Return with non zero exit code in case of fatal error

blockbook.go

@@ -33,6 +33,10 @@ const debounceResyncMempoolMs = 1009
 // store internal state about once every minute
 const storeInternalStatePeriodMs = 59699
 
+// exit codes from the main function
+const exitCodeOK = 0
+const exitCodeFatal = 255
+
 var (
 	blockchain = flag.String("blockchaincfg", "", "path to blockchain RPC service configuration json file")
 
@@ -100,6 +104,11 @@ func init() {
 }
 
 func main() {
+	os.Exit(mainWithExitCode())
+}
+
+// allow deferred functions to run even in case of fatal error
+func mainWithExitCode() int {
 	flag.Parse()
 
 	defer glog.Flush()
@@ -120,20 +129,20 @@ func main() {
 	if *repair {
 		if err := db.RepairRocksDB(*dbPath); err != nil {
 			glog.Errorf("RepairRocksDB %s: %v", *dbPath, err)
-			return
+			return exitCodeFatal
 		}
-		return
+		return exitCodeOK
 	}
 
 	if *blockchain == "" {
 		glog.Error("Missing blockchaincfg configuration parameter")
-		return
+		return exitCodeFatal
 	}
 
 	coin, coinShortcut, coinLabel, err := coins.GetCoinNameFromConfig(*blockchain)
 	if err != nil {
 		glog.Error("config: ", err)
-		return
+		return exitCodeFatal
 	}
 
 	// gspt.SetProcTitle("blockbook-" + normalizeName(coin))
@@ -141,31 +150,31 @@ func main() {
 	metrics, err = common.GetMetrics(coin)
 	if err != nil {
 		glog.Error("metrics: ", err)
-		return
+		return exitCodeFatal
 	}
 
-	if chain, mempool, err = getBlockChainWithRetry(coin, *blockchain, pushSynchronizationHandler, metrics, 60); err != nil {
+	if chain, mempool, err = getBlockChainWithRetry(coin, *blockchain, pushSynchronizationHandler, metrics, 120); err != nil {
 		glog.Error("rpc: ", err)
-		return
+		return exitCodeFatal
 	}
 
 	index, err = db.NewRocksDB(*dbPath, *dbCache, *dbMaxOpenFiles, chain.GetChainParser(), metrics)
 	if err != nil {
 		glog.Error("rocksDB: ", err)
-		return
+		return exitCodeFatal
 	}
 	defer index.Close()
 
 	internalState, err = newInternalState(coin, coinShortcut, coinLabel, index)
 	if err != nil {
 		glog.Error("internalState: ", err)
-		return
+		return exitCodeFatal
 	}
 	index.SetInternalState(internalState)
 	if internalState.DbState != common.DbStateClosed {
 		if internalState.DbState == common.DbStateInconsistent {
 			glog.Error("internalState: database is in inconsistent state and cannot be used")
-			return
+			return exitCodeFatal
 		}
 		glog.Warning("internalState: database was left in open state, possibly previous ungraceful shutdown")
 	}
@@ -175,15 +184,16 @@ func main() {
 		err = index.ComputeInternalStateColumnStats(chanOsSignal)
 		if err != nil {
 			glog.Error("internalState: ", err)
+			return exitCodeFatal
 		}
 		glog.Info("DB size on disk: ", index.DatabaseSizeOnDisk(), ", DB size as computed: ", internalState.DBSizeTotal())
-		return
+		return exitCodeOK
 	}
 
 	syncWorker, err = db.NewSyncWorker(index, chain, *syncWorkers, *syncChunk, *blockFrom, *dryRun, chanOsSignal, metrics, internalState)
 	if err != nil {
 		glog.Errorf("NewSyncWorker %v", err)
-		return
+		return exitCodeFatal
 	}
 
 	// set the DbState to open at this moment, after all important workers are initialized
@@ -191,17 +201,20 @@ func main() {
 	err = index.StoreInternalState(internalState)
 	if err != nil {
 		glog.Error("internalState: ", err)
-		return
+		return exitCodeFatal
 	}
 
 	if *rollbackHeight >= 0 {
-		performRollback()
+		err = performRollback()
-		return
+		if err != nil {
+			return exitCodeFatal
+		}
+		return exitCodeOK
 	}
 
 	if txCache, err = db.NewTxCache(index, chain, metrics, internalState, !*noTxCache); err != nil {
 		glog.Error("txCache ", err)
-		return
+		return exitCodeFatal
 	}
 
 	// report BlockbookAppInfo metric, only log possible error
@@ -214,7 +227,7 @@ func main() {
 		internalServer, err = startInternalServer()
 		if err != nil {
 			glog.Error("internal server: ", err)
-			return
+			return exitCodeFatal
 		}
 	}
 
@@ -223,7 +236,7 @@ func main() {
 		publicServer, err = startPublicServer()
 		if err != nil {
 			glog.Error("public server: ", err)
-			return
+			return exitCodeFatal
 		}
 	}
 
