render_command.rb in kubernetes-deploy-1.0.0.pre.1

- old
+ new
@@ -2,24 +2,32 @@
 
 module Krane
   module CLI
     class RenderCommand
       OPTIONS = {
-        bindings: { type: :array, banner: "foo=bar abc=def", desc: 'Bindings for erb' },
-        filenames: { type: :array, banner: 'config/deploy/production config/deploy/my-extra-resource.yml',
-                     required: true, aliases: 'f', desc: 'Directories and files to render' },
-        'current-sha': { type: :string, banner: "SHA", desc: "Expose SHA `current_sha` in ERB bindings" },
+        "bindings" => { type: :array, banner: "foo=bar abc=def", desc: 'Bindings for erb' },
+        "filenames" => { type: :array, banner: 'config/deploy/production config/deploy/my-extra-resource.yml',
+                         required: false, default: [], aliases: 'f', desc: 'Directories and files to render' },
+        "stdin" => { type: :boolean, desc: "Read resources from stdin", default: false },
+        "current-sha" => { type: :string, banner: "SHA", desc: "Expose SHA `current_sha` in ERB bindings" },
       }
 
       def self.from_options(options)
         require 'krane/render_task'
         require 'krane/bindings_parser'
         require 'krane/options_helper'
 
         bindings_parser = ::Krane::BindingsParser.new
         options[:bindings]&.each { |b| bindings_parser.add(b) }
 
-        ::Krane::OptionsHelper.with_processed_template_paths(options[:filenames]) do |paths|
+        # never mutate options directly
+        filenames = options[:filenames].dup
+        filenames << "-" if options[:stdin]
+        if filenames.empty?
+          raise Thor::RequiredArgumentMissingError, 'At least one of --filenames or --stdin must be set'
+        end
+
+        ::Krane::OptionsHelper.with_processed_template_paths(filenames) do |paths|
           runner = ::Krane::RenderTask.new(
             current_sha: options['current-sha'],
             template_paths: paths,
             bindings: bindings_parser.parse,
           )