Add allowFailure option

Implements #189

internal/backend.go

@@ -24,6 +24,7 @@ type Backend struct {
 	Path         string            `mapstructure:"path,omitempty"`
 	Key          string            `mapstructure:"key,omitempty"`
 	RequireKey   bool              `mapstructure:"requireKey,omitempty"`
+	AllowFailure bool              `mapstructure:"allowFailure,omitempty"`
 	Env          map[string]string `mapstructure:"env,omitempty"`
 	Rest         BackendRest       `mapstructure:"rest,omitempty"`
 	Options      Options           `mapstructure:"options,omitempty"`

internal/location.go

@@ -267,6 +267,13 @@ func (l Location) Backup(cron bool, specificBackend string) []error {
 
 		// If error save it and continue
 		if err != nil {
+			if backend.AllowFailure {
+				colors.Faint.Printf("skipping backend \"%s\" since allowFailure was set to \"true\"\n", to)
+				if flags.VERBOSE {
+					colors.Error.Printf("reason: %s", out)
+				}
+				continue
+			}
 			colors.Error.Println(out)
 			errors = append(errors, fmt.Errorf("%s@%s:\n%s%s", l.name, backend.name, out, err))
 			continue