Add registered clients feature

[moisespsena]

Add registered clients feature. See README.md for more details.

[mmatczuk]

Hi @moisespsena,
could you please elaborate on what this patch set does what is the motivation.
Overall it's a massive PR, I do not follow all the decisions such as moving cmd to cli could you give more insight to that too.

[moisespsena]

Hi @mmatczuk,

1. My motivation was a need to have multiple data collectors behind a router and that could be accessed externally. As these collectors are sent to various places on different projects, and because they have no control over these collectors, the need arose to release the tunnel only to registered collectors.

2. I moved cmd to cli to allow exposes "tunnel" and "tunneld" to be embedded.

Example for embed tunnel in your code.

package main

import "github.com/mmatczuk/go-http-tunnel/cli/tunnel"

func tunnelClient() {
	options, err := tunnel.ParseArgs(false, "mycmd", "start-all")
	if err != nil {
		panic(err)
	}
	tunnel.MainConfigOptions(&tunnel.ClientConfig{
		ServerAddr: "domain.com:2000",
		Tunnels: map[string]*tunnel.Tunnel{
			"main": {
				Protocol:   "tcp",
				LocalAddr:  "localhost:5000",
				RemoteAddr: "domain.com:5000",
			},
		},
	}, options)
}

func main() {
	go tunnelClient()

	// ... my system code
}

Example for embed tunneld in your code.

package main

import "github.com/mmatczuk/go-http-tunnel/cli/tunneld"

func main() {
	go tunneld.MainArgs("mycmd", "-log-level", "3", "-httpAddr", ":19000", "-httpsAddr", ":19001")

	// ... my system code
}

[mmatczuk]

Seems like it's not part of "Default backoff configuration."

[moisespsena]

This is only stdin file path reference.

[mmatczuk]

Why?

[moisespsena]

In the old version, the ParseArgs function uses the os.Args[0], for command name, now, uses the first passed argument.

[mmatczuk]

how about Path to tunnel configuration file, for reading from STDIN use '-'.?

[moisespsena]

I used as an example the "cat" command: cat -