Some random thoughts as somebody who codes a lot of Node.js at work and a lot Go in my freetime (and sometimes at work):
Did you try using pprof and the other tooling go provides to better understand your performance limitations? Tooling is a lot better in go ecosystem for understanding CPU and memory consumption, so if/when you run into into issues with Node you're going to be in a world of pain (this is basically a large portion of my job in a large node.js code base in the $day_job). You'll basically have to resort to using lldb and heapdumps in the Node world. I'm surprised the number of concurrent clients you go with Go was so small. I know lots of people using Go and Gorilla websockets that exceed 1.5k clients with similar memory constraints. To be perfectly honest, it sounds like you're doing something wrong.
As of Go 1.4, the default stack size per goroutine was 2KB and not 4KB.
If you add in TypeScript, you'll have a better type system than Go provides in the Node ecosystem. That's a huge point for using Node.js, especially if there are multiple contributors and the code base lasts for many years.
Having worked on large backend codebases in both TS and JS, the difference is stark. The TS API in my case had something like 90% less errors, and those were all subtle bugs in business logic.
On the other hand, the large JS API over time had all sorts of unexpected type errors and undefined behavior. I'm aware that this is anecdotal evidence, but TS is pretty much a no-brainer now on backend.
There are quite a few things I like about Go, but it's just so hard to leave the safety and reliability of TypeScript. Go's limited type system is its fatal handicap IMO.
> Tooling is a lot better in go ecosystem for understanding CPU and memory consumption, so if/when you run into into issues with Node you're going to be in a world of pain (this is basically a large portion of my job in a large node.js code base in the $day_job).
Is there no movement to change that? What about `node --inspect`?
It's interesting he's referencing the Disruptor pattern. I wrote the Go port of the Disruptor implementation that he links to (https://github.com/smartystreets/go-disruptor) a while back and it performed beautifully. That said, channels weren't slow either. Our finding showed that we could easily push 10-30 million messages per second through a channel, so I'm struggling to understand what he defines as slow. That said, with a few tweaks to the Go memory model and I think I could take the Disruptor project to completion. Without those tweaks, I have to do memory fences in assembly.
On a really slow, in-order-execution processor w/ tiny caches and fairly awful front-side bus that's also all responsible for managing the network connection over USB?
The thing about Intel non-Atom level hardware is that Intel has spent a lot of money over the better part of two decades packing processors full of features that make all kinds of theoretically inefficient things run pretty fast.
This is not true of the Broadcom SoCs on a Raspberry Pi.
have you tried seeing how many messages you can push if you change how often the garbage collector runs? after seeing the Golang garbage collector blog post from cloudflare?
"That said, I think Node is not the best system to build a massive server web. I would use Go for that. And honestly, that’s the reason why I left Node. It was the realization that: oh, actually, this is not the best server-side system ever."
Am I missing something? In the interview Ryan Dahl said that if he were to build a "massively distributed DNS server" he would not chose node. And then again "Node is not the best system to build a massive server web".
But he also said that for less massive projects Node could be the right fit.
I am a huge JS fan and I agree, for purely server side plays it’s probably not the best choice.
I actually think Node has not yet realized its best feature. It’s still in a research phase while it learns its best trick: components that bridge the client and server.
Meteor was an attempt. And server side boot in the MVC frameworks is another attempt. But both are wrong. Both try to create anonymous code that doesn’t know whether it’s on the client or server. But the client and server are different. The winning solution will acknowledge that, and just help the component do both. Once we have components that span client and server we can then write applications that don’t deal directly with HTTP. But not before.
OP is complaining about Goroutine stack size at 4kb per connection, his test shows that Node8 is taking up to 150MB of memory with 5k users, 4kb*5k = 20MB for Go memory, I don't understand how Nodejs can take less memory than Go, and without real numbers / test I'm pretty sure he's doing something wrong somewhere.
From my experience on some large prod deployment, Nodejs app takes much more memory and CPU vs Go app for doing similar work.
I count three goroutines per connection: One for ChatHandler.Loop (when invoked from ChatService), one for ChatHandler.socketReaderLoop and one for socketWriterLoop.
