I know that Lemmy is open source and it can only get better from here on out, but I do wonder if any experts can weigh in whether the foundation is well written? Or are we building on top of 4 years worth of tech debt?
It’s decent, but it isn’t scalable, at least not yet.
Right now the entire Lemmy backend is one big “monolith”. One app does everything from logins and signups to posting and commenting. This makes it a little harder to scale, and I wouldn’t be surprised to see it split out into multiple micro services sooner rather than later so some of the bigger instances can scale better.
I’d love to know where the higher level dev stuff is being discussed and if they’ve made a decision on why or why not microservices.
There’s no reason that a monolith can’t scale. In fact you scale a monolith the same way you scale micro services.
The real reason to use micro services is because you can have individual teams own a small set of services. Lemmy isn’t built by a huge corporation though so that doesn’t really make sense.
You definitely can’t scale a monolith the same way you can scale a micro service
You can easily scale a monolith. You typically horizontally replicate any web server (monolith or not) to handle whatever traffic you’re getting. It shouldn’t really matter what type of traffic it is. Plenty of the world’s biggest websites run monoliths in production. You know how people used to say “rails doesn’t scale”? Well they were wrong because Rails monoliths are behind some huge companies like GitHub and Shopify.
The lemmy backend is also quite lightweight and parallel so it’s cheap and effective to replicate.
In my professional experience microservices are usually a dumpster fire from both the dev perspective and an ops perspective (I’m a Site Reliability Engineer).
I disagree that it being a monolith is immediately a problem, but also
In fact you scale a monolith the same way you scale micro services.
This is just not true. With microservices, it is easy to scale out individual services to multiple instances as demand requires them. Hosting a fleet of entire Lemmy instances is far more expensive than just small slices of it that may require the additional processing power.
Lemmy’s backend is native code, not run in a virtual machine or interpreted from text. You’re not going to pay much extra for an extra megabyte or 10 of RAM being used per instance for the extra code sitting idle. It certainly shouldn’t use much processing power when not in use.
What microservices would you split Lemmy into? The database, image hosting and the UI are already separate.
You can easily scale a monolith. You typically horizontally replicate any web server (monolith or not) to handle whatever traffic you’re getting. It shouldn’t really matter what type of traffic it is. Plenty of the world’s biggest websites run monoliths in production. You know how people used to say “rails doesn’t scale”? Well they were wrong because Rails monoliths are behind some huge companies like GitHub and Shopify.
The lemmy backend is also quite lightweight and parallel so it’s cheap and effective to replicate.
In my professional experience microservices are usually a dumpster fire from both the dev perspective and an ops perspective (I’m a Site Reliability Engineer).
Microservices aren’t a silver bullet. There’s likely quite a lot that can be done until we need to split some parts out, and once that happens I expect that federation would be the thing to split out as that’s one of the more “active” parts of the app compared to logins and whatnot.
Definitely not a silver bullet, but should stop the app from locking up when one thing gets overloaded. I’m sure they have their reasons for how it’s designed now and I’m probably missing something that would explain it all.
I’m still not familiar enough with how federation works to speak to how easy that would be. Unfortunately this has happened all as I’ve started moving and I haven’t gotten a chance to dive into code like id want to.
It’s also not the only solution for high-availability system. Multiple monoliths with load-balancing can be used as well.
Also, a lot of people are self-hosting. In this case, microservice won’t give them any scaling benefit.
Microservices can oftentimes cause more performance issue than they solve, as soon as they need to start talking to each other. Here’s someone with more experience than me explaining how it often goes wrong.
There’s nothing stopping you from putting a load balancer and running multiple instances of a monolith connected to one database. Then the database will also become a bottleneck, but that would still happen with microservices.
Exactly, and nothing prevent a monolith from doing vertical slicing at the database level as long as the monolith is not crossing its boundaries. This is the only scaling part that is inherent to microservices. If the issue is the horizontal scaling, microservices doesn’t solve anything in this case.
Also specifically on what I understand of the Fediverse, you want something easy to host and monitor since a lot of people will roll out their own instances which are known issues when running microservices.
This is a discussion I’m also interested in. Migrating a monolith to microservices is a big decision that can have serious performance, maintainability and development impact.
