create the log file along with its parent directory if not present

io/logs/BUILD.bazel

@@ -13,6 +13,7 @@ go_library(
         "//cache/lru:go_default_library",
         "//config/params:go_default_library",
         "//crypto/rand:go_default_library",
+        "//io/file:go_default_library",
         "@com_github_hashicorp_golang_lru//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],

io/logs/logutil.go

@@ -6,9 +6,11 @@ import (
 	"io"
 	"net/url"
 	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/prysmaticlabs/prysm/v5/config/params"
+	"github.com/prysmaticlabs/prysm/v5/io/file"
 	"github.com/sirupsen/logrus"
 )
 
@@ -20,6 +22,9 @@ func addLogWriter(w io.Writer) {
 // ConfigurePersistentLogging adds a log-to-file writer. File content is identical to stdout.
 func ConfigurePersistentLogging(logFileName string) error {
 	logrus.WithField("logFileName", logFileName).Info("Logs will be made persistent")
+	if err := file.MkdirAll(filepath.Dir(logFileName)); err != nil {
+		return err
+	}
 	f, err := os.OpenFile(logFileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, params.BeaconIoConfig().ReadWritePermissions) // #nosec G304
 	if err != nil {
 		return err

io/logs/logutil_test.go

@@ -1,6 +1,8 @@
 package logs
 
 import (
+	"fmt"
+	"os"
 	"testing"
 
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
@@ -24,3 +26,38 @@ func TestMaskCredentialsLogging(t *testing.T) {
 		require.Equal(t, MaskCredentialsLogging(test.url), test.maskedUrl)
 	}
 }
+
+func TestConfigurePersistantLogging(t *testing.T) {
+	testParentDir := t.TempDir()
+
+	// 1. Test creation of file in an existing parent directory
+	logFileName := "test.log"
+	existingDirectory := "test-1-existing-testing-dir"
+
+	err := ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s", testParentDir, existingDirectory, logFileName))
+	require.NoError(t, err)
+
+	// 2. Test creation of file along with parent directory
+	nonExistingDirectory := "test-2-non-existing-testing-dir"
+
+	err = ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s", testParentDir, nonExistingDirectory, logFileName))
+	require.NoError(t, err)
+
+	// 3. Test creation of file in an existing parent directory with a non-existing sub-directory
+	existingDirectory = "test-3-existing-testing-dir"
+	nonExistingSubDirectory := "test-3-non-existing-sub-dir"
+	err = os.Mkdir(fmt.Sprintf("%s/%s", testParentDir, existingDirectory), 0700)
+	if err != nil {
+		return
+	}
+
+	err = ConfigurePersistentLogging(fmt.Sprintf("%s/%s/%s/%s", testParentDir, existingDirectory, nonExistingSubDirectory, logFileName))
+	require.NoError(t, err)
+
+	//4. Create log file in a directory without 700 permissions
+	existingDirectory = "test-4-existing-testing-dir"
+	err = os.Mkdir(fmt.Sprintf("%s/%s", testParentDir, existingDirectory), 0750)
+	if err != nil {
+		return
+	}
+}