1 00:00:02,180 --> 00:00:04,490 So let's create our first container. 2 00:00:04,490 --> 00:00:06,180 And let's get our hands dirty, 3 00:00:06,180 --> 00:00:09,040 even though I will say right away that at this point, 4 00:00:09,040 --> 00:00:11,840 we're not going to understand everything here. 5 00:00:11,840 --> 00:00:13,960 We're just going to write some code, 6 00:00:13,960 --> 00:00:15,310 and bring up a container, 7 00:00:15,310 --> 00:00:17,890 and we're going to understand all the details 8 00:00:17,890 --> 00:00:20,660 a little bit later in the next core section. 9 00:00:20,660 --> 00:00:23,740 I just wanna immediately get something up and running, 10 00:00:23,740 --> 00:00:26,550 we also have this example to validate 11 00:00:26,550 --> 00:00:29,190 that everything is working as it should. 12 00:00:29,190 --> 00:00:31,900 So here's the example, you'll find it attached. 13 00:00:31,900 --> 00:00:34,830 It's a very simple Node.js application. 14 00:00:34,830 --> 00:00:36,170 And by the way, 15 00:00:36,170 --> 00:00:38,990 I just wanna highlight, it's just an example. 16 00:00:38,990 --> 00:00:42,330 You don't need to know Node.js for this course. 17 00:00:42,330 --> 00:00:44,700 You can follow along, even if you don't know it, 18 00:00:44,700 --> 00:00:48,180 because we're not going to write any Node.js code. 19 00:00:48,180 --> 00:00:50,900 You can use Docker for any programming language 20 00:00:50,900 --> 00:00:53,843 and any project and application 21 00:00:53,843 --> 00:00:55,870 written with any technologies of your choice. 22 00:00:55,870 --> 00:00:58,250 What you learn in this course will apply. 23 00:00:58,250 --> 00:00:59,540 It's just an example, 24 00:00:59,540 --> 00:01:02,010 because I have to pick some programming language 25 00:01:02,010 --> 00:01:04,000 for the example in the end. 26 00:01:04,000 --> 00:01:08,160 So this is a Node.js application with some basic dummy code. 27 00:01:08,160 --> 00:01:09,000 And in the end, 28 00:01:09,000 --> 00:01:12,210 this will start up a web server on port 3000, 29 00:01:13,366 --> 00:01:17,770 which will listen to get requests on no particular path. 30 00:01:17,770 --> 00:01:21,080 And we'll then send back some dummy HTML. 31 00:01:21,080 --> 00:01:24,180 I also got this dummy database connection code, 32 00:01:24,180 --> 00:01:25,890 which doesn't really connect, 33 00:01:25,890 --> 00:01:28,700 but just set a timer of one second, 34 00:01:28,700 --> 00:01:31,400 until these servers launched in the end. 35 00:01:31,400 --> 00:01:33,190 And I'm having this here so that we have 36 00:01:33,190 --> 00:01:35,680 a top level await example, 37 00:01:35,680 --> 00:01:37,530 which is a Node.js feature 38 00:01:37,530 --> 00:01:40,260 for working with asynchronous code, 39 00:01:40,260 --> 00:01:45,260 which only works if you use Node.js version 14.3 or higher. 40 00:01:45,840 --> 00:01:47,860 So this is the Node.js code. 41 00:01:47,860 --> 00:01:50,140 If we would want to run it locally, 42 00:01:50,140 --> 00:01:52,770 without Docker and without containers, 43 00:01:52,770 --> 00:01:56,850 we would have to visit nodejs.org and then download that 44 00:01:56,850 --> 00:01:58,800 latest version of Node.js, 45 00:01:58,800 --> 00:02:01,540 whichever version that is when you're watching this. 46 00:02:01,540 --> 00:02:03,970 Walk through the installer that gives you, 47 00:02:03,970 --> 00:02:07,060 and then open up a new terminal, 48 00:02:07,060 --> 00:02:10,160 and then run this app mjs file. 49 00:02:10,160 --> 00:02:12,640 By running node app.mjs. 50 00:02:12,640 --> 00:02:14,660 And actually before we do that, 51 00:02:14,660 --> 00:02:16,700 we would have to run another command, 52 00:02:16,700 --> 00:02:20,290 npm install, which installs all dependencies 53 00:02:20,290 --> 00:02:22,510 listed here in packaged.json, 54 00:02:22,510 --> 00:02:24,870 which are simply third-party packages 55 00:02:24,870 --> 00:02:28,200 this app mjs file needs to work correctly. 