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UI Schema

The ui block in massdriver.yaml controls how the configuration form renders. It follows the React JSON Schema Form (RJSF) uiSchema format. Keys in ui match the property names in params, and nested objects and arrays nest the same way.

This page covers the RJSF options used most often and the form behavior Massdriver adds to every bundle. For validation rules, see Validation Patterns.

Common RJSF Options​

ui:
  ui:order:
    - database_name
    - instance_type
    - "*"
  database_name:
    ui:help: Choose a unique name. Cannot be changed after creation.
    ui:placeholder: my-database
  storage_gb:
    ui:widget: updown
  notes:
    ui:widget: textarea
  allowed_cidrs:
    ui:options:
      orderable: false
OptionDescription
ui:orderSets the field order. "*" places all fields that are not listed at that position.
ui:helpHelp text shown below the field.
ui:placeholderPlaceholder text in an empty input.
ui:widgetChanges the input type. Common values: updown, range, textarea, password, hidden.
ui:optionsWidget options. For arrays: addable, orderable, and removable (all true by default).

For the full list, see the RJSF uiSchema reference.

Built-in Form Behavior​

Every bundle form has this behavior. You do not configure it.

  • Markdown descriptions. A property's description renders as markdown, so you can use links, code, and emphasis.
  • Searchable dropdowns. A property with enum or oneOf renders as a dropdown that filters as you type.
  • Collapsible array items. Each array item renders as a collapsible card with a header. Each array has Expand all and Collapse all buttons. An item with a validation error shows an error icon in its header.

Array Item Titles​

Set itemTitle under ui:options on an array to control the header of each item. {{key}} is replaced with the value of that key in the item.

params:
  properties:
    subnets:
      type: array
      title: Subnets
      items:
        type: object
        title: Subnet
        properties:
          cidr:
            type: string
          availability_zone:
            type: string

ui:
  subnets:
    ui:options:
      itemTitle: "{{cidr}} ({{availability_zone}})"

A subnet with cidr: 10.0.0.0/24 and availability_zone: us-east-1a has the header 10.0.0.0/24 (us-east-1a).

Placeholders read only top-level keys of the item. {{network.cidr}} does not resolve.

The header uses the first rule that gives a value:

  1. itemTitle, when at least one placeholder has a value.
  2. The item's name, title, label, or id key, in that order.
  3. The title of items and the item position, for example Subnet 2. If items has no title, the header is Item 2.

For an array of strings or numbers, the header is the item value.

See Also​