Greetings, friends of all things DevAssistant. For eleven minor versions, DevAssistant has been the tool to set up your environment on your host system, on bare metal. That works very well, but an increasing number of developers can't use it for their use case. Why, you ask? Containers. While DevAssistant has very basic support for containers in the 'Docker' assistant, it still does all the magic on the host. What we need is a full-fledged containerised app support, and DevAssistant will have to change quite fundamentally to offer it. Right now, DevAssistant is pretty much a monolithic application that runs on the host machine, requires GTK+ for its GUI and makes some assumptions about what the environment looks like. That makes it quite hard to make it work reliably under Mac OS X or Windows, heck even different Linux distros. To overcome this problem, I suggest splitting DevAssistant based on the client/server architecture. The basic idea is that the server runs in a privileged container or on the host system, and very thin client connects to it and exchange information about assistants and commands through an API (for example using JSON). You may think about it as "DevAssistant as a service". When developing this architecture, I have heavily borrowed from Cockpit, the web-based sysadmin tool developed for Fedora, which uses a webserver to accept commands, and then, through a bridge app, issues calls to various system services. DevAssistant then should be reorganised into these components: The client ---------- While DevAssistant uses already a sort of a client-server architecture, the clients are still quite thick, and not easily replaceable. Our intention is to put only the bare minimum into the client - an engine to construct a user interface from the received data. That means that the command line interface will construct a help message with assistants and commands based on what is available on the server side. Similarly, the WebUI will construct a form based on fields that the server sends to it, generated from the arguments specified in an assistant. The client always runs under the user that wishes to run an assistant. I am acutely aware of the fact that by using the web interface for running commands under the root user, I am effectively delegating the security to the browser, but I doubt we currently have the resources to have a new full-fledged GUI based on some desktop graphical toolkit. The webserver ------------- The webserver is the front-facing part of the entire server, which interacts with the client. What it does is spin up a "bridge" instance (see below) for the user under whom the "client" is running, and pass messages between the two. The webserver itself doesn't touch the system or containers in any way, and will probably run under a unique user, for example 'devassistant'. I expect it will take the list of available users from /etc/passwd. I still don't know what webserver to use, but security is definitely what we should look at first. The bridge ---------- This is the core part of the new system, which will contain most of today's DevAssistant package. This part runs under the user who actually wants to execute the assistants, and is spawned by the webserver. It loads the available assistants, runs them with parameters supplied through the webserver, and if necessary, delegates the execution of superuser tasks to the "service" with elevated privileges. The service ----------- Since the bridge runs under a user that doesn't necessarily have all the permissions an assistant may require, there will be a service (DBus?) that accepts commands and executes them as the super user. When such a command is invoked, the service will ask an authentication agent if the user is authorised to perform such a command, and based on the agent's reply will carry it out appropriately. If an additional authentication is required, the bridge sends a request to the client for proper authentication. The agent --------- The last part of the system is an authentication agent. This agent, based on its policies, decides if a given user is permitted to carry out a command passed to the "service", and return a True/False reply. This will probably be a PolicyKit service. This is the general plan of remodelling DevAssistant to better suit containerised development. I would like to know your ideas about or criticisms of this outline, as it may shape the development for months or years to come. Cheers, Tomas Radej