WEBVTT 00:00.810 --> 00:02.730 Instructor: In the last section, we took a first stab 00:02.730 --> 00:06.090 at our docker file to build out this node JS project, 00:06.090 --> 00:07.290 but we very quickly saw 00:07.290 --> 00:09.690 that during the run NPM install step, 00:09.690 --> 00:13.470 we got an error message that said NPM not found. 00:13.470 --> 00:14.820 We're seeing this error message 00:14.820 --> 00:16.950 because during step number two right here, 00:16.950 --> 00:19.560 where we tried to execute the command NPM install 00:19.560 --> 00:21.500 inside of a temporary container, 00:21.500 --> 00:25.260 there is no copy of NPM available. 00:25.260 --> 00:27.720 We're seeing this because we are using alpine 00:27.720 --> 00:29.370 as our base image. 00:29.370 --> 00:32.070 Remember, we had said that we select our base image 00:32.070 --> 00:35.453 based upon the collection of default programs 00:35.453 --> 00:39.090 that we need to successfully build our image. 00:39.090 --> 00:41.940 By default, alpine is a very small image. 00:41.940 --> 00:44.220 It's only about five megabytes large, 00:44.220 --> 00:46.140 and so it has a rather limited set 00:46.140 --> 00:49.200 of default programs included inside of it. 00:49.200 --> 00:51.039 In fact, I kinda like this diagram right here. 00:51.039 --> 00:54.300 What programs are included in the alpine image? 00:54.300 --> 00:56.224 Well, this is supposed to be a tumbleweed of sorts, 00:56.224 --> 00:58.770 not much, so there's not a whole lot 00:58.770 --> 01:02.190 of stuff going on by default inside the alpine image. 01:02.190 --> 01:06.150 You get a couple of very default Linux or Unix programs. 01:06.150 --> 01:07.980 You get that package manager that we used 01:07.980 --> 01:09.990 just a little bit ago, but that's pretty much it. 01:09.990 --> 01:12.376 You don't get a lot of other stuff for free. 01:12.376 --> 01:15.090 So when you are using the alpine image, 01:15.090 --> 01:17.700 and you expect to run some fancy web application 01:17.700 --> 01:21.810 depending upon node JS or depending upon Ruby or Java, 01:21.810 --> 01:24.870 chances are you are gonna have to do some additional fixes 01:24.870 --> 01:27.660 or some additional setup to get this thing working. 01:27.660 --> 01:29.970 Now, to solve this issue, to solve the issue 01:29.970 --> 01:33.480 of NPM not being available inside of our base image, 01:33.480 --> 01:35.370 we have two options. 01:35.370 --> 01:39.270 The first option is to find a different base image. 01:39.270 --> 01:40.890 We can try to find a base image 01:40.890 --> 01:44.943 that already has node and NPM pre-installed inside of it. 01:45.870 --> 01:49.170 Alternatively, we can continue using the alpine image 01:49.170 --> 01:52.380 and run an additional command, like right here, 01:52.380 --> 01:57.120 to attempt to install node JS and NPM inside of our image. 01:57.120 --> 01:58.440 So two approaches. 01:58.440 --> 02:01.050 We can either essentially use someone else's work, 02:01.050 --> 02:04.410 or we can try to build up our own image from scratch. 02:04.410 --> 02:08.520 In our case, we're going to try using someone else's image. 02:08.520 --> 02:10.713 We're gonna find an image that has already been configured 02:10.713 --> 02:13.893 to have NPM pre-installed inside of it. 02:15.330 --> 02:17.910 So to get started, I'm gonna flip back over to my terminal, 02:17.910 --> 02:20.310 and we're going to navigate to Docker Hub, 02:20.310 --> 02:23.490 which you'll recall is a repository of public images 02:23.490 --> 02:26.700 that we can easily pull into our build process. 02:26.700 --> 02:28.500 So I'm gonna open up a new tab 02:28.500 --> 02:31.593 and navigate to hub.docker.com. 02:33.570 --> 02:36.520 And then on the top bar, I'm gonna find the explore button. 02:38.010 --> 02:39.240 You'll see a listing 02:39.240 --> 02:41.460 of very popular images immediately appear. 02:41.460 --> 02:43.920 And so of course, right there is alpine. 