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diff --git a/2022/captions/emacsconf-2022-dbus--the-wheels-on-dbus--ian-eure--answers.vtt b/2022/captions/emacsconf-2022-dbus--the-wheels-on-dbus--ian-eure--answers.vtt new file mode 100644 index 00000000..75b624a9 --- /dev/null +++ b/2022/captions/emacsconf-2022-dbus--the-wheels-on-dbus--ian-eure--answers.vtt @@ -0,0 +1,1691 @@ +WEBVTT + +00:00.000 --> 00:02.600 +the recording button here. + +00:02.600 --> 00:03.600 +OK. + +00:03.600 --> 00:05.180 +Thank you again for the great talk, + +00:05.180 --> 00:06.680 +even though I haven't been able to catch most of it + +00:06.680 --> 00:08.560 +because I've been running around behind the scenes. + +00:08.560 --> 00:11.360 +But very much interested in DBUS and Emacs. + +00:11.360 --> 00:13.240 +I'm very much looking forward to watching it + +00:13.240 --> 00:14.080 +after the conference. + +00:14.080 --> 00:18.360 +But for folks who were able to and did catch the talk, + +00:18.360 --> 00:21.680 +please, now it's time to send in your questions. + +00:21.680 --> 00:24.820 +You can either ask away on IRC or put them on the pad. + +00:24.820 --> 00:28.300 +And we'll also open up this PBB room in a little bit + +00:28.300 --> 00:31.960 +if you'd like to join here directly on asking questions. + +00:31.960 --> 00:34.520 +So, Ian, please take it away. + +00:34.520 --> 00:35.280 +Hey, thanks. + +00:35.280 --> 00:38.580 +Yeah, going to wait for some questions to come in. + +00:38.580 --> 00:41.320 +But there's a couple of points I wanted to make. + +00:41.320 --> 00:46.840 +So I'm going to share my screen here for a minute. + +00:46.840 --> 00:50.880 +If you're interested in exploring more about DBUS, + +00:50.880 --> 00:54.080 +there is a graphical client called dfeat. + +00:54.080 --> 00:56.200 +That's d-feat. + +00:56.200 --> 00:59.960 +I guess puns are strong when it comes to DBUS software. + +00:59.960 --> 01:03.400 +And this just gives you a graphical overview + +01:03.400 --> 01:06.160 +of what's going on with your bus. + +01:06.160 --> 01:09.920 +So in the case that I was looking at in Emacs, + +01:09.920 --> 01:11.600 +you can look. + +01:11.600 --> 01:13.280 +Here's the hostname1 service. + +01:13.280 --> 01:18.360 +And here's you can change the chassis of it or read. + +01:18.360 --> 01:20.240 +I'm on a desktop here. + +01:20.240 --> 01:23.940 +So I think this is a really great tool + +01:23.940 --> 01:30.720 +for just understanding what is available and what DBUS can do. + +01:30.720 --> 01:33.720 +I think I didn't do a great job of setting out a vision. + +01:33.720 --> 01:37.000 +So I want to try to reiterate that here. + +01:37.000 --> 01:41.320 +Ever since I started using X1 several years ago, + +01:41.320 --> 01:46.480 +and before that even, once I was learning about LISP machines, + +01:46.480 --> 01:48.920 +one of the things that I really want out of my computing + +01:48.920 --> 01:52.720 +experience is a full LISP environment, + +01:52.720 --> 01:54.400 +like a modern LISP machine. + +01:54.400 --> 01:59.440 +And I think Emacs and X1 are the closest thing to that + +01:59.440 --> 02:01.800 +that you can get on a modern machine. + +02:01.800 --> 02:03.760 +But if you're thinking about what + +02:03.760 --> 02:07.680 +are the gaps between that and a full blown desktop environment, + +02:07.680 --> 02:10.800 +there is many of them that make it inconvenient + +02:10.800 --> 02:12.760 +in a variety of different ways. + +02:12.760 --> 02:17.600 +And my vision is really to have an Emacs desktop environment. + +02:17.600 --> 02:21.080 +And I think DBUS is really key to making that work. + +02:21.080 --> 02:24.760 +And I would love, on the one to two year horizon, + +02:24.760 --> 02:29.080 +I would really like to see common system tasks be + +02:29.080 --> 02:32.680 +able to get done seamlessly from inside of Emacs. + +02:32.680 --> 02:34.640 +And what I mean by that is things + +02:34.640 --> 02:37.440 +like pairing with a Bluetooth device, + +02:37.440 --> 02:41.440 +connecting to a Wi-Fi network, rebooting your computer + +02:41.440 --> 02:44.440 +or putting it into suspend, or any of those things + +02:44.440 --> 02:47.800 +that you might think of doing in a full blown desktop + +02:47.800 --> 02:51.320 +environment, whether it's Mac OS, or Windows, or GNOME, or KDE, + +02:51.320 --> 02:53.920 +or whatever, you should be able to do all that from Emacs. + +02:53.920 --> 02:56.840 +You should be able to manage everything + +02:56.840 --> 02:59.200 +without having to leave that environment. + +02:59.200 --> 03:02.160 +Because I really prefer the Emacs environment. + +03:02.160 --> 03:05.520 +I would like to do all of that from inside Emacs. + +03:05.520 --> 03:07.380 +And when it comes to integrating with all + +03:07.380 --> 03:11.960 +those different things, DBUS is really key to making it work. + +03:11.960 --> 03:20.560 +But I do think that offering