refactor: use LogFailWithError to allow a unified exit code for golang commands when the app is missing

plugins/common/common.go

@@ -515,10 +515,17 @@ func isValidAppNameOld(appName string) error {
 	return errors.New("App name must begin with lowercase alphanumeric character, and cannot include uppercase characters, or colons")
 }
 
+// AppDoesNotExist wraps error to include the app name
+// and is used to distinguish between a normal error and an error
+// where the app is missing
 type AppDoesNotExist struct {
 	appName string
 }
 
+func (err *AppDoesNotExist) ExitCode() int {
+	return 20
+}
+
 func (err *AppDoesNotExist) Error() string {
 	return fmt.Sprintf("App %s does not exist", err.appName)
 }

plugins/common/log.go

@@ -8,6 +8,11 @@ import (
 	"strings"
 )
 
+// ErrWithExitCode wraps error and exposes an ExitCode method
+type ErrWithExitCode interface {
+	ExitCode() int
+}
+
 // LogFail is the failure log formatter
 // prints text to stderr and exits with status 1
 func LogFail(text string) {
@@ -15,6 +20,16 @@ func LogFail(text string) {
 	os.Exit(1)
 }
 
+// LogFailWithError is the failure log formatter
+// prints text to stderr and exits with the specified exit code
+func LogFailWithError(err error) {
+	fmt.Fprintln(os.Stderr, fmt.Sprintf(" !     %s", err.Error()))
+	if errExit, ok := err.(ErrWithExitCode); ok {
+		os.Exit(errExit.ExitCode())
+	}
+	os.Exit(1)
+}
+
 // LogFailQuiet is the failure log formatter (with quiet option)
 // prints text to stderr and exits with status 1
 func LogFailQuiet(text string) {

plugins/common/properties.go

@@ -16,7 +16,7 @@ import (
 func CommandPropertySet(pluginName, appName, property, value string, properties map[string]string, globalProperties map[string]bool) {
 	if appName != "--global" {
 		if err := VerifyAppName(appName); err != nil {
-			LogFail(err.Error())
+			LogFailWithError(err)
 		}
 	}
 	if appName == "--global" && !globalProperties[property] {
@@ -42,9 +42,8 @@ func CommandPropertySet(pluginName, appName, property, value string, properties
 		PropertyWrite(pluginName, appName, property, value)
 	} else {
 		LogInfo2Quiet(fmt.Sprintf("Unsetting %s", property))
-		err := PropertyDelete(pluginName, appName, property)
-		if err != nil {
-			LogFail(err.Error())
+		if err := PropertyDelete(pluginName, appName, property); err != nil {
+			LogFailWithError(err)
 		}
 	}
 }