1 00:00:00,690 --> 00:00:07,530 Hi and welcome to a new section in this course in this section, I'm going to talk about Mukti. 2 00:00:07,710 --> 00:00:10,110 I'm going to give you a quick introduction to that. 3 00:00:10,110 --> 00:00:11,490 You know what it's all about. 4 00:00:11,770 --> 00:00:16,620 And then in the next two lectures in this section, I'll show you how to install it on your Raspberry 5 00:00:16,620 --> 00:00:20,100 Pi and run a few simple experiments with it. 6 00:00:20,760 --> 00:00:25,590 So let's get started with a description of al Qaeda terror. 7 00:00:26,100 --> 00:00:32,910 Al Qaeda terror is a lightweight publish subscribe messaging protocol. 8 00:00:33,270 --> 00:00:38,370 It's built to be very easy to use and also very light on resources. 9 00:00:38,670 --> 00:00:44,520 And because of this, it has been very successful in the world of the Internet of Things. 10 00:00:44,910 --> 00:00:50,640 As you'll see in this section, there's only a few things that you need to know about and quiddity and 11 00:00:50,640 --> 00:00:52,840 you'll be able to use it within minutes. 12 00:00:53,220 --> 00:00:59,970 Compare that to various other protocols and you'll see that it is actually an amazing technology to 13 00:00:59,970 --> 00:01:00,920 be able to use. 14 00:01:01,440 --> 00:01:05,030 So it's paradigm is very simple. 15 00:01:05,460 --> 00:01:12,930 There is a broker which is depicted in this slide with the large box in the middle and then you've got 16 00:01:12,930 --> 00:01:13,670 a publisher. 17 00:01:13,680 --> 00:01:18,600 In this case, I've got a sensor that is sending a temperature update to the broker. 18 00:01:19,230 --> 00:01:23,550 You can have many publishers sending all sorts of data to the broker. 19 00:01:23,580 --> 00:01:25,320 It can be a single number. 20 00:01:25,320 --> 00:01:31,980 It could be text, it could be a whole Jason document or it could be a comma delimited line. 21 00:01:32,520 --> 00:01:36,770 Anything at all really can be sent as a message to the broker. 22 00:01:37,170 --> 00:01:39,990 On the other side, you've got subscribers. 23 00:01:40,110 --> 00:01:46,890 So subscribers are clients that want to read values that publishers are publishing to the broker. 24 00:01:47,520 --> 00:01:52,020 Now, a publisher and a subscriber don't need to know anything about each other. 25 00:01:52,320 --> 00:01:56,370 They actually are totally anonymous and they don't interact with each other at all. 26 00:01:56,640 --> 00:02:03,840 Everything happens via the broker, and the broker is responsible for managing the propagation of data 27 00:02:03,990 --> 00:02:06,720 from publishers to the subscribers. 28 00:02:07,830 --> 00:02:11,850 Now let's have a look at how we'll use it in our project. 29 00:02:12,390 --> 00:02:19,110 In the large books with the rounded corners in this slide is our Raspberry Pi, and in it you have already 30 00:02:19,110 --> 00:02:21,210 installed the Madrid server. 31 00:02:21,600 --> 00:02:24,990 Alongside of it will install the mosquito. 32 00:02:24,990 --> 00:02:33,420 Broca and Mosquito is an open source technology and it's implemented by many different types of brokers. 33 00:02:33,420 --> 00:02:39,090 Think of a broker as a server for this particular technology, for this particular protocol. 34 00:02:39,360 --> 00:02:43,170 And mosquito is and also open source implementation. 35 00:02:43,170 --> 00:02:44,640 Just like node read. 36 00:02:45,030 --> 00:02:46,950 It is very, very popular. 37 00:02:46,950 --> 00:02:53,850 It is very light on resources, which is what I like about it in relation to our project and installing 38 00:02:53,850 --> 00:02:57,720 it on Raspberry Pi and as you'll see, is very easy to use. 39 00:02:57,990 --> 00:02:59,490 Muskett is not one thing. 40 00:02:59,490 --> 00:03:03,780 It's an installation that comes with a couple of different tools, the Seabrooke itself. 41 00:03:03,780 --> 00:03:08,010 And then there's the publisher and the subscriber clients as well. 42 00:03:08,010 --> 00:03:11,400 And I'll show you how to use those on the left side. 43 00:03:11,400 --> 00:03:14,460 We've got the publisher and subscribers. 