End of support notice: On October 7, 2026, AWS will end support for AWS Proton. After October 7, 2026, you will no longer be able to access the AWS Proton console or AWS Proton resources. Your deployed infrastructure will remain intact. For more information, see [AWS Proton Service Deprecation and Migration Guide](https://docs.aws.amazon.com/proton/latest/userguide/proton-end-of-support.html). # Environment CloudFormation IaC file parameter details and examples You can define and reference parameters in your environment infrastructure as code (IaC) files. For a detailed description of AWS Proton parameters, parameter types, the parameter namespace, and how to use parameters in your IaC files, see [AWS Proton parameters](parameters.md). ## Define environment parameters You can define both input and output parameters for environment IaC files. + **Input parameters** – Define environment input parameters in your [schema file](ag-schema.md). The following list includes examples of environment input parameters for typical use cases. + VPC CIDR values + Load balancer settings + Database settings + A health check timeout As an administrator, you can provide values for input parameters when you [create an environment](ag-create-env.md): + Use the console to fill out a schema-based form that AWS Proton provides. + Use the CLI to provide a spec that includes the values. + **Output parameters** – Define environment outputs in your environment IaC files. You can then refer to these outputs in IaC files of other resources. ## Read parameter values in environment IaC files You can read parameters related to the environment in environment IaC files. You read a parameter value by referencing the parameter's name in the AWS Proton parameter namespace. + **Input parameters** – Read an environment input value by referencing `environment.inputs.input-name`. + **Resource parameters** – Read AWS Proton resource parameters by referencing names such as `environment.name`. **Note** No output parameters of other resources are available to environment IaC files. ## Example environment and service IaC files with parameters The following example demonstrates parameter definition and reference in an environment IaC file. The example then shows how environment output parameters defined in the environment IaC file can be referenced in a service IaC file. **Example Environment CloudFormation IaC file** Note the following in this example: + The `environment.inputs.` namespace refers to environment input parameters. + The Amazon EC2 Systems Manager (SSM) parameter `StoreInputValue` concatenates the environment inputs. + The `MyEnvParameterValue` output exposes the same input parameter concatenation as an output parameter. Three additional output parameters also expose the input parameters individually. + Six additional output parameters expose resources that the environment provisions. ``` Resources: StoreInputValue: Type: AWS::SSM::Parameter Properties: Type: String Value: "{{ environment.inputs.my_sample_input }} {{ environment.inputs.my_other_sample_input}} {{ environment.inputs.another_optional_input }}" # input parameter references # These output values are available to service infrastructure as code files as outputs, when given the # the 'environment.outputs' namespace, for example, service_instance.environment.outputs.ClusterName. Outputs: MyEnvParameterValue: # output definition Value: !GetAtt StoreInputValue.Value MySampleInputValue: # output definition Value: "{{ environment.inputs.my_sample_input }}" # input parameter reference MyOtherSampleInputValue: # output definition Value: "{{ environment.inputs.my_other_sample_input }}" # input parameter reference AnotherOptionalInputValue: # output definition Value: "{{ environment.inputs.another_optional_input }}" # input parameter reference ClusterName: # output definition Description: The name of the ECS cluster Value: !Ref 'ECSCluster' # provisioned resource ECSTaskExecutionRole: # output definition Description: The ARN of the ECS role Value: !GetAtt 'ECSTaskExecutionRole.Arn' # provisioned resource VpcId: # output definition Description: The ID of the VPC that this stack is deployed in Value: !Ref 'VPC' # provisioned resource PublicSubnetOne: # output definition Description: Public subnet one Value: !Ref 'PublicSubnetOne' # provisioned resource PublicSubnetTwo: # output definition Description: Public subnet two Value: !Ref 'PublicSubnetTwo' # provisioned resource ContainerSecurityGroup: # output definition Description: A security group used to allow Fargate containers to receive traffic Value: !Ref 'ContainerSecurityGroup' # provisioned resource ``` **Example Service CloudFormation IaC file** The `environment.outputs.` namespace refers to environment outputs from an environment IaC file. For example, the name `environment.outputs.ClusterName` reads the value of the `ClusterName` environment output parameter. ``` AWSTemplateFormatVersion: '2010-09-09' Description: Deploy a service on AWS Fargate, hosted in a public subnet, and accessible via a public load balancer. Mappings: TaskSize: x-small: cpu: 256 memory: 512 small: cpu: 512 memory: 1024 medium: cpu: 1024 memory: 2048 large: cpu: 2048 memory: 4096 x-large: cpu: 4096 memory: 8192 Resources: # A log group for storing the stdout logs from this service's containers LogGroup: Type: AWS::Logs::LogGroup Properties: LogGroupName: '{{service_instance.name}}' # resource parameter # The task definition. This is a simple metadata description of what # container to run, and what resource requirements it has. TaskDefinition: Type: AWS::ECS::TaskDefinition Properties: Family: '{{service_instance.name}}' # resource parameter Cpu: !FindInMap [TaskSize, {{service_instance.inputs.task_size}}, cpu] # input parameter Memory: !FindInMap [TaskSize, {{service_instance.inputs.task_size}}, memory] NetworkMode: awsvpc RequiresCompatibilities: - FARGATE ExecutionRoleArn: '{{environment.outputs.ECSTaskExecutionRole}}' # output reference to an environment infrastructure code file TaskRoleArn: !Ref "AWS::NoValue" ContainerDefinitions: - Name: '{{service_instance.name}}' # resource parameter Cpu: !FindInMap [TaskSize, {{service_instance.inputs.task_size}}, cpu] Memory: !FindInMap [TaskSize, {{service_instance.inputs.task_size}}, memory] Image: '{{service_instance.inputs.image}}' PortMappings: - ContainerPort: '{{service_instance.inputs.port}}' # input parameter LogConfiguration: LogDriver: 'awslogs' Options: awslogs-group: '{{service_instance.name}}' # resource parameter awslogs-region: !Ref 'AWS::Region' awslogs-stream-prefix: '{{service_instance.name}}' # resource parameter # The service_instance. The service is a resource which allows you to run multiple # copies of a type of task, and gather up their logs and metrics, as well # as monitor the number of running tasks and replace any that have crashed Service: Type: AWS::ECS::Service DependsOn: LoadBalancerRule Properties: ServiceName: '{{service_instance.name}}' # resource parameter Cluster: '{{environment.outputs.ClusterName}}' # output reference to an environment infrastructure as code file LaunchType: FARGATE DeploymentConfiguration: MaximumPercent: 200 MinimumHealthyPercent: 75 DesiredCount: '{{service_instance.inputs.desired_count}}'# input parameter NetworkConfiguration: AwsvpcConfiguration: AssignPublicIp: ENABLED SecurityGroups: - '{{environment.outputs.ContainerSecurityGroup}}' # output reference to an environment infrastructure as code file Subnets: - '{{environment.outputs.PublicSubnetOne}}' # output reference to an environment infrastructure as code file - '{{environment.outputs.PublicSubnetTwo}}' # output reference to an environment infrastructure as code file TaskDefinition: !Ref 'TaskDefinition' LoadBalancers: - ContainerName: '{{service_instance.name}}' # resource parameter ContainerPort: '{{service_instance.inputs.port}}' # input parameter TargetGroupArn: !Ref 'TargetGroup' [...] ```