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Now for this course section, I got another small example,

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which you again find attached.

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It's a very simple note JS API application again,

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with one note JS file.

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This app JS file, where we in the end again

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create a node server and listen 3000 in this case

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and where we then have two end points.

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We handle gets requests to our domain slash story.

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And we handle post requests to our domain slash story.

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And here in the post request handler,

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we in the end extract some text

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out of the incoming request.

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We check whether it's empty or not,

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and if it's not empty, we appended it to a file

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in our file path,

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which is this one here.

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Which in the end means we're looking for a story folder

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and in there a text dot text file.

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And there we add the text sent by the user

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through this request.

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Well, and forward to get route for this get request,

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which we're handling,

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We are reading that file

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and we are returning the data which we read.

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This is a very simple application

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and it will in the end to write data

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to this text text file into the story folder,

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which initially is empty of course.

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And so that we can see this in action,

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I prepared a Docker file

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for building this node application image

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and a Docker compose file for running that image

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and for building it and starting to build process as well

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because here I'm using volumes.

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Because of course I got some data into story folder here

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which showed survive container removal and restarts.

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And of course we could also just run our image

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with Docker run, and add a volume with the dash V flag

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but so that we don't have to write this

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a bit longer command,

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I prepared this Docker compose yammer file.

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So what we can do here

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is we can now run Docker compose up dash D

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maybe all the dash dash build

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to always ensure that the image is reevaluated

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and possibly rebuilt if something changed.

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And once that is up and running,

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you can use a tool like postman

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to send requests to this dockerized

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and now running application.

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For example, I gets request to local host slash story,

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to get any safe stories.

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And initially of course, that returns a valid response

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but an empty string here,

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but you can also send a post request

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to local host slash story,

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and then go to body and add a raw JSON body here.

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And then between curly braces and double quotes,

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add text like my text and send this

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and this will now be stored.

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And if you now reload or a resend to get request

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you see your text,

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and then this line break which is automatically added

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by the node JS code here

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when you store and use story here.

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So this works and of course

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since we're using a volume,

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if we run Docker compose down

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and therefore the container gets removed in the end

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it gets stopped and all the remove.

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We can of course ensure that everything

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what we have on containers is removed

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by running Docker container prune

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and then entering why to confirm this.

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So if that is all removed,

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if we rerun the up command Docker compose up,

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of course we'll see that if we sent this get request again

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this data is still there.

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Because even though the container was stopped

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and removed with the help of a volume,

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it was stored and therefore persisted.

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And that's not something new,

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that is something you already did learn about earlier

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on in the course,

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we learned how to work with volumes.

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And we learned that volumes are a powerful tool

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when working with Docker because volumes allow us

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to process data across container restarts

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and especially removals.

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So with that, I'm going to run Docker compose down again,

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to stop this container again.

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And I'm now going to dive into how this translates

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to Kubernetes and how we work with Kubernetes and volumes.