Each ChatHandler has three (buffered) channels: outgoingInfo.channel, sockChannel, readErrorChannel (not buffered)
There are some things that could cause bottle necks that are not related to goroutines and channels: Every published message calls GroupInfoManager.GetUsers to get a list of all the users in a group. That can be expensive (I don't know if it is or isn't). And then for every user in a channel, their userOutGoingInfo is retrieved.
I would suggest profiling before switching languages.
EDIT: changed "benchmarking" to "profiling"
EDIT2: changed "are likely to" to "could" (... cause bottle necks) since I don't know
It's 2 per connection, so that's 40MB of RAM. The OP also said that was minor compared to the channel overhead -- it seems the number of channels was exponential to the number of users in a room.
One thing to note is that they were using boltdb, which is an in process K/V store designed for high read loads, and doing a lot of writes to it. boltdb also tends to use a lot of memory, as it's using a mmap'd file. The switch also moved them to sqlite, which I would say is a much better fit for what they are doing, but means a lot of this is an apples and oranges comparison.
If instead of ditching Go he had posted some kind of help request to the 'gonuts' group / mailing list, I'm 100% certain that several people would've helped him with code reviews and feedback. I've seen this happen in the gonuts group countless times, including contributions/assistance from the core Go team that hang out there :)
As noted by other commenters, below, the code seems to have some issues. And, if it still didn't perform well after addressing those, somebody in gonuts would've helped teach how to profile it, and then expert-eyes could have looked over the profiler output and provided further feedback.
So, I am not a big fan of Javascript. I do not despise it or anything, I just never got to like it. I guess.
I did really love POE, though, so when I heard of Node.JS, I thought I will probably like this very much.
I am not sure what happened. I think it was the tutorials being always out of date. Node.js seem so be such a fast-moving target. I do not mind asynchronous, callback-driven code. But when a tutorial that was written three months ago fails to run because some library had a breaking API change in between, that tends to drive me away.
Think of Go what you want, but its policy towards backward compatibility is a big plus.
You're comparing core libraries of Go with non-core libraries of Node.js. Since Go libraries are not versioned without a tool like dep, you're putting trust that master doesn't have breaking changes vs hoping the maintainer follows SemVer correctly. In fact, even the core Go team has problem with this and has to revert changes to things under golang.org/x/ when they break backwards compatibility.
I feel his pain about the lack of decent WebSockets support in Rust. There's a few Websockets implementations but all of them are meant to run on a separate port from the web server. As in, they want you to run your web server on port 443 and the websocket on... Something else. Which makes zero sense (browsers will deny access to the second port because of security features related to SSL certificates).
Also, unless you go low level (lower than frameworks like Tokio) you can't easily access file descriptors to watch them (e.g. epoll) for data waiting to be read. It makes it difficult to use WebSockets for their intended purpose: Real-time stuff.
Rust needs a web framework that has built-in support for Websockets (running on the same port as the main web server) and also provides low-level access to things like epoll. Something like a very thin abstraction on top of mio (that still gives you direct access to the mio TcpListener directly).
In my attempts to get Tokio reading a raw file descriptor I just couldn't get it working. I opened a bug and was told that raw fd support wasn't really supported (not well-tested because it only works on Unix and cross-cross-platform stuff is a higher priority). Very frustrating.
I wish the Tokio devs didn't make the underlying mio TcpListener private in their structs.
Interesting - I wonder if a much thinner, simpler library is the answer here.
The part with websocket on same port is interesting, did you hear reasons why that hasn't been done?
I've dabbled a lot with Go. I've found it _very_ effective to a wide variety of problems I don't really have most of the time.
If I wanted to implement RAFT I would probably pick Go. If I want a simple REST/GraphSQL server then Node.js is so much easier. `async/await` is nicer for me than goroutines and I find my code easier to reason about.
Full disclosure: I'm a Node.js core team member and a Go fan. Part of my reasoning might be how much nicer Node.js got these last couple of years.
I think it's a decision between levels of abstraction, with Node being a level higher than Go in that area. Probably easier to use it to link services together (glue apps), because with Go you'll probably have to define types and such a lot.
