1 00:00:01,583 --> 00:00:03,870 Now for this module, 2 00:00:03,870 --> 00:00:07,939 I got another demo application which you find attached. 3 00:00:07,939 --> 00:00:11,020 And this application actually consists 4 00:00:11,020 --> 00:00:15,690 of three different back end APIs which will work together. 5 00:00:15,690 --> 00:00:19,070 Three different containers in the end. 6 00:00:19,070 --> 00:00:21,530 it's a Node.js application 7 00:00:21,530 --> 00:00:23,870 and you can definitely dive into the code. 8 00:00:23,870 --> 00:00:26,840 But it will just be a dummy application. 9 00:00:26,840 --> 00:00:29,140 We have this auth API, 10 00:00:29,140 --> 00:00:32,930 which in the end is dealing with verifying tokens 11 00:00:32,930 --> 00:00:36,743 and generating tokens for authenticated users. 12 00:00:37,610 --> 00:00:39,530 We got the users API, 13 00:00:39,530 --> 00:00:44,240 which is dealing with creating users and logging users in 14 00:00:44,240 --> 00:00:47,300 and all of that happens in a dummy mode. 15 00:00:47,300 --> 00:00:49,280 I'm not using a database here, 16 00:00:49,280 --> 00:00:51,380 I'm not storing data in files, 17 00:00:51,380 --> 00:00:54,900 we're just working with dummy data which is not stored. 18 00:00:54,900 --> 00:00:58,330 Because this module is not about storing data. 19 00:00:58,330 --> 00:01:01,980 It's about connecting these different services. 20 00:01:01,980 --> 00:01:04,780 And indeed this user is API 21 00:01:04,780 --> 00:01:08,880 will eventually reach out to this auth service here, 22 00:01:08,880 --> 00:01:11,900 to for example, get this token 23 00:01:11,900 --> 00:01:16,120 which is generated when a user is logging in for example. 24 00:01:16,120 --> 00:01:18,310 And then we get this tasks API, 25 00:01:18,310 --> 00:01:22,230 it's another very straightforward Node.js application. 26 00:01:22,230 --> 00:01:25,460 And in there, we basically can return a list 27 00:01:25,460 --> 00:01:29,400 of stored tasks and we can store a new task. 28 00:01:29,400 --> 00:01:32,690 And indeed, this will be stored in a file, 29 00:01:32,690 --> 00:01:36,010 which still only acts as a dummy storage Of course. 30 00:01:36,010 --> 00:01:39,640 A database would be a better storage in reality 31 00:01:39,640 --> 00:01:41,870 but again it's not about the storage. 32 00:01:41,870 --> 00:01:45,960 But instead this API also actually will receive 33 00:01:45,960 --> 00:01:49,400 a token, which identifies a logged in user. 34 00:01:49,400 --> 00:01:51,380 And therefore it will also reach out 35 00:01:51,380 --> 00:01:55,273 to this auth API to verify this token. 36 00:01:56,250 --> 00:02:00,370 So here's the general structure of our demo application. 37 00:02:00,370 --> 00:02:03,510 We have these free Node.js APIs, 38 00:02:03,510 --> 00:02:06,370 which will be in a cluster. 39 00:02:06,370 --> 00:02:09,509 And the users API for example, 40 00:02:09,509 --> 00:02:12,120 talks to the auth API. 41 00:02:12,120 --> 00:02:14,840 When we send the request to the users API 42 00:02:14,840 --> 00:02:16,660 to create a new user, 43 00:02:16,660 --> 00:02:19,970 the users API will talk to the auth API 44 00:02:19,970 --> 00:02:22,940 to generate a token for that user. 45 00:02:22,940 --> 00:02:26,640 These two containers the auth and users API, 46 00:02:26,640 --> 00:02:28,670 each runs in their own container 47 00:02:28,670 --> 00:02:31,420 will actually be created in the same pod. 48 00:02:31,420 --> 00:02:34,930 At least at the beginning of this course module. 49 00:02:34,930 --> 00:02:38,640 And we'll have pod-internal communication here 50 00:02:38,640 --> 00:02:40,950 because the auth API will actually 51 00:02:40,950 --> 00:02:44,550 not be reached from outside the cluster 52 00:02:44,550 --> 00:02:48,740 but only from inside that first pod. 53 00:02:48,740 --> 00:02:51,860 And the tasks API will run in another pod. 54 00:02:51,860 --> 00:02:54,360 And both pods will actually be reachable 55 00:02:54,360 --> 00:02:56,020 from the outside world. 56 00:02:56,020 --> 00:02:57,500 But as I just mentioned, 57 00:02:57,500 --> 00:03:01,180 the auth API will actually not directly be reached, 58 00:03:01,180 --> 00:03:03,157 it will not directly handle the requests 59 00:03:03,157 --> 00:03:04,980 from the outside world. 60 00:03:04,980 --> 00:03:07,290 Instead, only the users API will 61 00:03:07,290 --> 00:03:10,000 and will have this pod-internal communication 62 00:03:10,000 --> 00:03:11,473 in that pod then. 63 00:03:12,400 --> 00:03:14,390 Now this will not be the final picture 64 00:03:14,390 --> 00:03:17,310 we're going to refine it throughout this module. 