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Now that we've seen some notes on how we handle communication with micro services it's time to actually

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start writing some code.

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So in this video we're going to take a look at a mockup of the application we're going to build.

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To better understand these asynchronous communication patterns if we look at the mockup just a couple

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of quick notes.

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First off the goal this application is to really just get a taste of micros services architecture.

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We're going to work on a much larger more comprehensive project later on INSIDE THE COURSE.

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This first project is really just meant to get your feet wet and healthy just kind of expose you to

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some of these critical issues.

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We're also gonna have a goal inside this project of building as much as possible from scratch.

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So we're going to build out every last service by hand.

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We're going to build out the event broker by hand going to build out as much as we can by hand just

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to get really good idea of what is going on.

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Because of that because we're building this stuff from scratch I would not recommend using this project

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as a template for future micros services projects.

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The reason for that is that usually we're going to use a lot of packages to implement a lot of this

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stuff as opposed to doing it by hand.

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So on real projects you're going to want to use some packages as opposed to these kind of manual implementations

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that we're going to do.

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Again we're going to work on a very large project later on that's going to be a very serious professional

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grade project.

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So you are going to see how to use those other packages and whatnot.

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Ok so enough of that.

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What are we going to build.

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You're gonna make a very simple little application that's all about making posts like blog posts or

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something similar and allowing users to comment on them.

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So any user first comes to application we're gonna show a form like this where user can create some

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kind of post we're going to say that our posts only have titles there's not going to be any kind of

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body or anything like that.

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So a user might type inside of your my post and then hit submit once they do so we're then going to

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display the post they just created down here at the bottom the screen.

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That would be the post that was just created we'll show that title The Post will show the number of

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comments so as associate with it and we'll also have a little form right here to add some comments to

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that individual post.

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So for example I might type inside of here I'm a comment and then click on cement and if I did so I

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should see this post counter right here or the comment counter incremented by 1 and I should also see

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the comment listed out right underneath the actual title and then of course we can add in as many posts

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as you want so we could go back up here to the top put in post number two.

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Hit submit and then we should see post number two.

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Down here up here.

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And of course we show bill to add in comments like I'm a comment to that one as well.

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Hit submit and see that comment up here right there.

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So in total this application is pretty straightforward but I think that you're going to be kind of surprised

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at the level of complexity that we're going to encounter.

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Even for this very simple and straightforward application.

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All right.

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Now we've got an idea of what we're going to build.

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Let's start to break this thing down and consider some of the different technical aspects of it.

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So the first thing that we need to think about is what services we are going to create for this part

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of the course.

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And for a little bit going on into the future right now we're going to say that for every different

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unique resource that we have inside of application we're going to create a separate service.

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So in our application I would say that we have two different types of resources.

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We have posts which are these things we're creating down here at the big blue boxes and then we have

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comments which are the things right here the bullet points that are tied to individual posts.

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So in total we really have two different resources.

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So we're going to think about creating two different services.

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We're going to have a postal service that is in charge of storing all the different posts we have and

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retrieving them giving them back to us.

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And we'll have a common service that is going to be in charge of handling comment creation and listing

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all the different comments out so we start to think about these different services.

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The first thing we want to really do is really picture the different goals or responsibility of each

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service.

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So like I just said with a post service we probably want the ability to create a post and to a list

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all posts and for comments we probably want the ability to create a comment and list all comments.

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Now there's already some hidden complexity inside of here.

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The Postal Service is going to be pretty straightforward but if you really start to think about this

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and really drill down the common service is going to probably be a little bit more challenging than

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you might think at first glance.

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The reason for that is that the comment service whenever we create a comment we're going to really be

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tying a comment to a post.

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So there's going to kind of be a dependency of sorts between reading a comment and having some knowledge

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of what posts exist.

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So we're going to have to apply one of those asynchronous or synchronous communication patterns we just

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discussed to make sure that users can only create comments that are tied to a very specific post.

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In addition whenever we tried to list out some comments we probably don't want to just get all the comments

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that exist in the universe.

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Instead we probably want to somehow retrieve just comments that are associated with some very particular

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post.

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So in other words if we retrieve the top 10 most popular posts inside our application for example we

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probably only want to get comments tied to those specific top 10 posts.

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So even though I say right here list all comments well once again there's probably gonna be some kind

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of dependency inside of here where the comments that we're retrieving need to somehow be tied to the

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actual posts that we're retrieving as well if not that makes sense right now.

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That's totally fine.

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All I mean to say is that this application is going to be a little bit deceptively challenging even

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though it looks like it's really simple and straightforward in nature OK.

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So now we've got an idea of what we're going to build.

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And it's clear that we're going to run into some challenges along the way quick pause right here and

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we'll start to write some code in the next video.