Implement dry run mode

lib/producer/core/cli.rb

@@ -3,7 +3,7 @@ module Producer
     class CLI
       ArgumentError = Class.new(::ArgumentError)
 
-      USAGE = "Usage: #{File.basename $0} [-v] recipe_file"
+      USAGE = "Usage: #{File.basename $0} [-v] [-n] recipe_file"
 
       EX_USAGE = 64
 
@@ -33,6 +33,8 @@ module Producer
           case e
           when '-v'
             env.log_level = Logger::INFO
+          when '-n'
+            env.dry_run = true
           else
             m << e
           end

lib/producer/core/env.rb

@@ -2,13 +2,14 @@ module Producer
   module Core
     class Env
       attr_reader   :input, :output, :registry, :logger
-      attr_accessor :target
+      attr_accessor :target, :dry_run
 
       def initialize(input: $stdin, output: $stdout, remote: nil, registry: {})
         @input    = input
         @output   = output
         @registry = registry
         @remote   = remote
+        @dry_run  = false
       end
 
       def remote
@@ -43,6 +44,10 @@ module Producer
       def log_level=(level)
         logger.level = level
       end
+
+      def dry_run?
+        @dry_run
+      end
     end
   end
 end

lib/producer/core/worker.rb

@@ -17,7 +17,7 @@ module Producer
           env.log ' condition: met'
           task.actions.each do |e|
             env.log " action: #{e} applying"
-            e.apply
+            e.apply unless env.dry_run?
           end
         else
           env.log ' condition: NOT met'