As you can see, we only discussed how Docker will interact with the plugin service that you have written and didn't cover how you can actually write a plugin service.
The reason for this is that due to the plugin service that we would have had to cover, we would also need the following features:
- To be written in Go
- To be able run as a daemon
- To contain an HTTP server bound to a Unix socket or TCP port
- To be able to accept and answer requests made to it by the Docker daemon
- To translate the API requests that Docker is making to a filesystem or network service
As you can imagine, this has the potential of being an entire book by itself.
Also, building your own plugin is quite an undertaking as you already have to have the foundations of a service written. While it seems like there are a lot of Docker plugins out there, searching GitHub for Docker plugins only returns a few dozen plugins that have been written to use the Docker plugin API.
The other projects returned are all tools or plugins for third-party services (such as Jenkins, Maven, and so on) that communicate with the Docker Remote API.
In the next chapter, we are going to look at third-party tools to extend your infrastructure past using Docker Machine.