the ability of integrating Emacs + +03:20.560 --> 03:23.160 +into the desktop for people who don't + +03:23.160 --> 03:26.720 +want to go that route of having a full blown Emacs desktop + +03:26.720 --> 03:30.880 +environment, I think that's also a path to some really + +03:30.880 --> 03:35.200 +interesting feature opportunity that + +03:35.200 --> 03:39.760 +has been difficult to explore in Emacs in years past. + +03:39.760 --> 03:44.160 +So I really think it's just a great space to be exploring. + +03:44.160 --> 03:46.280 +And I'm really excited to see what kind of stuff + +03:46.280 --> 03:48.520 +I can build in there, and what things other people + +03:48.520 --> 03:49.600 +start building in there. + +03:53.400 --> 03:54.160 +Sounds great. + +03:54.160 --> 03:57.640 +Yeah, and I think DBUS is kind of, I guess, + +03:57.640 --> 04:00.680 +one of those essential key pieces of software + +04:00.680 --> 04:03.120 +on GNU Linux where, I mean, if it's working, + +04:03.120 --> 04:05.240 +and when it's working, it's pretty much, + +04:05.240 --> 04:06.800 +I mean, you don't even notice it. + +04:06.800 --> 04:07.760 +It's behind the scenes. + +04:07.760 --> 04:09.600 +Everything seems to be working hand in hand. + +04:09.600 --> 04:11.880 +So yeah, I remember, for example, + +04:11.880 --> 04:14.600 +when I first switched to using a custom window manager, + +04:14.600 --> 04:16.760 +you pretty much lose all of that sort + +04:16.760 --> 04:20.200 +of integration and togetherness right away + +04:20.200 --> 04:22.440 +if there is no DBUS. + +04:22.440 --> 04:24.560 +And yeah, a lot of beginners, like myself at the time + +04:24.560 --> 04:27.480 +at least, don't even know what they're missing out on. + +04:27.480 --> 04:33.200 +So kudos for taking this on and having this vision of essentially + +04:33.200 --> 04:35.840 +moving towards that direction of being able to use Emacs + +04:35.840 --> 04:38.840 +as a potentially fully featured desktop environment. + +04:38.840 --> 04:40.680 +I think that's awesome. + +04:40.680 --> 04:42.560 +Yeah, thank you. + +04:42.560 --> 04:44.880 +Looks like I have some questions in the pad, + +04:44.880 --> 04:47.160 +so I will cover some of those. + +04:47.160 --> 04:48.720 +No, it's not Web3. + +04:48.720 --> 04:49.320 +Not funny. + +04:52.440 --> 04:54.840 +I'm sorry, the question was, so is this a Web3 approach? + +04:54.840 --> 04:56.840 +No, it isn't. + +04:56.840 --> 04:58.160 +I have another question. + +04:58.160 --> 04:59.960 +This is such a great overview of DBUS. + +04:59.960 --> 05:01.800 +I haven't been paying attention to this space + +05:01.800 --> 05:05.120 +because it seems to be in flux 10 or 15 years ago. + +05:05.120 --> 05:07.040 +How long has DBUS been around, and what + +05:07.040 --> 05:09.160 +was in place before that? + +05:09.160 --> 05:11.960 +So I covered this real briefly in the beginning of the talk, + +05:11.960 --> 05:15.400 +but DBUS dates from 2002-ish. + +05:15.400 --> 05:21.760 +And I would say since 2010, 2012, that time frame, + +05:21.760 --> 05:26.080 +it has been pretty stable and has seen wide adoption + +05:26.080 --> 05:28.600 +in multiple desktop environments. + +05:28.600 --> 05:30.800 +Before DBUS, there wasn't anything like it. + +05:30.800 --> 05:33.120 +It didn't replace a similar feature. + +05:33.120 --> 05:35.320 +And if you wanted to do the sorts of things + +05:35.320 --> 05:40.160 +that DBUS does, you were pretty limited. + +05:40.160 --> 05:42.600 +Those of you who have been around for a while + +05:42.600 --> 05:45.600 +might remember that a lot of GUI software for Linux + +05:45.600 --> 05:49.840 +in the 90s was some variant of a shell, + +05:49.840 --> 05:53.720 +like a graphical shell program that just called out + +05:53.720 --> 05:57.160 +to an existing binary on the system. + +05:57.160 --> 05:59.200 +Like you might have a disk formatter, + +05:59.200 --> 06:01.320 +and it lets you has a dropdown for the file + +06:01.320 --> 06:03.400 +and lists your devices and whatever. + +06:03.400 --> 06:04.960 +But it was doing all the work. + +06:04.960 --> 06:06.200 +All it was was the interface. + +06:06.200 --> 06:09.480 +All the work was happening by delegating it to a program. + +06:09.480 --> 06:12.000 +And essentially, what that's doing + +06:12.000 --> 06:16.480 +is that's turning the text user interface, the command line + +06:16.480 --> 06:19.880 +user interface, into an API because you're using a program + +06:19.880 --> 06:22.680 +to talk to it, but it's not really meant for that. + +06:22.680 --> 06:27.400 +And there's a lot of details in that interface that + +06:27.400 --> 06:29.240 +are not stable. + +06:29.240 --> 06:33.480 +Like anyone who's used a Mac after using a Linux machine + +06:33.480 --> 06:37.240 +has probably been surprised that the find command didn't + +06:37.240 --> 06:38.960 +work how they expected. + +06:38.960 --> 06:40.480 +And there's a