On 12/06/2015 19:01, Steve Litt wrote:
The one thing I *do* know is that we need to provide a sd_notify interface, even if it does nothing at all and drops passed information on the floor.
Please don't do this. The more you bend to the systemd interfaces, the more it gets a foot in the door. By implementing a dummy sd_notify, you acknowledge the validity of the interface; you accept that the systemd people have created something worth using, and you validate the existence of (a part of) systemd. The thing is, the sd_notify interface is not *too* bad, but like the rest of systemd, it is overengineered, too complex, and mixes several different things in a monolithic way so that people who are trying to actually implement real support for sd_notify are bound to reinvent systemd one way or another. It's absolutely like the old Microsoft "embrace and extend" strategy, you know. They get one foot in the door by providing something useful, but then pile their own crap onto it, and people are already relying on it, so you want to implement support for it, and then you're captive, and the only way to be 100%-compatible is to use the original product. There's a much simpler mechanism that can be used to provide readiness notification, and that I suggest in http://skarnet.org/software/s6/notifywhenup.html and that is: write a given character on a descriptor, then close that descriptor. It doesn't get any simpler than that, it doesn't require linking daemons against any library, and it can be made to be compatible with *everything*. If a daemon supports that mechanism, it is very easy to write a systemd-notify program that would wrap that daemon and communicate with systemd via sd_notify to inform it of the daemon's readiness, the way s6-notifywhenup does for s6. Please KISS, and design good interfaces to be adopted, instead of letting yourselves get bullied by systemd forcing its interfaces down your throats and jumping through hoops to adapt to them. With a simpler interface and a trivial wrapper program, the influence of systemd only extends to the wrapper program, and not to the daemons themselves. -- Laurent _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
