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'What Erlang/Elixir force you to do, you can voluntarily do in other languages too'. Like immutability! :P Jokes aside, I agree for basic concurrency you can

'What Erlang/Elixir force you to do, you can voluntarily do in other languages too'. Like immutability! :P Jokes aside, I agree for basic concurrency you can get pretty far with other modern languages. I think it's what brings people's attention to Erlang/Elixir, but I don't think it's the most important differentiator. It also isn't the one that Erlang's community (I can't speak to Elixir) really touts, except as one that is easily understood by those outside of it. The real benefit is fault tolerance. Everything about Erlang, the concurrency and distribution stories included, is built around fault tolerance. You need concurrency and distribution to be fault tolerant (can't have one bad process choking out others; can't have one bad machine taking the service down, etc). The immutability, the supervision tree, those also are about fault tolerance. I've written production systems in Go. It scaled better with way less tweaking than the JVM based stuff we'd written previously required. But it wasn't nearly as resilient to failure, or as predictable, as the Erlang stuff I've run in prod was.

jerf 5y ago
The funny thing is that precisely what got me into Go was replacing an Erlang system that was constantly falling over despite quite considerable efforts with a Go system that ran on a fraction of the resources, ran much more quickly, and by comparison was rock-solid. I just ported the essence of supervision trees in to Go and was off to the races. This is part of what I mean; Erlang doesn't have access to special CPU instructions that make supervision trees possible. They're just code. There's no reason you can write them in other languages. It's not even particularly hard, unless you insist on exactly matching all the accidental details of the way Erlang implements them instead of implementing their essential details in a manner idiomatic to the base language.
- lostcolony 5y ago
  "It's not even particularly hard" Define hard here? Because there is a lot of bookkeeping involved, and, yes, to get some of the effects you have in Erlang that are necessary for reliability, you'd basically have to create your own runtime atop Go. I.e., yes, if you just want to "if this process fails, restart it", you can do that trivially in another language, but "if this process fails -kill these others and restart them from a known good state-" is devilishly hard, given that Go has no way to kill a running goroutine. You can send a message along a channel of "hey, you should stop", but if code execution in that goroutine never gets there, you have no guarantees. And while the CPU doesn't have special instructions, the VM -does-. Exit signals are guaranteed in the language spec; a colocated supervisor is guaranteed to be able to both detect a failed process, and to be able to kill others. Go offers no such tooling, let alone such guarantees. I'd be quite interested if you say you did that; I suspect it was, as mentioned, just "hey, if an error comes out of this response channel, restart the goroutine". Possibly also a "here's a channel we can send 'kill' commands on, downstream goroutines should check it occasionally to see if they should terminate". A lot of bookkeeping, no guarantees.
  - jerf 5y ago
