clojure-news-feed VS component

Your question is interesting to me. As a software architect, I study various tech stacks and programming languages. I concentrate mostly on open source and microservice architectures. I usually start with implementing the same feature identical rudimentary news feed microservice. Over time you start to see the similarities and differences between the various implementations. I blog about this over at https://glennengstrand.info and the source code can be found in https://github.com/gengstrand/clojure-news-feed

You are looking for a decision on what programming language and tech stack to learn next based on career mobility. Here are some questions to consider.

What kind of company are you most interested in working for? Think about the size of the company. Is it in a growth market or is profitability more important? Is it a technology company? Does the CEO view technology as a profit center or a cost center? Do they have a CTO? If they do, then who does the CTO report to, the CEO, the CIO, or the COO?

What kinds of programming languages and tech stacks are on the career pages for the kinds of companies that you are most interested in? Different kinds of companies tend to cluster around different tech stacks. There are other factors to filter for such as how deeply do they embrace remote work or commute distance to where you currently live or are willing to move to.

These are lagging indicators. They are going to be more accurate than leading indicators but that also might indicate that whatever you learn next based on these factors might have a shorter shelf life.

Finally, you should ask yourself what about your current programming language do you like? Try to pick something that you would also like. The Go programming language was originally invented as a better C and is enjoying some marketability right now. Maybe that would be something to look at.

I have a github repo where I implement a feature identical microservice in various tech stacks. I started that repo with a Clojure version that used community provided wrappers. See https://github.com/gengstrand/clojure-news-feed/blob/master/... as an example of calling Cassandra. Recently, I added another implementation with Clojure that just called the Java drivers directly. See https://github.com/gengstrand/clojure-news-feed/blob/master/... for that version of the same call. In the end, I decided to forego wrappers and make the calls directly because you end up with fewer dependencies and are more likely to be able to use latest versions of everything.

I have been exposed to many different tech stacks over the years. This https://github.com/gengstrand/clojure-news-feed repo contains the code used to evaluate thirteen different stacks which is what I can share publicly. What I can say is that the best choice of tech stack depends on what is being called for. Is this for an early stage startup or an intrepreneurial greenfield project? Is this for an MVP or just the next component in an already formalized microservice architecture? What are the skillsets of the developers that you will have access to? Have you reached agreement that you can throw it all away and start over or are you expected to have to live with the choice of tech stack for the life of the product? Are you mobile first? These are all important questions that very much shape the decision.

* Lifecycle management: Mount, Integrant or Component (https://github.com/tolitius/mount https://github.com/weavejester/integrant and https://github.com/stuartsierra/component)

When you start to have multiple stateful components (the database, the HTTP server, your Redis connection, a page cache, etc.), then you'll want to use a library like component that manages their (inter-)dependencies and provides a consistent notion of lifecycle.

Today I released a new version of Reveal Pro — dev.vlaaad/reveal-pro {:mvn/version "1.3.308"} — that adds sticker integration for system libraries such as mount, component and integrant!

I agree with the main sentiment from the article. Although I do think they are discussing Inversion of control more-so than dependency injection.

One of my first languages was .net and I was never able to really understand DI in that context that well.

Actually using javascript and ducktyping made me understand what it actually was.

I remember a .net job interview where I had to write a micro-service and opted to construct the dependency graph in the main function initialising "all" the classes there. Instead of discussing the pro's and con's of that approach they berated me for not using a DI framework (No I did not land that job, but in hindsight it was the most expensive job interview I've ever had. The room was filled with 8 developers going over my code).

The main thing the article glosses over is state. something people with a functional background hide from. But if you look at something like the httpclient in .net. I think it took the .net world like 10 years to start using the httpclient properly. Scope and lifetime of those kind of objects are important. managing connection pools, retry state, throttling or the incoming http request. DI does make that kind of thing easieR (I'm not saying it makes it better)

Look at clojure's component(https://github.com/stuartsierra/component), I'm not a clojure expert by far. But it is kinda DI/IOC in a functional language.

In closing we can agree that it is underused in the right places and overused in the wrong ones.

https://github.com/stuartsierra/component#no-function-should-take-the-entire-system-as-an-argument

Yeah like I mentioned I'm not like super sold on the everything-should-be-an-actor paradigm, but I find value in DDD + a light implementation of Components (similar to stuartsierra/component).

https://github.com/stuartsierra/component for managing components lifecycles in projects