Import xpub tweaks (#41)

README.md

@@ -20,6 +20,9 @@
   stores it in the database. This key is used to sign all API responses, and the
   signature is included in the response header `VSP-Signature`. Error responses
   are not signed.
+- An xpub key is provided to dcrvsp via config. The first time dcrvsp starts, it
+  imports this xpub to create a new wallet account. This account is used to
+  derive addresses for fee payments.
 - VSP API as described in [dcrstakepool #574](https://github.com/decred/dcrstakepool/issues/574)
   - Request fee amount (`GET /fee`)
   - Request fee address (`POST /feeaddress`)

config.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -31,8 +32,8 @@ type config struct {
 	Listen     string  `long:"listen" ini-name:"listen" description:"The ip:port to listen for API requests."`
 	LogLevel   string  `long:"loglevel" ini-name:"loglevel" description:"Logging level." choice:"trace" choice:"debug" choice:"info" choice:"warn" choice:"error" choice:"critical"`
 	Network    string  `long:"network" ini-name:"network" description:"Decred network to use." choice:"testnet" choice:"mainnet" choice:"simnet"`
-	FeeXPub    string  `long:"feexpub" ini-name:"feexpub" description:"cold wallet xpub used for collecting fees"`
-	VSPFee     float64 `long:"vspfee" ini-name:"vspfee" description:"The fee percentage charged for VSP use. eg. 0.01 (1%), 0.05 (5%)."`
+	FeeXPub    string  `long:"feexpub" ini-name:"feexpub" description:"Cold wallet xpub used for collecting fees."`
+	VSPFee     float64 `long:"vspfee" ini-name:"vspfee" description:"Fee percentage charged for VSP use. eg. 0.01 (1%), 0.05 (5%)."`
 	HomeDir    string  `long:"homedir" ini-name:"homedir" no-ini:"true" description:"Path to application home directory. Used for storing VSP database and logs."`
 	ConfigFile string  `long:"configfile" ini-name:"configfile" no-ini:"true" description:"Path to configuration file."`
 	WalletHost string  `long:"wallethost" ini-name:"wallethost" description:"The ip:port to establish a JSON-RPC connection with dcrwallet."`
@@ -181,11 +182,9 @@ func loadConfig() (*config, error) {
 	}
 
 	// Create the home directory if it doesn't already exist.
-	funcName := "loadConfig"
 	err = os.MkdirAll(cfg.HomeDir, 0700)
 	if err != nil {
-		str := "%s: failed to create home directory: %v"
-		err := fmt.Errorf(str, funcName, err)
+		err := fmt.Errorf("failed to create home directory: %v", err)
 		fmt.Fprintln(os.Stderr, err)
 		return nil, err
 	}
@@ -233,23 +232,17 @@ func loadConfig() (*config, error) {
 
 	// Ensure the dcrwallet RPC username is set.
 	if cfg.WalletUser == "" {
-		str := "%s: the walletuser option is not set"
-		err := fmt.Errorf(str, funcName)
-		return nil, err
+		return nil, errors.New("the walletuser option is not set")
 	}
 
 	// Ensure the dcrwallet RPC password is set.
 	if cfg.WalletPass == "" {
-		str := "%s: the walletpass option is not set"
-		err := fmt.Errorf(str, funcName)
-		return nil, err
+		return nil, errors.New("the walletpass option is not set")
 	}
 
 	// Ensure the dcrwallet RPC cert path is set.
 	if cfg.WalletCert == "" {
-		str := "%s: the walletcert option is not set"
-		err := fmt.Errorf(str, funcName)
-		return nil, err
+		return nil, errors.New("the walletcert option is not set")
 	}
 
 	// Add default port for the active network if there is no port specified.
@@ -259,18 +252,14 @@ func loadConfig() (*config, error) {
 	cfg.WalletCert = cleanAndExpandPath(cfg.WalletCert)
 	cfg.dcrwCert, err = ioutil.ReadFile(cfg.WalletCert)
 	if err != nil {
-		str := "%s: failed to read dcrwallet cert file: %s"
-		err := fmt.Errorf(str, funcName, err)
-		return nil, err
+		return nil, fmt.Errorf("failed to read dcrwallet cert file: %v", err)
 	}
 
 	// Create the data directory.
 	dataDir := filepath.Join(cfg.HomeDir, "data", cfg.netParams.Name)
 	err = os.MkdirAll(dataDir, 0700)
 	if err != nil {
-		str := "%s: failed to create data directory: %v"
-		err := fmt.Errorf(str, funcName, err)
-		return nil, err
+		return nil, fmt.Errorf("failed to create data directory: %v", err)
 	}
 
 	// Initialize loggers and log rotation.
@@ -282,9 +271,12 @@ func loadConfig() (*config, error) {
 	cfg.dbPath = filepath.Join(dataDir, "vsp.db")
 
