Dynamic UI definition specification

The main purpose of Dynamic UI is to generate application creation forms “on-the-fly”. The Murano dashboard does not know anything about applications that will be presented in the catalog and which web forms are required to create an application instance. So all application definitions should contain an instruction, which tells the dashboard how to create an application and what validations need to be applied. This document will help you to compose a valid UI definition for your application.

The UI definition should be a valid YAML file and may contain the following sections (for version 2.x):

  • Version

    Points out the syntax version in use. Optional

  • Templates

    An auxiliary section, used together with an Application section to help with object model composing. Optional

  • Application

    Object model description passed to murano engine and used for application deployment. Required

  • Forms

    Web form definitions. Required

Version

The syntax and format of dynamic UI definitions may change over time, so the concept of format versions is introduced. Each UI definition file may contain a top-level section called Version to indicate the minimum version of Murano Dynamic UI platform which is capable to process it. If the section is missing, the format version is assumed to be latest supported.

The version consists of two non-negative integer segments, separated by a dot, i.e. has a form of MAJOR.MINOR. Dynamic UI platforms having the same MAJOR version component are compatible: i.e. the platform having the higher version may process UI definitions with lower versions if their MAJOR segments are the same. For example, Murano Dynamic UI platform of version 2.2 is able to process UI definitions of versions 2.0, 2.1 and 2.2, but is unable to process 3.0 or 1.9.

Currently, the latest version of Dynamic UI platform is 2.3. It is incompatible with UI definitions of Version 1.0, which were used in Murano releases before Juno.

Note

Although the Version field is considered to be optional, its default value is the latest supported version. So if you intent to use applications with the previous stable murano version, verify that the version is set correctly.

Version history

Version Changes OpenStack Version
1.0
  • Initial Dynamic UI implementation
 Icehouse
2.0
  • instance field support is dropped
  • New Application section that describes engine object model
  • New Templates section for keeping reusable pieces of Object
 Juno, Kilo
2.1
  • New network field provides a selection of networks and their subnetworks as a dropdown populated with those which are available to the current tenant.
 Liberty
2.2
  • Now application name is added automatically to the last service form. It is needed for a user to recognize one created application from another in the UI. Previously all application definitions contained the name property. So to support backward compatibility, you need to manually remove name field from class properties.
 Liberty
2.3
  • Now password field supports confirmInput flag and validator overloading with single regexpValidator or multiple validators attribute.
 Mitaka

Application and Templates

The Application section describes an application object model. This model will be translated into json, and an application will be deployed according to that json. The application section should contain all necessary keys that are required by the murano-engine to deploy an application. Note that the system section of the object model goes under the ?. So murano recognizes that instead of simple value, MuranoPL object is used. You can pick parameters you got from a user (they should be described in the Forms section) and pick the right place where they should be set. To do this YAQL is used. Below is an example of how two YAQL functions are used for object model generation:

  • generateHostname is used for a machine hostname template generation; it accepts two arguments: name pattern (string) and index (integer). If ‘#’ symbol is present in name pattern, it will be replaced with the index provided. If pattern is not given, a random name will be generated.
  • repeat is used to produce a list of data snippets, given the template snippet (first argument) and number of times it should be reproduced (second argument). Inside that template snippet current step can be referenced as $index.

Note

While evaluating YAQL expressions referenced from Application section (as well as almost all attributes inside Forms section, see later), $ root object is set to the list of dictionaries with cleaned validated forms’ data. For example, to obtain a cleaned value of field name of form appConfiguration , you should reference it as $.appConfiguration.name. This context will be called as a standard context throughout the text.

Example:

Templates:
  primaryController:
     ?:
       type: io.murano.windows.activeDirectory.PrimaryController
     host:
       ?:
         type: io.murano.windows.Host
       adminPassword: $.appConfiguration.adminPassword
       name: generateHostname($.appConfiguration.unitNamingPattern, 1)
       flavor: $.instanceConfiguration.flavor
       image: $.instanceConfiguration.osImage

   secondaryController:
     ?:
       type: io.murano.windows.activeDirectory.SecondaryController
     host:
       ?:
         type: io.murano.windows.Host
       adminPassword: $.appConfiguration.adminPassword
       name: generateHostname($.appConfiguration.unitNamingPattern, $index + 1)
       flavor: $.instanceConfiguration.flavor
       image: $.instanceConfiguration.osImage

Application:
  ?:
    type: io.murano.windows.activeDirectory.ActiveDirectory
  primaryController: $primaryController
  secondaryControllers: repeat($secondaryController, $.appConfiguration.dcInstances - 1)

Forms

This section describes markup elements for defining forms, which are currently rendered and validated with Django. Each form has a name, field definitions (mandatory), and validator definitions (optionally).