Microservices can be very complex and hard to maintain compared to a monolith. Just the deployment and monitoring could turn into a hassle for instance maintainers. Ease of deployment and maintenance is a big deal in a federated environment. Add too much complexity and people won’t want to be part of it.
I’ve seen some teams do hybrids. Like allowing the codebase to be a single artifact or allowing it to be broken by functionalities. That way people can deploy it the easy way or the performant way, as their needs change.
That’s what I’m thinking. Microservices could be a huge pain in the ass, but a hybrid approach would make things much better. Smaller instances wouldn’t be a problem, but the larger instances would be able to separate out components.
To keep it possible to run monolithicly would probably need a lot of work, but it’s possible to do and would probably be the best approach.
I have a friend that’s a lot more technical than me and he said that Lemmy’s codebase is kinda messy and relies on libraries that are still in beta and have not been tested well in the real world (since Rust is a relatively new language). This was a few months ago though, I’m not sure how much things changed since it’s been getting a lot more support and rewrote the front-end. The good news is it’ll get a lot better as more developers contribute to it.
I think a lot of people assume that because it’s written in Rust that means it has to be super stable but that really isn’t the case.
Someone mentioned they had started out using websockets instead of http. I guess they’ve since migrated, but that design choice makes me wonder about the qualifications of the devs to make that kind of choice.
Web sockets are meant for applications where it’s important that you receive updates fast in a push fashion. E.g. collaborative editors like Google docs or a chat application. To scroll Lemmy or open a specific Lemmy post you don’t need that at all. You can just fetch the data once and have users refresh manually if for example they want to fetch the latest comments on a post. Using websockets for that type of application just puts unnecessary strain on the server.
Maybe they wanted a different type of user experience. But yeha, maybe that’s something Reddit could pull off because of their infrastructure… And they don’t even do it because there’s not much user value to it.
Although reddit does use some websockets so you can see how many users are also seeing the post at the same time.
But not websockets for EVERYTHING.
Someone mentioned they had started out using websockets instead of http. I guess they’ve since migrated, but that design choice makes me wonder about the qualifications of the devs to make that kind of choice.
Websocket was deprecated with 0.18.0 which is the latest official release, but a lot of instances are on the release candidate for 0.18.1. because of some major improvements. My login instance is on that one which is great for me because I’m using a desktop browser and it looks way nicer. A lot of fixes too.
Websocket is easier to implement so that’s probably why they started with it. It has heavy overhead and doesn’t scale well so that’s the down side. It wasn’t trivial for them to move to http. Websocket was probably a better starting point for them at the time, but they did realize its shortcomings and deprecate it in time to support growth. I don’t know if I’d hold that against them.
There are no good code bases, only less bad ones.
From some comments I’ve read, it’s at least in better shape than kbin? A few people expressed interest in helping with that project and then went running for the hills after reading through the code.
I read from one admin that a Lemmy instance is a lot easier to set up and maintain than a kbin instance. It’s initially more complicated to set up and updates are just a super headache to deal with. That sounds like a showstopper. I mean kbin is not going to get too far if it’s that difficult to run and maintain an instance, no matter how good or bad the code.
From a user perspective kbin has a really nice looking interface, though Lemmy has more features. I’d like to see kbin do well. It’s younger than Lemmy so it’s going to be behind, but hopefully the overhead in running an instance can be resolved.
It’s probably not the only reason, but Rust is a much more attractive language/platform for devs to work with than PHP. (Source: https://survey.stackoverflow.co/2023/#section-admired-and-desired-programming-scripting-and-markup-languages)
It’s also more scalable, because it’s a compiled multi-threaded technology, while PHP is interpreted and mono-threaded.
The best code base is the repo I just created and haven’t committed anything to.
Just clone this one. Guaranteed the best repo ever! https://github.com/kelseyhightower/nocode
No the answer is that it is written in a modern language, is in its infancy and needs a lot of work to be really great, but it’s based on a certified protocol ActivityPub, that Mastodon and other “fediverse” systems use. It’s going to be really great, eventually.
“It depends” is a reference to an inside joke between developers. I agree with you that it could be really great, whether or not a code base is “good” or “bad” is just a complicated and highly subjective question to answer
