arthas/tunnel-server/README.md

## How it works

Tunnel server/client use websocket protocol.

For example:

1. Arthas tunnel server listen at `192.168.1.10:7777`

1. Arthas tunnel client register to the tunnel server

    tunnel client connect to tunnel server with URL: `ws://192.168.1.10:7777/ws?method=agentRegister`

    tunnel server response a text frame message: `response:/?method=agentRegister&id=bvDOe8XbTM2pQWjF4cfw`

    This connection is `control connection`.

1. The browser try connect to remote arthas agent, start connect to tunnel server with URL: `'ws://192.168.1.10:7777/ws?method=connectArthas&id=bvDOe8XbTM2pQWjF4cfw`

1. Arthas server find the `control connection` with the id `bvDOe8XbTM2pQWjF4cfw`, then send a text frame to arthas client: `response:/?method=startTunnel&id=bvDOe8XbTM2pQWjF4cfw&clientConnectionId=AMku9EFz2gxeL2gedGOC`

1. Arhtas tunnel client open a new connection to tunnel server, URL: `ws://127.0.0.1:7777/ws/?method=openTunnel&clientConnectionId=AMku9EFz2gxeL2gedGOC&id=bvDOe8XbTM2pQWjF4cfw`. This connection is `tunnel connection`.

1. Arhtas tunnel client start connect to local arthas agent, URL: `ws://127.0.0.1:3658/ws`. This connection is `local connection`.

1. Forward websocket frame between `tunnel connection` and `local connection`.

```
browser <-> arthas tunnel server <-> arthas tunnel client <-> arthas agent
```