I've been working on a similar project lately which also uses the gorilla/websocket library. I just tested connecting 1500 connections in parallel like was done in this link for Raspchat, and my application only uses 75 MB along with all other overhead within it. I'm not sure how this would cause a Raspberry Pi with 512MB memory to thrash and come to a crawl unless Raspchat has a ton of other overhead outside of connection management.
I'm working on the exact opposite migration at the moment :)
(Most of our stack is Go, but we use the excellent Faye library written in Node)
The Node code is really well done. https://faye.jcoglan.com/
Nothing wrong with the Node codebase. In our case we just had to add a lot of business logic. I could have done that in Node (we did for a long time), but I decided that with the latest set of changes we'd bring this component in line with the rest of our infrastructure.
It's hard to know without the code, but the author seems to be doing a few things wrong:
1. You only need a few channels, not N. Maybe 4-5 is enough.
2. In terms of goroutines you only need as many as are actively communicating with your server. So creating a new connection creates a goroutine, sending a message to a channel creates a goroutine etc.
3. You need something like Redis if you want to support multiple nodes
Besides that, as many here have pointed out, this sounds like a problem somewhere hiding in the Go code ruining the performance, it is certainly true, that an event-handler based approach is increadible efficient to manage a high number of simple requests with limited resources. If every request can be handled in a single event, it only has advantages. It does not require many resources and you don't have to deal with any synchronisation issues.
In many typical web applications you have less if no interaction between the connections, but rather complex logic running at each request. There the event-based approach, which must not block, is getting more complex to manage and you want to use all cpus in the system. There a goroutine based approach should shine much stronger, as the goroutines may block and you don't have to spread your program logic across callbacks.
As someone who has neither Go, nodejs, or RPi experience the results seem surprising. Many have already commented that the author must have been doing something wrong; the code is there for everyone to see, so could some wiser gopher take a look and tell whats actually going on here?
I did, and wrote some else in here, but a lot of it boils down to poor choices in the Go code. They're using an embedded K/V store designed for high read loads and are writing to it often, there's really complex concurrent lockfree datastructures, and very poorly designed deserialization systems. On the flip side, they switched to Node and to a db that can deal with mixed read/write, nixed all the complex datastructures, and node can deal with unstructured JSON.
This is a very interesting direction to take. I've built a lot of my personal stuff on JS, and TBH, the one thing I really wish I had right now was a statically typed codebase.
I spend a lot of time thinking about why I'm creating a certain data model, whether I might need to change something in future, etc. About 60% of my productive time is spent thinking about how and why, so I hardly refactor. However, when the need arises, I wish I had something like Kotlin.
For the past few months I've been writing new JS code in TS, adding types here and there, I haven't tried out Kotlin on JS, but I'm hoping to go there.
I'm learning Go, but for other reasons. I find JS to be performant, my oldest active codebase has been around since the v0.8 days.
Even better, they play fairly well together. You can work in Purescript but still provide well typed integration points for contributors that can't.
And uh, no one here is talking about how fantastically slow Go channels are. But I just saw the code last night, and it's not hard for 20 year old techniques to beat out a "futex for literally every message send" technique.
I've refactored (or should I say, annotated) a >5K LOC node.js app to Typescript. It's an incredibly powerful system. Structural typing gives you 90% of the flexibility of dynamic typing with 90% of the security of classical static typing (of course this is just a feeling - it's not like I'm presenting a scientific result here).
I had more than 90% test coverage, with meaningful tests so I didn't really find too many bugs but I could delete a lot of tests and run-time checks which were making sure stupid input don't cause unexpected behavior.
When I check my commits & logs, LOC/hour didn't change significantly but bugs/month reduced to nearly half if my SQL skills aren't failing me.
I don't use Go but I find the reasoning fueled by a confirmation bias to pick JS.
goroutines are now 2k. If you use 2 goroutines per connection that's 4k. If you have 10k connections that's roughly 20mb only which is very reasonable.
Why two (or three) go routines per connection? Why not one net socket (for reads) and two channels (one for writes, other for pub/sub) and select() between them? It seems like the OP is trying too hard to avoid event loops.
