feat(cloud9): configure Connection Type of Ec2Environment (aws#20250)

Fixes aws#17027. Adds `connectionType` property to the L2 Construct `cloud9.Ec2Environment`. For the  connection type an enum was implemented which is either `"CONNECT_SSH` or `CONNECT_SSM`.

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-cloud9/lib/environment.ts

@@ -24,6 +24,20 @@ export interface IEc2Environment extends cdk.IResource {
   readonly ec2EnvironmentArn: string;
 }
 
+/**
+ * The connection type used for connecting to an Amazon EC2 environment.
+ */
+export enum ConnectionType {
+  /**
+   * Conect through SSH
+   */
+  CONNECT_SSH = 'CONNECT_SSH',
+  /**
+   * Connect through AWS Systems Manager
+   */
+  CONNECT_SSM = 'CONNECT_SSM'
+}
+
 /**
  * Properties for Ec2Environment
  */
@@ -70,6 +84,15 @@ export interface Ec2EnvironmentProps {
    */
   // readonly clonedRepositories?: Cloud9Repository[];
   readonly clonedRepositories?: CloneRepository[];
+
+  /**
+   * The connection type used for connecting to an Amazon EC2 environment.
+   *
+   * Valid values are: CONNECT_SSH (default) and CONNECT_SSM (connected through AWS Systems Manager)
+   *
+   * @default - CONNECT_SSH
+   */
+  readonly connectionType?: ConnectionType
 }
 
 /**
@@ -139,6 +162,7 @@ export class Ec2Environment extends cdk.Resource implements IEc2Environment {
         repositoryUrl: r.repositoryUrl,
         pathComponent: r.pathComponent,
       })) : undefined,
+      connectionType: props.connectionType ?? ConnectionType.CONNECT_SSH,
     });
     this.environmentId = c9env.ref;
     this.ec2EnvironmentArn = c9env.getAtt('Arn').toString();

packages/@aws-cdk/aws-cloud9/test/cloud9.environment.test.ts

@@ -1,8 +1,9 @@
-import { Template } from '@aws-cdk/assertions';
+import { Match, Template } from '@aws-cdk/assertions';
 import * as codecommit from '@aws-cdk/aws-codecommit';
 import * as ec2 from '@aws-cdk/aws-ec2';
 import * as cdk from '@aws-cdk/core';
 import * as cloud9 from '../lib';
+import { ConnectionType } from '../lib';
 
 let stack: cdk.Stack;
 let vpc: ec2.IVpc;
@@ -105,3 +106,20 @@ test('can use CodeCommit repositories', () => {
     ],
   });
 });
+
+test.each([
+  [ConnectionType.CONNECT_SSH, 'CONNECT_SSH'],
+  [ConnectionType.CONNECT_SSM, 'CONNECT_SSM'],
+  [undefined, 'CONNECT_SSH'],
+])('has connection type property (%s)', (connectionType, expected) => {
+  new cloud9.Ec2Environment(stack, 'C9Env', {
+    vpc,
+    connectionType,
+  });
+
+  Template.fromStack(stack).hasResourceProperties('AWS::Cloud9::EnvironmentEC2', {
+    InstanceType: Match.anyValue(),
+    ConnectionType: expected,
+    SubnetId: Match.anyValue(),
+  });
+});

packages/@aws-cdk/aws-cloud9/test/cloud9.integ.snapshot/C9Stack.template.json

@@ -360,6 +360,7 @@
   "C9EnvF05FC3BE": {
    "Type": "AWS::Cloud9::EnvironmentEC2",
    "Properties": {
+    "ConnectionType": "CONNECT_SSH",
     "InstanceType": "t2.micro",
     "Repositories": [
      {