@@ -231,8 +244,11 @@ func main() {
 		internalState.SyncMode = true
 		internalState.InitialSync = true
 		if err := syncWorker.ResyncIndex(nil, true); err != nil {
-			glog.Error("resyncIndex ", err)
+			if err != db.ErrSyncInterrupted {
-			return
+				glog.Error("resyncIndex ", err)
+				return exitCodeFatal
+			}
+			return exitCodeOK
 		}
 		// initialize mempool after the initial sync is complete
 		var addrDescForOutpoint bchain.AddrDescForOutpointFunc
@@ -242,12 +258,12 @@ func main() {
 		err = chain.InitializeMempool(addrDescForOutpoint, onNewTxAddr)
 		if err != nil {
 			glog.Error("initializeMempool ", err)
-			return
+			return exitCodeFatal
 		}
 		var mempoolCount int
 		if mempoolCount, err = mempool.Resync(); err != nil {
 			glog.Error("resyncMempool ", err)
-			return
+			return exitCodeFatal
 		}
 		internalState.FinishedMempoolSync(mempoolCount)
 		go syncIndexLoop()
@@ -272,8 +288,11 @@ func main() {
 
 		if !*synchronize {
 			if err = syncWorker.ConnectBlocksParallel(height, until); err != nil {
-				glog.Error("connectBlocksParallel ", err)
+				if err != db.ErrSyncInterrupted {
-				return
+					glog.Error("connectBlocksParallel ", err)
+					return exitCodeFatal
+				}
+				return exitCodeOK
 			}
 		}
 	}
@@ -290,6 +309,7 @@ func main() {
 		<-chanSyncMempoolDone
 		<-chanStoreInternalStateDone
 	}
+	return exitCodeOK
 }
 
 func getBlockChainWithRetry(coin string, configfile string, pushHandler func(bchain.NotificationType), metrics *common.Metrics, seconds int) (bchain.BlockChain, bchain.Mempool, error) {
@@ -355,11 +375,11 @@ func startPublicServer() (*server.PublicServer, error) {
 	return publicServer, err
 }
 
-func performRollback() {
+func performRollback() error {
 	bestHeight, bestHash, err := index.GetBestBlock()
 	if err != nil {
 		glog.Error("rollbackHeight: ", err)
-		return
+		return err
 	}
 	if uint32(*rollbackHeight) > bestHeight {
 		glog.Infof("nothing to rollback, rollbackHeight %d, bestHeight: %d", *rollbackHeight, bestHeight)
@@ -369,16 +389,17 @@ func performRollback() {
 			hash, err := index.GetBlockHash(height)
 			if err != nil {
 				glog.Error("rollbackHeight: ", err)
-				return
+				return err
 			}
 			hashes = append(hashes, hash)
 		}
 		err = syncWorker.DisconnectBlocks(uint32(*rollbackHeight), bestHeight, hashes)
 		if err != nil {
 			glog.Error("rollbackHeight: ", err)
-			return
+			return err
 		}
 	}
+	return nil
 }
 
 func blockbookAppInfoMetric(db *db.RocksDB, chain bchain.BlockChain, txCache *db.TxCache, is *common.InternalState, metrics *common.Metrics) error {

db/sync.go

@@ -45,6 +45,9 @@ func NewSyncWorker(db *RocksDB, chain bchain.BlockChain, syncWorkers, syncChunk
 
 var errSynced = errors.New("synced")
 
+// ErrSyncInterrupted is returned when synchronization is interrupted by OS signal
+var ErrSyncInterrupted = errors.New("ErrSyncInterrupted")
+
 // ResyncIndex synchronizes index to the top of the blockchain
 // onNewBlock is called when new block is connected, but not in initial parallel sync
 func (w *SyncWorker) ResyncIndex(onNewBlock bchain.OnNewBlockFunc, initialSync bool) error {
@@ -202,7 +205,8 @@ func (w *SyncWorker) connectBlocks(onNewBlock bchain.OnNewBlockFunc, initialSync
 		for {
 			select {
 			case <-w.chanOsSignal:
-				return errors.Errorf("connectBlocks interrupted at height %d", lastRes.block.Height)
+				glog.Info("connectBlocks interrupted at height ", lastRes.block.Height)
+				return ErrSyncInterrupted
 			case res := <-bch:
 				if res == empty {
 					break ConnectLoop
@@ -325,7 +329,8 @@ ConnectLoop:
 	for h := lower; h <= higher; {
 		select {
 		case <-w.chanOsSignal:
-			err = errors.Errorf("connectBlocksParallel interrupted at height %d", h)
+			glog.Info("connectBlocksParallel interrupted at height ", h)
+			err = ErrSyncInterrupted
 			// signal all workers to terminate their loops (error loops are interrupted below)
 			close(terminating)
 			break ConnectLoop

tests/sync/connectblocks.go

@@ -25,10 +25,8 @@ func testConnectBlocks(t *testing.T, h *TestHandler) {
 					close(ch)
 				}
 			}, true)
-			if err != nil {
+			if err != nil && err != db.ErrSyncInterrupted {
-				if !strings.HasPrefix(err.Error(), "connectBlocks interrupted at height") {
+				t.Fatal(err)
-					t.Fatal(err)
-				}
 			}
 
 			height, _, err := d.GetBestBlock()