1 00:00:01,507 --> 00:00:04,350 Now for that I open my Terminal here 2 00:00:04,350 --> 00:00:06,250 and I wanna start simple. 3 00:00:06,250 --> 00:00:09,970 I will run the node image just like this 4 00:00:09,970 --> 00:00:11,420 and keep in mind that node 5 00:00:11,420 --> 00:00:14,060 is an official image from Docker Hub. 6 00:00:14,060 --> 00:00:17,370 Now, if i execute this, it just starts. 7 00:00:17,370 --> 00:00:19,290 And immediately it stops. 8 00:00:19,290 --> 00:00:21,610 Because this is an image which we need to start 9 00:00:21,610 --> 00:00:26,400 in interactive mode so that it expects some input from us. 10 00:00:26,400 --> 00:00:29,200 And then it starts and we can execute 11 00:00:29,200 --> 00:00:32,870 some basic commands in node here. 12 00:00:32,870 --> 00:00:34,840 We can use it as a calculator 13 00:00:34,840 --> 00:00:38,070 but we can also run other node commands here. 14 00:00:38,070 --> 00:00:40,460 It's not the primary thing I wanna do here. 15 00:00:40,460 --> 00:00:41,490 I just wanna highlight 16 00:00:41,490 --> 00:00:44,420 that we can start this node container like that. 17 00:00:44,420 --> 00:00:46,100 It is something we did earlier 18 00:00:46,100 --> 00:00:48,070 in the course at the beginning. 19 00:00:48,070 --> 00:00:51,010 Now we can quit this by pressing CONTROL C twice. 20 00:00:51,010 --> 00:00:53,370 This will then also shuts down the container 21 00:00:53,370 --> 00:00:56,960 which is why we now see it here under stopped containers. 22 00:00:56,960 --> 00:00:59,680 And of course, with Docker container prune 23 00:00:59,680 --> 00:01:02,450 we can remove all those stopped containers. 24 00:01:02,450 --> 00:01:06,040 Okay, so that's how we can run a container. 25 00:01:06,040 --> 00:01:09,290 Now i will do something which might look strange at first. 26 00:01:09,290 --> 00:01:11,630 I'm going to run this node container again 27 00:01:11,630 --> 00:01:14,940 in interactive mode, but also in detached mode. 28 00:01:14,940 --> 00:01:17,700 That means we can't enter commands like this 29 00:01:17,700 --> 00:01:21,810 but internally this containers still is waiting for input, 30 00:01:21,810 --> 00:01:24,170 which will keep it up and running. 31 00:01:24,170 --> 00:01:26,160 So now this containers started. 32 00:01:26,160 --> 00:01:27,750 Hence we can see it here 33 00:01:27,750 --> 00:01:32,750 under this auto assigned name, under running containers. 34 00:01:32,770 --> 00:01:34,370 And now I wanna show you a command 35 00:01:34,370 --> 00:01:36,540 which we haven't used thus far. 36 00:01:36,540 --> 00:01:39,830 And that's the Docker exec command. 37 00:01:39,830 --> 00:01:43,310 The Docker exec command allows you to execute 38 00:01:43,310 --> 00:01:46,860 certain commands inside of a running container 39 00:01:46,860 --> 00:01:51,410 besides the default command, this container executes. 40 00:01:51,410 --> 00:01:54,460 So besides the command that might've been specified 41 00:01:54,460 --> 00:01:58,060 in a Docker file, that command still continues running. 42 00:01:58,060 --> 00:02:00,690 So the application still continues to run 43 00:02:00,690 --> 00:02:04,283 but you can't run additional commands inside of a container. 44 00:02:05,170 --> 00:02:08,330 That's something which sometimes could be useful. 45 00:02:08,330 --> 00:02:11,320 Now to use this command we need the name of a container 46 00:02:11,320 --> 00:02:12,720 of a running container. 47 00:02:12,720 --> 00:02:16,770 And then we can execute a command against that container. 48 00:02:16,770 --> 00:02:18,970 And we could try running npm init 49 00:02:18,970 --> 00:02:22,623 which creates a node project in that running node container. 50 00:02:23,850 --> 00:02:27,120 And you actually see that it started asking me 51 00:02:27,120 --> 00:02:30,200 some questions but then it finished immediately 52 00:02:30,200 --> 00:02:33,700 because exec just like run needs to be started 53 00:02:33,700 --> 00:02:37,370 in interactive mode if you want to stay connected 54 00:02:37,370 --> 00:02:39,730 to that process, you're starting up here 55 00:02:39,730 --> 00:02:42,340 and if you want to be able to provide input. 