 	// Validate the cold wallet xpub.
+	if cfg.FeeXPub == "" {
+		return nil, errors.New("the feexpub option is not set")
+	}
 	_, err = hdkeychain.NewKeyFromString(cfg.FeeXPub, cfg.netParams.Params)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to parse feexpub: %v", err)
 	}
 
 	return &cfg, nil

main.go

@@ -10,6 +10,11 @@ import (
 	"github.com/jholdstock/dcrvsp/database"
 	"github.com/jholdstock/dcrvsp/rpc"
 	"github.com/jholdstock/dcrvsp/webapi"
+	"github.com/jrick/wsrpc/v2"
+)
+
+const (
+	feeAccountName = "fees"
 )
 
 func main() {
@@ -68,42 +73,23 @@ func run(ctx context.Context) error {
 		shutdownWg.Wait()
 		return err
 	}
-  
-	// Get the masterpubkey from the fees account, if it exists, and make
-	// sure it matches the configuration.
-	var existingXPub string
-	err = walletClient.Call(ctx, "getmasterpubkey", &existingXPub, "fees")
+
+	// Ensure the wallet account for collecting fees exists and matches config.
+	err = setupFeeAccount(ctx, walletClient, cfg.FeeXPub)
 	if err != nil {
-		// TODO - ignore account not found
-		log.Errorf("dcrwallet RPC error: %v", err)
+		log.Errorf("Fee account error: %v", err)
 		requestShutdown()
 		shutdownWg.Wait()
 		return err
 	}
 
-
-		// account exists - make sure it matches the configuration.
-		if existingXPub != cfg.FeeXPub {
-			log.Errorf("fees account xpub differs: %s != %s", existingXPub, cfg.FeeXPub)
-			requestShutdown()
-			shutdownWg.Wait()
-			return err
-	} else {
-		// account does not exist - import xpub from configuration.
-		if err = walletClient.Call(ctx, "importxpub", nil, "fees"); err != nil {
-			log.Errorf("failed to import xpub: %v", err)
-			requestShutdown()
-			shutdownWg.Wait()
-			return err
-		}
- }
-
 	// Create and start webapi server.
 	apiCfg := webapi.Config{
-		SignKey:   signKey,
-		PubKey:    pubKey,
-		VSPFee:    cfg.VSPFee,
-		NetParams: cfg.netParams.Params,
+		SignKey:        signKey,
+		PubKey:         pubKey,
+		VSPFee:         cfg.VSPFee,
+		NetParams:      cfg.netParams.Params,
+		FeeAccountName: feeAccountName,
 	}
 	// TODO: Make releaseMode properly configurable. Release mode enables very
 	// detailed webserver logging and live reloading of HTML templates.
@@ -121,3 +107,37 @@ func run(ctx context.Context) error {
 
 	return ctx.Err()
 }
+
+func setupFeeAccount(ctx context.Context, walletClient *wsrpc.Client, feeXpub string) error {
+	// Check if account for fee collection already exists.
+	var accounts map[string]float64
+	err := walletClient.Call(ctx, "listaccounts", &accounts)
+	if err != nil {
+		return fmt.Errorf("dcrwallet RPC error: %v", err)
+	}
+
+	if _, ok := accounts[feeAccountName]; ok {
+		// Account already exists. Check xpub matches xpub from config.
+		var existingXPub string
+		err = walletClient.Call(ctx, "getmasterpubkey", &existingXPub, feeAccountName)
+		if err != nil {
+			return fmt.Errorf("dcrwallet RPC error: %v", err)
+		}
+
+		if existingXPub != feeXpub {
+			return fmt.Errorf("existing account xpub differs from config: %s != %s", existingXPub, feeXpub)
+		}
+
+		log.Debugf("Using existing wallet account %q to collect fees", feeAccountName)
+
+	} else {
+		// Account does not exist. Create it using xpub from config.
+		if err = walletClient.Call(ctx, "importxpub", nil, feeAccountName, feeXpub); err != nil {
+			log.Errorf("Failed to import xpub: %v", err)
+			return err
+		}
+		log.Debugf("Created new wallet account %q to collect fees", feeAccountName)
+	}
+
+	return nil
+}

webapi/methods.go

@@ -205,7 +205,7 @@ func feeAddress(c *gin.Context) {
 	}
 
 	var newAddress string
-	err = walletClient.Call(ctx, "getnewaddress", &newAddress, "fees")
+	err = walletClient.Call(ctx, "getnewaddress", &newAddress, cfg.FeeAccountName)
 	if err != nil {
 		log.Errorf("GetNewAddress error: %v", err)
 		sendErrorResponse("unable to generate fee address", http.StatusInternalServerError, c)

webapi/server.go

@@ -16,10 +16,11 @@ import (
 )
 
 type Config struct {
-	SignKey   ed25519.PrivateKey
-	PubKey    ed25519.PublicKey
-	VSPFee    float64
-	NetParams *chaincfg.Params
+	SignKey        ed25519.PrivateKey
+	PubKey         ed25519.PublicKey
+	VSPFee         float64
+	NetParams      *chaincfg.Params
+	FeeAccountName string
 }
 
 var cfg Config