Configuring inputs and outputs for your actions - Amazon Systems Manager
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Configuring inputs and outputs for your actions

Each automation action responds based on input that it receives. In most cases, you then pass output to the subsequent actions. In the visual design experience, you can configure an action's input and output data in the Inputs and Outputs tabs of the Form panel.

For detailed information about how to define and use output for automation actions, see Using action outputs as inputs.

Provide input data for an action

Each automation action has one or more inputs that you must provide a value for. The value you provide for an action's input is determined by the data type and format that's accepted by the action. For example, the aws:sleep actions requires an ISO 8601 formatted string value for the Duration input.

Generally, you use actions in your runbook's workflow that return output that you want to use in subsequent actions. It's important to make sure your input values are correct to avoid errors in your runbook's workflow. Input values are also important because they determine whether the action returns the expected output. For example, when using the aws:executeAwsApi action, you want to make sure that you're providing the right value for the API operation.

Define output data for an action

Some automation actions return output after performing their defined operations. Actions that return output either have predefined outputs, or allow you to define the outputs yourself. For example, the aws:createImage action has predefined outputs that return an ImageId and ImageState. Comparatively, with the aws:executeAwsApi action, you can define the outputs you that want from the specified API operation. As a result, you can return one or more values from a single API operation to use in subsequent actions.

Defining your own outputs for an automation action requires that you specify a name of the output, the data type, and the output value. To continue using the aws:executeAwsApi action as an example, let's say you're calling the DescribeInstances API operation from Amazon EC2. In this example, you want to return, or output, the State of an Amazon EC2 instance and branch your runbook's workflow based on the output. You choose to name the output InstanceState, and use the String data type.

The process to define the actual value of the output differs, depending on the action. For example, if you're using the aws:executeScript action, you must use return statements in your functions to provide data to your outputs. With other actions like aws:executeAwsApi, aws:waitForAwsResourceProperty, and aws:assertAwsResourceProperty, a Selector is required. The Selector, or PropertySelector as some actions refer to it, is a JSONPath string that is used to process the JSON response from an API operation. It's important to understand how the JSON response object from an API operation is structured so you can select the correct value for your output. Using the DescribeInstances API operation mentioned earlier, see the following example JSON response:

{ "reservationSet": { "item": { "reservationId": "r-1234567890abcdef0", "ownerId": 123456789012, "groupSet": "", "instancesSet": { "item": { "instanceId": "i-1234567890abcdef0", "imageId": "ami-bff32ccc", "instanceState": { "code": 16, "name": "running" }, "privateDnsName": "", "dnsName": "", "reason": "", "keyName": "my_keypair", "amiLaunchIndex": 0, "productCodes": "", "instanceType": "t2.micro", "launchTime": "2018-05-08T16:46:19.000Z", "placement": { "availabilityZone": "eu-west-1c", "groupName": "", "tenancy": "default" }, "monitoring": { "state": "disabled" }, "subnetId": "subnet-56f5f000", "vpcId": "vpc-11112222", "privateIpAddress": "", "ipAddress": "", "sourceDestCheck": true, "groupSet": { "item": { "groupId": "sg-e4076000", "groupName": "SecurityGroup1" } }, "architecture": "x86_64", "rootDeviceType": "ebs", "rootDeviceName": "/dev/xvda", "blockDeviceMapping": { "item": { "deviceName": "/dev/xvda", "ebs": { "volumeId": "vol-1234567890abcdef0", "status": "attached", "attachTime": "2015-12-22T10:44:09.000Z", "deleteOnTermination": true } } }, "virtualizationType": "hvm", "clientToken": "xMcwG14507example", "tagSet": { "item": { "key": "Name", "value": "Server_1" } }, "hypervisor": "xen", "networkInterfaceSet": { "item": { "networkInterfaceId": "eni-551ba000", "subnetId": "subnet-56f5f000", "vpcId": "vpc-11112222", "description": "Primary network interface", "ownerId": 123456789012, "status": "in-use", "macAddress": "02:dd:2c:5e:01:69", "privateIpAddress": "", "privateDnsName": "", "sourceDestCheck": true, "groupSet": { "item": { "groupId": "sg-e4076000", "groupName": "SecurityGroup1" } }, "attachment": { "attachmentId": "eni-attach-39697adc", "deviceIndex": 0, "status": "attached", "attachTime": "2018-05-08T16:46:19.000Z", "deleteOnTermination": true }, "association": { "publicIp": "", "publicDnsName": "", "ipOwnerId": "amazon" }, "privateIpAddressesSet": { "item": { "privateIpAddress": "", "privateDnsName": "", "primary": true, "association": { "publicIp": "", "publicDnsName": "", "ipOwnerId": "amazon" } } }, "ipv6AddressesSet": { "item": { "ipv6Address": "2001:db8:1234:1a2b::123" } } } }, "iamInstanceProfile": { "arn": "arn:aws:iam::123456789012:instance-profile/AdminRole", "id": "ABCAJEDNCAA64SSD123AB" }, "ebsOptimized": false, "cpuOptions": { "coreCount": 1, "threadsPerCore": 1 } } } } } }

In the JSON response object, the instance State is nested in an Instances object, which is nested in the Reservations object. To return the value of the instance State, use the following string for the Selector so the value can be used in our output: $.Reservations[0].Instances[0].State.Name.

To reference an output value in subsequent actions of your runbook's workflow, the following format is used: {{ StepName.NameOfOutput }}. For example, {{ GetInstanceState.InstanceState }}. In the visual design experience, you can choose output values to use in subsequent actions using the dropdown for the input. When using outputs in subsequent actions, the data type of the output must match the data type for the input. In this example, the InstanceState output is a String. Therefore, to use the value in a subsequent action's input, the input must accept a String.