02:43.920 --> 02:46.080 We're gonna scroll down a little bit, 02:46.080 --> 02:48.210 and a few options down, 02:48.210 --> 02:50.520 you'll see node listed right here. 02:50.520 --> 02:52.410 If you don't see node listed on here, 02:52.410 --> 02:53.730 you can always do a search up here 02:53.730 --> 02:55.230 at the top left-hand side. 02:55.230 --> 02:56.790 And we're essentially just looking 02:56.790 --> 02:58.590 for the repository called Node, 02:58.590 --> 03:02.040 and it should have a little sub-description of official. 03:02.040 --> 03:03.720 So we can click on this, 03:03.720 --> 03:05.730 we'll get a short description right here. 03:05.730 --> 03:08.790 Now the description in this case is not super helpful. 03:08.790 --> 03:11.340 It says, oh yeah, node JS, here's what it is. 03:11.340 --> 03:13.230 But well, what are we really downloading? 03:13.230 --> 03:15.240 Like what is this repository? 03:15.240 --> 03:18.030 This repository is a docker image 03:18.030 --> 03:21.450 that has node pre-installed on it. 03:21.450 --> 03:24.750 So if we want to, we can attempt to build our image 03:24.750 --> 03:26.340 based upon this node one. 03:26.340 --> 03:28.680 And this node image already has node pre-installed, 03:28.680 --> 03:30.300 already has NPM pre-installed. 03:30.300 --> 03:31.830 And so we don't have to worry 03:31.830 --> 03:33.630 about getting more errors like this, 03:33.630 --> 03:35.763 where NPM is not found. 03:36.918 --> 03:39.990 Now before we just go and use node willy-nilly, 03:39.990 --> 03:42.690 I wanna show you a little bit more inside this description. 03:42.690 --> 03:45.990 So you'll see this full description panel right here. 03:45.990 --> 03:49.200 And then first section here is supported tags 03:49.200 --> 03:51.420 and respective docker file links. 03:51.420 --> 03:54.060 So this is a listing of all the different versions 03:54.060 --> 03:55.920 of this image that is available. 03:55.920 --> 03:59.790 You can get different versions of node JS encapsulated 03:59.790 --> 04:01.680 in each of these different tags. 04:01.680 --> 04:03.810 So for example, if I have a application 04:03.810 --> 04:07.200 that requires node version 6.14, 04:07.200 --> 04:10.950 I can find the tag version 6.14 right here. 04:10.950 --> 04:12.750 And then inside of my docker file, 04:12.750 --> 04:15.300 when I specify my base image, 04:15.300 --> 04:20.100 I can say node, and I can specify the version of it 04:20.100 --> 04:22.860 specifically by adding on 6.14. 04:22.860 --> 04:24.690 So this will give me a image 04:24.690 --> 04:28.020 that contains a pre-installed version of node JS, 04:28.020 --> 04:31.683 specifically version 6.14 of node JS. 04:32.609 --> 04:35.970 Now in our case, we don't want version 6.14. 04:35.970 --> 04:38.520 Instead, I want you to scroll around just a little bit, 04:38.520 --> 04:42.390 and you'll eventually see one tag in here called alpine. 04:42.390 --> 04:45.180 You might have to do a command F search 04:45.180 --> 04:47.460 for alpine, and you'll see that well, yeah, 04:47.460 --> 04:49.860 there's a lot of examples on it on here. 04:49.860 --> 04:51.671 So here's alpine right here. 04:51.671 --> 04:54.150 I want you to remember this is a tag. 04:54.150 --> 04:56.400 So this is not the name of the repository. 04:56.400 --> 04:58.350 So when you see alpine right here, it doesn't mean 04:58.350 --> 05:00.216 that we're supposed to use like alpine, 05:00.216 --> 05:01.950 like we were just before. 05:01.950 --> 05:04.860 The first word right here is the name of the repository. 05:04.860 --> 05:08.940 You place a colon, and then you put down a tag name. 05:08.940 --> 05:11.520 And so in this case, when you see alpine right here, 05:11.520 --> 05:15.720 it means that we can optionally select node colon alpine. 