refactor: allow setting a custom mode when writing a slice to a file

plugins/buildpacks/functions.go

@@ -3,6 +3,7 @@ package buildpacks
 import (
 	"errors"
 	"fmt"
+	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -34,7 +35,11 @@ func rewriteBuildpacksFile(sourceWorkDir string) error {
 		buildpacks[i] = buildpack
 	}
 
-	return common.WriteSliceToFile(buildpacksPath, buildpacks)
+	return common.WriteSliceToFile(common.WriteSliceToFileInput{
+		Filename: buildpacksPath,
+		Lines:    buildpacks,
+		Mode:     os.FileMode(0600),
+	})
 }
 
 func validBuildpackURL(buildpack string) (string, error) {

plugins/common/io.go

@@ -217,33 +217,45 @@ func TouchFile(filename string) error {
 	}
 	defer file.Close()
 
-	file.Chmod(mode)
-	SetPermissions(filename, mode)
-	return nil
-}
-
-// WriteSliceToFile writes a slice of strings to a file
-func WriteSliceToFile(filename string, lines []string) error {
-	mode := os.FileMode(0600)
-	if strings.HasPrefix(filename, "/etc/sudoers.d/") {
-		mode = os.FileMode(0440)
-	}
-
-	file, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE|os.O_TRUNC, mode)
-	if err != nil {
+	if err := file.Chmod(mode); err != nil {
 		return err
 	}
 
+	if err := SetPermissions(filename, mode); err != nil {
+		return err
+	}
+	return nil
+}
+
+type WriteSliceToFileInput struct {
+	Filename string
+	Lines    []string
+	Mode     os.FileMode
+}
+
+// WriteSliceToFile writes a slice of strings to a file
+func WriteSliceToFile(input WriteSliceToFileInput) error {
+	file, err := os.OpenFile(input.Filename, os.O_RDWR|os.O_CREATE|os.O_TRUNC, input.Mode)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
 	w := bufio.NewWriter(file)
-	for _, line := range lines {
+	for _, line := range input.Lines {
 		fmt.Fprintln(w, line)
 	}
 	if err = w.Flush(); err != nil {
 		return err
 	}
 
-	file.Chmod(mode)
-	SetPermissions(filename, mode)
+	if err := file.Chmod(input.Mode); err != nil {
+		return err
+	}
+
+	if err := SetPermissions(input.Filename, input.Mode); err != nil {
+		return err
+	}
 
 	return nil
 }

plugins/docker-options/functions.go

@@ -32,5 +32,9 @@ func touchPhaseFile(appName string, phase string) error {
 
 func writeDockerOptionsForPhase(appName string, phase string, options []string) error {
 	phaseFilePath := getPhaseFilePath(appName, phase)
-	return common.WriteSliceToFile(phaseFilePath, options)
+	return common.WriteSliceToFile(common.WriteSliceToFileInput{
+		Filename: phaseFilePath,
+		Lines:    options,
+		Mode:     os.FileMode(0600),
+	})
 }

plugins/logs/functions.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"net/url"
+	"os"
 	"path/filepath"
 	"strings"
 	"time"
@@ -224,7 +225,11 @@ func writeVectorConfig() error {
 	b = bytes.Replace(b, []byte("\\u002B"), []byte("+"), -1)
 
 	vectorConfig := filepath.Join(common.GetDataDirectory("logs"), "vector.json")
-	if err := common.WriteSliceToFile(vectorConfig, []string{string(b)}); err != nil {
+	if err := common.WriteSliceToFile(common.WriteSliceToFileInput{
+		Filename: vectorConfig,
+		Lines:    []string{string(b)},
+		Mode:     os.FileMode(0600),
+	}); err != nil {
 		return err
 	}