Allow user to run spot instances

README.md

@@ -193,6 +193,7 @@ Now you're ready to go!
 | `ec2-instance-id`                                                                                                                                                            | Required if you use the `stop` mode.       | EC2 Instance Id of the created runner. <br><br> The id is provided by the output of the action in the `start` mode. <br><br> The id is used to terminate the EC2 instance when the runner is not needed anymore.                                                                                                                      |
 | `iam-role-name`                                                                                                                                                              | Optional. Used only with the `start` mode. | IAM role name to attach to the created EC2 runner. <br><br> This allows the runner to have permissions to run additional actions within the AWS account, without having to manage additional GitHub secrets and AWS users. <br><br> Setting this requires additional AWS permissions for the role launching the instance (see above). |
 | `aws-resource-tags`                                                                                                                                                          | Optional. Used only with the `start` mode. | Specifies tags to add to the EC2 instance and any attached storage. <br><br> This field is a stringified JSON array of tag objects, each containing a `Key` and `Value` field (see example below). <br><br> Setting this requires additional AWS permissions for the role launching the instance (see above).                         |
+| `use-spot-instances`                                                                                                                                                              | Optional. Used only with the `start` mode. | Use spot instances? Defaults to false. See [EC2 spot instance documentation](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances.html) for more information |
 
 ### Environment variables
 

action.yml

@@ -61,6 +61,11 @@ inputs:
       for example: '[{"Key": "TagKey1", "Value": "TagValue1"}, {"Key": "TagKey2", "Value": "TagValue2"}]'
     required: false
     default: '[]'
+  use-spot-instances:
+    description: >-
+      Use spot instances for cost savings?
+    default: false
+    required: false
 outputs:
   label:
     description: >-

src/aws.js

@@ -31,6 +31,12 @@ async function startEc2Instance(label, githubRegistrationToken) {
     TagSpecifications: config.tagSpecifications,
   };
 
+  if (config.input.useSpotInstances) {
+    params.InstanceMarketOptions = {
+      MarketType: 'spot'
+    };
+  }
+
   try {
     const result = await ec2.runInstances(params).promise();
     const ec2InstanceId = result.Instances[0].InstanceId;

src/config.js

@@ -13,6 +13,7 @@ class Config {
       label: core.getInput('label'),
       ec2InstanceId: core.getInput('ec2-instance-id'),
       iamRoleName: core.getInput('iam-role-name'),
+      useSpotInstances: core.getBooleanInput('use-spot-instances'),
     };
 
     const tags = JSON.parse(core.getInput('aws-resource-tags'));