56 00:02:28,200 --> 00:02:30,600 Again, if that all doesn't tell you too much, 57 00:02:30,600 --> 00:02:32,000 that's no problem here. 58 00:02:32,000 --> 00:02:35,440 These are the steps we just would have to execute, 59 00:02:35,440 --> 00:02:37,880 if we would want to run this code here 60 00:02:37,880 --> 00:02:40,140 locally on our machine. 61 00:02:40,140 --> 00:02:43,150 However, the idea with Docker was a different one. 62 00:02:43,150 --> 00:02:45,450 We want to run this code in a container. 63 00:02:45,450 --> 00:02:47,300 And for that, we first of all, 64 00:02:47,300 --> 00:02:49,420 need to create a so-called image, 65 00:02:49,420 --> 00:02:52,300 because containers are always based on images. 66 00:02:52,300 --> 00:02:54,130 And you're going to learn more about that 67 00:02:54,130 --> 00:02:56,720 and this relation between image and container 68 00:02:56,720 --> 00:02:59,010 in the next course section. 69 00:02:59,010 --> 00:03:01,590 For the moment to create such an image, 70 00:03:01,590 --> 00:03:03,950 we simply create a Docker file, 71 00:03:03,950 --> 00:03:06,900 so a file which is simply named Docker file 72 00:03:06,900 --> 00:03:08,500 without any extension. 73 00:03:08,500 --> 00:03:11,040 And in here, we now describe to Docker, 74 00:03:11,040 --> 00:03:14,380 how our container in the end should be set up. 75 00:03:14,380 --> 00:03:18,150 And we do this by adding a couple of instructions. 76 00:03:18,150 --> 00:03:19,870 Now, since we are going to dive 77 00:03:19,870 --> 00:03:22,540 into images and containers in greater detail 78 00:03:22,540 --> 00:03:24,080 in the next section, 79 00:03:24,080 --> 00:03:25,690 I don't want to waste your time 80 00:03:25,690 --> 00:03:27,030 with a bunch of instructions, 81 00:03:27,030 --> 00:03:29,420 which we don't fully understand yet. 82 00:03:29,420 --> 00:03:32,970 So instead attached to find a finished Docker file, 83 00:03:32,970 --> 00:03:36,150 which in the end just has a couple of instructions 84 00:03:36,150 --> 00:03:39,940 that we want to use Node.js as a base image 85 00:03:39,940 --> 00:03:42,870 so that we want to have Node.js available 86 00:03:42,870 --> 00:03:44,367 inside of our container, 87 00:03:44,367 --> 00:03:46,810 that we have a certain directory 88 00:03:46,810 --> 00:03:48,860 in the container file system. 89 00:03:48,860 --> 00:03:51,010 Every container has its own file system. 90 00:03:51,010 --> 00:03:53,490 So that we want to have a special directory in there 91 00:03:53,490 --> 00:03:55,030 in which you wanna work. 92 00:03:55,030 --> 00:03:57,550 That we then copy the package.json file, 93 00:03:57,550 --> 00:03:59,510 into our working directory. 94 00:03:59,510 --> 00:04:01,540 Then we run the npm install command 95 00:04:01,540 --> 00:04:04,870 to install all the dependencies our application needs. 96 00:04:04,870 --> 00:04:07,530 Then we copy the rest of the code here. 97 00:04:07,530 --> 00:04:11,240 Then we expose port 3000 to the outside world. 98 00:04:11,240 --> 00:04:14,800 Because that's the port our application is listening on 99 00:04:14,800 --> 00:04:16,870 and we wanna be able to reach that port 100 00:04:16,870 --> 00:04:18,579 from outside of the container, 101 00:04:18,579 --> 00:04:20,870 not just from inside the container. 102 00:04:20,870 --> 00:04:25,020 And then we execute app.mjs with the node command, 103 00:04:25,020 --> 00:04:26,180 which is available because 104 00:04:26,180 --> 00:04:28,390 we're running in a node environment. 105 00:04:28,390 --> 00:04:30,600 Again, this was a quick walk through. 106 00:04:30,600 --> 00:04:34,300 The details will follow in the next core section. 