fix(ecs): new arn format not supported (under feature flag)

packages/@aws-cdk/aws-ecs/lib/base/from-service-attributes.ts

@@ -1,8 +1,13 @@
-import { ArnFormat, Resource, Stack } from '@aws-cdk/core';
+import { ArnFormat, FeatureFlags, Fn, Resource, Stack, Token } from '@aws-cdk/core';
+import { ECS_ARN_FORMAT_INCLUDES_CLUSTER_NAME } from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { IBaseService } from '../base/base-service';
 import { ICluster } from '../cluster';
 
+// v2 - keep this import as a separate section to reduce merge conflict when forward merging with the v2 branch.
+// eslint-disable-next-line
+import { Construct as CoreConstruct } from '@aws-cdk/core';
+
 /**
  * The properties to import from the service.
  */
@@ -32,22 +37,38 @@ export function fromServiceAtrributes(scope: Construct, id: string, attrs: Servi
     throw new Error('You can only specify either serviceArn or serviceName.');
   }
 
+  const featureConstruct = new CoreConstruct(scope, randomString());
+  const newArnFormat = FeatureFlags.of(featureConstruct).isEnabled(ECS_ARN_FORMAT_INCLUDES_CLUSTER_NAME);
+
   const stack = Stack.of(scope);
   let name: string;
   let arn: string;
   if (attrs.serviceName) {
     name = attrs.serviceName as string;
+    const resourceName = newArnFormat ? `${attrs.cluster.clusterName}/${attrs.serviceName}` : attrs.serviceName as string;
     arn = stack.formatArn({
       partition: stack.partition,
       service: 'ecs',
       region: stack.region,
       account: stack.account,
       resource: 'service',
-      resourceName: name,
+      resourceName,
     });
   } else {
     arn = attrs.serviceArn as string;
-    name = stack.splitArn(arn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+    if (Token.isUnresolved(arn)) {
+      if (newArnFormat) {
+        const components = Fn.split(':', arn);
+        const lastComponents = Fn.split('/', Fn.select(5, components));
+        name = Fn.select(2, lastComponents);
+      } else {
+        name = stack.splitArn(arn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+      }
+    } else {
+      const resourceName = stack.splitArn(arn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+      const resourceNameSplit = resourceName.split('/');
+      name = resourceNameSplit.length === 1 ? resourceName : resourceNameSplit[1];
+    }
   }
   class Import extends Resource implements IBaseService {
     public readonly serviceArn = arn;
@@ -58,3 +79,8 @@ export function fromServiceAtrributes(scope: Construct, id: string, attrs: Servi
     environmentFromArn: arn,
   });
 }
+
+function randomString() {
+  // Crazy
+  return Math.random().toString(36).replace(/[^a-z0-9]+/g, '');
+}

packages/@aws-cdk/aws-ecs/lib/ec2/ec2-service.ts

@@ -1,5 +1,6 @@
 import * as ec2 from '@aws-cdk/aws-ec2';
-import { ArnFormat, Lazy, Resource, Stack } from '@aws-cdk/core';
+import { ArnFormat, FeatureFlags, Fn, Lazy, Resource, Stack, Token } from '@aws-cdk/core';
+import { ECS_ARN_FORMAT_INCLUDES_CLUSTER_NAME } from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { BaseService, BaseServiceOptions, DeploymentControllerType, IBaseService, IService, LaunchType } from '../base/base-service';
 import { fromServiceAtrributes } from '../base/from-service-attributes';
@@ -128,9 +129,25 @@ export class Ec2Service extends BaseService implements IEc2Service {
   public static fromEc2ServiceArn(scope: Construct, id: string, ec2ServiceArn: string): IEc2Service {
     class Import extends Resource implements IEc2Service {
       public readonly serviceArn = ec2ServiceArn;
-      public readonly serviceName = Stack.of(scope).splitArn(ec2ServiceArn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+      public readonly serviceName: string;
+      constructor() {
+        super(scope, id);
+        const resourceName = Stack.of(scope).splitArn(ec2ServiceArn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+        if (Token.isUnresolved(ec2ServiceArn)) {
+          if (FeatureFlags.of(this).isEnabled(ECS_ARN_FORMAT_INCLUDES_CLUSTER_NAME)) {
+            const components = Fn.split(':', ec2ServiceArn);
+            const lastComponents = Fn.split('/', Fn.select(5, components));
+            this.serviceName = Fn.select(2, lastComponents);
+          } else {
+            this.serviceName = resourceName;
+          }
+        } else {
+          const resourceNameSplit = resourceName.split('/');
+          this.serviceName = resourceNameSplit.length === 1 ? resourceName : resourceNameSplit[1];
+        }
+      }
     }
-    return new Import(scope, id);
+    return new Import();
   }
 
   /**

packages/@aws-cdk/aws-ecs/lib/fargate/fargate-service.ts

@@ -1,6 +1,7 @@
 import * as ec2 from '@aws-cdk/aws-ec2';
 import * as cdk from '@aws-cdk/core';
-import { ArnFormat } from '@aws-cdk/core';
+import { ArnFormat, FeatureFlags, Fn, Token } from '@aws-cdk/core';
+import { ECS_ARN_FORMAT_INCLUDES_CLUSTER_NAME } from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import { BaseService, BaseServiceOptions, DeploymentControllerType, IBaseService, IService, LaunchType } from '../base/base-service';
 import { fromServiceAtrributes } from '../base/from-service-attributes';
@@ -105,9 +106,25 @@ export class FargateService extends BaseService implements IFargateService {
   public static fromFargateServiceArn(scope: Construct, id: string, fargateServiceArn: string): IFargateService {
     class Import extends cdk.Resource implements IFargateService {
       public readonly serviceArn = fargateServiceArn;
-      public readonly serviceName = cdk.Stack.of(scope).splitArn(fargateServiceArn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+      public readonly serviceName: string;
+      constructor() {
+        super(scope, id);
+        const resourceName = cdk.Stack.of(scope).splitArn(fargateServiceArn, ArnFormat.SLASH_RESOURCE_NAME).resourceName as string;
+        if (Token.isUnresolved(fargateServiceArn)) {
+          if (FeatureFlags.of(this).isEnabled(ECS_ARN_FORMAT_INCLUDES_CLUSTER_NAME)) {
+            const components = Fn.split(':', fargateServiceArn);
+            const lastComponents = Fn.split('/', Fn.select(5, components));
+            this.serviceName = Fn.select(2, lastComponents);
+          } else {
+            this.serviceName = resourceName;
+          }
+        } else {
+          const resourceNameSplit = resourceName.split('/');
+          this.serviceName = resourceNameSplit.length === 1 ? resourceName : resourceNameSplit[1];
+        }
+      }
     }
-    return new Import(scope, id);
+    return new Import();
   }
 
   /**