Fn::ListMerge concatenates two or more lists into a single list.
Declaration
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JSON
{ "Fn::ListMerge": [ [ "list_1_item_1", "list_1_item_2", ... ], [ "list_2_item_1", "list_2_item_2", ... ], ... ] } -
YAML
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Syntax for the full function name:
Fn::ListMerge: - - list_1_item_1 - list_1_item_2 - ... - - list_2_item_1 - list_2_item_2 - ... -
Syntax for the short form:
!ListMerge [[list_1_item_1, list_1_item_2, ...], [list_2_item_1, list_2_item_2, ...], ...]
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Parameters
list_1_item_1, list_1_item_2, ...: the first list to merge.list_2_item_1, list_2_item_2, ...: the second list to merge.
Examples
The following example attaches two Elastic Compute Service (ECS) instance groups to a Server Load Balancer (SLB) instance. Fn::ListMerge combines the instance IDs from both groups into a single backend server list.
ROSTemplateFormatVersion: '2015-09-01'
Resources:
LoadBalancer:
Type: ALIYUN::SLB::LoadBalancer
Properties:
LoadBalancerName: ros
AddressType: internet
InternetChargeType: paybybandwidth
BackendServer1:
Type: ALIYUN::ECS::InstanceGroup
Properties:
ImageId: m-2ze9uqi7wo61hwep****
InstanceType: ecs.t1.small
SecurityGroupId: sg-2ze8yxgempcdsq3i****
MaxAmount: 1
MinAmount: 1
BackendServer2:
Type: ALIYUN::ECS::InstanceGroup
Properties:
ImageId: m-2ze9uqi7wo61hwep****
InstanceType: ecs.t1.small
SecurityGroupId: sg-2ze8yxgempcdsq3i****
MaxAmount: 1
MinAmount: 1
Attachment:
Type: ALIYUN::SLB::BackendServerAttachment
Properties:
LoadBalancerId: !Ref LoadBalancer
BackendServerList: !ListMerge [!GetAtt BackendServer1.InstanceIds, !GetAtt BackendServer2.InstanceIds]!GetAtt BackendServer1.InstanceIds and !GetAtt BackendServer2.InstanceIds each return a list of instance IDs. !ListMerge concatenates them into one list, which is passed to BackendServerList.