clojure-news-feed VS schema

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.

Plumatic schema (https://github.com/plumatic/schema) , or friends I might be wrong, but I think schema might make more sense to you coming from the F# world (might be wrong)

This one? I didn't. I hear good things about it, and it's reached a point of maturity, being widely used in production.

Uhhh spec has existed for a long time and before that, schema Nowadays we also have the excellent malli. If his codebase is full of functions where the shape of the data isn’t obvious, isn’t documented and isn’t specified in a specific/schema, that’s on him and his bad coding practices and really no different from passing data in other dynamic languages. A class by itself (without additional effort) only gives you field names.

I don't understand this reputation either. There are very large systems built on other Lisps. For example, Emacs has a massive amount of Elisp. Elisp is much more primitive than Clojure, and traditionally libraries don't use e.g. data schemas [1] as runtime contracts for data.

Obviously, once a system built on top of a dynamic language grows beyond certain threshold, you need to be very disciplined as there are no static types to ensure some degree of correctness.

[1] https://github.com/plumatic/schema

Try to learn a schema library early, like Malli or Prismatic Schema. Do not mistook them as "static-typing" things - it's more for data validation and coercion than "security that things will get the right typing information". The idea to learn them early is how you'll shape future code: validating all "output data" first, them using that data inside your program without "defensive programming" like checking every time if a specific value on a map is nil, etc

In Clojure, declarative data specifications for validation and generation are also very mainstream. Schema was first out the door, Clojure Spec is the most popular library, while malli is gaining popularity fast at the moment.