feat: Add GetAppSetting() convenience API

internal/app/service.go

@@ -323,6 +323,20 @@ func (svc *Service) ApplicationSettings() map[string]string {
 	return svc.config.ApplicationSettings
 }
 
+// GetAppSettingStrings returns the string for the specified App Setting.
+func (svc *Service) GetAppSetting(setting string) (string, error) {
+	if svc.config.ApplicationSettings == nil {
+		return "", fmt.Errorf("%s setting not found: ApplicationSettings section is missing", setting)
+	}
+
+	settingValue, ok := svc.config.ApplicationSettings[setting]
+	if !ok {
+		return "", fmt.Errorf("%s setting not found in ApplicationSettings section", setting)
+	}
+
+	return settingValue, nil
+}
+
 // GetAppSettingStrings returns the strings slice for the specified App Setting.
 func (svc *Service) GetAppSettingStrings(setting string) ([]string, error) {
 	if svc.config.ApplicationSettings == nil {
@@ -331,7 +345,7 @@ func (svc *Service) GetAppSettingStrings(setting string) ([]string, error) {
 
 	settingValue, ok := svc.config.ApplicationSettings[setting]
 	if !ok {
-		return nil, fmt.Errorf("%s setting not found in ApplicationSettings", setting)
+		return nil, fmt.Errorf("%s setting not found in ApplicationSettings section", setting)
 	}
 
 	valueStrings := util.DeleteEmptyAndTrim(strings.FieldsFunc(settingValue, util.SplitComma))

internal/app/service_test.go

@@ -195,6 +195,33 @@ func TestApplicationSettingsNil(t *testing.T) {
 	require.Nil(t, appSettings, "returned application settings expected to be nil")
 }
 
+func TestGetAppSetting(t *testing.T) {
+	goodSettingName := "ExportUrl"
+	expectedGoodValue := "http:/somewhere.com"
+	badSettingName := "DeviceName"
+
+	svc := Service{
+		config: &common.ConfigurationStruct{
+			ApplicationSettings: map[string]string{
+				goodSettingName: expectedGoodValue,
+			},
+		},
+	}
+
+	actual, err := svc.GetAppSetting(goodSettingName)
+	require.NoError(t, err)
+	assert.EqualValues(t, expectedGoodValue, actual, "actual application setting values not as expected")
+
+	_, err = svc.GetAppSetting(badSettingName)
+	require.Error(t, err)
+	assert.EqualError(t, err, fmt.Sprintf("%s setting not found in ApplicationSettings section", badSettingName))
+
+	svc.config.ApplicationSettings = nil
+	_, err = svc.GetAppSetting(goodSettingName)
+	require.Error(t, err)
+	assert.EqualError(t, err, fmt.Sprintf("%s setting not found: ApplicationSettings section is missing", goodSettingName))
+}
+
 func TestGetAppSettingStrings(t *testing.T) {
 	setting := "DeviceNames"
 	expected := []string{"dev1", "dev2"}

pkg/interfaces/service.go

@@ -60,9 +60,13 @@ type ApplicationService interface {
 	AddRoute(route string, handler func(http.ResponseWriter, *http.Request), methods ...string) error
 	// ApplicationSettings returns the key/value map of custom settings
 	ApplicationSettings() map[string]string
+	// GetAppSetting is a convenience function return a setting from the ApplicationSetting
+	// section of the service configuration.
+	// An error is returned if the specified setting is not found.
+	GetAppSetting(setting string) (string, error)
 	// GetAppSettingStrings is a convenience function that parses the value for the specified custom
 	// application setting as a comma separated list. It returns the list of strings.
-	// An error is returned if the specified setting is no found.
+	// An error is returned if the specified setting is not found.
 	GetAppSettingStrings(setting string) ([]string, error)
 	// SetFunctionsPipeline set the functions pipeline with the specified list of Application Functions.
 	// Note that the functions are executed in the order provided in the list.