feat(apprunner): add AutoScalingConfiguration for AppRunner Service (a…

…ws#30358)

### Issue # (if applicable)

Closes aws#30353 .

### Reason for this change
At the moment, L2 Construct does not support a custom auto scaling configuration for the AppRunner Service.


### Description of changes
* Add `AutoScalingConfiguration` Class
* Add `autoScalingConfiguration` property to the `Service` Class



### Description of how you validated changes
Add unit tests and integ tests.


### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*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-apprunner-alpha/README.md

@@ -154,6 +154,27 @@ when required.
 
 See [App Runner IAM Roles](https://docs.aws.amazon.com/apprunner/latest/dg/security_iam_service-with-iam.html#security_iam_service-with-iam-roles) for more details.
 
+## Auto Scaling Configuration
+
+To associate an App Runner service with a custom Auto Scaling Configuration, define `autoScalingConfiguration` for the service.
+
+```ts
+const autoScalingConfiguration = new apprunner.AutoScalingConfiguration(this, 'AutoScalingConfiguration', {
+  autoScalingConfigurationName: 'MyAutoScalingConfiguration',
+  maxConcurrency: 150,
+  maxSize: 20,
+  minSize: 5,
+});
+
+new apprunner.Service(this, 'DemoService', {
+  source: apprunner.Source.fromEcrPublic({
+    imageConfiguration: { port: 8000 },
+    imageIdentifier: 'public.ecr.aws/aws-containers/hello-app-runner:latest',
+  }),
+  autoScalingConfiguration,
+});
+```
+
 ## VPC Connector
 
 To associate an App Runner service with a custom VPC, define `vpcConnector` for the service.

