feat: restart signer on new config

app/app.go

@@ -157,6 +157,9 @@ func Run() error {
 	solverConfig, err := solverConfig.FetchSolverConfig(ctx, solverConfigOpts...)
 	panicOnError(err)
 
+	configChanged, err := config.StartConfigWatcher(ctx, solverConfig, solverConfigOpts)
+	panicOnError(err)
+
 	keyshare, err := keyshareStore.GetKeyshare()
 	var mpcAddress common.Address
 	if err == nil {
@@ -432,9 +435,20 @@ func Run() error {
 		statusHandler,
 		confirmationsHandler)
 
-	sig := <-sysErr
-	log.Info().Msgf("terminating got ` [%v] signal", sig)
-	return nil
+	for {
+		select {
+		case sig := <-sysErr:
+			{
+				log.Info().Msgf("terminating got ` [%v] signal", sig)
+				return nil
+			}
+		case <-configChanged:
+			{
+				log.Info().Msgf("terminating to reload config")
+				return nil
+			}
+		}
+	}
 }
 
 func panicOnError(err error) {

config/watcher.go

@@ -0,0 +1,80 @@
+package config
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/rs/zerolog/log"
+
+	solverConfig "github.com/sprintertech/solver-config/go/config"
+)
+
+const (
+	ConfigWatcherInterval = time.Minute * 1
+)
+
+// StartConfigWatcher starts a goroutine that periodically checks for config changes.
+// Panics to induce a restart if the config has changed
+func StartConfigWatcher(ctx context.Context, config *solverConfig.SolverConfig, opts []solverConfig.Option) (<-chan struct{}, error) {
+	configChanged := make(chan struct{}, 1)
+	configHash, err := calculateConfigHash(config)
+	if err != nil {
+		return configChanged, err
+	}
+
+	go func() {
+		ticker := time.NewTicker(ConfigWatcherInterval)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ticker.C:
+				hasChanged, err := hasConfigChanged(ctx, configHash, opts)
+				if err != nil {
+					log.Warn().Msgf("Failed checking has config changed: %s", err)
+					continue
+				}
+
+				if hasChanged {
+					configChanged <- struct{}{}
+				}
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+
+	return configChanged, nil
+}
+
+// hasConfigChanged fetches config and returns true if it has changed
+func hasConfigChanged(ctx context.Context, initialHash string, opts []solverConfig.Option) (bool, error) {
+	solverConfig, err := solverConfig.FetchSolverConfig(ctx, opts...)
+	if err != nil {
+		return false, err
+	}
+
+	newHash, err := calculateConfigHash(solverConfig)
+	if err != nil {
+		return false, err
+	}
+
+	if initialHash == newHash {
+		return false, nil
+	}
+
+	return true, nil
+}
+
+func calculateConfigHash(config *solverConfig.SolverConfig) (string, error) {
+	jsonBytes, err := json.Marshal(config)
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal config: %w", err)
+	}
+
+	hash := sha256.Sum256(jsonBytes)
+	return fmt.Sprintf("%x", hash), nil
+}