bus: return error on startup if wallet is disabled

Typically the case when disablewallet=1 is specified in bitcoin.conf,
or if bitcoind is compiled without wallet features.

This is useful with Raspiblitz, where wallet is disabled by default.

Closes #11.

Author: onyb

bus/errors.go

@@ -7,6 +7,10 @@ var (
 	// was not successful. Use this error during sanity checks.
 	ErrBitcoindUnreachable = errors.New("bitcoind unreachable")
 
+	// ErrWalletDisabled indicates that wallet features have been disabled on
+	// the connected Bitcoin node. SatStack relies on wallet RPCs to function.
+	ErrWalletDisabled = errors.New("bitcoind wallet is disabled")
+
 	// ErrUnsupportedBitcoindVersion indicates that the connected bitcoind node
 	// has a version that is not supported by SatStack.
 	ErrUnsupportedBitcoindVersion = errors.New("unsupported bitcoind version")

bus/infrastructure.go

@@ -6,16 +6,13 @@ import (
 	"sync"
 	"time"
 
-	"github.com/btcsuite/btcutil"
-
+	"github.com/btcsuite/btcd/btcjson"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
-
+	"github.com/btcsuite/btcd/rpcclient"
+	"github.com/btcsuite/btcutil"
 	"github.com/ledgerhq/satstack/config"
 	"github.com/ledgerhq/satstack/utils"
-
 	"github.com/patrickmn/go-cache"
-
-	"github.com/btcsuite/btcd/rpcclient"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -93,6 +90,10 @@ func New(host string, user string, pass string, noTLS bool) (*Bus, error) {
 	client := <-pool
 	defer func() { pool <- client }()
 
+	if walletDisabled(client) {
+		return nil, ErrWalletDisabled
+	}
+
 	info, err := client.GetBlockChainInfo()
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", ErrBitcoindUnreachable, err)
@@ -181,6 +182,20 @@ func CurrencyFromChain(chain string) (Currency, error) {
 	}
 }
 
+// walletDisabled detects if wallet features have been disabled in the Bitcoin
+// node, and returns a boolean value accordingly.
+//
+// This maps to the option disablewallet=1 in bitcoin.conf.
+func walletDisabled(client *rpcclient.Client) bool {
+	if _, err := client.GetWalletInfo(); err != nil {
+		if err.(*btcjson.RPCError).Code == btcjson.ErrRPCMethodNotFound.Code {
+			return true
+		}
+	}
+
+	return false
+}
+
 // txIndexEnabled can be used to detect if the bitcoind server being connected
 // has a transaction index (enabled by option txindex=1).
 //