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Data Types

data_types are useful for grouping and re-using a common set of properties, together with their types and default values.

Supported Definitions

To use data_types, the definitions version must be cloudify_dsl_1_2 or higher.

Declaration

data_types:

  data_type1:
    description: ...
    properties: ...

  data_type2:
    derived_from: data_type1
    description: ...
    properties: ...

Schema

Keyname Required Type Description
description no string Description for the data type.
properties no dictionary Dictionary of the data type properties.
derived_from no string Parent data type.

description

This property can be used to describe the data type.

properties

The properties property is used to define the data type schema.

properties is a dictionary from a property name to a dictionary describing the property.

Property Schema:

Keyname Required Type Description
description no string Description for the property.
type no string Property type. If you do not specify a data type, the type can be anything (including types not listed in the valid types). Valid types: string, integer, float, boolean or a another custom data type.
default no <any> An optional default value for the property.
required no boolean Specifies whether the property is required. (Default: true, Supported since: cloudify_dsl_1_2)

derived_from

The derived_from property can be used to build over and extend an existing data type.

When a data type derives from another data type, its properties are merged with the parent’s properties. The merge is at the property level. A property defined on the parent type is overridden by a property with the same name that is defined on the deriving type. An exception to this rule is when a property type references some other custom data type. This is explained in detail in the following examples.

Features and Examples

Basic Usage

In this example, a my.datatypes.Endpoint data type is defined with two properties: ip and port. The, a DatabaseService node type is defined to represent an external database service. In this type’s properties, an endpoint property is defined, it’s type being the endpoint data type that was previously defined. Finally, a node template with a DatabaseService type is defined. This node template fully configures the endpoint properties (i.e. the ip and port).

tosca_definitions_version: cloudify_dsl_1_2

data_types:

  my.datatypes.Endpoint:
    description: Socket endpoint details
    properties:
      ip:
        description: the endpoint IP
        type: string
      port:
        description: the endpoint port
        type: integer

node_types:

  DatabaseService:
    derived_from: cloudify.nodes.DBMS
    properties:
      endpoint:
        type: my.datatypes.Endpoint

node_templates:

  my_db_service:
    type: DatabaseService
    properties:
      endpoint:
        ip: 192.168.15.85
        port: 2233

Schema Validations

If a property is missed or an additional property spcified under endpoint, the blueprint will fail validation. For example

node_templates:
  my_db_service2:
    type: DatabaseService
    properties:
      endpoint:
        ip: 192.168.15.85

will fail validation because of the missing port property. (Note that if port had its required attribute set to false, there would not be a validation failure.)

Similarly,

node_templates:
  my_db_service3:
    type: DatabaseService
    properties:
      endpoint:
        ip: 192.168.15.85
        port: 2233
        some_other_property: the_value

will fail validation because of the unexpected some_other_property, which is not specified in endpoint's schema.

Inheritance

You can derive from previously-defined data types, to extend their schema. For example, consider the my.datatypes.Endpoint defined in the previous example. You can derive from it, to create an endpoint data type that also includes a user name, as shown below.

tosca_definitions_version: cloudify_dsl_1_2

data_types:

  my.datatypes.Endpoint:
    ...

  my.datatypes.ExtendedEndpoint:
    derived_from: my.datatypes.Endpoint
    properties:
      username:
        description: Username used to connect to the endpoint
        type: string

node_types:

  DatabaseService:
    derived_from: cloudify.nodes.DBMS
    properties:
      endpoint:
        type: my.datatypes.ExtendedEndpoint

node_templates:

  my_db_service:
    type: DatabaseService
    properties:
      endpoint:
        ip: 192.168.15.85
        port: 2233
        username: jimmy

Composition

Data type property types can themselves be other data types. Using the previously defined my.datatypes.Endpoint, in the following example, a my.datatypes.Connection is created that will hold endpoint information and authentication details.

tosca_definitions_version: cloudify_dsl_1_2

data_types:

  my.datatypes.Endpoint:
    ...

  my.datatypes.Connection:
    properties:
      endpoint:
        type: my.datatypes.Endpoint
      auth:
        type: my.datatypes.Auth

  my.datatypes.Auth:
    properties:
      username:
        type: string
      password:
        type: string

node_types:

