Merge pull request #3179 from keep-network/ensure-app-dir-exists

Ensure existence of the application storage directory

So far, the client exited with an error in case the appropriate storage directory 
for the beacon or tbtc application was missing. Here we check whether the storage 
directory exists, and we create a fresh one in case it is missing.

cmd/start.go

@@ -3,7 +3,6 @@ package cmd
 import (
 	"context"
 	"fmt"
-
 	"github.com/keep-network/keep-core/pkg/tbtc"
 
 	"github.com/keep-network/keep-core/config"
@@ -142,6 +141,19 @@ func initializePersistence(clientConfig *config.Config, application string) (
 	persistence.Handle,
 	error,
 ) {
+	err := persistence.EnsureDirectoryExists(
+		clientConfig.Storage.DataDir,
+		application,
+	)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"cannot create storage directory for "+
+				"application [%v]: [%w]",
+			application,
+			err,
+		)
+	}
+
 	path := fmt.Sprintf("%s/%s", clientConfig.Storage.DataDir, application)
 
 	diskHandle, err := persistence.NewDiskHandle(path)