Migrate applications to Stable/Kilo

In Kilo, there are no breaking changes that affect backward compatibility. But there are two new features which you can use since Kilo.

1. Pluggable Pythonic classes for murano

Now you can create plug-ins for MuranoPL. A plug-in (extension) is an independent Python package implementing functionality which you want to add to the workflow of your application.

For a demo application demonstrating the usage of plug-ins, see the murano/contrib/plugins/murano_exampleplugin folder.

The application consist of the following components:

• An ImageValidatorMixin class that inherits the generic instance class (io.murano.resources.Instance) and adds a method capable of validating the instance image for having an appropriate murano metadata type. This class may be used as a mixin when added to inheritance hierarchy of concrete instance classes.

• A concrete class called DemoInstance that inherits from io.murano.resources.LinuxMuranoInstance and ImageValidatorMixin to add the image validation logic to a standard, murano-enabled and Linux-based instance.

• An application that deploys a single VM using the DemoInstance class if the tag on the user-supplied image matches the user-supplied constant.

The ImageValidatorMixin demonstrates the instantiation of plug-in provided class and its usage, as well as handling of exception which may be thrown if the plug-in is not installed in the environment.

2. Murano mistral integration

The core library has a new system class for mistral client that allows to call Mistral APIs from the murano application model.

The system class allows you to:

• Upload a mistral workflow to mistral.

• Trigger the mistral workflow that is already deployed, wait for completion and return the execution output.

To use this feature, add some mistral workflow to Resources folder of your package. For example, create file TestEcho_MistralWorkflow.yaml:

version: '2.0'

test_echo:
  type: direct
  input:
    - input_1
  output:
    out_1: <% $.task1_output_1 %>
    out_2: <% $.task2_output_2 %>
    out_3: <% $.input_1 %>
 tasks:
   my_echo_test:
     action: std.echo output='just a string'
     publish:
       task1_output_1: 'task1_output_1_value'
       task1_output_2: 'task1_output_2_value'
     on-success:
       - my_echo_test_2

   my_echo_test_2:
     action: std.echo output='just a string'
     publish:
       task2_output_1: 'task2_output_1_value'
       task2_output_2: 'task2_output_2_value'

And provide workflow to use the mistral client:

Namespaces:
=: io.murano.apps.test
std: io.murano
sys: io.murano.system


Name: MistralShowcaseApp

Extends: std:Application

Properties:
  name:
    Contract: $.string().notNull()

  mistralClient:
    Contract: $.class(sys:MistralClient)
    Usage: Runtime


Methods:
  initialize:
    Body:
      - $this.mistralClient: new(sys:MistralClient)

  deploy:
    Body:
      - $resources: new('io.murano.system.Resources')
      - $workflow: $resources.string('TestEcho_MistralWorkflow.yaml')
      - $.mistralClient.upload(definition => $workflow)
      - $output: $.mistralClient.run(name => 'test_echo', inputs => dict(input_1 => input_1_value))
      - $this.find(std:Environment).reporter.report($this, $output.get('out_3'))