  DatabaseService:
    derived_from: cloudify.nodes.DBMS
    properties:
      connection:
        type: my.datatypes.Connection

node_templates:

  my_db_service:
    type: DatabaseService
    properties:
      connection:
        endpoint:
          ip: 192.168.15.85
          port: 2233
        auth:
          username: jimmy
          password: secret

Default Values

Default values can help make highly configurable components easy to use by setting default values where it is logical to do so. Consider the previously defined my.datatypes.Connection. Its usage can be simplified if, for example, you know that port by default will be 2233 and username by default will be admin.

tosca_definitions_version: cloudify_dsl_1_2

data_types:

  my.datatypes.Connection:
    properties:
      endpoint:
        type: my.datatypes.Endpoint
      auth:
        type: my.datatypes.Auth

  my.datatypes.Endpoint:
    description: Socket endpoint details
    properties:
      ip:
        description: the endpoint IP
        type: string
      port:
        default: 2233
        type: integer

  my.datatypes.Auth:
    properties:
      username:
        default: admin
        type: string
      password:
        type: string

node_types:

  DatabaseService:
    derived_from: cloudify.nodes.DBMS
    properties:
      connection:
        type: my.datatypes.Connection

node_templates:

  my_db_service:
    type: DatabaseService
    properties:
      connection:
        endpoint:
          ip: 192.168.15.85
        auth:
          password: secret

Notice how the my_db_service node template only specified the connection.endpoint.ip and connection.auth.password. The other properties received the default 2233 port and admin user.

Overriding Default Values

You can override default values in same way as you would configure properties without default values. For example:

node_templates:

  my_db_service:
    type: DatabaseService
    properties:
      connection:
        endpoint:
          ip: 192.168.15.85
          port: 2244
        auth:
          password: secret

In the example, the default connection.endpoint.port value is replaced and the default connection.auth.username value is retained.

Nested Merging Semantics

Data Types, Node Types, and Node Template

In this example, a data type datatypes.Data1 is defined with three properties that have their default values set. Next, a node type nodes.MyApp that has a data1 property of type datatypes.Data1 is defined. In this type, the single nested property prop2 of the data1 property is overridden. Finally, a node template my_app of type nodes.MyApp is configured. This node template overrides another single nested property, prop3 of the data1 property.

tosca_definitions_version: cloudify_dsl_1_2

data_types:

  datatypes.Data1:
    properties:
      prop1:
        default: prop1_default
      prop2:
        default: prop2_default
      prop3:
        default: prop3_default

node_types:

  nodes.MyApp:
    properties:
      data1:
        type: datatypes.Data1
        default:
          prop2: prop2_override

node_templates:

  my_app:
    type: nodes.MyApp
    properties:
      data1:
        prop3: prop3_override

After the blueprint is parsed, the my_app node template properties will be:

data1:
  prop1: prop1_default
  prop2: prop2_override
  prop3: prop3_override

This also applies for compound data types, for example:

data_types:
  datatypes.Data1:
    ...

  datatypes.Data2:
    properties:
      data1:
        type: datatypes.Data1
        default:
          prop2: prop2_override

In which case, datatypes.Data2's data1 property default value will be: 

data1:
  prop1: prop1_default
  prop2: prop2_override
  prop3: prop3_default

Nested Merging and Inheritance

When a node type derives from another node type, if it overrides a property that has a custom data type and it keeps that type explicitly, a similar nested merging logic will apply, as described previously. For example:

tosca_definitions_version: cloudify_dsl_1_2

data_types:

  datatypes.Data1:
    properties:
      prop1:
        default: prop1_default
      prop2:
        default: prop2_default
      prop3:
        default: prop3_default

node_types:

  nodes.MyApp:
    properties:
      data2:
        type: datatypes.Data1
        default:
          prop2: prop2_override

  nodes.DerivedFromMyApp:
    derived_from: nodes.MyApp
    properties:
      data2:
        type: datatypes.Data1
        default:
          prop3: prop3_override

node_templates:

  my_app:
    type: nodes.DerivedFromMyApp

After the blueprint is parsed, the my_app node template properties will be:

data1:
  prop1: prop1_default
  prop2: prop2_override
  prop3: prop3_override