GSoC at AsyncAPI: Part 1

My GSoC experience blog

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Green leaves

Oh man, it's been quite some time since the last blog. Lots of exciting stuff going on in my life nowadays, and I wanted to share it with you :)

Brief Overview of my project

You can get a brief overview of my project from my previous blog.

What's this blog(and following more) is going to be about?

This blog will document what I did during my GSoC coding period(in this case: week 1 and 2), I will briefly explain the changes I made during this period, what was my experience, what skills I gained, etc. Basically a lot of stuff. So, buckle up!

Week 1

During the first week, I was tasked to

Since, the whole project will be written in TypeScript, I had to set up all the essential TS stuff, like importing the @types/node package and the TS compiler as well as configuring the tsconfig.json file. Added eslint and the rules, for linting. For testing, we are gonna use jest(+ts-jest).

All in all, it was pretty straightforward to set up the project. No specific code written at this point.

I made the PR, got some reviews, resolved it, and it got merged. First step taken 💪.

Now, it was time to implement the functionality of parsing the AsyncAPI document(using AsyncAPI parser).

This basically meant that we will have a module which exports a single function called parser having two parameters, and we will pass in the path(local or URL) as those parameters, which our parser function will parse. The output by this function will be an object containing the parsed output of both those AsyncAPI documents which we passed through the path.

Here's an illustration of what I said above: parser-module-illustrastion

Going a bit deep

This section will be about the explanation of code inside the Parser module, so If you don't care about that stuff, you can skip this section :)

The approach:

Here's what my approach looked like when tackling this problem:

  • Get the two path parameters.
  • Check whether the passed parameter is a local path or a URL.
  • In case of a local path, resolve the path, then read the contents of the file from that path.
  • In case of a URL, check whether the passed URL is valid or not. If not valid, throw an error. If valid, pass the URL to parseFromUrl function exported by @asyncapi/parser package.
  • For local path, after the content of file has been read, pass that data to parse function present in @asyncapi/parser.
  • Put the parsed document returned from the parser into an object and return that object.

Here's what our main function looks like:

export interface ParsedOutput {
  firstDocument: AsyncAPIDocument;
  secondDocument: AsyncAPIDocument;

export async function parser(
  firstPath: string,
  secondPath: string
): Promise<ParsedOutput> {
  const firstDocument = await parseDocument(firstPath),
    secondDocument = await parseDocument(secondPath);
  return { firstDocument, secondDocument };

parseDocument's job is to take the path, and return the parsed AsyncAPI data from that path. Here's how it looks like:

async function parseDocument(path: string) {
  if (isUrl(path)) {
    return parseFromUrl(path);
  return parse(await readDocument(path));

Here we are checking whether the given path is a URL or not using the isUrl function. If true, we will parse from URL, otherwise we will read the file and parse it.

I don't want to go into the implementation details of isUrl function and readDocument functions. You can take a look at those at this PR.

Learning experience

I learned some new things during this process:

  • JSDoc — The way we use JSDoc for documenting our project, I always thought that this feature is implemented with a certain package, but I was really surprised to know that this feature is built-in into editors. JSDoc is one of the best ways to document your code, so I will definitely use it in my other projects :D.

  • Unit Testing — I had some experience with Integration testing, but never with Unit testing. So, getting familiar with testing a “unit” of code was pretty cool experience for me.

Other stuff

Some other stuff that happened during this week were:

  • My mentor(Vinit Shahdeo) introduced me to Anubhav Vats who has been tremendously helpful. You can say he is my 2nd mentor as well :)
  • I have been working on this issue which is planned for the 2.1.0 release of AsyncAPI spec. I picked up this issue because I wanted to get comfortable with GitHub Actions. I had some experience with GH Action, but I was still not that comfortable with them.

That concluded my first week as a GSoC student. Can't wait to see what's to come next :D.

Week 2

It's the start of second week. Last week was really fun :D.

This week I was tasked to come up with a diff “standard”.

What's the diff standard?

The diff standard will be a markdown document file containing a list of decision/rules. These rules will govern what changes to an AsyncAPI document will be considered a “breaking” or “non-breaking” change.

What do I mean by “breaking”/”non-breaking” changes?

Since my project is about generating the diff between two versions of AsyncAPI documents, we should have a common understanding that changing the value of a property in the second version of the document may cause an existing service to break(or stop functioning) which used to depend on the first version of the document.

For example, here's the first version of an AsyncAPI document

    # some data

and here's what the changes have been made (the second version of the document)

    # some data
    # some data

We are making the rules based on the Point of View of a Consumer(client/server). So a change that may not affect the consumer will be considered a non-breaking change.

Suppose, a consumer has been using a service which was based on the first version, so it can connect to production server and do the work.

Now, after making changes to the document, the service is again built-up again.

But this time, the consumer will fail to work, because it used to connect to the production server(which has been renamed to api/production).

This is what we consider a "breaking" change.

The addition of another server called api/development will be a non-breaking change because no existing consumer is using that server, so we won't have any point of failure in that case.

Learning experience

AsyncAPI specification — During this time, I had to understand the AsyncAPI spec in order to judge the changes in the properties of the spec. Honestly, I love how straightforward and powerful the spec is. You can just spin up a demo service in seconds.

Many thanks for Anubhav Vats for helping me a lot during this process. His insights were really great on how can we judge the changes, how to think about the change, and much more.

You can check out my PR which documents this diff standard here.

Other stuff

Some other stuff that happened during this week were:

  • Work still going on this issue which is planned for the 2.1.0 release of AsyncAPI spec. I made the GitHub action file, now working on the website side, where we have to display the new spec file.

And, that concludes my second week as a GSoC student. Let's see what's to come next :)


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