feat: allow log level to be set to any level (#1345)

Co-authored-by: nils måsén <nils@piksel.se>

cmd/root.go

@@ -87,11 +87,11 @@ func PreRun(cmd *cobra.Command, _ []string) {
 		})
 	}
 
-	if enabled, _ := f.GetBool("debug"); enabled {
-		log.SetLevel(log.DebugLevel)
-	}
-	if enabled, _ := f.GetBool("trace"); enabled {
-		log.SetLevel(log.TraceLevel)
+	rawLogLevel, _ := f.GetString(`log-level`)
+	if logLevel, err := log.ParseLevel(rawLogLevel); err != nil {
+		log.Fatalf("Invalid log level: %s", err.Error())
+	} else {
+		log.SetLevel(logLevel)
 	}
 
 	scheduleSpec, _ = f.GetString("schedule")

docs/arguments.md

@@ -71,6 +71,10 @@ Environment Variable: WATCHTOWER_REMOVE_VOLUMES
 ## Debug
 Enable debug mode with verbose logging.
 
+!!! note "Notes"  
+    Alias for `--log-level debug`. See [Maximum log level](#maximum-log-level).  
+    Does _not_ take an argument when used as an argument. Using `--debug true` will **not** work.
+
 ```text
             Argument: --debug, -d
 Environment Variable: WATCHTOWER_DEBUG
@@ -81,6 +85,10 @@ Environment Variable: WATCHTOWER_DEBUG
 ## Trace
 Enable trace mode with very verbose logging. Caution: exposes credentials!
 
+!!! note "Notes"  
+    Alias for `--log-level trace`. See [Maximum log level](#maximum-log-level).  
+    Does _not_ take an argument when used as an argument. Using `--trace true` will **not** work.
+
 ```text
             Argument: --trace
 Environment Variable: WATCHTOWER_TRACE
@@ -88,6 +96,17 @@ Environment Variable: WATCHTOWER_TRACE
              Default: false
 ```
 
+## Maximum log level
+
+The maximum log level that will be written to STDERR (shown in `docker log` when used in a container).
+
+```text
+            Argument: --log-level
+Environment Variable: WATCHTOWER_LOG_LEVEL
+     Possible values: panic, fatal, error, warn, info, debug or trace
+             Default: info
+```
+
 ## ANSI colors
 Disable ANSI color escape codes in log output.
 

internal/flags/flags.go

@@ -182,6 +182,10 @@ func RegisterSystemFlags(rootCmd *cobra.Command) {
 		viper.GetString("WATCHTOWER_PORCELAIN"),
 		`Write session results to stdout using a stable versioned format. Supported values: "v1"`)
 
+	flags.String(
+		"log-level",
+		viper.GetString("WATCHTOWER_LOG_LEVEL"),
+		"The maximum log level that will be written to STDERR. Possible values: panic, fatal, error, warn, info, debug or trace")
 }
 
 // RegisterNotificationFlags that are used by watchtower to send notifications
@@ -374,6 +378,7 @@ func SetDefaults() {
 	viper.SetDefault("WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT", 25)
 	viper.SetDefault("WATCHTOWER_NOTIFICATION_EMAIL_SUBJECTTAG", "")
 	viper.SetDefault("WATCHTOWER_NOTIFICATION_SLACK_IDENTIFIER", "watchtower")
+	viper.SetDefault("WATCHTOWER_LOG_LEVEL", "info")
 }
 
 // EnvConfig translates the command-line options into environment variables
@@ -561,6 +566,23 @@ func ProcessFlagAliases(flags *pflag.FlagSet) {
 		interval, _ := flags.GetInt(`interval`)
 		flags.Set(`schedule`, fmt.Sprintf(`@every %ds`, interval))
 	}
+
+	if flagIsEnabled(flags, `debug`) {
+		flags.Set(`log-level`, `debug`)
+	}
+
+	if flagIsEnabled(flags, `trace`) {
+		flags.Set(`log-level`, `trace`)
+	}
+
+}
+
+func flagIsEnabled(flags *pflag.FlagSet, name string) bool {
+	value, err := flags.GetBool(name)
+	if err != nil {
+		log.Fatalf(`The flag %q is not defined`, name)
+	}
+	return value
 }
 
 func appendFlagValue(flags *pflag.FlagSet, name string, values ...string) error {

internal/flags/flags_test.go

@@ -129,11 +129,6 @@ func TestIsFile(t *testing.T) {
 	assert.True(t, isFile(os.Args[0]), "the currently running binary path should always be considered a file")
 }
 
-func TestReadFlags(t *testing.T) {
-	logrus.StandardLogger().ExitFunc = func(_ int) { t.FailNow() }
-
-}
-
 func TestProcessFlagAliases(t *testing.T) {
 	logrus.StandardLogger().ExitFunc = func(_ int) { t.FailNow() }
 	cmd := new(cobra.Command)
@@ -145,6 +140,7 @@ func TestProcessFlagAliases(t *testing.T) {
 	require.NoError(t, cmd.ParseFlags([]string{
 		`--porcelain`, `v1`,
 		`--interval`, `10`,
+		`--trace`,
 	}))
 	flags := cmd.Flags()
 	ProcessFlagAliases(flags)
@@ -163,6 +159,28 @@ func TestProcessFlagAliases(t *testing.T) {
 
 	sched, _ := flags.GetString(`schedule`)
 	assert.Equal(t, `@every 10s`, sched)
+
+	logLevel, _ := flags.GetString(`log-level`)
+	assert.Equal(t, `trace`, logLevel)
+}
+
+func TestProcessFlagAliasesLogLevelFromEnvironment(t *testing.T) {
+	cmd := new(cobra.Command)
+	err := os.Setenv("WATCHTOWER_DEBUG", `true`)
+	require.NoError(t, err)
+	defer os.Unsetenv("WATCHTOWER_DEBUG")
+
+	SetDefaults()
+	RegisterDockerFlags(cmd)
+	RegisterSystemFlags(cmd)
+	RegisterNotificationFlags(cmd)
+
+	require.NoError(t, cmd.ParseFlags([]string{}))
+	flags := cmd.Flags()
+	ProcessFlagAliases(flags)
+
+	logLevel, _ := flags.GetString(`log-level`)
+	assert.Equal(t, `debug`, logLevel)
 }
 
 func TestProcessFlagAliasesSchedAndInterval(t *testing.T) {