Graceful swan takes flight. Hunter eyes his prey. KABLAM! Hunter falls. Swan holsters gun. Server continues running.

grace lets you restart your server without interrupting current users. It's a runtime configurable, port forwarder.

Install the dependencies:

pip install Twisted
pip install PyOpenSSL # if you want SSL support

Either clone repo:

git clone https://github.com/iffy/grace.git grace.git
cd grace.git

Or download a tar:

wget https://github.com/iffy/grace/tarball/master
tar xf master
cd iffy-grace-*

Then install:

python setup.py install

Start forwarding TCP traffic from port 9000 to port 7500 on the local machine:

grace start tcp:9000 tcp:host=127.0.0.1:port=7500

Switch traffic from port 7500 to port 7600 (without disconnecting anyone still connected to port 7500):

grace switch tcp:9000 tcp:host=127.0.0.1:port=7600

List forwarding rules:

grace ls

Wait for previous forwards to finish:

grace wait

Stop forwarding:

grace stop

Because grace uses Twisted's excellent endpoints, you can forward just about any traffic to just about anywhere. Here's SSL to TCP:

grace start ssl:443:privateKey=key.pem:certKey=crt.pem tcp:host=127.0.0.1:port=7500

TCP to SSL:

grace start tcp:9000 ssl:host=www.google.com:port=443:caCertsDir=/etc/ssl/certs

TCP to domain socket:

grace start tcp:9000 unix:/var/foo/bar

Domain socket to TCP:

grace start unix:/var/foo/bar tcp:host=127.0.0.1:port=7500

Upgrade grace to a new version and swap out the current grace process with a new one:

grace restart

Specify where logs, pid and control socket go (XXX needs more explanation):

grace -d /tmp/foo start tcp:9000 tcp:host=127.0.0.1:port=7500

Use trial to run the tests:

trial grace