56 00:02:42,340 --> 00:02:44,070 So just as with run, 57 00:02:44,070 --> 00:02:48,000 we can add the dash IT Flag here on exec 58 00:02:48,000 --> 00:02:51,040 then execute a command against this container 59 00:02:51,040 --> 00:02:54,520 and execute the npm init command against it. 60 00:02:54,520 --> 00:02:56,090 And if we now hit Enter 61 00:02:56,090 --> 00:02:58,990 I'm walked through these questions here 62 00:02:58,990 --> 00:03:01,500 where I provide a name and some other settings 63 00:03:01,500 --> 00:03:05,120 to a new project which is now created 64 00:03:05,120 --> 00:03:06,753 inside of that container. 65 00:03:07,600 --> 00:03:10,920 And now that means that we can run this command 66 00:03:10,920 --> 00:03:14,420 without node and npm being installed in our system 67 00:03:14,420 --> 00:03:17,930 because it runs inside of this container. 68 00:03:17,930 --> 00:03:21,660 Now that's still not too useful here because 69 00:03:21,660 --> 00:03:23,400 well if it's in the container, 70 00:03:23,400 --> 00:03:25,410 we created the project in here 71 00:03:25,410 --> 00:03:27,670 and we have no access to that project 72 00:03:27,670 --> 00:03:32,130 but it's just a first demo showing you what we can do. 73 00:03:32,130 --> 00:03:35,970 There's also is one AVR syntax that can be interesting. 74 00:03:35,970 --> 00:03:39,050 Let's stop this container. 75 00:03:39,050 --> 00:03:41,630 So let's stop this container by its name 76 00:03:43,170 --> 00:03:45,450 and thereafter, let's start it again 77 00:03:45,450 --> 00:03:47,770 but let's start it differently 78 00:03:47,770 --> 00:03:51,150 with Docker exec we can execute commands 79 00:03:51,150 --> 00:03:53,850 in a running container without interrupting 80 00:03:53,850 --> 00:03:57,800 the default command which starts when the container starts. 81 00:03:57,800 --> 00:04:01,580 We also can override that default command though. 82 00:04:01,580 --> 00:04:03,440 Now, when we start the node container 83 00:04:03,440 --> 00:04:06,040 the default command that is executed 84 00:04:06,040 --> 00:04:10,750 in the container is the node executable itself 85 00:04:10,750 --> 00:04:12,800 which enters the so called a Rebel 86 00:04:12,800 --> 00:04:15,020 which is just an interactive mode 87 00:04:15,020 --> 00:04:17,070 where we can run node commands. 88 00:04:17,070 --> 00:04:18,529 That's the default command, 89 00:04:18,529 --> 00:04:22,560 the node image will execute when we started. 90 00:04:22,560 --> 00:04:25,760 And if we use interactive mode, we stay connected 91 00:04:25,760 --> 00:04:30,760 and we can then work with that interactive node input mode. 92 00:04:31,000 --> 00:04:33,530 Now we can override this default command 93 00:04:33,530 --> 00:04:37,060 by adding a new command after the image name. 94 00:04:37,060 --> 00:04:40,440 And that's another syntax we haven't used thus far. 95 00:04:40,440 --> 00:04:43,530 And here I could then specify npm init 96 00:04:43,530 --> 00:04:46,010 to overwrite the default command 97 00:04:46,010 --> 00:04:49,280 which would be to go into this interactive 98 00:04:49,280 --> 00:04:54,280 enter some node code mode and instead execute npm init. 99 00:04:54,680 --> 00:04:58,860 If I now hit Enter we again are prompted to provide 100 00:04:58,860 --> 00:05:01,870 the configuration for this node project, 101 00:05:01,870 --> 00:05:03,907 which we create with npm init. 102 00:05:03,907 --> 00:05:07,530 And if I now hit enter this finishes and therefore, 103 00:05:07,530 --> 00:05:10,070 it also stopped the container thereafter 104 00:05:10,070 --> 00:05:12,980 because we overrode the default command 105 00:05:12,980 --> 00:05:16,650 which would have opened this ongoing node interactive mode 106 00:05:16,650 --> 00:05:20,570 with the npm init command, which just creates a project 107 00:05:20,570 --> 00:05:22,493 and then stops once it finished. 108 00:05:23,370 --> 00:05:25,890 And at this moment, that's all not too useful. 109 00:05:25,890 --> 00:05:28,140 I'm just getting started with these commands 110 00:05:28,140 --> 00:05:32,110 to make you aware of this feature Docker also offers. 111 00:05:32,110 --> 00:05:34,930 Docker exec could be useful for example 112 00:05:34,930 --> 00:05:37,760 to read some log files, which were written inside 113 00:05:37,760 --> 00:05:41,640 of a container without interrupting the main process. 114 00:05:41,640 --> 00:05:44,170 But now did we know about these commands? 115 00:05:44,170 --> 00:05:48,030 Let's build a utility Docker container 116 00:05:48,030 --> 00:05:51,030 or image and then a container based on that. 117 00:05:51,030 --> 00:05:54,403 And let's see how that actually may help us.