107 00:04:34,300 --> 00:04:38,430 Now with the Docker file created, we open up a terminal. 108 00:04:38,430 --> 00:04:39,360 For example, here, 109 00:04:39,360 --> 00:04:43,210 I'm using the terminal integrated into visual studio code, 110 00:04:43,210 --> 00:04:45,300 the editor I'm using here. 111 00:04:45,300 --> 00:04:46,750 And with Docker setup, 112 00:04:46,750 --> 00:04:50,271 which we have at this point, we run Docker build . 113 00:04:50,271 --> 00:04:53,260 and this builds the image the Docker file. 114 00:04:53,260 --> 00:04:56,170 It finds in the directory in which you run this. 115 00:04:56,170 --> 00:04:59,200 And therefore I'm using this integrated terminal here 116 00:04:59,200 --> 00:05:01,390 because this automatically launches 117 00:05:01,390 --> 00:05:03,260 in this project directory. 118 00:05:03,260 --> 00:05:05,270 So any commands I execute here, 119 00:05:05,270 --> 00:05:07,690 run inside of this directory. 120 00:05:07,690 --> 00:05:11,810 So now this will build an image based on this Docker file, 121 00:05:11,810 --> 00:05:14,750 which is the first thing we need to do. 122 00:05:14,750 --> 00:05:16,780 So simply hit enter here. 123 00:05:16,780 --> 00:05:18,520 If you're getting an error at this point, 124 00:05:18,520 --> 00:05:21,570 make sure you got Docker installed and started. 125 00:05:21,570 --> 00:05:24,160 Start Docker desktop if you installed that 126 00:05:24,160 --> 00:05:26,850 and make sure Docker is running in the background. 127 00:05:26,850 --> 00:05:30,070 And therefore at some point, this should then work. 128 00:05:30,070 --> 00:05:34,610 And what this now does is, it grabs this node environment, 129 00:05:34,610 --> 00:05:36,170 which already exists, 130 00:05:36,170 --> 00:05:38,070 it downloads it from the cloud, 131 00:05:38,070 --> 00:05:41,560 from Docker Hub to be precise, but more on that later. 132 00:05:41,560 --> 00:05:43,630 And then it will set up an image 133 00:05:43,630 --> 00:05:45,380 for a container to be launched 134 00:05:45,380 --> 00:05:48,300 with all these setup steps being executed 135 00:05:48,300 --> 00:05:49,720 inside of the image. 136 00:05:49,720 --> 00:05:50,990 So it will give us an image 137 00:05:50,990 --> 00:05:54,490 which has prepared to be started as a container. 138 00:05:54,490 --> 00:05:57,290 So this now walks through all these steps 139 00:05:57,290 --> 00:06:00,170 and after some time it should be done. 140 00:06:00,170 --> 00:06:03,440 You get us successfully built and then some ID 141 00:06:03,440 --> 00:06:05,890 for this image output. 142 00:06:05,890 --> 00:06:07,640 As a side note on Windows, 143 00:06:07,640 --> 00:06:09,890 your output looks slightly different. 144 00:06:09,890 --> 00:06:14,764 There you find the idea of the image which was built here. 145 00:06:14,764 --> 00:06:17,850 Now we can use this ID here, 146 00:06:17,850 --> 00:06:20,190 and then run a container based on this image 147 00:06:20,190 --> 00:06:22,310 with the docker run command. 148 00:06:22,310 --> 00:06:25,600 Like this, docker run, and then the image ID. 149 00:06:25,600 --> 00:06:30,600 However, actually, since our container here has a port 150 00:06:30,899 --> 00:06:33,130 to which you wanna communicate, 151 00:06:33,130 --> 00:06:36,840 we actually need to publish that port on the container, 152 00:06:36,840 --> 00:06:38,040 which we want to run. 153 00:06:38,040 --> 00:06:40,550 And we do it as by adding the -p flag 154 00:06:40,550 --> 00:06:42,340 on docker run here. 155 00:06:42,340 --> 00:06:47,340 And we then publish port 3000 on port 3000. 156 00:06:47,680 --> 00:06:51,780 Which means we can use our local host, on our local system 157 00:06:51,780 --> 00:06:55,280 to reach the application running on port 3000 158 00:06:55,280 --> 00:06:56,850 instead of the container. 