After reading Sam Hartman's comments on the situation with SysV init, systemd init, and the issues faced with maintaining both, I did some thinking. In particular regarding the part of Hartman's DPL e-mail where he mentioned many Debian packages have systemd unit files, but no equivalent init.d style scripts.
This got me thinking that it would be useful if we had either an init-agnostic service manager which could work with unit files, allowing sysvinit, runit, etc to use systemd unit files without depending on the whole systemd suite... Or a tool that could read systemd unit files and produce mostly-ready-to-use init.d scripts that could be patched into Debian packages. With these two thoughts in mind, I did a little tinkering this past weekend and wrote a crude library which parses systemd unit files to find the key bits of information (dependency information, commands to run when starting/stopping services) and put together a little demo program. Right now the program is very very simplistic and crude. (Really really crude.) But it will search the system for systemd unit files, load them all into memory, and work out the dependencies for each unit file. This evening I got it to the point where it'll recursively find dependencies for a given unit. With a few small modifications it will run a unit's dependencies followed by the unit itself. I'm trying to write the code in a way which will allow it to be used as a library that could portentially be used in multiple applications. Such as a systemd-to-init.d converter or a service manager that gets launched by PID 1 and runs in the background. The code hasn't been uploaded yet (did I mention it's still very crude?) but it's functional on my Debian system and I'm curious if anyone else is interested in exploring these types of applications or would find them useful. That'll help me direct my attention on what this library of functions can do and the demo programs I might make with it. - Jesse
