## Amazon Chime Messaging Resources

### Example

See [example/lib/messaging-resource-example.ts](example/lib/messaging-resource-example.ts) for an example of deploying Amazon Chime Messaging resources. To deploy: `yarn cdk deploy MessagingResources`

This example includes

- Amazon Chime [App Instance](https://docs.aws.amazon.com/chime-sdk/latest/dg/create-app-instance.html)
- Amazon Chime [Channel Flow](https://docs.aws.amazon.com/chime-sdk/latest/dg/using-channel-flows.html)
- Amazon Chime [App Instance User](https://docs.aws.amazon.com/chime-sdk/latest/dg/create-app-instance-user.html)
- Amazon Chime [App Instance Admin](https://docs.aws.amazon.com/chime-sdk/latest/dg/auth-by-role.html#appinstanceadmin)
- Amazon Chime [Streaming Message Data](https://docs.aws.amazon.com/chime-sdk/latest/dg/streaming-export.html)
- Amazon Chime [Message Retention](https://docs.aws.amazon.com/chime-sdk/latest/dg/manage-retention.html)

## Amazon Chime Messaging Resources

### Amazon Chime Messaging App Instance

[API Reference](https://docs.aws.amazon.com/chime-sdk/latest/APIReference/API_identity-chime_CreateAppInstance.html)

```typescript
const appInstance = new chime.MessagingAppInstance(this, 'appInstance', {
  name: 'MessagingAppInstanceExample',
});
```

This will create an Amazon Chime Messaging App Instance and will return the `AppInstanceArn`.

### Amazon Chime App Instance User

```typescript
const appInstanceUser = new chime.MessagingAppInstanceUser(
  this,
  'appInstanceUser',
  {
    appInstanceArn: appInstance.appInstanceArn,
    appInstanceUserId: '1234',
  },
);
```

This will create an App Instance User that is associated with the previously created Amazon Chime SDK Messaging App Instance. This User can then be promoted to an App Instance Admin.

### Amazon Chime App Instance Admin

```typescript
new chime.MessagingAppInstanceAdmin(this, 'appInstanceAdmin', {
  appInstanceAdminArn: appInstanceUser.appInstanceUserArn,
  appInstanceArn: appInstance.appInstanceArn,
});
```

Using the previously created App Instance and the previously created App Instance User, an App Instance Admin can be created.

### Amazon Chime Messaging Channel Flow

[API Reference](https://docs.aws.amazon.com/chime-sdk/latest/APIReference/API_messaging-chime_CreateChannelFlow.html)

#### Preparing AWS Lambda for Channel Flow Processor

Take note of the [required permissions](https://docs.aws.amazon.com/chime-sdk/latest/dg/processor-setup.html) for the AWS Lambda in the example to allow the Amazon Chime service to invoke the associated Lambda.

```typescript
const channelFlowLambdaRole = new iam.Role(this, 'channelFlowLambdaRole', {
  assumedBy: new iam.ServicePrincipal('lambda.amazonaws.com'),
  inlinePolicies: {
    ['chimePolicy']: new iam.PolicyDocument({
      statements: [
        new iam.PolicyStatement({
          resources: [
            `arn:aws:chime:${this.region}:${this.account}:app-instance/*`,
          ],
          actions: ['chime:ChannelFlowCallback'],
        }),
      ],
    }),
  },
  managedPolicies: [
    iam.ManagedPolicy.fromAwsManagedPolicyName(
      'service-role/AWSLambdaBasicExecutionRole',
    ),
  ],
});

const channelFlowHandler = new Function(this, 'channelFlowHandler', {
  runtime: Runtime.PYTHON_3_9,
  handler: 'channelFlowHandler.lambda_handler',
  code: Code.fromAsset('src'),
  role: channelFlowLambdaRole,
});

channelFlowHandler.addPermission('Chime Resource Policy', {
  principal: new iam.ServicePrincipal('chime.amazonaws.com'),
  sourceArn: `arn:aws:chime:${this.region}:${this.account}:app-instance/*`,
  sourceAccount: `${this.account}`,
});
```

#### Creating Channel Flow Processor

```typescript
const channelFlow = new chime.ChannelFlow(this, 'channelFlow', {
  appInstanceArn: appInstance.appInstanceArn,
  processors: [
    {
      name: 'channelFlowName',
      configuration: {
        lambda: {
          resourceArn: channelFlowHandler.functionArn,
          invocationType: chime.InvocationType.ASYNC,
        },
      },
      executionOrder: 1,
      fallbackAction: chime.FallbackAction.ABORT,
    },
  ],
  clientRequestToken: uuidv4(),
});
```

### Streaming Messaging Data

[API Reference](https://docs.aws.amazon.com/chime-sdk/latest/APIReference/API_PutAppInstanceStreamingConfigurations.html)

```typescript
const kinesisStream = new kinesis.Stream(this, 'kinesisStream', {
  streamName: 'chime-messaging-channel-stream',
  shardCount: 2,
  encryption: kinesis.StreamEncryption.MANAGED,
});

appInstance.streaming([
  {
    appInstanceDataType: chime.AppInstanceDataType.CHANNEL,
    resourceArn: kinesisStream.streamArn,
  },
]);
```

Take note of the requirements for the Kinesis Stream for streaming messaging data:

- Kinesis streams must be in the same AWS account as the AppInstance.
- A stream must be in the same region as the AppInstance.
- Stream names have a prefix that starts with chime-messaging-.
- You must configure at least two shards. Each shard can receive data up to 1MB per second, so scale your stream accordingly.
- You must enable server-side encryption (SSE).

### Message Retention

[API Reference](https://docs.aws.amazon.com/chime-sdk/latest/APIReference/API_PutAppInstanceRetentionSettings.html)

```typescript
appInstance.retention(2);
```

Pass a number in days for message retention.

## Output

The output from the example CDK will include [AWS Command Line Interface](https://aws.amazon.com/cli/) commands to show the output from the CDK.

```bash
aws chime-sdk-identity list-app-instance-admins --app-instance-arn arn:aws:chime:us-east-1:111111111111:app-instance/df3ad5fd-acac-477a-acb4-50407b5f4be4
aws chime-sdk-identity describe-app-instance --app-instance-arn arn:aws:chime:us-east-1:111111111111:app-instance/df3ad5fd-acac-477a-acb4-50407b5f4be4
aws chime-sdk-messaging list-channel-flows --app-instance-arn arn:aws:chime:us-east-1:111111111111:app-instance/df3ad5fd-acac-477a-acb4-50407b5f4be4
aws chime get-app-instance-retention-settings --app-instance-arn arn:aws:chime:us-east-1:111111111111:app-instance/df3ad5fd-acac-477a-acb4-50407b5f4be4
aws chime get-app-instance-streaming-configurations --app-instance-arn arn:aws:chime:us-east-1:111111111111:app-instance/df3ad5fd-acac-477a-acb4-50407b5f4be4
```