deb-murano/doc/source/appdev-guide/app_migrating/app_migrate_to_liberty.rst

Migrate applications to Stable/Liberty

In Liberty a number of useful features that can be used by developers creating their murano applications were implemented. This document describes these features and steps required to include them to new apps.

1. Versioning

Package version

Now murano packages have a new optional attribute in their manifest called Version - a standard SemVer format version string. All MuranoPL classes have the version of the package they contained in. To specify the version of your package, add a new section to the manifest file:

Version: 0.1.0

If no version specified, the package version will be equal to 0.0.0.

Package requirements

There are cases when packages may require other packages for their work. Now you need to list such packages in the Require section of the manifest file:

Require:
  package1_FQN: version_spec_1
  ...
  packageN_FQN: version_spec_N

version_spec here denotes the allowed version range. It can be either in semantic_version specification pip-like format or as partial version string. If you do not want to specify the package version, leave this value empty:

Require:
  package1_FQN: >=0.0.3
  package2_FQN:

In this case, the last dependency 0.x.y is used.

Note

All packages depend on the io.murano package (core library). If you do not specify this requirement in the list (or the list is empty or even there is no Require key in package manifest), then dependency io.murano: 0 will be automatically added.

Object version

Now you can specify the version of objects in UI definition when your application requires specific version of some class. To do this, add new key classVersion to section ? describing object:

?:
  type: io.test.apps.TestApp
  classVersion: 0.0.1

classVersion of all classes included to package equals Version of this package.

2. YAQL

In Liberty, murano was updated to use yaql 1.0.0. The new version of yaql allows you to use a number of new functions and features that help to increase the speed of developing new applications.

Note

Usage of these features makes your applications incompatible with older versions of murano.

Also, in Liberty you can change Format in the manifest of package from 1.0 to 1.1 or 1.2.

• 1.0 - supported by all versions of murano.
• 1.1 - supported by Liberty+. Specify it, if you want to use features from yaql 0.2 and yaql 1.0.0 at the same time in your application.
• 1.2 - supported by Liberty+. A number of features from yaql 0.2 do not work with this format (see the list below). We recommend you to use it for new applications where compatibility with Kilo is not required.

Some examples of yaql 0.2 features that are not compatible with the 1.2 format

• Several functions now cannot be called as MuranoObject methods: id(), cast(), super(), psuper(), type().
• Now you do not have the ability to compare non-comparable types. For example "string != false"
• Dicts are not iterable now, so you cannot do this: If: $key in $dict. Use $key in $dict.keys() or $v in $dict.values()
• Tuples are not available. => always means keyword argument.

3. Simple software configuration

Previously, you always had to create execution plans even when some short scripts had to be executed on a VM. This process included creating a template file, creating a script, and describing the sending of the execution plan to the murano agent.

Now you can use a new class io.murano.configuration.Linux from murano core-library. This allows sending short commands to the VM and putting files from the Resources folder of packages to some path on the VM without the need of creating execution plans.

To use this feature you need to:

• Declare a namespace (for convenience)

  Namespaces:
    conf: io.murano.configuration
    ...

• Create object of io.murano.configuration.Linux class in workflow of your application:

  $linux: new(conf:Linux)

• Run one of the two feature methods: runCommand or putFile:

  # first agrument is agent of instance, second - your command
  $linux.runCommand($.instance.agent, 'service apache2 restart')

  or:

  # getting content of file from 'Resources' folder
  - $resources: new(sys:Resources)
  - $fileContent: $resources.string('your_file.name')
  # put this content to some directory on VM
  - $linux.putFile($.instance.agent, $fileContent, '/tmp/your_file.name')

Note

At the moment, you can use this feature only if your app requires an instance of LinuxMuranoInstance type.

4. UI network selection element

Since Liberty, you can provide users with the ability to choose where to join their VM: to a new network created during the deployment, or to an already existing network. Dynamic UI now has a new type of field - NetworkChoiseField. This field provides a selection of networks and their subnetworks as a dropdown populated with those which are available to the current project (tenant).

To use this feature, you should make the following updates in the Dynamic UI of an application:

• Add network field:

  fields:
    - name: network
      type: network
      label: Network
      description: Select a network to join. 'Auto' corresponds to a default environment's network.
      required: false
      murano_networks: translate

  To see the full list of the network field arguments, refer to the UI forms specification <DynamicUISpec>.

• Add template:

  Templates:
    customJoinNet:
      - ?:
          type: io.murano.resources.ExistingNeutronNetwork
        internalNetworkName: $.instanceConfiguration.network[0]
        internalSubnetworkName: $.instanceConfiguration.network[1]

• Add declaration of networks instance property:

  Application:
    ?:
      type: com.example.exampleApp
    instance:
      ?:
        type: io.murano.resources.LinuxMuranoInstance
    networks:
      useEnvironmentNetwork: $.instanceConfiguration.network[0]=null
      useFlatNetwork: false
      customNetworks: switch($.instanceConfiguration.network[0], $=null=>list(), $!=null=>$customJoinNet)

For more details about this feature, see use-cases <use-cases>

Note

To use this feature, the version of UI definition must be 2.1+

5. Remove name field from fields and object model in dynamic UI

Previously, each class of an application had a name property. It had no built-in predefined meaning for MuranoPL classes and mostly used for dynamic UI purposes.

Now you can create your applications without this property in classes and without a corresponding field in UI definitions. The field for app name will be automatically generated on the last management form before start of deployment. Bonus of deleting this - to remove unused property from muranopl class that is needed for dashboard only.

So, to update existing application developer should make 3 steps:

1. remove name field and property declaration from UI definition;
2. remove name property from class of application and make sure that it is not used anywhere in workflow
3. set version of UI definition to 2.2 or higher