lot of that. + +06:40.480 --> 06:43.000 +In order to make that stuff really reliable, + +06:43.000 --> 06:47.600 +you end up having to build a lot of special cases into it, + +06:47.600 --> 06:49.680 +but you're doing it at the wrong layer. + +06:49.680 --> 06:51.440 +And what DBUS does is it really lets + +06:51.440 --> 06:55.320 +you have a separate architecture where the service is what + +06:55.320 --> 06:59.200 +encapsulates all of the differences between kernels, + +06:59.200 --> 07:02.280 +distributions, flavors of tooling, + +07:02.280 --> 07:05.440 +and just abstracts all of that and gives you a proper API + +07:05.440 --> 07:06.400 +that you can use. + +07:06.400 --> 07:07.860 +And I think that's great because that + +07:07.860 --> 07:12.600 +lets you build these high-level interactive components + +07:12.600 --> 07:15.320 +at an abstract level where you don't necessarily + +07:15.320 --> 07:17.280 +need to care about the implementation details. + +07:17.280 --> 07:19.480 +I think that's really great. + +07:19.480 --> 07:21.400 +So that's really what was happening there. + +07:21.400 --> 07:23.680 +And when it comes to two-way stuff, + +07:23.680 --> 07:26.480 +it was like a fancy version of Unix pipes. + +07:26.480 --> 07:29.760 +You would run your program, and maybe if you were lucky, + +07:29.760 --> 07:32.360 +it had some sort of machine-readable output + +07:32.360 --> 07:33.960 +switch you could turn on so that you + +07:33.960 --> 07:37.480 +could have a progress bar or something like that. + +07:37.480 --> 07:38.600 +That was the sort of thing. + +07:38.600 --> 07:40.720 +But there wasn't really anything exactly like DBUS. + +07:45.240 --> 07:46.480 +I have another question. + +07:46.480 --> 07:48.360 +Forgive me if this question is silly. + +07:48.360 --> 07:53.320 +Why is everything DBUS prefixed with org dot? + +07:53.320 --> 07:57.800 +Not everything is, but most things are. + +07:57.800 --> 08:00.800 +Those identifiers are reverse FQDN. + +08:00.800 --> 08:03.560 +So if you think about the Java namespaces, + +08:03.560 --> 08:05.960 +that's what they're ripping off there. + +08:05.960 --> 08:09.680 +And it's org because most of it is written by nonprofits. + +08:09.680 --> 08:12.320 +So in particular, Free Desktop is + +08:12.320 --> 08:15.040 +what it sponsors development of DBUS. + +08:15.040 --> 08:17.320 +And so there is an inordinate number + +08:17.320 --> 08:22.480 +of org dot Free Desktop dot whatever services on DBUS + +08:22.480 --> 08:28.480 +just because they build so many of them. + +08:28.480 --> 08:32.680 +In your investigations, do most OS desktop environment window + +08:32.680 --> 08:35.360 +manager interop well over DBUS? + +08:35.360 --> 08:38.160 +Which ones have proven more challenging, if any? + +08:40.960 --> 08:45.280 +I'm not sure I quite understand this question. + +08:45.280 --> 08:49.720 +DBUS is fairly abstract, and those graphical programs + +08:49.720 --> 08:53.360 +can choose to use it or not. + +08:53.360 --> 08:58.440 +But you're not interacting with the desktop environment + +08:58.440 --> 08:59.040 +too much. + +08:59.040 --> 09:01.200 +You're interacting with a service. + +09:01.200 --> 09:03.720 +So what you're doing is you're taking any program + +09:03.720 --> 09:06.520 +and you're breaking it into a client server model. + +09:06.520 --> 09:09.680 +The DBUS service does all of the work, + +09:09.680 --> 09:12.360 +and then there's a graphical environment on top of it. + +09:12.360 --> 09:14.640 +So they're communicating back and forth. + +09:14.640 --> 09:16.320 +And if you want to do those same things, + +09:16.320 --> 09:18.080 +you want to communicate with the service, + +09:18.080 --> 09:22.400 +you don't need to communicate with the actual GUI program + +09:22.400 --> 09:25.000 +unless you want to control the program. + +09:25.000 --> 09:27.240 +If you want to do the same thing the program is doing, + +09:27.240 --> 09:28.680 +you can use a DBUS service. + +09:28.680 --> 09:30.960 +I guess in the case of something like a word processor, + +09:30.960 --> 09:32.720 +you might want to have a DBUS API that + +09:32.720 --> 09:35.720 +lets you add a heading or something like that. + +09:35.720 --> 09:39.160 +That's not an area I've explored too much. + +09:39.160 --> 09:40.760 +So I'm not sure how that works. + +09:40.760 --> 09:42.760 +Work done. + +09:46.120 --> 09:49.080 +Regarding using XWIM as a desktop environment, + +09:49.080 --> 09:55.040 +does XWIM provide a session manager daemon? + +09:55.040 --> 09:57.200 +Whoever wrote that, if you could add some more context, + +09:57.200 --> 09:58.080 +I would appreciate it. + +09:58.080 --> 10:01.000 +I'm not sure I can answer that as it is written. + +10:04.120 --> 10:07.560 +No, I don't know. + +10:07.560 --> 10:08.720 +Next question. + +10:08.720 --> 10:11.600 +There is a lot of criticism against DBUS out there. + +10:11.600 --> 10:13.280 +Why