1 00:00:02,090 --> 00:00:05,160 At the moment, this basic utility container, 2 00:00:05,160 --> 00:00:09,210 which I created here, allows us to run any command. 3 00:00:09,210 --> 00:00:13,190 Now that is useful, that is definitely not too bad. 4 00:00:13,190 --> 00:00:17,390 But maybe we know that it should be a utility container, 5 00:00:17,390 --> 00:00:21,960 a utility image, which allows us to run npm commands. 6 00:00:21,960 --> 00:00:25,480 So not any command, but restricted to npm. 7 00:00:25,480 --> 00:00:28,730 For example, npm init for initialization. 8 00:00:28,730 --> 00:00:31,720 But then npm install for installing. 9 00:00:31,720 --> 00:00:32,960 Of course, we can do this. 10 00:00:32,960 --> 00:00:35,090 I can run npm install here, 11 00:00:35,090 --> 00:00:38,600 but maybe I just want to run docker run, it, 12 00:00:38,600 --> 00:00:40,970 then my bind mount, then the image name, 13 00:00:40,970 --> 00:00:42,700 and then just install. 14 00:00:42,700 --> 00:00:45,820 And under the hood, inside of the container 15 00:00:45,820 --> 00:00:50,800 that should prepend npm here to run npm install. 16 00:00:50,800 --> 00:00:54,200 So that we have a more restricted utility container 17 00:00:54,200 --> 00:00:55,960 where we can't do everything. 18 00:00:55,960 --> 00:00:58,110 Also to protect ourselves, 19 00:00:58,110 --> 00:01:00,730 so that I don't accidentally run some command 20 00:01:00,730 --> 00:01:03,560 in the container, which deletes everything. 21 00:01:03,560 --> 00:01:05,360 And then because of the bind mount, 22 00:01:05,360 --> 00:01:08,260 it starts deleting content on my host machine as well. 23 00:01:08,260 --> 00:01:10,960 So for this reason, as well, it might be interesting 24 00:01:10,960 --> 00:01:13,970 to restrict the commands we can run. 25 00:01:13,970 --> 00:01:17,480 And for that, we got an extra instruction in the Dockerfile, 26 00:01:17,480 --> 00:01:19,440 which we haven't used thus far. 27 00:01:19,440 --> 00:01:22,800 And that's the entrypoint instruction. 28 00:01:22,800 --> 00:01:26,130 It is quite similar to the command instruction, 29 00:01:26,130 --> 00:01:28,730 but it has one key difference. 30 00:01:28,730 --> 00:01:33,280 If we add a command after the image name on docker run, 31 00:01:33,280 --> 00:01:36,740 then this command, in this case npm install 32 00:01:36,740 --> 00:01:40,720 overwrites the command specified in a Dockerfile. 33 00:01:40,720 --> 00:01:41,810 If there is one. 34 00:01:41,810 --> 00:01:43,360 We didn't have one thus far. 35 00:01:43,360 --> 00:01:46,600 But if we had one, this command in the Dockerfile 36 00:01:46,600 --> 00:01:49,210 would be overwritten by this command 37 00:01:49,210 --> 00:01:52,270 after the image name on docker run. 38 00:01:52,270 --> 00:01:54,830 With the entrypoint that's different. 39 00:01:54,830 --> 00:01:58,630 For the entrypoint, whatever you enter here 40 00:01:58,630 --> 00:02:00,810 after your image name on docker run 41 00:02:00,810 --> 00:02:04,400 is appended after the entry point. 42 00:02:04,400 --> 00:02:05,880 And that's pretty cool. 43 00:02:05,880 --> 00:02:09,860 That means that here, we could specify npm. 44 00:02:09,860 --> 00:02:14,860 And now we could append any npm command after our image name 45 00:02:15,410 --> 00:02:17,750 once we rebuild this image. 46 00:02:17,750 --> 00:02:18,640 So let's do that. 47 00:02:18,640 --> 00:02:21,000 Let's add this entrypoint. 48 00:02:21,000 --> 00:02:23,930 And then let's build this image again, 49 00:02:23,930 --> 00:02:26,370 maybe with a tag of mynpm, 50 00:02:26,370 --> 00:02:29,670 because it's my own version of npm in a container. 51 00:02:29,670 --> 00:02:31,590 So let's do that. 52 00:02:31,590 --> 00:02:35,880 And then we can run docker run mynpm in interactive mode, 53 00:02:35,880 --> 00:02:39,090 in case some input is required from our side 54 00:02:39,090 --> 00:02:41,010 with our volume added. 55 00:02:41,010 --> 00:02:43,800 So again, I'll copy this path, 56 00:02:43,800 --> 00:02:46,390 I will delete this package.json file by the way, 57 00:02:46,390 --> 00:02:49,630 so that we can recreate it and see that in action. 