sample_simple_websockets_chat_app

This repository is a Rust implementation of aws-samples/simple-websockets-chat-app.

Build Environment

The execution environment is assumed to be provided.al2 (Amazon Linux 2)/arm64. Therefore, the default build target is aarch64-unknown-linux-musl. If you are building on macOS, use FiloSottile/homebrew-musl-cross or emk/rust-musl-builder.

Build

Packages are built for each of API Gateway's default websocket routes and custom routes.

# Build all packages
cargo build --release --workspace

# Build per package
cargo build --release --package <package_name>

Deployment

ws_sendmessage

Set the following environment variables. The environment variables can also be obtained from the WebSocket URL (no need to set AWS_REGION).

wss://{AWS_API_ID}.execute-api.{AWS_REGION}.amazonaws.com/{AWS_STAGE}

AWS_API_ID
AWS_STAGE
DYNAMO_TABLE_NAME

DynamoDB

The partition key for the DynamoDB table should be set as connectionId.

IAM

Configure the Execution role of Lambda functions as follows:

Permissions

Grant the following permissions to enable access to the related services:

• AmazonAPIGatewayInvokeFullAccess
• AmazonDynamoDBFullAccess
• AWSXRayDaemonWriteAccess
• AWSLambdaBasicExecutionRole

Trust relationships

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

Testing the chat API

To test the WebSocket API, you can use wscat, an open-source command line tool.

1. Install NPM.
2. Install wscat:

$ npm install -g wscat

3. On the console, connect to your published API endpoint by executing the following command:

$ wscat -c wss://{YOUR-API-ID}.execute-api.{YOUR-REGION}.amazonaws.com/{STAGE}

4. To test the sendMessage function, send a JSON message like the following example. The Lambda function sends it back using the callback URL:

$ wscat -c wss://{YOUR-API-ID}.execute-api.{YOUR-REGION}.amazonaws.com/prod
connected (press CTRL+C to quit)
> {"action":"sendmessage", "data":"hello world"}
< hello world