packages/@aws-cdk/aws-apprunner-alpha/lib/auto-scaling-configuration.ts

@@ -0,0 +1,202 @@
+import * as cdk from 'aws-cdk-lib/core';
+import { Construct } from 'constructs';
+import { CfnAutoScalingConfiguration } from 'aws-cdk-lib/aws-apprunner';
+
+/**
+ * Properties of the App Runner Auto Scaling Configuration.
+ */
+export interface AutoScalingConfigurationProps {
+  /**
+   * The name for the Auto Scaling Configuration.
+   *
+   * @default - a name generated by CloudFormation
+   */
+  readonly autoScalingConfigurationName?: string;
+
+  /**
+   * The maximum number of concurrent requests that an instance processes.
+   * If the number of concurrent requests exceeds this limit, App Runner scales the service up.
+   *
+   * Must be between 1 and 200.
+   *
+   * @default 100
+   */
+  readonly maxConcurrency?: number;
+
+  /**
+   * The maximum number of instances that a service scales up to.
+   * At most maxSize instances actively serve traffic for your service.
+   *
+   * Must be between 1 and 25.
+   *
+   * @default 25
+   */
+  readonly maxSize?: number;
+
+  /**
+   * The minimum number of instances that App Runner provisions for a service.
+   * The service always has at least minSize provisioned instances.
+   *
+   *
+   * Must be between 1 and 25.
+   *
+   * @default 1
+   */
+  readonly minSize?: number;
+}
+
+/**
+ * Attributes for the App Runner Auto Scaling Configuration.
+ */
+export interface AutoScalingConfigurationAttributes {
+  /**
+   * The name of the Auto Scaling Configuration.
+   */
+  readonly autoScalingConfigurationName: string;
+
+  /**
+   * The revision of the Auto Scaling Configuration.
+   */
+  readonly autoScalingConfigurationRevision: number;
+}
+
+/**
+ * Represents the App Runner Auto Scaling Configuration.
+ */
+export interface IAutoScalingConfiguration extends cdk.IResource {
+  /**
+   * The ARN of the Auto Scaling Configuration.
+   * @attribute
+   */
+  readonly autoScalingConfigurationArn: string;
+
+  /**
+   * The Name of the Auto Scaling Configuration.
+   * @attribute
+   */
+  readonly autoScalingConfigurationName: string;
+
+  /**
+   * The revision of the Auto Scaling Configuration.
+   * @attribute
+   */
+  readonly autoScalingConfigurationRevision: number;
+}
+
+/**
+ * The App Runner Auto Scaling Configuration.
+ *
+ * @resource AWS::AppRunner::AutoScalingConfiguration
+ */
+export class AutoScalingConfiguration extends cdk.Resource implements IAutoScalingConfiguration {
+  /**
+   * Imports an App Runner Auto Scaling Configuration from attributes
+   */
+  public static fromAutoScalingConfigurationAttributes(scope: Construct, id: string,
+    attrs: AutoScalingConfigurationAttributes): IAutoScalingConfiguration {
+    const autoScalingConfigurationName = attrs.autoScalingConfigurationName;
+    const autoScalingConfigurationRevision = attrs.autoScalingConfigurationRevision;
+
+    class Import extends cdk.Resource implements IAutoScalingConfiguration {
+      public readonly autoScalingConfigurationName = autoScalingConfigurationName;
+      public readonly autoScalingConfigurationRevision = autoScalingConfigurationRevision;
+      public readonly autoScalingConfigurationArn = cdk.Stack.of(this).formatArn({
+        resource: 'autoscalingconfiguration',
+        service: 'apprunner',
+        resourceName: `${attrs.autoScalingConfigurationName}/${attrs.autoScalingConfigurationRevision}`,
+      });
+    }
+
+    return new Import(scope, id);
+  }
+
+  /**
+   * Imports an App Runner Auto Scaling Configuration from its ARN
+   */
+  public static fromArn(scope: Construct, id: string, autoScalingConfigurationArn: string): IAutoScalingConfiguration {
+    const resourceParts = cdk.Fn.split('/', autoScalingConfigurationArn);
+
+    if (!resourceParts || resourceParts.length < 3) {
+      throw new Error(`Unexpected ARN format: ${autoScalingConfigurationArn}`);
+    }
+
+    const autoScalingConfigurationName = cdk.Fn.select(0, resourceParts);
+    const autoScalingConfigurationRevision = Number(cdk.Fn.select(1, resourceParts));
+
+    class Import extends cdk.Resource implements IAutoScalingConfiguration {
+      public readonly autoScalingConfigurationName = autoScalingConfigurationName;
+      public readonly autoScalingConfigurationRevision = autoScalingConfigurationRevision;
+      public readonly autoScalingConfigurationArn = autoScalingConfigurationArn;
+    }
+
+    return new Import(scope, id);
+  }
+
+  /**
+    * The ARN of the Auto Scaling Configuration.
+    * @attribute
+    */
+  readonly autoScalingConfigurationArn: string;
+
+  /**
+    * The name of the Auto Scaling Configuration.
+    * @attribute
+    */
+  readonly autoScalingConfigurationName: string;
+
+  /**
+   * The revision of the Auto Scaling Configuration.
+   * @attribute
+   */
+  readonly autoScalingConfigurationRevision: number;
+
+  public constructor(scope: Construct, id: string, props: AutoScalingConfigurationProps = {}) {
+    super(scope, id, {
+      physicalName: props.autoScalingConfigurationName,
+    });
+
+    this.validateAutoScalingConfiguration(props);
+
+    const resource = new CfnAutoScalingConfiguration(this, 'Resource', {
+      autoScalingConfigurationName: props.autoScalingConfigurationName,
+      maxConcurrency: props.maxConcurrency,
+      maxSize: props.maxSize,
+      minSize: props.minSize,
+    });
+
+    this.autoScalingConfigurationArn = resource.attrAutoScalingConfigurationArn;
+    this.autoScalingConfigurationRevision = resource.attrAutoScalingConfigurationRevision;
+    this.autoScalingConfigurationName = resource.ref;
+  }
+
+  private validateAutoScalingConfiguration(props: AutoScalingConfigurationProps) {
+    if (
+      props.autoScalingConfigurationName !== undefined &&
+      !cdk.Token.isUnresolved(props.autoScalingConfigurationName) &&
+      !/^[A-Za-z0-9][A-Za-z0-9\-_]{3,31}$/.test(props.autoScalingConfigurationName)
+    ) {
+      throw new Error(`autoScalingConfigurationName must match the ^[A-Za-z0-9][A-Za-z0-9\-_]{3,31}$ pattern, got ${props.autoScalingConfigurationName}`);
+    }
+
+    const isMinSizeDefined = typeof props.minSize === 'number';
+    const isMaxSizeDefined = typeof props.maxSize === 'number';
+    const isMaxConcurrencyDefined = typeof props.maxConcurrency === 'number';
+
+    if (isMinSizeDefined && (props.minSize < 1 || props.minSize > 25)) {
+      throw new Error(`minSize must be between 1 and 25, got ${props.minSize}`);
+    }
+
+    if (isMaxSizeDefined && (props.maxSize < 1 || props.maxSize > 25)) {
+      throw new Error(`maxSize must be between 1 and 25, got ${props.maxSize}`);
+    }
+
+    if (isMinSizeDefined && isMaxSizeDefined && !(props.minSize < props.maxSize)) {
+      throw new Error('maxSize must be greater than minSize');
+    }
+
+    if (isMaxConcurrencyDefined && (props.maxConcurrency < 1 || props.maxConcurrency > 200)) {
+      throw new Error(`maxConcurrency must be between 1 and 200, got ${props.maxConcurrency}`);
+    }
+  }
+
+}

packages/@aws-cdk/aws-apprunner-alpha/lib/index.ts

@@ -1,3 +1,4 @@
 // AWS::AppRunner CloudFormation Resources:
+export * from './auto-scaling-configuration';
 export * from './service';
 export * from './vpc-connector';

packages/@aws-cdk/aws-apprunner-alpha/lib/service.ts

@@ -9,6 +9,7 @@ import { Lazy } from 'aws-cdk-lib/core';
 import { Construct } from 'constructs';
 import { CfnService } from 'aws-cdk-lib/aws-apprunner';
 import { IVpcConnector } from './vpc-connector';
+import { IAutoScalingConfiguration } from './auto-scaling-configuration';
 