44 00:03:14,460 --> 00:03:23,040 In this case, it's the ESB 32, so we'll have an ISP 32 and on it will run a simple sketch that is 45 00:03:23,040 --> 00:03:32,490 making use of an entity compatible library to both publish and subscribe to topics on the integrated 46 00:03:32,490 --> 00:03:33,090 Broca. 47 00:03:34,350 --> 00:03:40,920 I mentioned the word topic a couple of times, so let's have a look at what a topic is in the context 48 00:03:40,920 --> 00:03:46,290 of an quiddity topic is like a Eurail or like an address. 49 00:03:46,950 --> 00:03:54,090 A publisher will publish its data to a specific topic and then on the other side, subscribers would 50 00:03:54,090 --> 00:04:01,920 subscribe to a topic to get updates from the broker with any new data published from a publisher to 51 00:04:01,920 --> 00:04:03,390 that specific topic. 52 00:04:03,780 --> 00:04:10,080 So you can see here in this example, I've got a broker depicted with the large yellow box, and there 53 00:04:10,080 --> 00:04:16,170 are multiple topics that I'm actually using in our project in this project right here. 54 00:04:16,470 --> 00:04:22,820 It can see the project uses Slasher's to allow us to create multi levels. 55 00:04:22,820 --> 00:04:27,480 So, for example, I've got take expressions for terrarium and then below terrarium. 56 00:04:27,780 --> 00:04:33,780 I've got individual topics for air temperature control, whether the pump should be on or off, air 57 00:04:33,780 --> 00:04:35,940 humidity and so on. 58 00:04:36,750 --> 00:04:41,760 It's possible to also use wildcards for the subscriber's in particular. 59 00:04:41,760 --> 00:04:49,080 And for example, you can have a subscriber to subscribe to to take expression's for terrarium, for 60 00:04:49,080 --> 00:04:53,940 slash hash, for example, which hash is the wild card here. 61 00:04:53,940 --> 00:04:59,880 And then it will automatically subscribe this, subscribe to everything below. 62 00:05:00,070 --> 00:05:06,550 The terrorism level, in the end of this lecture, I'll give you pointers to documentation to talk more 63 00:05:06,550 --> 00:05:12,870 about both topics and wild cards immediately. 64 00:05:12,880 --> 00:05:16,930 It's also possible to set quality of service levels. 65 00:05:16,930 --> 00:05:23,440 And there are three levels in terms of quality of service that indicated to support the latest version 66 00:05:23,440 --> 00:05:25,390 of it here, which is television five. 67 00:05:25,990 --> 00:05:33,790 In most cases, we are satisfied with level zero of quality of service where the broker or the client 68 00:05:34,030 --> 00:05:37,640 will deliver the message just once without any confirmation. 69 00:05:37,930 --> 00:05:44,530 You also have level one where the broker or client will deliver the message at least once with confirmation. 70 00:05:44,830 --> 00:05:51,100 And then level two is where the broker and client will deliver the message exactly once by using a Forestier 71 00:05:51,100 --> 00:05:51,610 pancake. 72 00:05:51,660 --> 00:05:56,380 So it's the most reliable way of passing on messages to a client. 73 00:05:56,920 --> 00:06:05,950 And you can assign a quality of service to the broker, but also the client can request a specific quality 74 00:06:05,950 --> 00:06:07,750 of service from the broker. 75 00:06:08,290 --> 00:06:09,220 And you can sit at the bottom. 76 00:06:09,220 --> 00:06:14,830 I've got a source, a euro, where you can find more information about quality of service. 77 00:06:16,570 --> 00:06:22,270 There's not much more to it, so I'm about to conclude this lecture, there's three things that I wanted 78 00:06:22,270 --> 00:06:25,820 you to remember coming out of this lecture in particular. 79 00:06:26,200 --> 00:06:31,960 So first, in general, a broker will receive a message from a publisher and immediately forwarded to 80 00:06:31,960 --> 00:06:32,860 subscribers. 81 00:06:33,160 --> 00:06:34,730 It will not store it. 82 00:06:34,750 --> 00:06:40,830 So essentially, a broker is just forward and forget there's no storage mechanism, at least in general. 