05:15.720 --> 05:17.910 So now you might be curious, why would we do this? 05:17.910 --> 05:21.712 Like what is the purpose of alpine being tied onto node? 05:21.712 --> 05:25.050 Well, alpine is a term in the docker world 05:25.050 --> 05:28.959 for an image that is as small and compact as possible. 05:28.959 --> 05:32.982 Many popular repositories are going to offer alpine versions 05:32.982 --> 05:34.890 of their image. 05:34.890 --> 05:37.350 And an alpine version of node in particular means 05:37.350 --> 05:39.120 that you're not going to get a bunch 05:39.120 --> 05:41.610 of additional pre-installed programs. 05:41.610 --> 05:43.800 So the default node installation 05:43.800 --> 05:46.530 might include extra programs like say git, 05:46.530 --> 05:48.840 or a package manager, or I don't know, 05:48.840 --> 05:52.140 some fancy text editing tools inside that image. 05:52.140 --> 05:54.630 When you get the alpine version of an image, 05:54.630 --> 05:56.550 it means you're getting the absolute 05:56.550 --> 05:59.670 most stripped down version of that image possible. 05:59.670 --> 06:01.950 So it's going to essentially have node JS 06:01.950 --> 06:04.020 and pretty much nothing else. 06:04.020 --> 06:05.880 It will have some very basic programs, 06:05.880 --> 06:08.460 like say the ping command, maybe, 06:08.460 --> 06:10.170 you know, you have to look at the actual image 06:10.170 --> 06:11.003 to figure that out. 06:11.003 --> 06:12.720 But it might have the ping command. 06:12.720 --> 06:16.500 You'll have say cat, maybe a simple text editor, LS, 06:16.500 --> 06:17.940 simple programs like that. 06:17.940 --> 06:20.580 But in general, you're getting a very stripped down version 06:20.580 --> 06:22.020 of that image. 06:22.020 --> 06:24.930 So for us, the alpine version works just fine, 06:24.930 --> 06:28.800 'cause essentially, all you and I need is node and NPM, 06:28.800 --> 06:31.710 and NPM is included in this node image right here, 06:31.710 --> 06:34.410 and we need absolutely nothing else. 06:34.410 --> 06:37.290 So we are totally fine using the alpine version 06:37.290 --> 06:39.063 of the node image. 06:40.050 --> 06:41.796 All right, so with all that in mind, 06:41.796 --> 06:44.850 now that we've made the change to the from right here, 06:44.850 --> 06:47.040 we now have specified a base image 06:47.040 --> 06:50.310 that hopefully is going to include NPM inside of it. 06:50.310 --> 06:52.080 And I can tell you, it definitely is. 06:52.080 --> 06:54.420 This is going to have NPM pre-installed, 06:54.420 --> 06:55.980 we're definitely good to go. 06:55.980 --> 06:58.230 So let's now try to rebuild our image 06:58.230 --> 07:01.107 with this change and see if that error message goes away. 07:01.107 --> 07:02.970 First things first, do make sure 07:02.970 --> 07:06.729 that you save the docker file, and then once you save it, 07:06.729 --> 07:09.395 we'll flip back over to the terminal 07:09.395 --> 07:12.843 and do a docker build dot again. 07:14.700 --> 07:16.200 All right, so now you can see 07:16.200 --> 07:19.530 that we're downloading the new node alpine image. 07:19.530 --> 07:21.990 We then get down to step number two right here 07:21.990 --> 07:23.700 where we run NPM install. 07:23.700 --> 07:24.840 But very shortly after that, 07:24.840 --> 07:26.400 we get a series of error messages, 07:26.400 --> 07:27.870 s and the first of which says 07:27.870 --> 07:31.860 no such file or directory package dot json. 07:31.860 --> 07:34.590 So the package dot json is a file that exists 07:34.590 --> 07:36.540 inside of our current working directory, 07:36.540 --> 07:38.640 but it looks like the container is complaining that, 07:38.640 --> 07:40.590 hey, I don't have this file available. 07:40.590 --> 07:42.750 Like, where's the package dot json file? 07:42.750 --> 07:45.671 I need this to know which dependencies I need to install. 07:45.671 --> 07:47.195 So let's take a quick pause right here, 07:47.195 --> 07:48.600 and we're gonna start to investigate 07:48.600 --> 07:50.523 why we're seeing this error message.