Please upvote parent. This is the first thing that struck my mind too. golang offers `select` for non-blocking calls. Deeply skeptical that node.js is the best solution for a chat service. (unless the backend is serving rendered UI's)
> Since go does not have generics or unions my only option right now is to decode message in a base message struct with just the @ JSON field and then based on that try to decode message in a full payload struct.
If he is in control of his protocol, why did he not shape it to suit his parser library? Instead of this:
I support ports of a Golang library and protocol that did this and I am very tired of having to suffer Go's anemic type system in every other language I work with.
Please stop infecting us with Go-specific type tags (that btw make the protocol versioning story much more complicated) and either demand Go support generics like every other modern statically typed language, or accept your language is ill-equipped for parsing and check if things = nil a lot more.
Don't advocate for pushing your tooling's problems out on your peers.
Better pattern is http://eagain.net/articles/go-json-kind/
Then you do one switch to get the correct message type to decode into, and boom, you can just `.Run` or `.Handle` or however you design the interface, and you are done.
This is "an" option for go, but I prefer a type or kind field. This plays better in other languages like C#, Java, TypeScript, and etc in my experience.
I know very little about both Node and Go (currently learning the latter but haven't done anything really interesting so far :) - but, really it's hard to believe that Elixir/Phoenix would be disregarded so quickly if the crux of the problem is to have good pub/sub support.
I think it’s the event loop model reuses more per connection. He mentions nothing is stopping you from implementing an event loop model for the pub-sub in go, just there wasn’t any library support and he didn’t want to spend time building it out when it is the default model in Node.
I actually did some experiments with Elixir, and my conclusion from benchmarking them was that Elixir is in fact significatively faster and consumed less memory than Node. In any case, Elixir is a great language, and even if BEAM was slower than Node I would still suggest to choose Elixir (+Phoenix) over JavaScript.
[+] [-] iends|8 years ago|reply
Did you try using pprof and the other tooling go provides to better understand your performance limitations? Tooling is a lot better in go ecosystem for understanding CPU and memory consumption, so if/when you run into into issues with Node you're going to be in a world of pain (this is basically a large portion of my job in a large node.js code base in the $day_job). You'll basically have to resort to using lldb and heapdumps in the Node world. I'm surprised the number of concurrent clients you go with Go was so small. I know lots of people using Go and Gorilla websockets that exceed 1.5k clients with similar memory constraints. To be perfectly honest, it sounds like you're doing something wrong.
As of Go 1.4, the default stack size per goroutine was 2KB and not 4KB.
If you add in TypeScript, you'll have a better type system than Go provides in the Node ecosystem. That's a huge point for using Node.js, especially if there are multiple contributors and the code base lasts for many years.
[+] [-] chmln|8 years ago|reply
Having worked on large backend codebases in both TS and JS, the difference is stark. The TS API in my case had something like 90% less errors, and those were all subtle bugs in business logic.
On the other hand, the large JS API over time had all sorts of unexpected type errors and undefined behavior. I'm aware that this is anecdotal evidence, but TS is pretty much a no-brainer now on backend.
[+] [-] ryanplant-au|8 years ago|reply
[+] [-] MuffinFlavored|8 years ago|reply
Is there no movement to change that? What about `node --inspect`?
[+] [-] jonathanoliver|8 years ago|reply
[+] [-] im_down_w_otp|8 years ago|reply
The thing about Intel non-Atom level hardware is that Intel has spent a lot of money over the better part of two decades packing processors full of features that make all kinds of theoretically inefficient things run pretty fast.
This is not true of the Broadcom SoCs on a Raspberry Pi.
[+] [-] Zekio|8 years ago|reply
[+] [-] unknown|8 years ago|reply
[deleted]
[+] [-] MrBuddyCasino|8 years ago|reply
"That said, I think Node is not the best system to build a massive server web. I would use Go for that. And honestly, that’s the reason why I left Node. It was the realization that: oh, actually, this is not the best server-side system ever."
Full interview: https://www.mappingthejourney.com/single-post/2017/08/31/epi...
[+] [-] monsieurbanana|8 years ago|reply
But he also said that for less massive projects Node could be the right fit.
Isn't that basically agreeing with the blog post?
I don't see what's your point.
