A Brief Guide to OTP in Elixir
serokell.io
A Brief Guide to OTP in Elixir
1–10 of 100 posts
Re: A Brief Guide to OTP in Elixir
#2I'd just like to point out that while knowledge of OTP is a good thing for an Elixir developer, it isn't really needed for most application development. There are excellent libraries and frameworks that leverage OTP to provide a lot of value to their users, and most of us who use Elixir in industry just use those libraries.
Re: A Brief Guide to OTP in Elixir
#3OTP = Open Telecom Platform [1], though I think the full name is avoided nowadays.
On an unrelated note, I've always been fascinated with the Erlang VM. The idea that you could hot-load modules and have multiple versions of the same module running at once seems really useful. I wonder why other runtimes haven't adopted these features?
Re: A Brief Guide to OTP in Elixir
#4> Every time the loop runs, it will check the top of the mailbox (mailbox is last-in-first-out) for messages that match what we need and process them.
Nope, erlang mailbox is fifo with filtering. When a process sends messages, they are delivered in the same order they were sent.
Re: A Brief Guide to OTP in Elixir
#5> In real life, we don’t need to write code with receive do loops. Instead, we use one of the behaviours created by people much smarter than us.
I make more than half of my income from Elixir. That said, the naive receive loop is much easier to understand than any of the GenServer examples. They pollute the module logic with all that handle_* boilerplate. I believe that neither Erlang nor Elixir got the right abstraction there. Method definition in any OO language is easier to understand. At least Elixir should have taken Agent and made it an invisible part of the language. All those calls to Agent in this example https://elixir-lang.org/getting-started/mix-otp/agent.html are still boilerplate.
Re: A Brief Guide to OTP in Elixir
#6OTP = Open Telecom Platform [1], though I think the full name is avoided nowadays. On an unrelated note, I've always been fascinated with the Erlang VM. The idea that you could hot-load modules and have multiple versions of the same module running at once seems really useful. I wonder why other runtimes haven't adopted these features? [1] https://en.wikipedia.org/wiki/Open_Telecom_Platform
> I wonder why other runtimes haven't adopted these features?
Probably mainly due to shared memory. When you know your data can be modified only in one place, changing data structure is easier. Try changing a struct when some other code is using it. It would require a lock for every object in memory.
Re: A Brief Guide to OTP in Elixir
#7> In real life, we don’t need to write code with receive do loops. Instead, we use one of the behaviours created by people much smarter than us. I make more than half of my income from Elixir. That said, the naive receive loop is much easier to understand than any of the GenServer examples. They pollute the module logic with all that handle_* boilerplate. I believe that neither Erlang nor Elixir got the right abstrac…
There are libraries that do this, like https://github.com/sasa1977/exactor but the Elixir community nowadays seems more conservative about macro "magic" than it was a few years ago. Sasa has written an entire book about OTP and if he doesn't recommend using his own library I wouldn't argue with him, but I haven't written a Genserver myself in years despite writing Elixir for a living the past 3.5 years. If you are going to learn how they work though, it makes sense to stick to how Erlang actually implements them.
Re: A Brief Guide to OTP in Elixir
#8I'd just like to point out that while knowledge of OTP is a good thing for an Elixir developer, it isn't really needed for most application development. There are excellent libraries and frameworks that leverage OTP to provide a lot of value to their users, and most of us who use Elixir in industry just use those libraries.
Would you mind linking to a couple of them? I don't know anything about Elixir (but am very comfortable in a lot of other languages), and am interested in the kind of thing more experienced people are using with Elixir. Thanks!
Re: A Brief Guide to OTP in Elixir
#9> Forget using a million different technologies for things like background jobs, OTP can supply you with everything.
It's true but in practice this usually doesn't pan out.
For example with just background jobs alone there's the idea of queues, tracking failures / successes, exponential back-off retries, guaranteeing uniqueness, draining, periodic tasks and everything else you'd likely want in a production ready app.
Typically you'd use Redis, Postgres or something else to help with this. Fortunately https://github.com/sorentwo/oban exists and uses Postgres as a back-end with close to 10,000 lines of Elixir.
Re: A Brief Guide to OTP in Elixir
#10I'd just like to point out that while knowledge of OTP is a good thing for an Elixir developer, it isn't really needed for most application development. There are excellent libraries and frameworks that leverage OTP to provide a lot of value to their users, and most of us who use Elixir in industry just use those libraries.
Would you mind linking to a couple of them? I don't know anything about Elixir (but am very comfortable in a lot of other languages), and am interested in the kind of thing more experienced people are using with Elixir. Thanks!
For web applications, Phoenix is very popular: https://github.com/phoenixframework/phoenix; it uses some OTP directly and its dependencies like the web-server Cowboy use it as well.
DB development usually uses Ecto: https://github.com/elixir-ecto/ecto, it has OTP servers for connection pooling and other tasks.
For managing background tasks I use Honeydew: https://github.com/koudelka/honeydew