58 00:02:49,630 --> 00:02:52,940 Then use my absolute path here for the bind mount. 59 00:02:52,940 --> 00:02:54,920 And bind this to slash app, 60 00:02:54,920 --> 00:02:58,820 which is the folder inside of the container 61 00:02:58,820 --> 00:03:01,810 against which these commands will be executed. 62 00:03:01,810 --> 00:03:05,250 Entrypoint also adheres to work directory. 63 00:03:05,250 --> 00:03:08,820 And then here after my npm, so after this image name, 64 00:03:08,820 --> 00:03:12,570 I just need to run init, not npm init, 65 00:03:12,570 --> 00:03:13,740 but just init. 66 00:03:13,740 --> 00:03:16,900 Because we have npm already in the entrypoint. 67 00:03:16,900 --> 00:03:18,370 And if I hit Enter, 68 00:03:18,370 --> 00:03:21,170 now again, we can go through these questions 69 00:03:21,170 --> 00:03:24,470 and once we're done, we got this package.json file. 70 00:03:24,470 --> 00:03:27,830 And now we can run any npm commands against this. 71 00:03:27,830 --> 00:03:29,810 For example, npm install. 72 00:03:29,810 --> 00:03:32,170 If I add install here, this now installs 73 00:03:32,170 --> 00:03:34,763 all the dependencies it finds in package.json. 74 00:03:35,640 --> 00:03:37,490 And keep in mind by the way, 75 00:03:37,490 --> 00:03:39,560 that the container always shuts down 76 00:03:39,560 --> 00:03:41,130 once the command is done. 77 00:03:41,130 --> 00:03:44,220 But it was still able to run npm install here, 78 00:03:44,220 --> 00:03:47,940 because of course, since my local folder is the bind mount, 79 00:03:47,940 --> 00:03:50,860 the package.json file, which I already had 80 00:03:50,860 --> 00:03:53,560 was copied into the app folder, 81 00:03:53,560 --> 00:03:57,010 and therefore npm install being executed in the app folder, 82 00:03:57,010 --> 00:03:59,810 was able to pick up this package.json file 83 00:03:59,810 --> 00:04:02,300 and use it inside of the container. 84 00:04:02,300 --> 00:04:04,400 Now I deleted the package lock.json file, 85 00:04:04,400 --> 00:04:06,350 because of course here the install command 86 00:04:06,350 --> 00:04:07,690 didn't do too much. 87 00:04:07,690 --> 00:04:10,280 Since we got absolutely no dependencies specified 88 00:04:10,280 --> 00:04:12,220 in package.json. 89 00:04:12,220 --> 00:04:14,290 Well, we could add them manually here 90 00:04:14,290 --> 00:04:17,350 by adding a dependencies node and adding dependencies 91 00:04:17,350 --> 00:04:19,709 in case we know their names and versions. 92 00:04:19,709 --> 00:04:21,620 Or again, we don't do this, 93 00:04:21,620 --> 00:04:25,440 and instead I run my npm image with install 94 00:04:25,440 --> 00:04:29,740 and then here I could add express 95 00:04:29,740 --> 00:04:32,490 and this would install the express dependency, 96 00:04:32,490 --> 00:04:34,780 maybe with the dash dash save flag, 97 00:04:34,780 --> 00:04:37,610 which is a flag the npm install command accepts 98 00:04:37,610 --> 00:04:42,610 to add express as a package as a dependency to this project. 99 00:04:42,930 --> 00:04:46,350 So for now hit Enter this now installs express, 100 00:04:46,350 --> 00:04:49,100 and you see it creates the node_modules file 101 00:04:49,100 --> 00:04:53,580 and mirrors that back into our local folder here 102 00:04:53,580 --> 00:04:55,123 because of that bind mount. 103 00:04:56,240 --> 00:04:58,040 So that's really useful 104 00:04:58,040 --> 00:05:00,210 and that's a pattern you will also see 105 00:05:00,210 --> 00:05:01,820 in many Docker project, 106 00:05:01,820 --> 00:05:04,290 and it's also a pattern we will use 107 00:05:04,290 --> 00:05:06,303 in some parts of this course. 108 00:05:07,270 --> 00:05:08,103 Now nonetheless, 109 00:05:08,103 --> 00:05:10,510 at the moment our approach here has a downside. 110 00:05:10,510 --> 00:05:12,210 It has a disadvantage. 111 00:05:12,210 --> 00:05:15,820 We have to run these relatively long commands 112 00:05:15,820 --> 00:05:18,340 in the terminal in the command prompt. 113 00:05:18,340 --> 00:05:21,170 And we already learned about a solution for that. 114 00:05:21,170 --> 00:05:23,190 We learned about Docker-compose. 115 00:05:23,190 --> 00:05:25,913 So maybe it can help us here as well.