID,
@@ -42,23 +205,6 @@ func New(
 		BaseHeight:         doc.Height,
 		PublicKeyBlacklist: doc.Consensus.Parameters.PublicKeyBlacklist,
 	}
-
-	switch config.GlobalConfig.Mode {
-	case config.ModeArchive:
-		cfg := full.ArchiveConfig{
-			CommonConfig: commonCfg,
-		}
-		return full.NewArchive(ctx, cfg)
-	default:
-		cfg := full.Config{
-			CommonConfig:       commonCfg,
-			TimeoutCommit:      doc.Consensus.Parameters.TimeoutCommit,
-			EmptyBlockInterval: doc.Consensus.Parameters.EmptyBlockInterval,
-			SkipTimeoutCommit:  doc.Consensus.Parameters.SkipTimeoutCommit,
-			Upgrader:           upgrader,
-		}
-		return full.New(ctx, p2p, cfg)
-	}
 }
 
 // NewLightService creates a new CometBFT light client service.

go/consensus/cometbft/config/config.go

@@ -51,6 +51,10 @@ type Config struct {
 	// LightClient contains light client configuration.
 	LightClient LightClientConfig `yaml:"light_client,omitempty"`
 
+	// Providers contains the CometBFT node addresses the stateless client
+	// connects to in order to fetch consensus-related data.
+	Providers []string `yaml:"providers,omitempty"`
+
 	// Supplementary sanity checks configuration.
 	SupplementarySanity SupplementarySanityConfig `yaml:"supplementary_sanity,omitempty"`