Add --dry option to view the generated spec without saving (#1504)

pkg/fission-cli/cmd/function/create.go

@@ -301,10 +301,15 @@ func (opts *CreateSubCommand) complete(input cli.Input) error {
 // It also prints warning/error if necessary.
 func (opts *CreateSubCommand) run(input cli.Input) error {
 	// if we're writing a spec, don't create the function
+	// save to spec file or display the spec to console
+	if input.Bool(flagkey.SpecDry) {
+		return spec.SpecDry(*opts.function)
+	}
+
 	if input.Bool(flagkey.SpecSave) {
 		err := spec.SpecSave(*opts.function, opts.specFile)
 		if err != nil {
-			return errors.Wrap(err, "error creating function spec")
+			return errors.Wrap(err, "error saving function spec")
 		}
 		return nil
 	}