65 00:03:17,310 --> 00:03:19,290 But that's what we're going to start with 66 00:03:19,290 --> 00:03:23,870 and actually, I'm going to start with an even simpler setup. 67 00:03:23,870 --> 00:03:26,920 I just wanna start with the users API, 68 00:03:26,920 --> 00:03:30,550 for the moment not communicate with the auth API 69 00:03:30,550 --> 00:03:34,330 and just ensure that the users API is able 70 00:03:34,330 --> 00:03:36,890 to handle incoming requests. 71 00:03:36,890 --> 00:03:39,860 Now before we translate this into Kubernetes, 72 00:03:39,860 --> 00:03:43,030 you can absolutely play around with this API 73 00:03:43,030 --> 00:03:45,330 because I do provide Docker files 74 00:03:45,330 --> 00:03:47,723 and a Docker compose file already. 75 00:03:48,700 --> 00:03:52,830 So of course you can run Docker compose up -d --build 76 00:03:52,830 --> 00:03:55,050 and this application will be built 77 00:03:55,050 --> 00:03:56,530 the images will be built 78 00:03:56,530 --> 00:03:59,030 and these free containers will be startup. 79 00:03:59,030 --> 00:04:01,403 And all the code should already work then. 80 00:04:02,610 --> 00:04:05,660 And you could then use postman to send the request 81 00:04:05,660 --> 00:04:09,270 to localhost 8080/login for example, 82 00:04:09,270 --> 00:04:12,610 with some dummy email and password body data. 83 00:04:12,610 --> 00:04:15,510 And that would reach the users API 84 00:04:15,510 --> 00:04:20,130 which is listening on this port 8080 85 00:04:20,130 --> 00:04:22,280 and that's the port I mapping here 86 00:04:22,280 --> 00:04:24,590 in the Docker compose file too 87 00:04:24,590 --> 00:04:28,290 and then for the log in requests which are just sent here. 88 00:04:28,290 --> 00:04:30,300 This will then indeed, 89 00:04:30,300 --> 00:04:33,260 extract email and password briefly verify it 90 00:04:33,260 --> 00:04:34,660 in a very simple way. 91 00:04:34,660 --> 00:04:37,820 And then reach out to the auth API 92 00:04:37,820 --> 00:04:40,650 to actually send my password there 93 00:04:40,650 --> 00:04:43,400 and a hashed version of the password 94 00:04:43,400 --> 00:04:45,980 of course just using some dummy hashing data. 95 00:04:45,980 --> 00:04:48,460 And then we'll get back a token 96 00:04:48,460 --> 00:04:51,730 which is actually sent back with the response 97 00:04:51,730 --> 00:04:55,691 and that's the token you see here in the response. 98 00:04:55,691 --> 00:04:58,260 Now you can also try sending a request 99 00:04:58,260 --> 00:05:01,470 to the auth API directly and this will fail 100 00:05:01,470 --> 00:05:04,840 because it's not exposed publicly in this setup, 101 00:05:04,840 --> 00:05:07,530 only other containers are able to talk to it. 102 00:05:07,530 --> 00:05:11,200 And you can try fetching tasks initially that fails 103 00:05:11,200 --> 00:05:14,700 but if you do store a new task by sending a post request 104 00:05:14,700 --> 00:05:18,250 to localhost 80/tasks with a body 105 00:05:18,250 --> 00:05:20,790 that contains a text and a title. 106 00:05:20,790 --> 00:05:23,500 If you do that then this task will be stored 107 00:05:23,500 --> 00:05:25,820 and there after if you send a get request 108 00:05:25,820 --> 00:05:28,100 to localhost 8002 tasks 109 00:05:28,100 --> 00:05:30,083 you can see that task here. 110 00:05:32,850 --> 00:05:35,400 Now whenever you run Docker compose down, 111 00:05:35,400 --> 00:05:36,920 all the data will be lost 112 00:05:36,920 --> 00:05:39,070 because I'm not using volumes here. 113 00:05:39,070 --> 00:05:41,070 Because again, the data storage 114 00:05:41,070 --> 00:05:43,500 is not the thing I wanna focus on here. 115 00:05:43,500 --> 00:05:47,380 Instead it's the container and service interaction. 116 00:05:47,380 --> 00:05:49,082 Now Feel free to dive deeper into the code 117 00:05:49,082 --> 00:05:52,120 and play around with that a little bit. 118 00:05:52,120 --> 00:05:55,420 But for the moment, I will actually not do that. 119 00:05:55,420 --> 00:05:57,610 I will run Docker compose down 120 00:05:57,610 --> 00:06:00,830 because of course I don't wanna use Docker compose here 121 00:06:00,830 --> 00:06:03,620 instead the goal is to use Kubernetes. 122 00:06:03,620 --> 00:06:05,380 And that's what we're going to get started 123 00:06:05,380 --> 00:06:07,647 with in the next lecture therefore.