tcp-multiplexer
Use it in front of target server and let your client programs connect it, if target server only allows you to create limited tcp connections concurrently. While it has its limitation: increased latency as incoming request will block each other. Suitable for testing purpose.
arch
┌──────────┐
│ ┌────────┴──┐ ┌─────────────────┐ ┌───────────────┐
│ │ ├─────►│ │ │ │
│ │ client(s) │ │ tcp-multiplexer ├─────►│ target server │
└─┤ ├─────►│ │ │ │
└───────────┘ └─────────────────┘ └───────────────┘
─────► tcp connection
drawn by https://asciiflow.com/
Unlike reverse proxy, tcp connection between tcp-multiplexer and target server will be reused for all clients' tcp connections.
Multiplexer is simple. For every tcp connection from clients, the handling logic:
for {
get lock...
data pipe:
1. get request message from client
2. forward request message to target server
3. get response message from target server
4. forward response message to client
release lock...
}
lock make sure that at the same time, tcp connection to target server will be used in exactly one request-response loop. That's key point for every connection from clients share one tcp connection to target server.
Next key point is how to detect message (e.g., HTTP Message format) from tcp data stream.
supported application protocol
Every application protocol (request–response message exchange pattern) has it's own message format. For now, support:
- echo: \n terminated
- http1 (not include https, websocket): not fully supported
- iso8583: with 2 bytes header of the length of iso8583 message
$ ./tcp-multiplexer list
* iso8583
* echo
* http
usage for example: ./tcp-multiplexer server -p echo
See detailed: https://github.com/XUJiahua/tcp-multiplexer/tree/master/example
usage
$ ./tcp-multiplexer server -h
start multiplexer proxy server
Usage:
tcp-multiplexer server [flags]
Flags:
-p, --applicationProtocol string multiplexer will parse to message echo/http/iso8583 (default "echo")
-h, --help help for server
-l, --listen string multiplexer will listen on (default "8000")
-t, --targetServer string multiplexer will forward message to (default "127.0.0.1:1234")
Global Flags:
-v, --verbose verbose log
multiplexing echo server
start echo server (listen on port 1234)
$ go run example/echo-server/main.go
1: 127.0.0.1:1234 <-> 127.0.0.1:58088
start tcp multiplexing (listen on port 8000)
$ ./tcp-multiplexer server -p echo -t 127.0.0.1:1234 -l 8000
INFO[2021-05-09T02:06:40+08:00] creating target connection
INFO[2021-05-09T02:06:40+08:00] new target connection: 127.0.0.1:58088 <-> 127.0.0.1:1234
INFO[2021-05-09T02:07:57+08:00] #1: 127.0.0.1:58342 <-> 127.0.0.1:8000
INFO[2021-05-09T02:08:16+08:00] closed: 127.0.0.1:58342 <-> 127.0.0.1:8000
INFO[2021-05-09T02:08:19+08:00] #2: 127.0.0.1:58402 <-> 127.0.0.1:8000
client test
$ nc 127.0.0.1 8000
kkk
kkk
^C
$ nc 127.0.0.1 8000
mmm
mmm
