Getting the image

Build the image with:

docker build --tag=conky .

or if you want the commandline version:

docker build --build-arg X11=no --tag=conkycmd .

Running the container

After building you can run the graphical version with:

docker run --rm -ti --net=host -e DISPLAY -v ~/.Xauthority:/root/.Xauthority conky

The commandline version is easier:

docker run --rm -ti conkycmd

If you want to pass some options to conky you can just add them if you mention 'conky' twice. Once for the image and once for the command. For example:

docker run --rm -ti --net=host -e DISPLAY -v ~/.Xauthority:/root/.Xauthority conky conky --version

will show you the version of conky. Since you don't need X for this you could also do:

docker run --rm -ti conkycmd conky --version

If you want to fiddle around a bit with the configuration first you could do:

docker run --rm -ti --net=host -e DISPLAY -v ~/.Xauthority:/root/.Xauthority conky bash

change things is in the configuration

conky -c configurationfile ; exit

See the docker docs to a lot of other ways to (ab)use this container

Why?

Disadvantages of using the docker:

You'll have to install docker. This can be done by following the instructions in https://docs.docker.com/install/ to install docker CE. But just using the packagemanager of your distro like you would do with other software will work.
A lot of info will be about the current container instead of the whole system
At the moment our docker image is still in development fase.

Advantages of using docker:

During the installation you won't have to care about which compilers, libraries, ... are installed. Neither should you care about how to use them.
The containerization of conky will make it a lot harder to let problems with conky affect the rest of the system.
Your Conky will run in exactly the same environment as everyone else's, so if it works for someone it will work for everyone. No matter which distro you are using or how you configured that distro. (The conky configuration itself will matter and also the version of conky)
Problems will be easier to recreate by developers causing faster debugging.