83 00:06:40,840 --> 00:06:47,170 It is possible, though, to configure storage if needed in order to improve persistence. 84 00:06:47,530 --> 00:06:50,310 But we're not going to be doing that in this project. 85 00:06:50,530 --> 00:06:57,970 We are going to go with the default way off and quiddity propagation of messages without storage. 86 00:06:59,080 --> 00:07:05,920 A mentioned thing number two in the previous lecture as well, it is possible for a publisher to send 87 00:07:05,920 --> 00:07:10,360 a message to topic at a different quality of service to our subscriber. 88 00:07:10,690 --> 00:07:18,340 So publishers and subscribers are free to set their own quality of service level with the broker, and 89 00:07:18,340 --> 00:07:21,290 they're not bound by their individual settings. 90 00:07:21,310 --> 00:07:29,230 Remember earlier I said that quiddity publishers and subscribers are totally independent and there's 91 00:07:29,230 --> 00:07:31,170 no way for one to influence the other. 92 00:07:31,480 --> 00:07:35,290 The broker sits right in the middle and keeps them separate. 93 00:07:36,450 --> 00:07:42,060 And number three thing, which is something that I've also mentioned earlier, is that immediately topics 94 00:07:42,060 --> 00:07:44,830 can contain wild cards. 95 00:07:45,060 --> 00:07:47,030 There are two wild cards in empty kitty. 96 00:07:47,230 --> 00:07:48,150 It's a plus. 97 00:07:48,300 --> 00:07:56,550 And the sharp wild card, the plus sign is used as a wild card for a single level of hierarchy, and 98 00:07:56,550 --> 00:08:01,230 the sharp one can be used as a wild card for all remaining levels of hierarchy. 99 00:08:01,230 --> 00:08:04,350 So you put it in the end of a topic. 100 00:08:04,740 --> 00:08:12,240 So again, have a look at the documentation there in the Mosquito Dog website, where you see examples 101 00:08:12,240 --> 00:08:14,400 of how those wild cards can be used. 102 00:08:15,630 --> 00:08:19,980 And finally here, I've got some suggested readings, definitely. 103 00:08:20,400 --> 00:08:24,000 And dog and mosquito, a tautology. 104 00:08:24,350 --> 00:08:30,890 The two required readings not just suggested, but required readings for Makatea team. 105 00:08:31,260 --> 00:08:34,530 Let me show you really quickly a couple of pages that you should look at. 106 00:08:35,310 --> 00:08:38,230 First is the dog website. 107 00:08:38,250 --> 00:08:45,260 This is where all the official announcement from the people that work on he published. 108 00:08:45,270 --> 00:08:51,990 So as you can see, the latest one is back in 2019 in relation to the publication of EMCDDA to version 109 00:08:51,990 --> 00:08:52,600 five. 110 00:08:53,310 --> 00:08:55,860 There's also a wiki right here. 111 00:08:55,860 --> 00:09:00,210 You can access the Wiki and have a look at the information that is published here, including things 112 00:09:00,210 --> 00:09:03,080 such as basic concepts and design principles. 113 00:09:03,300 --> 00:09:06,760 There's a very short documents well worth spending a few minutes to look at. 114 00:09:07,530 --> 00:09:10,740 I also find that the muscular website is very, very useful. 115 00:09:10,740 --> 00:09:19,060 And you can see here that the manual page of the main page contains a synopsis of it. 116 00:09:21,580 --> 00:09:29,560 The military manual page contains concise information about topics you can see examples of topics and 117 00:09:29,560 --> 00:09:37,710 how the wild card characters can be used and as well as information about quality of service and a few 118 00:09:37,720 --> 00:09:41,260 other bits and pieces that, in my opinion, it is for our project of secondary. 119 00:09:41,290 --> 00:09:47,920 For example, there's the concept of wheels that is available in it, but we're not going to worry about 120 00:09:47,920 --> 00:09:48,400 it at all. 121 00:09:49,150 --> 00:09:51,700 So take a few minutes to have a look at this documentation. 122 00:09:51,700 --> 00:09:57,940 And when you are ready, go on to the next lecture where I'll show you how to install a continuous kit 123 00:09:57,940 --> 00:09:59,470 of broke out on the Raspberry Pi.