do you think that might be? + +10:13.280 --> 10:15.200 +Well, it's because it's not very good. + +10:18.600 --> 10:21.960 +I mean, I love what it unlocks feature wise, + +10:21.960 --> 10:25.240 +but I do think it is not the best implementation + +10:25.240 --> 10:28.240 +for doing what it does. + +10:28.240 --> 10:31.640 +But when in Rome, you want to do those things, + +10:31.640 --> 10:32.760 +I want to do those things, I don't + +10:32.760 --> 10:34.480 +want to rewrite everything in the way + +10:34.480 --> 10:36.960 +I think it should have been to get it done because I'll never + +10:36.960 --> 10:37.760 +get it done. + +10:37.760 --> 10:39.880 +The whole point is you just shove it in a corner, + +10:39.880 --> 10:41.600 +you don't have to care about it, and you + +10:41.600 --> 10:43.440 +use high level bindings. + +10:43.440 --> 10:46.040 +I would say the specific criticisms I've seen + +10:46.040 --> 10:54.720 +are using XML is something that is not popular these days. + +10:54.720 --> 10:58.260 +And if I had to criticize a thing about it, + +10:58.260 --> 11:02.240 +I would say it doesn't have strong guidelines + +11:02.240 --> 11:03.680 +for how to make a good API. + +11:03.680 --> 11:06.120 +And so the quality of one service to another + +11:06.120 --> 11:09.120 +can be extremely variable. + +11:09.120 --> 11:12.360 +And different services have different ways + +11:12.360 --> 11:14.440 +of doing very similar tasks. + +11:14.440 --> 11:16.960 +So I would love to see, if anything, a little more + +11:16.960 --> 11:19.960 +uniformity in those APIs. + +11:19.960 --> 11:22.840 +I generally could care less that it's sending XML around + +11:22.840 --> 11:23.760 +or whatever. + +11:23.760 --> 11:30.920 +I think people who are offended that XML is being used + +11:30.920 --> 11:37.560 +don't have their hearts in the right place, basically. + +11:37.560 --> 11:45.320 +Which system services come to mind + +11:45.320 --> 11:47.000 +when thinking about applications, + +11:47.000 --> 11:49.760 +be it at the OS desktop environment, window manager + +11:49.760 --> 11:50.440 +level? + +11:50.440 --> 11:53.520 +So the stuff that I am interested in using this for + +11:53.520 --> 11:56.600 +is, like I was saying, connecting to wireless networks, + +11:56.600 --> 11:59.360 +pairing with Bluetooth devices, that kind of stuff. + +11:59.360 --> 12:04.520 +Things that don't have a streamlined way of accomplishing + +12:04.520 --> 12:07.960 +it without using D-Bus and some graphical client. + +12:07.960 --> 12:09.360 +And I would just like to not have + +12:09.360 --> 12:11.360 +to deal with the client end of it. + +12:11.360 --> 12:14.160 +I would like the UI to be in Emacs. + +12:19.720 --> 12:21.160 +When it comes to managing devices, + +12:21.160 --> 12:23.760 +how are D-Bus and U-Dev related? + +12:23.760 --> 12:25.760 +U-Dev is a D-Bus service. + +12:25.760 --> 12:30.520 +So it is a daemon that is running at some point + +12:30.520 --> 12:31.760 +in the background. + +12:31.760 --> 12:33.520 +If it's not running, D-Bus will start it + +12:33.520 --> 12:35.040 +when you send it a message. + +12:35.040 --> 12:42.120 +And I'm sorry, I'm mistaking U-Dev for U-Disks. + +12:42.120 --> 12:46.640 +U-Dev is unrelated to D-Bus. + +12:46.640 --> 12:53.400 +U-Dev is a way of dynamically populating your devices + +12:53.400 --> 12:56.520 +and having triggers that run when they are plugged in + +12:56.520 --> 12:57.600 +or unplugged. + +12:57.600 --> 12:59.840 +They're orthogonal. + +12:59.840 --> 13:02.120 +D-Bus and U-Dev don't interact. + +13:02.120 --> 13:08.520 +But D-Bus, I suspect some of the D-Bus services, like U-Disks, + +13:08.520 --> 13:11.720 +too, probably need to talk to U-Dev in order + +13:11.720 --> 13:13.080 +to do their job. + +13:13.080 --> 13:16.200 +But this is a service by service thing, + +13:16.200 --> 13:27.400 +rather than D-Bus is integrated with U-Dev sort of thing. + +13:27.400 --> 13:29.320 +Skip one of these. + +13:29.320 --> 13:32.200 +If you want to do the kinds of things that D-Bus does, + +13:32.200 --> 13:33.280 +you're limited. + +13:33.280 --> 13:35.880 +What is something D-Bus does that you couldn't do before? + +13:35.880 --> 13:37.520 +What is a really cool use of D-Bus + +13:37.520 --> 13:39.880 +in a modern desktop environment? + +13:39.880 --> 13:43.680 +So again, I think that the hardware and dynamic refresh + +13:43.680 --> 13:47.520 +is the use case that I keep coming back to. + +13:47.520 --> 13:50.760 +You walk somewhere where there's a new Wi-Fi network + +13:50.760 --> 13:52.960 +or there's an open Wi-Fi network to connect to, + +13:52.960 --> 13:55.240 +and maybe you get a notification somewhere. + +13:55.240 --> 13:57.360 +You plug in some hardware and it shows up + +13:57.360 --> 13:59.880 +in some list or some user interface + +13:59.880 --> 14:01.880 +to make it easy to use. + +14:01.880 --> 14:03.600 +You unplug it, it