[+] [-] erikpukinskis|8 years ago|reply
I actually think Node has not yet realized its best feature. It’s still in a research phase while it learns its best trick: components that bridge the client and server.
Meteor was an attempt. And server side boot in the MVC frameworks is another attempt. But both are wrong. Both try to create anonymous code that doesn’t know whether it’s on the client or server. But the client and server are different. The winning solution will acknowledge that, and just help the component do both. Once we have components that span client and server we can then write applications that don’t deal directly with HTTP. But not before.
That’ll be a huge thing.
[+] [-] spraak|8 years ago|reply
[+] [-] Thaxll|8 years ago|reply
From my experience on some large prod deployment, Nodejs app takes much more memory and CPU vs Go app for doing similar work.
[+] [-] sebcat|8 years ago|reply
Each ChatHandler has three (buffered) channels: outgoingInfo.channel, sockChannel, readErrorChannel (not buffered)
There are some things that could cause bottle necks that are not related to goroutines and channels: Every published message calls GroupInfoManager.GetUsers to get a list of all the users in a group. That can be expensive (I don't know if it is or isn't). And then for every user in a channel, their userOutGoingInfo is retrieved.
I would suggest profiling before switching languages.
EDIT: changed "benchmarking" to "profiling" EDIT2: changed "are likely to" to "could" (... cause bottle necks) since I don't know
[+] [-] bryanlarsen|8 years ago|reply
[+] [-] tootie|8 years ago|reply
[+] [-] Vendan|8 years ago|reply
[+] [-] Vendan|8 years ago|reply
Boltdb was being handled badly: https://github.com/maxpert/raspchat/blob/79315d861968c126670... You should be using bolt's helper funcs, so you don't forget to close the transaction
https://github.com/maxpert/raspchat/blob/79315d861968c126670... At least this is actually deferred, but still.
https://github.com/maxpert/raspchat/blob/79315d861968c126670... These messages are horrifying, would be much better switching back to json and implementing a strategy like http://eagain.net/articles/go-dynamic-json/
It copies in an unlicensed "snowflake generation" thing? https://github.com/maxpert/raspchat/blob/79315d861968c126670... and then essentially relicenses it? That's illegal...?
They do have a better json pattern for some stuff: https://github.com/maxpert/raspchat/blob/79315d861968c126670... but I'd still steer away from reflection based, there's so much better ways of doing this stuff, like so: http://eagain.net/articles/go-json-kind/
[+] [-] jimsmart|8 years ago|reply
As noted by other commenters, below, the code seems to have some issues. And, if it still didn't perform well after addressing those, somebody in gonuts would've helped teach how to profile it, and then expert-eyes could have looked over the profiler output and provided further feedback.
[+] [-] krylon|8 years ago|reply
I did really love POE, though, so when I heard of Node.JS, I thought I will probably like this very much.
I am not sure what happened. I think it was the tutorials being always out of date. Node.js seem so be such a fast-moving target. I do not mind asynchronous, callback-driven code. But when a tutorial that was written three months ago fails to run because some library had a breaking API change in between, that tends to drive me away.
Think of Go what you want, but its policy towards backward compatibility is a big plus.
[+] [-] iends|8 years ago|reply
[+] [-] marcusramberg|8 years ago|reply
[+] [-] riskable|8 years ago|reply
Also, unless you go low level (lower than frameworks like Tokio) you can't easily access file descriptors to watch them (e.g. epoll) for data waiting to be read. It makes it difficult to use WebSockets for their intended purpose: Real-time stuff.
Rust needs a web framework that has built-in support for Websockets (running on the same port as the main web server) and also provides low-level access to things like epoll. Something like a very thin abstraction on top of mio (that still gives you direct access to the mio TcpListener directly).
In my attempts to get Tokio reading a raw file descriptor I just couldn't get it working. I opened a bug and was told that raw fd support wasn't really supported (not well-tested because it only works on Unix and cross-cross-platform stuff is a higher priority). Very frustrating.
I wish the Tokio devs didn't make the underlying mio TcpListener private in their structs.
