Remove a bunch of fmt.Sprintf

accounter/accounter.go

@@ -3,6 +3,7 @@ package accounter
 import (
 	"encoding/hex"
 	"fmt"
+	"log"
 	"sync"
 	"time"
 
@@ -199,7 +200,7 @@ func (a *Accounter) balance() uint64 {
 				balance -= prev.vout[txin.index].value
 				if prev.vout[txin.index].spentBy != nil {
 					// sanity check: an output can only be spent by one transaction.
-					panic(fmt.Sprintf("%s and %s, both spending %s", hash, *prev.vout[txin.index].spentBy, txin.prevHash))
+					log.Panicf("%s and %s, both spending %s", hash, *prev.vout[txin.index].spentBy, txin.prevHash)
 				}
 				prev.vout[txin.index].spentBy = &hash
 			}

backend/btcd_backend.go

@@ -2,6 +2,7 @@ package backend
 
 import (
 	"fmt"
+	"log"
 	"sync"
 
 	"github.com/btcsuite/btcd/btcjson"
@@ -76,7 +77,7 @@ func NewBtcdBackend(hostPort, user, pass string, network utils.Network) (*BtcdBa
 		return nil, errors.Wrap(err, "GetBlockHash(0) failed")
 	}
 	if genesis.String() != utils.GenesisBlock(network) {
-		return nil, errors.New(fmt.Sprintf("Unexpected genesis block %s != %s", genesis.String(), utils.GenesisBlock(network)))
+		return nil, errors.Errorf("Unexpected genesis block %s != %s", genesis.String(), utils.GenesisBlock(network))
 	}
 
 	height, err := client.GetBlockCount()
@@ -161,17 +162,17 @@ func (b *BtcdBackend) processRequests() {
 		case addr := <-b.addrRequests:
 			err := b.processAddrRequest(addr)
 			if err != nil {
-				panic(fmt.Sprintf("processAddrRequest failed: %+v", err))
+				log.Panicf("processAddrRequest failed: %+v", err)
 			}
 		case tx := <-b.txRequests:
 			err := b.processTxRequest(tx)
 			if err != nil {
-				panic(fmt.Sprintf("processTxRequest failed: %+v", err))
+				log.Panicf("processTxRequest failed: %+v", err)
 			}
 		case block := <-b.blockRequests:
 			err := b.processBlockRequest(block)
 			if err != nil {
-				panic(fmt.Sprintf("processBlockRequest failed: %+v", err))
+				log.Panicf("processBlockRequest failed: %+v", err)
 			}
 		case <-b.doneCh:
 			break
@@ -261,21 +262,21 @@ func (b *BtcdBackend) processBlockRequest(height uint32) error {
 		if jerr, ok := err.(*btcjson.RPCError); ok {
 			switch jerr.Code {
 			case btcjson.ErrRPCInvalidAddressOrKey:
-				return errors.Wrap(err, fmt.Sprintf("blockchain doesn't have block %d", height))
+				return errors.Wrapf(err, "blockchain doesn't have block %d", height)
 			}
 		}
-		return errors.Wrap(err, fmt.Sprintf("could not fetch block %d", height))
+		return errors.Wrapf(err, "could not fetch block %d", height)
 	}
 
 	header, err := b.client.GetBlockHeader(hash)
 	if err != nil {
 		if jerr, ok := err.(*btcjson.RPCError); ok {
 			switch jerr.Code {
 			case btcjson.ErrRPCInvalidAddressOrKey:
-				return errors.Wrap(err, fmt.Sprintf("blockchain doesn't have block %d", height))
+				return errors.Wrapf(err, "blockchain doesn't have block %d", height)
 			}
 		}
-		return errors.Wrap(err, fmt.Sprintf("could not fetch block %d", height))
+		return errors.Wrapf(err, "could not fetch block %d", height)
 	}
 
 	b.blockResponses <- &BlockResponse{
@@ -297,7 +298,7 @@ func (b *BtcdBackend) cacheTxs(txs []*btcjson.SearchRawTransactionsResult) {
 
 		height, err := b.getBlockHeight(tx.BlockHash)
 		if err != nil {
-			panic(fmt.Sprintf("error getting block height for hash %s: %s", tx.BlockHash, err.Error()))
+			log.Panicf("error getting block height for hash %s: %s", tx.BlockHash, err.Error())
 		}
 
 		b.transactionsMu.Lock()

backend/electrum_backend.go

@@ -443,7 +443,7 @@ func (eb *ElectrumBackend) cacheTxs(txs []*electrum.Transaction) {
 	for _, tx := range txs {
 		height, exists := eb.transactions[tx.Hash]
 		if exists && (height != int64(tx.Height)) {
-			panic(fmt.Sprintf("inconsistent cache: %s %d != %d", tx.Hash, height, tx.Height))
+			log.Panicf("inconsistent cache: %s %d != %d", tx.Hash, height, tx.Height)
 		}
 		eb.transactions[tx.Hash] = int64(tx.Height)
 	}

backend/fixture_backend.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
 	"sync"
 
@@ -185,7 +186,7 @@ func (b *FixtureBackend) processBlockRequest(height uint32) {
 		b.blockResponses <- &resp
 		return
 	}
-	panic(fmt.Sprintf("fixture doesn't contain block %d", height))
+	log.Panicf("fixture doesn't contain block %d", height)
 }
 
 func (fb *FixtureBackend) loadFromFile(f *os.File) error {

deriver/address_deriver.go

@@ -156,7 +156,7 @@ func (d *AddressDeriver) multiSigSegwitDerive(change uint32, addressIndex uint32
 
 		pubKeyBytes := pubKey.SerializeCompressed()
 		if len(pubKeyBytes) != 33 {
-			panic(fmt.Sprintf("expected pubkey length 33, got %d", len(pubKeyBytes)))
+			log.Panicf("expected pubkey length 33, got %d", len(pubKeyBytes))
 		}
 
 		pubKeysBytes = append(pubKeysBytes, pubKeyBytes)

utils/utils.go

@@ -2,6 +2,7 @@ package utils
 
 import (
 	"fmt"
+	"log"
 
 	"github.com/btcsuite/btcd/chaincfg"
 )
@@ -47,7 +48,7 @@ func XpubToNetwork(xpub string) Network {
 	case "tpub":
 		return Testnet
 	default:
-		panic(fmt.Sprintf("unknown prefix: %s", xpub))
+		log.Panicf("unknown prefix: %s", xpub)
 	}
 }
 
@@ -64,7 +65,7 @@ func AddressToNetwork(addr string) Network {
 	case '3':
 		return Mainnet // script hash
 	default:
-		panic(fmt.Sprintf("unknown prefix: %s", addr))
+		log.Panicf("unknown prefix: %s", addr)
 	}
 }