goes away. + +14:03.600 --> 14:05.960 +Those are the things that I think are really interesting + +14:05.960 --> 14:10.600 +because when you use a full blown desktop environment, + +14:10.600 --> 14:14.240 +you have come to expect that kind of interactivity + +14:14.240 --> 14:17.760 +and that kind of integration from the low level + +14:17.760 --> 14:21.760 +of the hardware up to whatever graphical layer you're using. + +14:21.760 --> 14:26.440 +And Emacs doesn't have that, and I want it to have that. + +14:26.440 --> 14:32.000 +So I think that's the thing that D-Bus really gives me. + +14:32.000 --> 14:34.240 +I would say in particular, you plug in hardware + +14:34.240 --> 14:37.240 +and it shows up in a list, that's pretty damn cool. + +14:37.240 --> 14:40.640 +That's a thing that I don't remember seeing done + +14:40.640 --> 14:43.400 +without D-Bus, or the way it was done + +14:43.400 --> 14:47.240 +was not portable and very complicated. + +14:47.240 --> 14:50.320 +D-Bus allows you to build those types of interfaces + +14:50.320 --> 14:53.280 +with a lot less work, and I think that's pretty great. + +14:58.640 --> 14:59.680 +Let's see. + +14:59.680 --> 15:02.040 +As an average GNU slash Linux user, + +15:02.040 --> 15:05.320 +I've used signals and methods before but not properties. + +15:05.320 --> 15:07.600 +You gave an example involving properties, + +15:07.600 --> 15:08.880 +but it kind of flew by. + +15:08.880 --> 15:11.640 +Can you explain briefly what clients and services + +15:11.640 --> 15:13.960 +can do with properties? + +15:13.960 --> 15:20.880 +Sure, so let me share this screen real quick. + +15:20.880 --> 15:26.000 +So just looking at hostname1 because this + +15:26.000 --> 15:28.480 +is a pretty simple and straightforward. + +15:28.480 --> 15:32.920 +Actually, let me look at U disks. + +15:32.920 --> 15:36.720 +So here's a whole mess of disks that are connected, + +15:36.720 --> 15:39.360 +and you can see here's a block device + +15:39.360 --> 15:41.960 +and it has all of these different properties to it. + +15:41.960 --> 15:46.600 +So hit system will say, is this a system device? + +15:46.600 --> 15:48.680 +Is this a fixed device, something + +15:48.680 --> 15:50.400 +that the system is in control of mounting, + +15:50.400 --> 15:53.000 +or is this something that a user might want to interact with? + +15:53.000 --> 15:55.160 +That property is how you're going to know + +15:55.160 --> 15:56.600 +which one of those things are, and I + +15:56.600 --> 15:58.880 +think that's really important when you're building a UI. + +15:58.880 --> 16:00.480 +Maybe you want to hide the system disks + +16:00.480 --> 16:04.280 +because you can see them, but there's not much you can do. + +16:04.280 --> 16:07.440 +I can't unmount my root device without turning the computer + +16:07.440 --> 16:07.960 +off. + +16:07.960 --> 16:11.760 +So the things you might want to do + +16:11.760 --> 16:15.800 +at a graphical interactive level are pretty limited, + +16:15.800 --> 16:19.440 +and that property lets you figure that out. + +16:19.440 --> 16:22.400 +Here's a crypto vacuum device that read only + +16:22.400 --> 16:24.240 +what drives it's associated with. + +16:24.240 --> 16:28.280 +They really bundle up just a lot of metadata about the thing, + +16:28.280 --> 16:31.400 +and they have a lot of links in between the different objects. + +16:31.400 --> 16:36.480 +So looking at one thing, you can connect it up + +16:36.480 --> 16:39.560 +to other parts of it at different levels. + +16:39.560 --> 16:43.440 +There's the notion of a drive, which contains a block device, + +16:43.440 --> 16:45.560 +which can have some partition tables, which + +16:45.560 --> 16:49.200 +can have file systems, or maybe an encryption container that + +16:49.200 --> 16:50.800 +has more of those things. + +16:50.800 --> 16:57.160 +So it's really a tree, but it's a strangely modeled tree + +16:57.160 --> 17:00.880 +where you have to walk the different leaves. + +17:00.880 --> 17:03.200 +It's not a single tree that encapsulates everything. + +17:03.200 --> 17:07.360 +It is a tree of links into other bits of the tree, + +17:07.360 --> 17:07.960 +essentially. + +17:07.960 --> 17:11.920 +So they're important to use for that sort of thing. + +17:16.320 --> 17:17.680 +The other thing that properties do + +17:17.680 --> 17:24.440 +is the signals let you know when a property has been updated. + +17:24.440 --> 17:28.640 +So if your hostname changes, you can + +17:28.640 --> 17:30.600 +get a signal that says, hey, my hostname changed, + +17:30.600 --> 17:32.840 +and maybe give a notice. + +17:32.840 --> 17:35.440 +Or if your active network connection changes + +17:35.440 --> 17:39.320 +or disconnects, a signal is going to be what tells you that, + +17:39.320 --> 17:43.200 +and the change in property is what will drive the signal. + +17:43.200 --> 17:44.840 +So it's kind of related to that. + +17:49.920 --> 17:53.120 +Naive question, me not knowing much about D-Bus. + +17:53.120 --> 17:56.400 +Is there such a thing as a D-Bus reflection browser, + +17:56.400 --> 17:58.280 +maybe Emacs-based, that lets you discover + +17:58.280 --> 18:02.160 +all the behavior different D-Bus app participants provide? + +18:02.160 --> 18:04.160 +And actually, wait, I think you're showing it. + +18:04.160 --> 18:06.320 +Defeat is that. + +18:06.320 --> 18:11.440 +Definitely a to-do item is to build an Emacs Lisp interface + +18:11.440 --> 18:16.520 +that is akin to Defeat, but I have not done that. + +18:16.520 --> 18:17.760 +So pull requests, welcome. + +18:17.760 --> 18:25.920 +Next question, D-Bus seems great for extensibility, + +18:25.920 --> 18:28.240 +but then Emacs has no such mechanism + +18:28.240 --> 18:30.680 +and is fantastically more extensible. + +18:30.680 --> 18:31.960 +Why do you think this is so? + +18:34.680 --> 18:37.840 +I don't think I agree with the premise. + +18:37.840 --> 18:42.400 +D-Bus is not really that extensible in the way + +18:42.400 --> 18:46.560 +that you might think in the same context as Emacs. + +18:46.560 --> 18:49.360 +You can add new functionality by adding a new service, + +18:49.360 --> 18:51.080 +but you can't add new functionality + +18:51.080 --> 18:54.000 +to an existing service without changing it. + +18:54.000 --> 18:57.120 +So I'm not sure I would say that's + +18:57.120 --> 19:01.080 +extensible in the same way, whereas Emacs is very malleable + +19:01.080 --> 19:06.120 +and you can change how it works even while it's running. + +19:06.120 --> 19:12.120 +So I think it's a different kind of extensibility, really. + +19:12.120 --> 19:15.840 +And Emacs can participate on D-Bus, + +19:15.840 --> 19:21.080 +so Emacs has a superset of what D-Bus can do, really. + +19:25.200 --> 19:27.120 +Do you have any other cool D-Bus ideas? + +19:27.120 --> 19:29.480 +I think I have dropped them all. + +19:29.480 --> 19:32.600 +Definitely remote org capture is a thing + +19:32.600 --> 19:34.840 +that I have wanted a couple of times + +19:34.840 --> 19:38.160 +because if I'm browsing around somewhere, + +19:38.160 --> 19:40.520 +I'd really love to have a simple flow that + +19:40.520 --> 19:44.720 +allows me to turn a web page into an org capture. + +19:44.720 --> 19:47.640 +And I think D-Bus could be a good way of accomplishing that, + +19:47.640 --> 19:49.920 +although I haven't messed with the browser integration + +19:49.920 --> 19:50.400 +end of it. + +19:54.640 --> 19:57.920 +Are there buses besides system and session? + +19:57.920 --> 19:59.920 +Is there anything more to a bus besides a way + +19:59.920 --> 20:03.920 +to group objects? + +20:03.920 --> 20:09.920 +There are always at least a system bus and a session bus. + +20:09.920 --> 20:12.760 +And actually, that's maybe not completely true. + +20:12.760 --> 20:15.640 +There's always at least a system bus, session bus + +20:15.640 --> 20:19.800 +as long as there is at least one logged in session. + +20:19.800 --> 20:22.720 +And there's really more than one session bus. + +20:22.720 --> 20:26.800 +There's one bus per session so that you're not leaking stuff + +20:26.800 --> 20:28.880 +across sessions on the same computer + +20:28.880 --> 20:32.960 +because despite this being 2022, Unix + +20:32.960 --> 20:34.840 +is still a multi-user operating system + +20:34.840 --> 20:38.280 +and you have to think about that stuff. + +20:38.280 --> 20:43.640 +There are an unlimited number of D-Bus buses. + +20:43.640 --> 20:47.040 +You can create ones that have limited sets of services. + +20:47.040 --> 20:51.760 +You can connect to ones over a TCP socket. + +20:51.760 --> 20:55.320 +There are always generally at least system and session. + +20:55.320 --> 20:58.360 +There can additionally be other ones. + +20:58.360 --> 21:02.800 +But it is uncommon to have any other bus. + +21:02.800 --> 21:06.080 +Generally, well-behaved D-Bus services + +21:06.080 --> 21:10.000 +will attach to one or the other of those two buses. + +21:10.000 --> 21:13.760 +And in fact, PulseAudio is, it has D-Bus support + +21:13.760 --> 21:16.440 +but it is not a good D-Bus citizen + +21:16.440 --> 21:18.960 +because it does not use the session bus. + +21:18.960 --> 21:22.000 +It has, it's very weird actually. + +21:22.000 --> 21:25.240 +It has a D-Bus plug-in that hooks into the session bus + +21:25.240 --> 21:28.640 +but all it has is a method that returns the path to the Unix + +21:28.640 --> 21:31.560 +socket of the real D-Bus which you then + +21:31.560 --> 21:34.640 +have to connect to separately which strikes me + +21:34.640 --> 21:37.840 +as not the best way of doing that. + +21:41.800 --> 21:43.680 +Cool. + +21:43.680 --> 21:46.840 +All right, I think that is all of the questions. + +21:50.000 --> 21:52.520 +Cool, I think we still have about like six and a half + +21:52.520 --> 21:55.160 +or seven more minutes of Q&A