[+] [-] indream|8 years ago|reply
https://github.com/tomaka/rouille
https://github.com/actix/actix-web
Ref: https://github.com/flosse/rust-web-framework-comparison
[+] [-] stmw|8 years ago|reply
[+] [-] inglor|8 years ago|reply
If I wanted to implement RAFT I would probably pick Go. If I want a simple REST/GraphSQL server then Node.js is so much easier. `async/await` is nicer for me than goroutines and I find my code easier to reason about.
Full disclosure: I'm a Node.js core team member and a Go fan. Part of my reasoning might be how much nicer Node.js got these last couple of years.
[+] [-] Cthulhu_|8 years ago|reply
[+] [-] dullgiulio|8 years ago|reply
Can you elaborate on why you think async/await is easier (for you) to reason about than a goroutine and a channel?
[+] [-] clandry94|8 years ago|reply
[+] [-] tschellenbach|8 years ago|reply
It's hard to know without the code, but the author seems to be doing a few things wrong:
1. You only need a few channels, not N. Maybe 4-5 is enough. 2. In terms of goroutines you only need as many as are actively communicating with your server. So creating a new connection creates a goroutine, sending a message to a channel creates a goroutine etc. 3. You need something like Redis if you want to support multiple nodes
For inspiration check out this awesome project: https://github.com/faye/faye-redis-node
This will perform well in Node and even better in Go.
[+] [-] _ph_|8 years ago|reply
In many typical web applications you have less if no interaction between the connections, but rather complex logic running at each request. There the event-based approach, which must not block, is getting more complex to manage and you want to use all cpus in the system. There a goroutine based approach should shine much stronger, as the goroutines may block and you don't have to spread your program logic across callbacks.
[+] [-] zokier|8 years ago|reply
[+] [-] Vendan|8 years ago|reply
[+] [-] nevi-me|8 years ago|reply
I spend a lot of time thinking about why I'm creating a certain data model, whether I might need to change something in future, etc. About 60% of my productive time is spent thinking about how and why, so I hardly refactor. However, when the need arises, I wish I had something like Kotlin.
For the past few months I've been writing new JS code in TS, adding types here and there, I haven't tried out Kotlin on JS, but I'm hoping to go there.
I'm learning Go, but for other reasons. I find JS to be performant, my oldest active codebase has been around since the v0.8 days.
[+] [-] KirinDave|8 years ago|reply
TypeScript and PureScript.
Even better, they play fairly well together. You can work in Purescript but still provide well typed integration points for contributors that can't.
And uh, no one here is talking about how fantastically slow Go channels are. But I just saw the code last night, and it's not hard for 20 year old techniques to beat out a "futex for literally every message send" technique.
[+] [-] egeozcan|8 years ago|reply
I had more than 90% test coverage, with meaningful tests so I didn't really find too many bugs but I could delete a lot of tests and run-time checks which were making sure stupid input don't cause unexpected behavior.
When I check my commits & logs, LOC/hour didn't change significantly but bugs/month reduced to nearly half if my SQL skills aren't failing me.
[+] [-] halayli|8 years ago|reply
goroutines are now 2k. If you use 2 goroutines per connection that's 4k. If you have 10k connections that's roughly 20mb only which is very reasonable.
[+] [-] tankenmate|8 years ago|reply
[+] [-] lenkite|8 years ago|reply
[+] [-] majewsky|8 years ago|reply
If he is in control of his protocol, why did he not shape it to suit his parser library? Instead of this:
Do this: Then you can read both types of messages into a single Go type, After parsing, that element which is not nil tells you which type of message was sent.[+] [-] KirinDave|8 years ago|reply
Please stop infecting us with Go-specific type tags (that btw make the protocol versioning story much more complicated) and either demand Go support generics like every other modern statically typed language, or accept your language is ill-equipped for parsing and check if things = nil a lot more.
Don't advocate for pushing your tooling's problems out on your peers.
[+] [-] Vendan|8 years ago|reply
[+] [-] Rapzid|8 years ago|reply
[+] [-] dudul|8 years ago|reply
[+] [-] _Codemonkeyism|8 years ago|reply
[+] [-] mattnewton|8 years ago|reply
[+] [-] igotsideas|8 years ago|reply
[+] [-] iends|8 years ago|reply
[+] [-] kenhwang|8 years ago|reply
[+] [-] pera|8 years ago|reply