WEBVTT 00:00.870 --> 00:02.730 Instructor: In the last section, we made a little change 00:02.730 --> 00:05.850 to our docker file and then tried rebuilding the image. 00:05.850 --> 00:08.460 The good news is that npm is now clearly being 00:08.460 --> 00:10.320 included inside of our container, 00:10.320 --> 00:12.260 and so it's attempting to install dependencies. 00:12.260 --> 00:14.760 However, npm itself very quickly 00:14.760 --> 00:16.620 throughout a error message right here, 00:16.620 --> 00:18.870 complaining that there is no file 00:18.870 --> 00:21.550 called package.json available. 00:21.550 --> 00:23.790 Now, just in case you weren't around, 00:23.790 --> 00:25.410 or you kind of skipped over the section 00:25.410 --> 00:28.077 where we put together the package.json file together, 00:28.077 --> 00:31.230 that is a file inside of our project directory right here. 00:31.230 --> 00:33.960 Its purpose is to list out all the different dependencies 00:33.960 --> 00:36.990 that are required to successfully run our project. 00:36.990 --> 00:38.679 So when we run npm install, 00:38.679 --> 00:41.190 npm is going to try to find this file, 00:41.190 --> 00:43.860 it's gonna find all the dependencies that are listed, 00:43.860 --> 00:46.503 and then it's going to try to install each of those. 00:47.400 --> 00:48.690 So clearly the issue here is 00:48.690 --> 00:51.390 that npm is not finding that file. 00:51.390 --> 00:53.580 So let's talk about why it is. 00:53.580 --> 00:54.993 All right, so quick diagram. 00:55.889 --> 00:57.825 We've looked at this one before. 00:57.825 --> 00:59.607 We've got our container on the right-hand side. 00:59.607 --> 01:02.130 We've got the steps out of our docker file, 01:02.130 --> 01:04.770 and then down here is a little representation 01:04.770 --> 01:07.800 of the node alpine image that we're making use of. 01:07.800 --> 01:09.420 So let's imagine what is going on 01:09.420 --> 01:12.546 inside of our image-building process right now. 01:12.546 --> 01:15.630 First off, we specify node alpine. 01:15.630 --> 01:16.463 That downloads the alpine image, 01:16.463 --> 01:19.170 or excuse me, the node image to be precise. 01:19.170 --> 01:21.487 And then the next step starts up and it says, 01:21.487 --> 01:23.610 "Okay, I'm gonna go back to the previous step 01:23.610 --> 01:24.660 and get the image from there, 01:24.660 --> 01:27.240 and then create a temporary container out of it." 01:27.240 --> 01:30.030 So as soon as run npm install starts to boot up, 01:30.030 --> 01:32.100 we can imagine that we take this file system 01:32.100 --> 01:34.080 snapshot right here. 01:34.080 --> 01:37.863 And we kind of put it into this very temporary container. 01:38.861 --> 01:41.403 And then we execute npm install. 01:41.403 --> 01:43.590 Now, I got a quick question for you. 01:43.590 --> 01:46.650 Do you see anywhere inside of this file system right here? 01:46.650 --> 01:48.659 Do you see a package.json file? 01:48.659 --> 01:50.240 Well, the answer is no. 01:50.240 --> 01:53.700 There is no package.json file available 01:53.700 --> 01:55.650 inside of the container. 01:55.650 --> 01:58.110 The only files and folders that are available 01:58.110 --> 02:01.890 inside the container is exactly whatever came out 02:01.890 --> 02:05.313 of the file system snapshot from the node image. 02:06.150 --> 02:07.560 Remember, we are only working 02:07.560 --> 02:11.537 with a segment of our hard drive inside this container. 02:11.537 --> 02:15.030 There's this entire other rest of the hard drive 02:15.030 --> 02:18.390 kind of like not connected inside this container. 02:18.390 --> 02:20.490 And somewhere inside the rest of the hard drive, 02:20.490 --> 02:22.920 is where our package.json file is. 02:22.920 --> 02:25.680 And that is not at all being communicated 02:25.680 --> 02:27.240 into the container. 02:27.240 --> 02:29.820 And so we do successfully run npm install, 02:29.820 --> 02:34.230 but they're just plain is no package.json file available. 02:34.230 --> 02:36.900 So the takeaway here is that when you are building an image, 02:36.900 --> 02:39.390 none of the files inside of your project directory 02:39.390 --> 02:42.480 right here are available inside the container by default. 02:42.480 --> 02:45.150 They are all a hundred percent sectioned off, 02:45.150 --> 02:46.539 completely segmented out, they are not at all available, 02:46.539 --> 02:51.000 and you cannot assume that any of these files are available 02:51.000 --> 02:55.053 unless you specifically allow it inside of your docker file. 02:56.070 --> 02:59.220 So as my guess, that's exactly what we're going to do. 02:59.220 --> 03:01.620 We're going to add in one line of configuration 03:01.620 --> 03:05.460 to our docker file to make sure that both our index.js file 03:05.460 --> 03:09.510 and package.json file are available inside the container 03:09.510 --> 03:12.412 when we try to run the npm install command. 03:12.412 --> 03:14.040 Let's take a quick pause right here 03:14.040 --> 03:16.320 and then we're going to add in that additional instruction 03:16.320 --> 03:17.343 in the next section.