on the stream. + +21:55.160 --> 21:57.920 +So if there are any more questions, folks, + +21:57.920 --> 21:59.480 +please feel free to post them on the pad + +21:59.480 --> 22:03.120 +or come up here, join us on BBB. + +22:03.120 --> 22:06.240 +Yeah, we can hang out here for a little bit longer. + +22:06.240 --> 22:07.960 +The stream will move on at some point + +22:07.960 --> 22:10.960 +but Ian, of course, and anyone else who is interested + +22:10.960 --> 22:14.280 +is welcome to hang out if Ian is around. + +22:14.280 --> 22:15.560 +Yeah. + +22:15.560 --> 22:16.960 +I will be around for a bit. + +22:16.960 --> 22:20.280 +I am on IRC all the time but I'm not always + +22:20.280 --> 22:21.280 +paying attention to it. + +22:21.280 --> 22:23.080 +You're welcome to reach out to me there. + +22:26.680 --> 22:32.160 +This is with almost all of my Emacs packages and stuff. + +22:32.160 --> 22:36.400 +This is in my Emacs Weirdware project on Codeburg. + +22:36.400 --> 22:40.360 +So codeburg.org slash Emacs dash weirdware + +22:40.360 --> 22:45.200 +has everything that I demoed and some other wonderful goodies + +22:45.200 --> 22:49.040 +that maybe you already know about and maybe you don't. + +22:49.040 --> 22:52.280 +I saw one other question from the chat, which + +22:52.280 --> 22:56.720 +is what do you use this for? + +22:56.720 --> 23:01.760 +Well, I mean, the main thing I use it for + +23:01.760 --> 23:07.600 +is discomfort for managing external devices. + +23:07.600 --> 23:13.040 +But this has been a really great research project + +23:13.040 --> 23:20.000 +just to understand D-Bus better, see what it can offer, + +23:20.000 --> 23:26.240 +and write some interesting code because what I really like + +23:26.240 --> 23:31.480 +is writing code that unlocks new possibilities + +23:31.480 --> 23:33.680 +to where people can look at it and say, + +23:33.680 --> 23:35.200 +oh, that gives me a great idea. + +23:35.200 --> 23:36.680 +I want to do this with it. + +23:36.680 --> 23:41.560 +And I see D-Base and this talk as really just pushing + +23:41.560 --> 23:43.360 +mindshare on this stuff. + +23:43.360 --> 23:47.160 +And really, the best result of this talk + +23:47.160 --> 23:50.960 +is for people to come out of it and say, wow, that was awesome. + +23:50.960 --> 23:55.120 +I can't wait to build something with it and go build new stuff. + +23:55.120 --> 23:57.120 +And just kind of building those platforms + +23:57.120 --> 24:00.600 +that other people can use and find helpful + +24:00.600 --> 24:03.120 +in whatever their programming journey is. + +24:03.120 --> 24:05.040 +That's the thing that I really like. + +24:05.040 --> 24:06.040 +That means a lot to me. + +24:06.040 --> 24:09.000 +So I hope that someone watches this + +24:09.000 --> 24:32.360 +and comes away with a good idea and goes and hacks on it. + +24:32.360 --> 24:34.360 +Looks like there's one more question. + +24:34.360 --> 24:38.520 +I'm not sure if we have time. + +24:38.520 --> 24:44.160 +I'll follow up in the pad if we end up over time on that. + +24:44.160 --> 24:45.840 +Yeah, we still have a couple more minutes, + +24:45.840 --> 25:12.480 +so it should be good. + +25:12.480 --> 25:15.040 +OK, so the last question is, it looks + +25:15.040 --> 25:19.400 +like D-Bus is mostly useful for Emacs to do IPC. + +25:19.400 --> 25:20.880 +If I understand correctly, this is + +25:20.880 --> 25:24.440 +how SIGTEX works when working with LaTeX docs. + +25:24.440 --> 25:26.960 +How does it compare with other ways of doing IPC, + +25:26.960 --> 25:29.360 +for example, communicating over a socket with MPD? + +25:32.960 --> 25:36.000 +So the main way that it's different + +25:36.000 --> 25:40.320 +is that MPD has its own protocol that you + +25:40.320 --> 25:46.280 +have to build support for in whatever your client is. + +25:46.280 --> 25:49.800 +D-Bus gives you a single, uniform way + +25:49.800 --> 25:52.520 +of talking to any service. + +25:52.520 --> 25:55.720 +So instead of having to reinvent that socket code + +25:55.720 --> 25:59.080 +and write the protocol support for MPD or whatever else, + +25:59.080 --> 26:02.280 +where you're taking the concrete, what + +26:02.280 --> 26:04.280 +are the bytes over the wire, and building + +26:04.280 --> 26:07.840 +an abstract programming interface that wraps that + +26:07.840 --> 26:12.360 +and drives those things, D-Bus already provides all of that. + +26:12.360 --> 26:15.240 +So you can say, here's a description of everything + +26:15.240 --> 26:18.760 +that I already do, and you can code gen stuff + +26:18.760 --> 26:20.800 +to do all of it. + +26:20.800 --> 26:24.840 +So I think that's the main difference between them. + +26:24.840 --> 26:26.840 +But it is over a socket. + +26:26.840 --> 26:31.040 +It's over a Unix socket for local stuff, TCP for remote. + +26:31.040 --> 26:33.000 +It is very similar. + +26:33.000 --> 26:34.480 +The main difference is that it is + +26:34.480 --> 26:37.080 +a framework for multiple applications + +26:37.080 --> 26:39.960 +rather than an application-specific mechanism, + +26:39.960 --> 26:42.200 +which makes it very easy to reuse + +26:42.200 --> 26:43.880 +in a variety of different contexts. + +26:43.880 --> 26:46.520 +And I think that's been key to its popularity + +26:46.520 --> 26:49.240 +over the last 10 years or so is the fact + +26:49.240 --> 26:52.880 +that it provides just enough opinion about how stuff should + +26:52.880 --> 26:56.400 +work that you don't have to think too hard about what + +26:56.400 --> 26:57.600 +should the protocol be. + +26:57.600 --> 26:58.640 +Should it be binary? + +26:58.640 --> 26:59.560 +Should it be text? + +26:59.560 --> 27:01.520 +Should it be S expressions? + +27:01.520 --> 27:02.640 +Should it be JSON? + +27:02.640 --> 27:05.080 +It's already done for you, and you can just think about, + +27:05.080 --> 27:06.880 +how do I connect it up? + +27:06.880 --> 27:08.840 +And I think that provides a lot of value. + +27:12.280 --> 27:14.440 +Yeah, and I can second that. + +27:14.440 --> 27:16.520 +It's been adopted by all sorts of different software + +27:16.520 --> 27:19.040 +projects, one of which I worked on. + +27:19.040 --> 27:21.560 +Jammy, people might know, GNU package + +27:21.560 --> 27:23.760 +for basically universal communication. + +27:23.760 --> 27:27.280 +It's basically a text messaging and also audio video calling + +27:27.280 --> 27:28.680 +and conferencing application. + +27:28.680 --> 27:31.400 +And it's Daemon, which runs in the background. + +27:31.400 --> 27:34.800 +It also supports D-Bus, so you can do all sorts of things, + +27:34.800 --> 27:38.280 +write little Python scripts or whatever, + +27:38.280 --> 27:40.480 +talk with it through D-Bus, give it commands + +27:40.480 --> 27:43.560 +to take calls from a particular point + +27:43.560 --> 27:46.920 +or just hang up calls or just do all sorts of things + +27:46.920 --> 27:48.080 +over D-Bus. + +27:48.080 --> 27:51.640 +And it is all, like you said, sort of application agnostic. + +27:51.640 --> 27:53.920 +It's not specific to, oh, how would I + +27:53.920 --> 27:58.520 +do this in a different way for each individual application? + +27:58.520 --> 27:59.200 +Yeah, exactly. + +27:59.200 --> 28:02.080 +It's the de facto way of doing that sort of stuff + +28:02.080 --> 28:04.680 +on Linux machines these days. + +28:04.680 --> 28:09.920 +And you can look back to some of the other message passing + +28:09.920 --> 28:13.920 +stuff in Windows and see it's drawn some inspiration + +28:13.920 --> 28:18.480 +from a variety of different places and different ways + +28:18.480 --> 28:21.560 +of doing that kind of interactivity. + +28:21.560 --> 28:24.080 +But it is, I mean, I don't think there was ever + +28:24.080 --> 28:26.240 +really a serious competitor to it, + +28:26.240 --> 28:28.080 +but it is the de facto standard if you + +28:28.080 --> 28:31.960 +want to do any kind of graphical program that + +28:31.960 --> 28:36.960 +manipulates your system or a batch program that + +28:36.960 --> 28:41.120 +drives an otherwise purely interactive graphical program. + +28:41.120 --> 28:42.720 +That's the tool. + +28:42.720 --> 28:47.880 +And there is not really any competitive landscape or reason + +28:47.880 --> 28:50.720 +to go reinventing it at this time. + +28:50.720 --> 28:51.480 +Sounds good. + +28:51.480 --> 28:52.760 +And I think that's all the time that we + +28:52.760 --> 28:53.720 +have on the live stream. + +28:53.720 --> 28:55.840 +Folks, you are welcome to stick around on IRC + +28:55.840 --> 28:58.160 +or come here on BBB and continue talking to Ian. + +28:58.160 --> 28:59.560 +Thank you, Ian. + +28:59.560 --> 29:00.080 +Wonderful. + +29:00.080 --> 29:01.240 +Thank you so much. + +29:01.240 --> 29:02.240 +Cheers. + +29:11.560 --> 29:12.040 +All right. + +29:12.040 --> 29:13.880 +I think the stream has moved on. + +29:13.880 --> 29:15.960 +Yeah, you're welcome to stay here, Ian, if you like, + +29:15.960 --> 29:18.080 +or just continue catching up with folks in IRC. + +29:20.840 --> 29:21.320 +Great. + +29:21.320 --> 29:22.960 +I will hang out here for a little bit + +29:22.960 --> 29:28.360 +in case someone wants to jump in and just write + +29:28.360 --> 29:30.560 +some stuff in the pad. + +29:30.560 --> 29:31.360 +Sounds good. + +29:31.360 --> 29:31.880 +Thank you. + +29:31.880 --> 29:34.680 +And I do see people are still writing or posting on the pad, + +29:34.680 --> 29:35.600 +so that's awesome. + +29:35.600 --> 29:36.720 +Yeah, sure thing. + +29:36.720 --> 29:37.240 +Awesome. + +29:37.240 --> 29:38.120 +Thank you so much. + +29:38.120 --> 29:38.600 +All right. + +29:38.600 --> 29:38.960 +Cheers. + +29:38.960 --> 29:39.480 +Welcome. + +29:39.480 --> 29:41.480 +And yeah, see you around on IRC. + +29:41.480 --> 29:42.880 +All right. + +29:42.880 --> 30:11.440 +All right. + |