 /**
  * The image repository types
@@ -656,6 +657,18 @@ export interface ServiceProps {
    */
   readonly autoDeploymentsEnabled?: boolean;
 
+  /**
+   * Specifies an App Runner Auto Scaling Configuration.
+   *
+   * A default configuration is either the AWS recommended configuration,
+   * or the configuration you set as the default.
+   *
+   * @see https://docs.aws.amazon.com/apprunner/latest/dg/manage-autoscaling.html
+   *
+   * @default - the latest revision of a default auto scaling configuration is used.
+   */
+  readonly autoScalingConfiguration?: IAutoScalingConfiguration;
+
   /**
    * The number of CPU units reserved for each instance of your App Runner service.
    *
@@ -1272,6 +1285,7 @@ export class Service extends cdk.Resource implements iam.IGrantable {
       encryptionConfiguration: this.props.kmsKey ? {
         kmsKey: this.props.kmsKey.keyArn,
       } : undefined,
+      autoScalingConfigurationArn: this.props.autoScalingConfiguration?.autoScalingConfigurationArn,
       networkConfiguration: {
         egressConfiguration: {
           egressType: this.props.vpcConnector ? 'VPC' : 'DEFAULT',

packages/@aws-cdk/aws-apprunner-alpha/test/auto-scaling-configuration.test.ts

@@ -0,0 +1,110 @@
+import { Match, Template } from 'aws-cdk-lib/assertions';
+import * as cdk from 'aws-cdk-lib';
+import { AutoScalingConfiguration } from '../lib';
+
+let stack: cdk.Stack;
+beforeEach(() => {
+  stack = new cdk.Stack();
+});
+
+test.each([
+  ['MyAutoScalingConfiguration'],
+  ['my-autoscaling-configuration_1'],
+])('create an Auto scaling Configuration with all properties (name: %s)', (autoScalingConfigurationName: string) => {
+  // WHEN
+  new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+    autoScalingConfigurationName,
+    maxConcurrency: 150,
+    maxSize: 20,
+    minSize: 5,
+  });
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::AppRunner::AutoScalingConfiguration', {
+    AutoScalingConfigurationName: autoScalingConfigurationName,
+    MaxConcurrency: 150,
+    MaxSize: 20,
+    MinSize: 5,
+  });
+});
+
+test('create an Auto scaling Configuration without all properties', () => {
+  // WHEN
+  new AutoScalingConfiguration(stack, 'AutoScalingConfiguration');
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::AppRunner::AutoScalingConfiguration', {
+    AutoScalingConfigurationName: Match.absent(),
+    MaxConcurrency: Match.absent(),
+    MaxSize: Match.absent(),
+    MinSize: Match.absent(),
+  });
+});
+
+test.each([-1, 0, 26])('invalid minSize', (minSize: number) => {
+  expect(() => {
+    new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+      minSize,
+    });
+  }).toThrow(`minSize must be between 1 and 25, got ${minSize}`);
+});
+
+test.each([0, 26])('invalid maxSize', (maxSize: number) => {
+  expect(() => {
+    new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+      maxSize,
+    });
+  }).toThrow(`maxSize must be between 1 and 25, got ${maxSize}`);
+});
+
+test('minSize greater than maxSize', () => {
+  expect(() => {
+    new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+      minSize: 5,
+      maxSize: 3,
+    });
+  }).toThrow('maxSize must be greater than minSize');
+});
+
+test.each([0, 201])('invalid maxConcurrency', (maxConcurrency: number) => {
+  expect(() => {
+    new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+      maxConcurrency,
+    });
+  }).toThrow(`maxConcurrency must be between 1 and 200, got ${maxConcurrency}`);
+});
+
+test.each([
+  ['tes'],
+  ['test-autoscaling-configuration-name-over-limitation'],
+  ['-test'],
+  ['test-?'],
+])('invalid autoScalingConfigurationName (name: %s)', (autoScalingConfigurationName: string) => {
+  expect(() => {
+    new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+      autoScalingConfigurationName,
+    });
+  }).toThrow(`autoScalingConfigurationName must match the ^[A-Za-z0-9][A-Za-z0-9\-_]{3,31}$ pattern, got ${autoScalingConfigurationName}`);
+});
+
+test('create an Auto scaling Configuration with tags', () => {
+  // WHEN
+  const autoScalingConfiguration = new AutoScalingConfiguration(stack, 'AutoScalingConfiguration', {
+    autoScalingConfigurationName: 'my-autoscaling-config',
+    maxConcurrency: 150,
+    maxSize: 20,
+    minSize: 5,
+  });
+
+  cdk.Tags.of(autoScalingConfiguration).add('Environment', 'production');
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::AppRunner::AutoScalingConfiguration', {
+    Tags: [
+      {
+        Key: 'Environment',
+        Value: 'production',
+      },
+    ],
+  });
+});