From 6fc2b8fa66940959f8ea1c544c5ef8fa73275e2a Mon Sep 17 00:00:00 2001
From: Gui Iribarren <gui@altermundi.net>
Date: Tue, 9 Jan 2024 14:21:26 +0100
Subject: [PATCH] vochain: add StateSync* and SnapshotInterval flags

---
 cmd/node/main.go | 10 ++++++++++
 config/config.go | 13 +++++++++++++
 vochain/app.go   | 10 ++++++++--
 vochain/start.go |  4 ++++
 4 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/cmd/node/main.go b/cmd/node/main.go
index bde17c199..745d2ee1a 100644
--- a/cmd/node/main.go
+++ b/cmd/node/main.go
@@ -188,6 +188,16 @@ func loadConfig() *config.Config {
 		"do not wait for Vochain to synchronize (for testing only)")
 	flag.Int("vochainMempoolSize", 20000,
 		"vochain mempool size")
+	flag.Int("vochainSnapshotInterval", 0,
+		"create state snapshot every N blocks (0 to disable)")
+	flag.Bool("vochainStateSyncEnabled", false,
+		"during startup, let cometBFT ask peers for available snapshots and use them to bootstrap the state")
+	flag.StringSlice("vochainStateSyncRPCServers", []string{},
+		"list of RPC servers to fetch snapshots from (minimum 2)")
+	flag.String("vochainStateSyncTrustHash", "",
+		"hash of the trusted block")
+	flag.Int64("vochainStateSyncTrustHeight", 0,
+		"height of the trusted block")
 
 	flag.Int("vochainMinerTargetBlockTimeSeconds", 10,
 		"vochain consensus block time target (in seconds)")
diff --git a/config/config.go b/config/config.go
index 957e531ff..6150b5484 100644
--- a/config/config.go
+++ b/config/config.go
@@ -125,6 +125,19 @@ type VochainCfg struct {
 	IsSeedNode bool
 	// OffChainDataDownload specifies if the node is configured to download off-chain data
 	OffChainDataDownload bool
+	// SnapshotInterval enables creating a state snapshot every N blocks (0 to disable)
+	SnapshotInterval int
+	// StateSyncEnabled allows cometBFT during startup, to ask peers for available snapshots
+	// and use them to bootstrap the state
+	StateSyncEnabled bool
+	// StateSyncRPCServers to fetch the snapshots from (minimum 2 needed)
+	StateSyncRPCServers []string
+	// StateSyncTrustHeight and TrustHash must both be provided to force the trusting of a
+	// particular header.
+	StateSyncTrustHeight int64
+	// StateSyncTrustHeight and TrustHash must both be provided to force the trusting of a
+	// particular header.
+	StateSyncTrustHash string
 }
 
 // IndexerCfg handles the configuration options of the indexer
diff --git a/vochain/app.go b/vochain/app.go
index 9f1d6cc22..fa115c5b6 100644
--- a/vochain/app.go
+++ b/vochain/app.go
@@ -76,6 +76,9 @@ type BaseApplication struct {
 	// blockTime is the target block time that miners use
 	blockTime time.Duration
 
+	// snapshotInterval create state snapshot every N blocks (0 to disable)
+	snapshotInterval int
+
 	// endBlockTimestamp is the last block end timestamp calculated from local time.
 	endBlockTimestamp atomic.Int64
 	// startBlockTimestamp is the current block timestamp from tendermint's
@@ -154,6 +157,7 @@ func NewBaseApplication(vochainCfg *config.VochainCfg) (*BaseApplication, error)
 		TransactionHandler: transactionHandler,
 		blockCache:         blockCache,
 		dataDir:            vochainCfg.DataDir,
+		snapshotInterval:   vochainCfg.SnapshotInterval,
 		genesisInfo:        &comettypes.GenesisDoc{},
 	}, nil
 }
@@ -205,8 +209,10 @@ func (app *BaseApplication) CommitState() ([]byte, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot save state: %w", err)
 	}
-	// perform state snapshot (DISABLED)
-	if false && app.Height()%50000 == 0 && !app.IsSynchronizing() { // DISABLED
+	// perform state snapshot
+	if app.snapshotInterval > 0 &&
+		app.Height()%uint32(app.snapshotInterval) == 0 &&
+		!app.IsSynchronizing() {
 		startTime := time.Now()
 		log.Infof("performing a state snapshot on block %d", app.Height())
 		if _, err := app.State.Snapshot(); err != nil {
diff --git a/vochain/start.go b/vochain/start.go
index 6d9107fb7..8f52bd489 100644
--- a/vochain/start.go
+++ b/vochain/start.go
@@ -184,6 +184,10 @@ func newTendermint(app *BaseApplication,
 	tconfig.Mempool.MaxTxsBytes = int64(tconfig.Mempool.Size * tconfig.Mempool.MaxTxBytes)
 	tconfig.Mempool.CacheSize = 100000
 	tconfig.Mempool.Broadcast = true
+	tconfig.StateSync.Enable = localConfig.StateSyncEnabled
+	tconfig.StateSync.RPCServers = localConfig.StateSyncRPCServers
+	tconfig.StateSync.TrustHeight = localConfig.StateSyncTrustHeight
+	tconfig.StateSync.TrustHash = localConfig.StateSyncTrustHash
 
 	log.Debugf("mempool config: %+v", tconfig.Mempool)
 	// tmdbBackend defaults to goleveldb, but switches to cleveldb if