Merge pull request #2723 from guardian/deployment-id

feat(experimental-ec2-pattern): Echo `RiffRaffDeploymentId` in user-data

Author: akash1810

.changeset/ninety-pants-leave.md

@@ -0,0 +1,9 @@
+---
+"@guardian/cdk": minor
+---
+
+feat(experimental-ec2-pattern): Echo RiffRaffDeploymentId in user-data
+
+This change adds a new CloudFormation parameter, `RiffRaffDeploymentId`, to be set by Riff-Raff during deployment (see guardian/riff-raff#1469).
+This parameter is echoed out in the user-data. This means a redeployment of the same build creates a CloudFormation changeset with a new launch template.
+Consequently, the running EC2 instances are cycled. This means scheduled deployments are possible.

src/experimental/patterns/__snapshots__/ec2-app.test.ts.snap

@@ -24,6 +24,7 @@ exports[`The GuEc2AppExperimental pattern matches the snapshot 1`] = `
       "GuApplicationLoadBalancer",
       "GuApplicationTargetGroup",
       "GuHttpsApplicationListener",
+      "GuRiffRaffDeploymentIdParameter",
     ],
     "gu:cdk:version": "TEST",
   },
@@ -53,6 +54,10 @@ exports[`The GuEc2AppExperimental pattern matches the snapshot 1`] = `
       "Description": "SSM parameter containing the Name (not ARN) on the kinesis stream",
       "Type": "AWS::SSM::Parameter::Value<String>",
     },
+    "RiffRaffDeploymentId": {
+      "Description": "Used by Riff-Raff to inject the deployment ID.",
+      "Type": "String",
+    },
     "VpcId": {
       "Default": "/account/vpc/primary/id",
       "Description": "Virtual Private Cloud to run EC2 instances within. Should NOT be the account default VPC.",
@@ -840,6 +845,11 @@ aws s3 cp 's3://",
                   },
                   "/test-stack/TEST/test-gu-ec2-app/test-gu-ec2-app-123.deb' '/test-gu-ec2-app/test-gu-ec2-app-123.deb'
 dpkg -i /test-gu-ec2-app/test-gu-ec2-app-123.deb
+echo "Launch template last updated by Riff-Raff deployment ID: ",
+                  {
+                    "Ref": "RiffRaffDeploymentId",
+                  },
+                  ""
 # GuEc2AppExperimental Instance Health Check Start
 
       TOKEN=$(curl -X PUT "http://169.254.169.254/latest/api/token" -H "X-aws-ec2-metadata-token-ttl-seconds: 21600")

src/experimental/patterns/ec2-app.ts

@@ -342,6 +342,25 @@ export interface GuUserDataForRollingUpdateExperimentalProps {
   slowStartDuration?: Duration;
 }
 
+class GuRiffRaffDeploymentIdParameter extends CfnParameter {
+  private static instance: GuRiffRaffDeploymentIdParameter | undefined;
+
+  private constructor(scope: GuStack) {
+    super(scope, "RiffRaffDeploymentId", {
+      type: "String",
+      description: "Used by Riff-Raff to inject the deployment ID.",
+    });
+  }
+
+  public static getInstance(stack: GuStack): GuRiffRaffDeploymentIdParameter {
+    if (!this.instance || !isSingletonPresentInStack(stack, this.instance)) {
+      this.instance = new GuRiffRaffDeploymentIdParameter(stack);
+    }
+
+    return this.instance;
+  }
+}
+
 /**
  * Modifies the user-data script (which runs whenever an instance is launched) to make it compatible with the new
  * rolling update deployment mechanism.
@@ -357,6 +376,13 @@ export class GuUserDataForRollingUpdateExperimental {
     const { autoScalingGroup, targetGroup, applicationPort, buildIdentifier, slowStartDuration } = props;
     const cfnAutoScalingGroup = autoScalingGroup.node.defaultChild as CfnAutoScalingGroup;
 
+    const deploymentId = GuRiffRaffDeploymentIdParameter.getInstance(scope);
+
+    // This allows redeployment of the same build to cycle instances
+    autoScalingGroup.userData.addCommands(
+      `echo "Launch template last updated by Riff-Raff deployment ID: ${deploymentId.valueAsString}"`,
+    );
+
     /*
       `aws` is available via AMIgo baked AMIs.
       See https://github.com/guardian/amigo/tree/main/roles/aws-tools.