Modern real-time chat platform in scalable architecture, written in go.

Kafka is used for message Pub/Sub. Checkout this branch for the Redis Pub/Sub version.

• Real-time communication and efficient websocket handling using Melody.
• Microservices architecture. All services are stateless and can be horizontally scaled on demand.
  • web: frontend server
  • user: user account server
  • match: user matching server
  • chat: messaging server
  • forwarder: message forwarding server that maps message receivers to specific chat servers
  • uploader: file uploader
• Use gRPC for inter-service communication
  • with retry, timeout, and circuit breaker
• Use cobra and viper for CLI and configuration management respectively.
• Dependency injection using wire.
• Graceful shutdown.
• Observability using Golang Prometheus client for monitoring and opentelemetry-go for tracing.
• At-least-once delivery for message Pub/Sub using Kafka.
• Persist messages and chat channel metadata in Cassandra, an open source NoSQL distributed database for scalability and high availability.
• Automatically generate RESTful API documentation with Swagger 2.0.
• User login session management using http-only cookie.
• Support Google OAuth2 login.
• User matching with idempotency.
• Chat channel authentication using JWT.
• S3-compatible object storage for uploaded files.
• Channel-level file access control using S3 presigned URLs.
• Support uploading images from clipboard.
• Use Traefik FowardAuth for file upload authentication.
• Protect file upload api with distributed rate limiting (token bucket algorithm).
• Message seen feature.
• Auto-scroll to the first unseen message.
• Persist chat history on browser close or page refresh.
• Automatic websocket reconnection.
• Responsive web design.

Prerequisite:

• Docker-Compose v2
• Root permission

First, create OAuth client ID credentials and replace USER_OAUTH_GOOGLE_CLIENTID and USER_OAUTH_GOOGLE_CLIENTSECRET with your credentials in run.sh.

Example setting:

To run locally, execute the following command:

cd deployments
sudo ./run.sh add-host
./run.sh start

run.sh add-host needs root permission to alias minio to localhost in /etc/hosts.

Check cassandra connection:

docker exec deployments-cassandra-1 bash -c "cat /opt/bitnami/cassandra/logs/cassandra.log"
docker exec deployments-cassandra-1 bash -c "cqlsh -u ming -p cassandrapass"

This will spin up all services declared in docker-compose.yaml. Visit http://localhost and you will see the application home page.

Bucket myfilebucket will be created automatically on minio by createbucket. However, if minio is still initializing after 5 retries of createbucket, the bucket creation will fail. If this happens, please run the following command once minio is up and running:

docker restart deployments-createbucket-1

• Visit http://localhost for the application home page.
• Visit http://localhost:8080 for Traefik dashboard.
• VIsit http://localhost:9001 for Minio dashboard.
• Visit http://localhost:9090 for Prometheus dashboard.
• Visit http://localhost:16686 for Jaeger dashboard.
• Visit http://localhost/api/<svc>/swagger/index.html for API documentation, where <svc> could be user, match, chat, or uploader.

Example configuration: config.example.yaml.

A common scenario is that one deploys the application behind a reverse proxy with SSL termination. If that is your case, remember to correctly configure your proxy for websocket. For example, in Google Cloud Platform, for websocket traffic sent through a Google Cloud external HTTP(S) load balancer, the backend service timeout is interpreted as the maximum amount of time that a WebSocket connection can remain open, whether idle or not. Therefore, you may want to use a timeoutSec value larger than the default 30 seconds in your BackendConfig.