Note that each form is splitted into 2 parts:

  • input area - left side, where all the controls are located
  • description area - right side, where descriptions of the controls are located

Each field should contain:

  • name - system field name, could be any
  • type - system field type

Currently supported options for type attribute are:

  • string - text field (no inherent validations) with one-line text input
  • boolean - boolean field, rendered as a checkbox
  • text - same as string, but with a multi-line input
  • integer - integer field with an appropriate validation, one-line text input
  • password - text field with validation for strong password, rendered as two masked text inputs (second one is for password confirmation)
  • clusterip - specific text field, used for entering cluster IP address (validation for valid IP address syntax)
  • databaselist - specific field, a list of databases (comma-separated list of databases’ names, where each name has the following syntax first symbol should be latin letter or underscore; subsequent symbols can be latin letter, numeric, underscore, at the sign, number sign or dollar sign), rendered as one-line text input
  • image - specific field, used for filtering suitable images by image type provided in murano metadata in glance properties.
  • flavor - specific field, used for selection instance flavor from a list
  • keypair - specific field, used for selecting a keypair from a list
  • azone - specific field, used for selecting instance availability zone from a list
  • network - specific field, used to select a network and subnet from a list of the ones available to the current user
  • any other value is considered to be a fully qualified name for some Application package and is rendered as a pair of controls: one for selecting already existing Applications of that type in an Environment, second - for creating a new Application of that type and selecting it

Other arguments (and whether they are required or not) depends on a field’s type and other attributes values. Most of them are standard Django field attributes. The most common attributes are the following:

  • label - name, that will be displayed in the form; defaults to name being capitalized.

  • description - description, that will be displayed in the description area. Use yaml line folding character >- to keep the correct formatting during data transferring.

  • descriptionTitle - title of the description, defaults to label; displayed in the description area

  • hidden whether field should be visible or not in the input area. Note that hidden field’s description will still be visible in the descriptions area (if given). Hidden fields are used storing some data to be used by other, visible fields.

  • minLength, maxLength (for string fields) and minValue, maxValue (for integer fields) are transparently translated into django validation properties.

  • regexpValidator - regular expression to validate user input. Used with string or password field.

  • errorMessages - dictionary with optional ‘invalid’ and ‘required’ keys that set up what message to show to the user in case of errors.

  • validators is a list of dictionaries, each dictionary should at least have expr key, under that key either some YAQL expression is stored, either one-element dictionary with regexpValidator

    key (and some regexp string as value).

    Another possible key of a validator dictionary is message, and although it is not required, it is highly desirable to specify it - otherwise, when validator fails (i.e. regexp doesn’t match or YAQL expression evaluates to false) no message will be shown. Note that field-level validators use YAQL context different from all other attributes and section: here $ root object is set to the value of field being validated (to make expressions shorter).

    - name: someField
  type: string
  label: Domain Name
  validators:
    - expr:
        regexpValidator: '(^[^.]+$|^[^.]{1,15}\..*$)'
      message: >-
           NetBIOS name cannot be shorter than 1 symbol and
           longer than 15 symbols.
    - expr:
       regexpValidator: '(^[^.]+$|^[^.]*\.[^.]{2,63}.*$)'
     message: >-
       DNS host name cannot be shorter than 2 symbols and
       longer than 63 symbols.
  helpText: >-
    Just letters, numbers and dashes are allowed.
    A dot can be used to create subdomains

    Using of regexpValidator and validators attributes with password field was introduced in version 2.3. By default, password should have at least 7 characters, 1 capital letter, 1 non-capital letter, 1 digit, and 1 special character. If you do not want password validation to be so strong, you can override it by setting a custom validator or multiple validators for password. For that add regexpValidator or validators to the password field and specify custom regexp string as value, just like with any string field.

