Update wrapper recipe to make it simpler and more dev-friendly.

slapos/recipe/wrapper.py

@@ -30,25 +30,32 @@ import shlex
 from slapos.recipe.librecipe import GenericBaseRecipe
 
 class Recipe(GenericBaseRecipe):
-
     def install(self):
-
         command_line = shlex.split(self.options['command-line'])
-
+        wrapper_path = self.options['wrapper-path']
         wait_files = self.options.get('wait-for-files')
+        environment = self.options.get('environment')
+
+        if not wait_files and not environment:
+          # Create a simple wrapper as shell script
+          return [self.createWrapper(
+             name=wrapper_path,
+             command=command_line[0],
+             parameters=command_line[1:],
+          )]
+
+        # More complex needs: create a Python script as wrapper
+
         if wait_files is not None:
             wait_files = [filename.strip() for filename in wait_files.split()
                           if filename.strip()]
-
-        environment = self.options.get('environment')
         if environment is not None:
             environment = dict((k.strip(), v.strip()) for k, v in [
                              line.split('=')
                              for line in environment.split('\n')
                            ])
-
         return [self.createPythonScript(
-            self.options['output'],
+            wrapper_path,
             'slapos.recipe.librecipe.execute.generic_exec',
             (command_line, wait_files, environment,),
         )]