Merge pull request ElementsProject#206 from nepet/202306-add-sync-che…

…ck-for-elements

Wait for Elementsd to be synced

cmd/peerswap-plugin/main.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"time"
 
+	"github.com/elementsproject/peerswap/elements"
 	"github.com/elementsproject/peerswap/isdev"
 	"github.com/elementsproject/peerswap/log"
 	"github.com/elementsproject/peerswap/version"
@@ -176,7 +177,13 @@ func run(ctx context.Context, lightningPlugin *clightning.ClightningClient) erro
 			config.Liquid.RpcPort,
 			config.Liquid.RpcHost,
 		)
-		liquidCli, err = getElementsClient(lightningPlugin.GetLightningRpc(), config)
+		// This call is blocking, waiting for elements to come alive and sync.
+		liquidCli, err = elements.NewClient(
+			config.Liquid.RpcUser,
+			config.Liquid.RpcPassword,
+			config.Liquid.RpcHost,
+			config.Liquid.RpcPort,
+		)
 		if err != nil {
 			return err
 		}
@@ -420,16 +427,6 @@ func getBitcoinChain(li *glightning.Lightning) (*chaincfg.Params, error) {
 	}
 }
 
-func getElementsClient(li *glightning.Lightning, config *clightning.Config) (*gelements.Elements, error) {
-	elementsCli := gelements.NewElements(config.Liquid.RpcUser, config.Liquid.RpcPassword)
-	err := elementsCli.StartUp(config.Liquid.RpcHost, config.Liquid.RpcPort)
-	if err != nil {
-		log.Infof("Could not connect to elements: %s", err.Error())
-		return nil, err
-	}
-
-	return elementsCli, nil
-}
 func getBitcoinClient(li *glightning.Lightning, pluginConfig *clightning.Config) (*gbitcoin.Bitcoin, error) {
 	rpcUser := pluginConfig.Bitcoin.RpcUser
 	rpcPassword := pluginConfig.Bitcoin.RpcPassword

cmd/peerswaplnd/peerswapd/main.go

@@ -16,6 +16,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/elementsproject/peerswap/elements"
 	"github.com/elementsproject/peerswap/isdev"
 	"github.com/elementsproject/peerswap/lnd"
 	"github.com/elementsproject/peerswap/log"
@@ -197,20 +198,19 @@ func run() error {
 	if cfg.LiquidEnabled {
 		supportedAssets = append(supportedAssets, "lbtc")
 		log.Infof("Liquid swaps enabled")
-		// blockchaincli
 		liquidConfig := cfg.ElementsConfig
-		liquidCli = gelements.NewElements(liquidConfig.RpcUser, liquidConfig.RpcPassword)
-		err = liquidCli.StartUp(liquidConfig.RpcHost, liquidConfig.RpcPort)
-		if err != nil {
-			return err
-		}
-		// Wallet
-		liquidWalletCli := gelements.NewElements(liquidConfig.RpcUser, liquidConfig.RpcPassword)
-		err = liquidWalletCli.StartUp(liquidConfig.RpcHost, liquidConfig.RpcPort)
+
+		// This call is blocking, waiting for elements to come alive and sync.
+		liquidCli, err = elements.NewClient(
+			liquidConfig.RpcUser,
+			liquidConfig.RpcPassword,
+			liquidConfig.RpcHost,
+			liquidConfig.RpcPort,
+		)
 		if err != nil {
 			return err
 		}
-		liquidRpcWallet, err = wallet.NewRpcWallet(liquidWalletCli, liquidConfig.RpcWallet)
+		liquidRpcWallet, err = wallet.NewRpcWallet(liquidCli, liquidConfig.RpcWallet)
 		if err != nil {
 			return err
 		}

elements/client.go

@@ -0,0 +1,51 @@
+package elements
+
+import (
+	"strings"
+	"time"
+
+	"github.com/elementsproject/glightning/gelements"
+	"github.com/elementsproject/peerswap/log"
+)
+
+type ElementsClientBuilder struct {
+}
+
+func NewClient(rpcUser, rpcPassword, rpcHost string, rpcPort uint) (*gelements.Elements, error) {
+	c := gelements.NewElements(rpcUser, rpcPassword)
+
+	var backoff int64 = 1
+	for {
+		err := c.StartUp(rpcHost, rpcPort)
+		if err != nil {
+			log.Infof("Could not connect to elements: %s", err.Error())
+			// Check if error starts with -28 indicating, that we can not connect
+			// to elementsd as it is starting up and not ready yet.
+			if strings.HasPrefix(strings.TrimSpace(err.Error()), "-28") {
+				// wait a bit and try again.
+				time.Sleep(time.Duration(backoff*10) * time.Second)
+				backoff *= 2
+				continue
+			}
+			// Other errors fail.
+			return nil, err
+		}
+		break
+	}
+
+	backoff = 1
+	for {
+		info, err := c.GetChainInfo()
+		if err != nil {
+			return nil, err
+		}
+		if info.VerificationProgress < 1. {
+			// Waiting for block verification to catch up.
+			log.Infof("Elementsd still syncing, progress: %d", info.VerificationProgress)
+			time.Sleep(time.Duration(backoff*10) * time.Second)
+			backoff *= 2
+			continue
+		}
+		return c, nil
+	}
+}