test(flags): ensure temp files are cleaned up (#1727)

internal/flags/flags.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 	"time"
@@ -469,12 +468,14 @@ func GetSecretsFromFiles(rootCmd *cobra.Command) {
 		"notification-url",
 	}
 	for _, secret := range secrets {
-		getSecretFromFile(flags, secret)
+		if err := getSecretFromFile(flags, secret); err != nil {
+			log.Fatalf("failed to get secret from flag %v: %s", secret, err)
+		}
 	}
 }
 
 // getSecretFromFile will check if the flag contains a reference to a file; if it does, replaces the value of the flag with the contents of the file.
-func getSecretFromFile(flags *pflag.FlagSet, secret string) {
+func getSecretFromFile(flags *pflag.FlagSet, secret string) error {
 	flag := flags.Lookup(secret)
 	if sliceValue, ok := flag.Value.(pflag.SliceValue); ok {
 		oldValues := sliceValue.GetSlice()
@@ -483,7 +484,7 @@ func getSecretFromFile(flags *pflag.FlagSet, secret string) {
 			if value != "" && isFile(value) {
 				file, err := os.Open(value)
 				if err != nil {
-					log.Fatal(err)
+					return err
 				}
 				scanner := bufio.NewScanner(file)
 				for scanner.Scan() {
@@ -493,25 +494,26 @@ func getSecretFromFile(flags *pflag.FlagSet, secret string) {
 					}
 					values = append(values, line)
 				}
+				if err := file.Close(); err != nil {
+					return err
+				}
 			} else {
 				values = append(values, value)
 			}
 		}
-		sliceValue.Replace(values)
+		return sliceValue.Replace(values)
-		return
 	}
 
 	value := flag.Value.String()
 	if value != "" && isFile(value) {
-		file, err := ioutil.ReadFile(value)
+		content, err := os.ReadFile(value)
 		if err != nil {
-			log.Fatal(err)
+			return err
-		}
-		err = flags.Set(secret, strings.TrimSpace(string(file)))
-		if err != nil {
-			log.Error(err)
 		}
+		return flags.Set(secret, strings.TrimSpace(string(content)))
 	}
+
+	return nil
 }
 
 func isFile(s string) bool {
@@ -564,15 +566,15 @@ func ProcessFlagAliases(flags *pflag.FlagSet) {
 	// update schedule flag to match interval if it's set, or to the default if none of them are
 	if intervalChanged || !scheduleChanged {
 		interval, _ := flags.GetInt(`interval`)
-		flags.Set(`schedule`, fmt.Sprintf(`@every %ds`, interval))
+		_ = flags.Set(`schedule`, fmt.Sprintf(`@every %ds`, interval))
 	}
 
 	if flagIsEnabled(flags, `debug`) {
-		flags.Set(`log-level`, `debug`)
+		_ = flags.Set(`log-level`, `debug`)
 	}
 
 	if flagIsEnabled(flags, `trace`) {
-		flags.Set(`log-level`, `trace`)
+		_ = flags.Set(`log-level`, `trace`)
 	}
 
 }
@@ -593,7 +595,7 @@ func appendFlagValue(flags *pflag.FlagSet, name string, values ...string) error
 
 	if flagValues, ok := flag.Value.(pflag.SliceValue); ok {
 		for _, value := range values {
-			flagValues.Append(value)
+			_ = flagValues.Append(value)
 		}
 	} else {
 		return fmt.Errorf(`the value for flag %q is not a slice value`, name)

internal/flags/flags_test.go

@@ -1,20 +1,18 @@
 package flags
 
 import (
-	"io/ioutil"
-	"os"
-	"testing"
-
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"os"
+	"testing"
 )
 
 func TestEnvConfig_Defaults(t *testing.T) {
 	// Unset testing environments own variables, since those are not what is under test
-	os.Unsetenv("DOCKER_TLS_VERIFY")
+	_ = os.Unsetenv("DOCKER_TLS_VERIFY")
-	os.Unsetenv("DOCKER_HOST")
+	_ = os.Unsetenv("DOCKER_HOST")
 
 	cmd := new(cobra.Command)
 	SetDefaults()
@@ -48,10 +46,7 @@ func TestEnvConfig_Custom(t *testing.T) {
 
 func TestGetSecretsFromFilesWithString(t *testing.T) {
 	value := "supersecretstring"
-
+	t.Setenv("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD", value)
-	err := os.Setenv("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD", value)
-	require.NoError(t, err)
-	defer os.Unsetenv("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD")
 
 	testGetSecretsFromFiles(t, "notification-email-server-password", value)
 }
@@ -60,18 +55,15 @@ func TestGetSecretsFromFilesWithFile(t *testing.T) {
 	value := "megasecretstring"
 
 	// Create the temporary file which will contain a secret.
-	file, err := ioutil.TempFile(os.TempDir(), "watchtower-")
+	file, err := os.CreateTemp(t.TempDir(), "watchtower-")
 	require.NoError(t, err)
-	defer os.Remove(file.Name()) // Make sure to remove the temporary file later.
 
 	// Write the secret to the temporary file.
-	secret := []byte(value)
+	_, err = file.Write([]byte(value))
-	_, err = file.Write(secret)
 	require.NoError(t, err)
+	require.NoError(t, file.Close())
 
-	err = os.Setenv("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD", file.Name())
+	t.Setenv("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD", file.Name())
-	require.NoError(t, err)
-	defer os.Unsetenv("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD")
 
 	testGetSecretsFromFiles(t, "notification-email-server-password", value)
 }
@@ -80,16 +72,15 @@ func TestGetSliceSecretsFromFiles(t *testing.T) {
 	values := []string{"entry2", "", "entry3"}
 
 	// Create the temporary file which will contain a secret.
-	file, err := ioutil.TempFile(os.TempDir(), "watchtower-")
+	file, err := os.CreateTemp(t.TempDir(), "watchtower-")
 	require.NoError(t, err)
-	defer os.Remove(file.Name()) // Make sure to remove the temporary file later.
 
 	// Write the secret to the temporary file.
 	for _, value := range values {
 		_, err = file.WriteString("\n" + value)
 		require.NoError(t, err)
 	}
-	file.Close()
+	require.NoError(t, file.Close())
 
 	testGetSecretsFromFiles(t, "notification-url", `[entry1,entry2,entry3]`,
 		`--notification-url`, "entry1",
@@ -166,9 +157,7 @@ func TestProcessFlagAliases(t *testing.T) {
 
 func TestProcessFlagAliasesLogLevelFromEnvironment(t *testing.T) {
 	cmd := new(cobra.Command)
-	err := os.Setenv("WATCHTOWER_DEBUG", `true`)
+	t.Setenv("WATCHTOWER_DEBUG", `true`)
-	require.NoError(t, err)
-	defer os.Unsetenv("WATCHTOWER_DEBUG")
 
 	SetDefaults()
 	RegisterDockerFlags(cmd)
@@ -202,9 +191,7 @@ func TestProcessFlagAliasesSchedAndInterval(t *testing.T) {
 func TestProcessFlagAliasesScheduleFromEnvironment(t *testing.T) {
 	cmd := new(cobra.Command)
 
-	err := os.Setenv("WATCHTOWER_SCHEDULE", `@hourly`)
+	t.Setenv("WATCHTOWER_SCHEDULE", `@hourly`)
-	require.NoError(t, err)
-	defer os.Unsetenv("WATCHTOWER_SCHEDULE")
 
 	SetDefaults()
 	RegisterDockerFlags(cmd)