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In the last section we made a little change to our darker file and then tried rebuilding the image.

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The good news is that NPM is now clearly being included inside of our container and so it's attempting

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to install dependencies.

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However NPM itself very quickly throw a error message right here complaining that there is no file called

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package dot Jason available now just in case you weren't around or you kind of skipped over the section

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where we put together the package that Jason filed together.

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That is a file inside of our project directory right here.

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Its purpose is to list out all the different dependencies that are required to successfully run our

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project.

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So when we run npm install NPM is going to try to find this file that's going to find all the dependencies

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that are listed and then it's going to try to install each of those so clearly the issue here is that

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NPM is not finding that file.

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So let's talk about why it is all right.

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So a quick diagram.

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We've looked at this one before.

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We've got our container on the right hand side.

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We've got the steps out of our Docker file and then down here is a little representation of the node

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Alpine image that we're making use of.

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So let's imagine what is going on inside of our image building process right now.

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First off we specify node Alpine that downloads the Alpine image or the node image to be precise and

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then the next step starts up.

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And it says I'm going to go back to the previous step and get the image from there and then create a

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temporary container out of it.

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So as soon as run npm install starts to boot up we can imagine that we take this file system snapshot

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right here and we kind of put it into this very temporary container and then we execute npm install.

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Now I want got a quick question for you.

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Do you see anywhere inside of this file system right here.

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Do you see a package not just on file.

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Well the answer is No.

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There is no package dot JS on file available inside of the container.

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The only files and folders that are available inside the container is exactly whatever came out of the

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file system snapshot from the node image.

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Remember we are only working with a segment of our hard drive inside this container.

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There's this entire other rest of the hard drive kind of like not connected inside this container.

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And somewhere inside the rest of the hard drive is where our package dock Chase on file is.

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And that is not at all being communicated into the container.

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And so what we do successfully run npm install but they're just plain is no package not just on file

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available.

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So the takeaway here is that when you are building an image none of the files inside of your project

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director right here are available inside the container.

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By default they are all 100 percent sectioned off completely segmented out.

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They are not at all available and you can not assume that any of these files are available unless you

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specifically allow it inside of your Docker file.

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So as my guest.

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That's exactly what we're going to do.

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We're going to add in one line of configuration to our Docker file to make sure that both are indexed

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not just file in package not just on file are available inside the container when we try to run the

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NPM install command.

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Let's take a quick pause right here and then we're going to add in that additional instruction in the

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next section.