    I think you're making a mistake a lot of Erlang/BEAM/etc. (let me call it just Erlang after this) advocates make, which is to conflate Erlang's solutions to problems with the only solutions to problems. Almost no software is written in a language that has the ability to actively kill running threads externally. This is not a catastrophic problem that causes the rest of us to routinely break down in tears; it is a thing that occasionally causes bugs, merely one on a long list of such things. On the scale of problems I have, this isn't even in my top 50. When systems are written with that understanding, it's only a minor roadbump. So the fact that I don't have Erlang's exact solution to that problem isn't even remotely worth me switching (back) to Erlang for. Is it a problem? Yes, absolutely. Is it a problem worth spending extremely valuable language design budget on? Heck no, and the fact that Erlang does is a negative to me, because what they gave up to get that capability is way more important to me. Does my solution exactly match Erlang? No. Of course not. But it gets me 90% of what I care about for 10% of the effort, and in the meantime I get the other things that directly impact my job on a minute-by-minute basis, like an even halfway decent type system (it's not like Go's is some sort of masterpiece here, but it's much better than BEAM's), which Erlang sacrificed as part of its original plan. I understand why they have the type system they have, and what they got out of it, and I'd rather have a decent static type system and solve those problems another way, which happens to be the conclusion pretty much everyone else has come to as well. Again, genius thinking in the 1990s, way ahead of everyone else, don't let my current assessment of Erlang diminish the fact I deeply respect what it did in its time... but not a solution I have much interest in in 2021.
  - nivertech 5y ago
    The idiomatic solution for GoLang would be to use kubernetes, but it will come with the increase in the operational complexity.
- pdimitar 5y ago
  > The funny thing is that precisely what got me into Go was replacing an Erlang system that was constantly falling over despite quite considerable efforts As the meme goes, Will Ferrel gets a deep puff of smoke from his cigarette and says "I don't believe you". I agree that Go has better type system and Erlang/Elxir/BEAM languages in general. Absolutely. But I think you're showing bias and were already looking for an excuse not to use Erlang. That's completely fair but I think you are non-fairly misrepresenting the exact merits of the decision. > This is part of what I mean; Erlang doesn't have access to special CPU instructions that make supervision trees possible. They're just code. Everything is "just code", dude. Yours is no more an argument than technologically advanced aliens visiting us and exclaiming "How come you don't have super-alloys that can withstand atmosphere entry without losing atoms? It's just chemistry!" --- I am getting the vibe that you're one of those super-programmers that can tinker with everything and the computers have no secrets from them. That, or you are bragging too much. And you should know something else -- I am not a huge fan of Elixir these days. I work with it for 5 years but it's showing some cracks and lack of community (and core team) attention in critically important areas for the ecosystem's advancement -- like compiler instrumentation, or tooling to modify code in an automated way -- not to mention the dynamic typing. I get it, it's far from the magic many fans are making it out to be. But you are discounting very real advantages in a very dismissive manner. For the record, if one Rust runtime gains most of Erlang's OTP capabilities tomorrow then I'll switch to Rust for 100% of my work next week. But nobody has surpassed OTP's capabilities. Finally, I'll also agree that we don't need 100% of OTP -- that much we are in complete agreement on. But as you yourself pointed out, cancelling running background threads is still mostly an unsolved problem so just scoffing at a technology that has mostly achieved that is a very uncharitable take that makes me question your other arguments and wonder if they are not emotional arguments. I am by no means a super-programmer. On my non-humble bragging days I'd say that I'm only very slightly above average. But I've tried to duplicate OTP in at least 3 other languages and I failed miserably every time (Java was one of them). So yeah, don't just say "meh, I can invent OTP everywhere else". No. You really can't. If you can, open-source this effort and I'll donate, I promise.

