Repeat construct
You can use the repeat construct of a component to build multiple configuration objects of the same type.
In the following example, the members-svcg-comp component is used to bind the list of services to the service group created by the parent component. In order to create a configuration object that binds each server to the service group, use the repeat construct to iterate over the list of services specified for the parameter svc-servers. During the iteration, the component creates a NITRO object of type servicegroup_servicegroupmember_binding for each service (referred to as srv in the repeat-item construct) in the service group, and it sets the ip attribute in each NITRO object to the IP address of the corresponding service.
Example:
components:
-
name: my-lbvserver-comp
type: ns::lbvserver
properties:
name: $parameters.name + "-lb"
servicetype: HTTP
ipv46: $parameters.ip
port: 80
lbmethod: $parameters.lb-alg
components:
-
name: my-svcg-comp
type: ns::servicegroup
properties:
name: $parameters.name + "-svcgrp"
servicetype: HTTP
components:
-
name: lbvserver-svg-binding-comp
type: ns::lbvserver\servicegroup\binding
properties:
name: $parent.parent.properties.name
servicegroupname: $parent.properties.name
-
name: members-svcg-comp
type: ns::servicegroup\servicegroupmember\binding
repeat:
repeat-list: $parameters.svc-servers
repeat-item: srv
properties:
ip: $srv
port: $parameters.svc-port
servicegroupname: $parent.properties.name
<!--NeedCopy-->
The repeat is an object by itself, and repeat-list and repeat-item are attributes for the repeat object.
- repeat-list is a mandatory attribute that identifies the list that the component iterates on.
- repeat-item is optional, and is used to give a friendly name to the current item in the iteration.
If not specified, the current item can be accessed using the expression $repeat-item. The last component in the above example can also be written as follows:
-
name: members-svcg-comp
type: ns::servicegroup_servicegroupmember_binding
repeat:
repeat-list: $parameters.svc-servers
properties:
ip: $repeat-item
port: $parameters.svc-port
servicegroupname: $parent.properties.name
<!--NeedCopy-->
In addition to being able to refer to the current item white iterating over a list, it is also possible to refer to the current index of the item in the list using repeat-index. In the following example, repeat-index is used to calculate a port number based on the current index:
name: services
type: ns::service
repeat:
repeat-list: $parameters.app-services
repeat-item: srv
properties:
ip: $parameters.app-ip
port: $parameters.base-port + repeat-index
servicegroupname: $parent.properties.name
<!--NeedCopy-->
Similar to the repeat-item construct, you can assign a different variable name to refer to the current index of the iteration. The previous example is equivalent to the following example:
-
name: services
type: ns::service
repeat:
repeat-list: $parameters.app-services
repeat-item: srv
repeat-index: idx
properties:
ip: $parameters.app-ip
port: $parameters.base-port + $idx
servicegroupname: $parent.properties.name
<!--NeedCopy-->