Merge pull request #136 from dogecoinfoundation/rc-wait-initial-sync

Wait for Initial Block Download in core

pkg/chaintracker/chainfollower.go

@@ -10,10 +10,11 @@ import (
 )
 
 const (
-	RETRY_DELAY       = 5 * time.Second        // for RPC and Database errors.
-	WRONG_CHAIN_DELAY = 5 * time.Minute        // for "Wrong Chain" error (essentially stop)
-	CONFLICT_DELAY    = 250 * time.Millisecond // for Database conflicts (concurrent transactions)
-	BLOCKS_PER_COMMIT = 10                     // number of blocks per database commit.
+	RETRY_DELAY        = 5 * time.Second        // for RPC and Database errors.
+	WRONG_CHAIN_DELAY  = 5 * time.Minute        // for "Wrong Chain" error (essentially stop)
+	WAIT_INITIAL_BLOCK = 30 * time.Second       // for Initial Block Download
+	CONFLICT_DELAY     = 250 * time.Millisecond // for Database conflicts (concurrent transactions)
+	BLOCKS_PER_COMMIT  = 10                     // number of blocks per database commit.
 )
 
 type ChainFollower struct {
@@ -154,6 +155,14 @@ func (c *ChainFollower) fetchStartingPos() ChainPos {
 			continue
 		}
 		c.chain = chain
+		// Wait for Core to be fully synced, otherwise fetchBlockCount will give
+		// us an early block and we'll follow the whole chain.
+		info := c.fetchBlockchainInfo()
+		if info.InitialBlockDownload {
+			log.Println("ChainFollower: waiting for Core initial block download")
+			c.sleepForRetry(nil, WAIT_INITIAL_BLOCK)
+			continue
+		}
 		if state.BestBlockHash != "" {
 			// Resume sync.
 			// Make sure we're syncing the same blockchain as before.
@@ -688,6 +697,18 @@ func (c *ChainFollower) fetchBlockHash(height int64) string {
 	}
 }
 
+func (c *ChainFollower) fetchBlockchainInfo() giga.RpcBlockchainInfo {
+	for {
+		info, err := c.l1.GetBlockchainInfo()
+		if err != nil {
+			log.Println("ChainFollower: error retrieving blockchain info (will retry):", err)
+			c.sleepForRetry(err, 0)
+		} else {
+			return info
+		}
+	}
+}
+
 func (c *ChainFollower) fetchBlockCount() int64 {
 	for {
 		count, err := c.l1.GetBlockCount()

pkg/core/rpc.go

@@ -71,6 +71,10 @@ func (l *L1CoreRPC) request(method string, params []any, result any) error {
 	if err != nil {
 		return fmt.Errorf("json-rpc read response: %v", err)
 	}
+	// check for error response
+	if res.StatusCode != 200 {
+		return fmt.Errorf("json-rpc error status: %v", res.StatusCode)
+	}
 	// cannot use json.NewDecoder: "The decoder introduces its own buffering
 	// and may read data from r beyond the JSON values requested."
 	var rpcres rpcResponse
@@ -149,6 +153,11 @@ func (l *L1CoreRPC) GetBlockCount() (blockCount int64, err error) {
 	return
 }
 
+func (l *L1CoreRPC) GetBlockchainInfo() (info giga.RpcBlockchainInfo, err error) {
+	err = l.request("getblockchaininfo", []any{}, &info)
+	return
+}
+
 func (l *L1CoreRPC) GetTransaction(txnHash string) (txn giga.RawTxn, err error) {
 	decode := true // to get back JSON rather than HEX
 	err = l.request("getrawtransaction", []any{txnHash, decode}, &txn)

pkg/dogecoin.go

@@ -26,6 +26,7 @@ type L1 interface {
 	GetBlockHash(height int64) (string, error)
 	GetBestBlockHash() (string, error)
 	GetBlockCount() (int64, error)
+	GetBlockchainInfo() (RpcBlockchainInfo, error)
 	GetTransaction(txnHash string) (RawTxn, error)
 	Send(txnHex string) (txid string, err error)
 	EstimateFee(confirmTarget int) (feePerKB CoinAmount, err error)
@@ -171,3 +172,22 @@ type RpcBlockHeader struct {
 	PreviousBlockHash string          `json:"previousblockhash"` // (string) The hash of the previous block (hex)
 	NextBlockHash     string          `json:"nextblockhash"`     // (string) The hash of the next block (hex)
 }
+
+// RpcBlockchainInfo from Core
+type RpcBlockchainInfo struct {
+	Chain                string  `json:"chain"`                // (string) current network name (main, test, regtest)
+	Blocks               int64   `json:"blocks"`               // (numeric) the height of the most-work fully-validated chain. The genesis block has height 0
+	Headers              int64   `json:"headers"`              // (numeric) the current number of headers we have validated
+	BestBlockHash        string  `json:"bestblockhash"`        // (string) the hash of the currently best block
+	Difficulty           float64 `json:"difficulty"`           // (numeric) the current difficulty
+	MedianTime           int64   `json:"mediantime"`           // (numeric) median time for the current best block
+	VerificationProgress float64 `json:"verificationprogress"` // (numeric) estimate of verification progress [0..1]
+	InitialBlockDownload bool    `json:"initialblockdownload"` // (boolean) (debug information) estimate of whether this node is in Initial Block Download mode
+	ChainWord            string  `json:"chainwork"`            // (string) total amount of work in active chain, in hexadecimal
+	SizeOnDisk           int64   `json:"size_on_disk"`         // (numeric) the estimated size of the block and undo files on disk
+	Pruned               bool    `json:"pruned"`               // (boolean) if the blocks are subject to pruning
+	PruneHeight          int64   `json:"pruneheight"`          // (numeric) lowest-height complete block stored (only present if pruning is enabled)
+	AutomaticPruning     bool    `json:"automatic_pruning"`    // (boolean) whether automatic pruning is enabled (only present if pruning is enabled)
+	PruneTargetSize      int64   `json:"prune_target_size"`    // (numeric) the target size used by pruning (only present if automatic pruning is enabled)
+
+}

pkg/dogecoin/libdogecoin.go

@@ -213,6 +213,13 @@ func (l L1Libdogecoin) GetBlockCount() (blockCount int64, err error) {
 	return 0, fmt.Errorf("not implemented")
 }
 
+func (l L1Libdogecoin) GetBlockchainInfo() (info giga.RpcBlockchainInfo, err error) {
+	if l.fallback != nil {
+		return l.fallback.GetBlockchainInfo()
+	}
+	return giga.RpcBlockchainInfo{}, fmt.Errorf("not implemented")
+}
+
 func (l L1Libdogecoin) GetTransaction(txnHash string) (txn giga.RawTxn, err error) {
 	if l.fallback != nil {
 		return l.fallback.GetTransaction(txnHash)

pkg/dogecoin/mock.go

@@ -57,6 +57,10 @@ func (l L1Mock) GetBlockCount() (blockCount int64, err error) {
 	return 100, nil
 }
 
+func (l L1Mock) GetBlockchainInfo() (info giga.RpcBlockchainInfo, err error) {
+	return giga.RpcBlockchainInfo{}, fmt.Errorf("not implemented")
+}
+
 func (l L1Mock) GetTransaction(txnHash string) (txn giga.RawTxn, err error) {
 	return giga.RawTxn{}, nil
 }