jerf 5y ago

The funny thing is that precisely what got me into Go was replacing an Erlang system that was constantly falling over despite quite considerable efforts with a Go system that ran on a fraction of the resources, ran much more quickly, and by comparison was rock-solid. I just ported the essence of supervision trees in to Go and was off to the races. This is part of what I mean; Erlang doesn't have access to special CPU instructions that make supervision trees possible. They're just code. There's no reason you can write them in other languages. It's not even particularly hard, unless you insist on exactly matching all the accidental details of the way Erlang implements them instead of implementing their essential details in a manner idiomatic to the base language.

lostcolony 5y ago
"It's not even particularly hard" Define hard here? Because there is a lot of bookkeeping involved, and, yes, to get some of the effects you have in Erlang that are necessary for reliability, you'd basically have to create your own runtime atop Go. I.e., yes, if you just want to "if this process fails, restart it", you can do that trivially in another language, but "if this process fails -kill these others and restart them from a known good state-" is devilishly hard, given that Go has no way to kill a running goroutine. You can send a message along a channel of "hey, you should stop", but if code execution in that goroutine never gets there, you have no guarantees. And while the CPU doesn't have special instructions, the VM -does-. Exit signals are guaranteed in the language spec; a colocated supervisor is guaranteed to be able to both detect a failed process, and to be able to kill others. Go offers no such tooling, let alone such guarantees. I'd be quite interested if you say you did that; I suspect it was, as mentioned, just "hey, if an error comes out of this response channel, restart the goroutine". Possibly also a "here's a channel we can send 'kill' commands on, downstream goroutines should check it occasionally to see if they should terminate". A lot of bookkeeping, no guarantees.
- jerf 5y ago
  I think you're making a mistake a lot of Erlang/BEAM/etc. (let me call it just Erlang after this) advocates make, which is to conflate Erlang's solutions to problems with the only solutions to problems. Almost no software is written in a language that has the ability to actively kill running threads externally. This is not a catastrophic problem that causes the rest of us to routinely break down in tears; it is a thing that occasionally causes bugs, merely one on a long list of such things. On the scale of problems I have, this isn't even in my top 50. When systems are written with that understanding, it's only a minor roadbump. So the fact that I don't have Erlang's exact solution to that problem isn't even remotely worth me switching (back) to Erlang for. Is it a problem? Yes, absolutely. Is it a problem worth spending extremely valuable language design budget on? Heck no, and the fact that Erlang does is a negative to me, because what they gave up to get that capability is way more important to me. Does my solution exactly match Erlang? No. Of course not. But it gets me 90% of what I care about for 10% of the effort, and in the meantime I get the other things that directly impact my job on a minute-by-minute basis, like an even halfway decent type system (it's not like Go's is some sort of masterpiece here, but it's much better than BEAM's), which Erlang sacrificed as part of its original plan. I understand why they have the type system they have, and what they got out of it, and I'd rather have a decent static type system and solve those problems another way, which happens to be the conclusion pretty much everyone else has come to as well. Again, genius thinking in the 1990s, way ahead of everyone else, don't let my current assessment of Erlang diminish the fact I deeply respect what it did in its time... but not a solution I have much interest in in 2021.
- nivertech 5y ago
  The idiomatic solution for GoLang would be to use kubernetes, but it will come with the increase in the operational complexity.
pdimitar 5y ago
> The funny thing is that precisely what got me into Go was replacing an Erlang system that was constantly falling over despite quite considerable efforts As the meme goes, Will Ferrel gets a deep puff of smoke from his cigarette and says "I don't believe you". I agree that Go has better type system and Erlang/Elxir/BEAM languages in general. Absolutely. But I think you're showing bias and were already looking for an excuse not to use Erlang. That's completely fair but I think you are non-fairly misrepresenting the exact merits of the decision. > This is part of what I mean; Erlang doesn't have access to special CPU instructions that make supervision trees possible. They're just code. Everything is "just code", dude. Yours is no more an argument than technologically advanced aliens visiting us and exclaiming "How come you don't have super-alloys that can withstand atmosphere entry without losing atoms? It's just chemistry!" --- I am getting the vibe that you're one of those super-programmers that can tinker with everything and the computers have no secrets from them. That, or you are bragging too much. And you should know something else -- I am not a huge fan of Elixir these days. I work with it for 5 years but it's showing some cracks and lack of community (and core team) attention in critically important areas for the ecosystem's advancement -- like compiler instrumentation, or tooling to modify code in an automated way -- not to mention the dynamic typing. I get it, it's far from the magic many fans are making it out to be. But you are discounting very real advantages in a very dismissive manner. For the record, if one Rust runtime gains most of Erlang's OTP capabilities tomorrow then I'll switch to Rust for 100% of my work next week. But nobody has surpassed OTP's capabilities. Finally, I'll also agree that we don't need 100% of OTP -- that much we are in complete agreement on. But as you yourself pointed out, cancelling running background threads is still mostly an unsolved problem so just scoffing at a technology that has mostly achieved that is a very uncharitable take that makes me question your other arguments and wonder if they are not emotional arguments. I am by no means a super-programmer. On my non-humble bragging days I'd say that I'm only very slightly above average. But I've tried to duplicate OTP in at least 3 other languages and I failed miserably every time (Java was one of them). So yeah, don't just say "meh, I can invent OTP everywhere else". No. You really can't. If you can, open-source this effort and I'll donate, I promise.