Chat Server

This is a sample project for playing with websocket with integration test built in it.

How to test

Execute the following command:

$ go test -timeout 30s -parallel 10 ./...

Note:

The -parallel 10 flag is necessary because the test uses parallel testing to simulate concurrent connections of 10 clients (9 consumers and 1 sender).

Flow

1. Client connect via websocket to /messages/listen (done)
2. Publisher publishes Messages via HTTP endpoint POST /messages
3. Message will be stored in data store, and then pushed back to the connected clients

Experimental / TODO

• Enable Publisher to publish message by replying to the websocket
• Enable multiple connection per user
• Message order synchronization

Lesson Learned

Message order synchronization

Problem:

Spawning goroutine to send message A (goroutine A) prior to message B (goroutine B) doesn't guarantee that goroutine A will be executed prior to goroutine B.

Solution:

Spawn a worker (goroutine) within the connection to write message. Message is extracted from internal message queue which guarantees the message order.