    Example

    - name: password
  type: password
  label: Password
  descriptionTitle: Password
     description: >-
       Please, provide password for the application. Password should be
        5-50 characters long and consist of alphanumeric characters
  regexpValidator: '^[a-zA-Z0-9]{5,50}?$'

  • confirmInput is a flag used only with password field and defaults to true. If you decided to turn off automatic password field cloning, you should set it to false. In this case password confirmation is not required from a user.

  • widgetMedia sets some custom CSS and JavaScript used for the field’s widget rendering. Note, that files should be placed to Django static folder in advance. Mostly they are used to do some client-side field enabling/disabling, hiding/unhiding etc.

  • requirements is used only with flavor field and prevents user to pick unstable for a deployment flavor. It allows to set minimum ram (in MBs), disk space (in GBs) or virtual CPU quantity.

    Example that shows how to hide items smaller than regular small flavor in a flavor select field:

    - name: flavor
       type: flavor
       label: Instance flavor
       requirements:
           min_disk: 20
           min_vcpus: 2
           min_memory_mb: 2048

  • include_subnets is used only with network field. True by default. If True, the field list includes all the possible combinations of network and subnet. E.g. if there are two available networks X and Y, and X has two subnets A and B, while Y has a single subnet C, then the list will include 3 items: (X, A), (X, B), (Y, C). If set to False only network names will be listed, without their subnets.

  • filter is used only with network field. None by default. If set to a regexp string, will be used to display only the networks with names matching the given regexp.

  • murano_networks is used only with network field. None by default. May have values None, exclude or translate. Defines the handling of networks which are created by murano. Such networks usually have very long randomly generated names, and thus look ugly when displayed in the list. If this value is set to exclude then these networks are not shown in the list at all. If set to translate the names of such networks are replaced by a string Network of %env_name%.

    Note

    This functionality is based on the simple string matching of the network name prefix and the names of all the accessible murano environments. If the environment is renamed after the initial deployment this feature will not be able to properly translate or exclude its network name.

  • allow_auto is used only with network field. True by default. Defines if the default value of the dropdown (labeled “Auto”) should be present in the list. The default value is a tuple consisting of two None values. The logic on how to treat this value is up to application developer. It is suggested to use this field to indicate that the instance should join default environment network. For use-cases where such behavior is not desired, this parameter should be set to False.

Network field and its specific attributes (include_subnets, filter, murano_networks, allow_auto) are available since version 2.1. Before that, there was no way for the end user to select existing network in the UI. The only way to change the default networking behavior was the usage of networking.yaml file. It allows to override the networking setting at the environment level, for all the murano environments of all the tenants. Now you can simple add a network field to your form definition and provide the ability to select the desired network for the specific application.

Example

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

Besides field-level validators, form-level validators also exist. They use standard context for YAQL evaluation and are required when there is a need to validate some form’s constraint across several fields.

Example

Forms:
  - appConfiguration:
      fields:
        - name: dcInstances
          type: integer
          hidden: true
          initial: 1
          required: false
          maxLength: 15
          helpText: Optional field for a machine hostname template
        - name: unitNamingPattern
          type: string
          label: Instance Naming Pattern
          required: false
          maxLength: 64
          regexpValidator: '^[a-zA-Z][-_\w]*$'
          errorMessages:
           invalid: Just letters, numbers, underscores and hyphens are allowed.
         helpText: Just letters, numbers, underscores and hyphens are allowed.
         description: >-
           Specify a string that will be used in a hostname instance.
           Just A-Z, a-z, 0-9, dash, and underline are allowed.


  - instanceConfiguration:
        fields:
          - name: title
            type: string
            required: false
            hidden: true
            descriptionTitle: Instance Configuration
            description: Specify some instance parameters based on which service will be created.
          - name: flavor
            type: flavor
            label: Instance flavor
            description: >-
              Select a flavor registered in OpenStack. Consider that service performance
              depends on this parameter.
            required: false
          - name: osImage
            type: image
            imageType: windows
            label: Instance image
            description: >-
              Select valid image for a service. Image should already be prepared and
              registered in glance.
          - name: availabilityZone
            type: azone
            label: Availability zone
            description: Select an availability zone, where service will be installed.
            required: false

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