captnbp / docker-tcp-proxy

Stupid TCP Proxy

What?

Yes, this is a simply and stupid TCP proxy that listens in one address and talks to another one

Why?

Because when you develop, you don't want your project to talk to real API, IMAP, POP3, SMTP, SSH, ACME or [insert your acronym here] servers.

So, instead of configuring your app to talk to that server, you configure it to talk to the stupid proxy, and then the stupid proxy redirects connections to the correct server and port depending on the docker-compose environment you turn on.

Also you can use it to whitelist services in an internal network (see the related issue).

How?

We use the official [Alpine][]-based [HAProxy][] image with a small configuration file.

Usage

Available environment variables

Currently there are only these:

$LISTEN

This variable defines the port where the underlying [HAProxy][] will listen, and it must be written in the format used by the [bind][] directive.

By default (:100), it listens in every connection at port 100 (port 100? that's stupid!... Yes, read the title ☝️😑).

$TALK

The target TCP server and port that the proxy will be talking to, in the format required by [HAProxy][]'s [server][] directive.

By default (192.168.1.1:100), it talks to a host IP in port 100 too.

$TIMEOUT_CLIENT

Default: 5s

This variable sets the maximum inactivity time on the client side.

$TIMEOUT_CLIENT_FIN

Default: 5s

This variable sets the inactivity timeout on the client side for half-closed connections.

$TIMEOUT_CONNECT

Default: 5s

This variable sets the maximum time to wait for a connection attempt to a server to succeed.

$TIMEOUT_SERVER

Default: 5s

This variable sets the maximum inactivity time on the server side.

$TIMEOUT_SERVER_FIN

Default: 5s

This variable sets the inactivity timeout on the server side for half-closed connection.

$TIMEOUT_TUNNEL

Default: 5s

This variable sets the maximum inactivity time on the client and server side for tunnels.

The production environment (production.yaml file)

version: "2.1"
services:
    # Random app that needs an IMAP server at tcp://imap:143
    app:
        build: .
        links:
            - imap
    # Production address to your real IMAP server
    imap:
        image: tecnativa/tcp-proxy
        environment:
            LISTEN: ":143"
            TALK: "192.168.1.1:993"

The development environment (development.yaml file)

version: "2.1"
services:
    # Same configuration as in production for your app
    app:
        build: .
        links:
            - imap
    # Connect to a fake IMAP server
    imap:
        image: tecnativa/tcp-proxy
        environment:
            LISTEN: ":143"
            TALK: "192.168.1.1:143"