# tproxy
English | [简体中文](readme-cn.md) | [日本語](readme-ja.md)
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## Why I wrote this tool
When I develop backend services and write [go-zero](https://github.com/zeromicro/go-zero), I often need to monitor the network traffic. For example:
1. monitoring gRPC connections, when to connect and when to reconnect
2. monitoring MySQL connection pools, how many connections and figure out the lifetime policy
3. monitoring any TCP connections on the fly
## Installation
```shell
$ go install github.com/kevwan/tproxy@latest
```
Or use docker images:
```shell
$ docker run --rm -it -p : -p : kevinwan/tproxy:v1 tproxy -l 0.0.0.0 -p -r host.docker.internal:
```
For arm64:
```shell
$ docker run --rm -it -p : -p : kevinwan/tproxy:v1-arm64 tproxy -l 0.0.0.0 -p -r host.docker.internal:
```
On Windows, you can use [scoop](https://scoop.sh/):
```shell
$ scoop install tproxy
```
## Usages
```shell
$ tproxy --help
Usage of tproxy:
-d duration
the delay to relay packets
-down int
Downward speed limit(bytes/second)
-l string
Local address to listen on (default "localhost")
-p int
Local port to listen on, default to pick a random port
-q Quiet mode, only prints connection open/close and stats, default false
-r string
Remote address (host:port) to connect
-s Enable statistics
-t string
The type of protocol, currently support http2, grpc, redis and mongodb
-up int
Upward speed limit(bytes/second)
```
## Examples
### Monitor gRPC connections
```shell
$ tproxy -p 8088 -r localhost:8081 -t grpc -d 100ms
```
- listen on localhost and port 8088
- redirect the traffic to `localhost:8081`
- protocol type to be gRPC
- delay 100ms for each packets
### Monitor MySQL connections
```shell
$ tproxy -p 3307 -r localhost:3306
```
### Check the connection reliability (Retrans rate and RTT)
```shell
$ tproxy -p 3307 -r remotehost:3306 -s -q
```
### Learn the connection pool behaviors
```shell
$ tproxy -p 3307 -r localhost:3306 -q -s
```
## Give a Star! ⭐
If you like or are using this project, please give it a **star**. Thanks!