159 00:06:56,850 --> 00:06:58,910 Because by default, there is no connection 160 00:06:58,910 --> 00:07:01,970 between container and our host operating system. 161 00:07:01,970 --> 00:07:05,330 If we wanna send HTTP request for example, 162 00:07:05,330 --> 00:07:07,690 to an application running in a container, 163 00:07:07,690 --> 00:07:10,930 we need to open up the port on the container 164 00:07:10,930 --> 00:07:12,560 to which we wanna communicate. 165 00:07:12,560 --> 00:07:16,130 Otherwise it's a locked network in the container and we 166 00:07:16,130 --> 00:07:18,490 can't reach it from outside. 167 00:07:18,490 --> 00:07:20,800 With that however we can hit enter, 168 00:07:20,800 --> 00:07:23,450 and this now we'll run this container 169 00:07:23,450 --> 00:07:25,070 and you can tell that it's running 170 00:07:25,070 --> 00:07:29,090 by the fact that you now can't enter any more commands here, 171 00:07:29,090 --> 00:07:32,320 but that instead, this command is stuck. 172 00:07:32,320 --> 00:07:35,630 It's stuck because we have a running web server. 173 00:07:35,630 --> 00:07:38,250 Now you can visit local host 3000, 174 00:07:38,250 --> 00:07:40,950 and you should see "Hi there!", there. 175 00:07:40,950 --> 00:07:44,170 And that's our first Dockerized application, 176 00:07:44,170 --> 00:07:46,210 even though of course, at this point, 177 00:07:46,210 --> 00:07:48,640 we haven't written the stalker file ourselves 178 00:07:48,640 --> 00:07:51,290 and we don't fully understand what's happening there. 179 00:07:51,290 --> 00:07:53,130 But we're going to learn all of that 180 00:07:53,130 --> 00:07:55,300 throughout the next sections. 181 00:07:55,300 --> 00:07:57,010 To now stop this container, 182 00:07:57,010 --> 00:07:58,670 we can open up a new terminal, 183 00:07:58,670 --> 00:08:00,760 by clicking on this plus here, 184 00:08:00,760 --> 00:08:03,620 and then you can run docker ps, 185 00:08:03,620 --> 00:08:06,350 which will list all running containers 186 00:08:06,350 --> 00:08:08,870 and then grab this name of this container, 187 00:08:08,870 --> 00:08:12,680 which was started, it's an automatic your assigned name 188 00:08:12,680 --> 00:08:15,900 and run dockers stop, and then this name, 189 00:08:15,900 --> 00:08:20,330 and this will now stop this container and shut it down. 190 00:08:20,330 --> 00:08:22,300 This can also take a couple of seconds, 191 00:08:22,300 --> 00:08:25,680 but thereafter this container is not running anymore. 192 00:08:25,680 --> 00:08:27,680 And therefore once this did stop, 193 00:08:27,680 --> 00:08:30,340 if you reload local host 3000, 194 00:08:30,340 --> 00:08:32,342 you can't reach the site anymore. 195 00:08:33,850 --> 00:08:37,280 Although in that terminal, where you ran docker run, 196 00:08:37,280 --> 00:08:40,240 you now are out of this running process again, 197 00:08:40,240 --> 00:08:42,730 and you can enter more commands. 198 00:08:42,730 --> 00:08:46,700 And that's it, that's this very first basic example, 199 00:08:46,700 --> 00:08:47,940 not too fancy. 200 00:08:47,940 --> 00:08:50,900 And of course not a lot of work from our side. 201 00:08:50,900 --> 00:08:54,520 But it shows us that docker was installed successfully, 202 00:08:54,520 --> 00:08:58,870 that it works and that we kind of did create 203 00:08:58,870 --> 00:09:01,230 such a containerized application. 204 00:09:01,230 --> 00:09:05,420 Because we definitely did not install Node.js on our system. 205 00:09:05,420 --> 00:09:08,580 We did not run npm install in this project folder, 206 00:09:08,580 --> 00:09:10,870 to install all third-party dependencies 207 00:09:10,870 --> 00:09:15,200 and still we were able to bring up that web server 208 00:09:15,200 --> 00:09:17,970 and visited on local host 3000. 209 00:09:17,970 --> 00:09:21,023 And that was possible because of Docker.