feat(ec2): add GenericWindowsImage (#3454)

* feat(ec2): Use custom Windows AMI (#3400)
* Created new GenericWindowsImaeProps
* Created new Class GenericWindowsImage

* Add tests

packages/@aws-cdk/aws-ec2/lib/machine-image.ts

@@ -235,6 +235,18 @@ export interface GenericLinuxImageProps {
   readonly userData?: UserData;
 }
 
+/**
+ * Configuration options for GenericWindowsImage
+ */
+export interface GenericWindowsImageProps {
+  /**
+   * Initial user data
+   *
+   * @default - Empty UserData for Windows machines
+   */
+  readonly userData?: UserData;
+}
+
 /**
  * Construct a Linux machine image from an AMI map
  *
@@ -264,6 +276,34 @@ export class GenericLinuxImage implements IMachineImage  {
   }
 }
 
+/**
+ * Construct a Windows machine image from an AMI map
+ *
+ * Allows you to create a generic Windows EC2 , manually specify an AMI map.
+ */
+export class GenericWindowsImage implements IMachineImage  {
+  constructor(private readonly amiMap: {[region: string]: string}, private readonly props: GenericWindowsImageProps = {}) {
+  }
+
+  public getImage(scope: Construct): MachineImageConfig {
+    const region = Stack.of(scope).region;
+    if (Token.isUnresolved(region)) {
+      throw new Error(`Unable to determine AMI from AMI map since stack is region-agnostic`);
+    }
+
+    const ami = region !== 'test-region' ? this.amiMap[region] : 'ami-12345';
+    if (!ami) {
+      throw new Error(`Unable to find AMI in AMI map: no AMI specified for region '${region}'`);
+    }
+
+    return {
+      imageId: ami,
+      userData: this.props.userData,
+      osType: OperatingSystemType.WINDOWS,
+    };
+  }
+}
+
 /**
  * The OS type of a particular image
  */

packages/@aws-cdk/aws-ec2/test/example.images.lit.ts

@@ -21,8 +21,18 @@ const linux = new ec2.GenericLinuxImage({
     'eu-west-1': 'ami-12345678',
     // ...
 });
+
+// For other custom (Windows) images, instantiate a `GenericWindowsImage` with
+// a map giving the AMI to in for each region:
+
+const genericWindows = new ec2.GenericWindowsImage({
+  'us-east-1': 'ami-97785bed',
+  'eu-west-1': 'ami-12345678',
+  // ...
+});
 /// !hide
 
 Array.isArray(windows);
 Array.isArray(amznLinux);
 Array.isArray(linux);
+Array.isArray(genericWindows);

packages/@aws-cdk/aws-ec2/test/test.machine-image.ts

@@ -0,0 +1,46 @@
+import { Stack } from '@aws-cdk/core';
+import { Test } from 'nodeunit';
+import ec2 = require('../lib');
+
+export = {
+  'can make and use a Windows image'(test: Test) {
+    // GIVEN
+    const stack = new Stack(undefined, undefined, {
+      env: { region: 'testregion' }
+    });
+
+    // WHEN
+    const image = new ec2.GenericWindowsImage({
+      testregion: 'ami-1234'
+    });
+
+    // THEN
+    const details = image.getImage(stack);
+    test.equals(details.imageId, 'ami-1234');
+    test.equals(details.osType, ec2.OperatingSystemType.WINDOWS);
+
+    test.done();
+  },
+
+  'WindowsImage retains userdata'(test: Test) {
+    // GIVEN
+    const stack = new Stack(undefined, undefined, {
+      env: { region: 'testregion' }
+    });
+
+    // WHEN
+    const ud = ec2.UserData.forWindows();
+
+    const image = new ec2.GenericWindowsImage({
+      testregion: 'ami-1234',
+    }, {
+      userData: ud
+    });
+
+    // THEN
+    const details = image.getImage(stack);
+    test.equals(details.userData, ud);
+
+    test.done();
+  },
+};