4 ms·

Nginx and Lua

61 points by transmit101 14y ago

jot 14y ago
Can you provide us with an idea of how much this improved performance or how many more requests it allowed you to handle? Were there time or cost savings compared to alternative approaches?
- transmit101 14y ago
  There's no single self-contained solution in the post really, it's more an illustration of a number of useful things that Lua can be used for. I might try to put another post together at some stage though. For us our main goal is to prevent the majority of requests from even reaching the Rails stack. We've done this by introducing full page caching across the site, for both logged in and logged out users. This means that only a small percentage of requests at peak times need to touch Rails or any database at all - everything is served by Nginx. This hasn't been without its challenges. The last section of this post might give a clue as to how we've solved the most difficult ones. I will think about a post tackling this whole subject but I need to think about how to get it across, it's not easy.
  - themgt 14y ago
    Yeah, we're using this to map hosts->upstream servers/redirects in a redis DB, and then there's no need for managing vhost files to add/remove/scale sites (or adding/swapping nginx servers). Writing code instead of config files is very powerful
- taligent 14y ago
  It is non-blocking and executed within Nginx itself so it is supposed to be very fast. The Lua work has been done by Chinese engineers from Taobao and Weibo which obviously get a huge amount of traffic.
  - transmit101 14y ago
    I didn't know about the Weibo connection. It is a very fast module, and non-blocking, but just as importantly it provides the flexibility to avoid sending requests from Nginx to slow backend servers (Ruby, Python, whatever) at all. In real-life situations, this is the most important bit. As I said in another thread, we've done some good work to tie this in with our Rails app. We now page cache almost every important request, even for logged in users. This means Rails and our databases are protected from most spikes of traffic. I would like to write a post describing this in more detail, I need to think how to get it across though.
voxx 14y ago
LUA ON THE FRONT PAGE There is a god
slurgfest 14y ago
Is there any reason in principle why this has to be done with Lua and not with other interpreted languages? Once you are writing interpreted code which reads request data and interacts with Redis you are not that far from what a normal Ruby or Python web app does anyway.
- FraaJad 14y ago
  Two reasons: 1. Lua is very easy to embed into C code. Python and Ruby, not even in the same ball park ... 2. This nginx+lua config is often implemented using LuaJIT. Luajit is the fastest dynamic language. it's speed is very close to Java's in many cases. So, very little performance penalty..
  - slurgfest 14y ago
    Are there real numbers showing that the Python interpreter's performance would be unsuitable for this purpose? (How about pypy's, since JIT seems to be one of the keywords here?) Or has it been decided (as if a priori) that Lua is the only workable solution?
    - ansible 14y ago
      Is Python unsuitable? No, it can probably be made to work. It is just a question of performance, and effort needed to integrate it. Will a Python implementation run slower and use more memory than a Lua one? Probably. what other requirements were you thinking of that would be helped with a Python implementation? You don't need to be afraid of Lua. It is a nice little language, kind of like a Scheme wrapped in a Python syntax.
- justincormack 14y ago
  1. Lua is designed to be embedded, it is much easier than trying to embed Ruby or Python into a web server. 2. It is a way off an app as it runs in the same process as the web server. 3. Lua is very small and very fast, so it is fine to use it just for doing tiny things like reading cookies, there is no real overhead (most people use LuaJIT so it is compiled anyway). Remember that the point of many of these examples is to offload from Ruby as it is too slow... Also, Lua is a very nice language, easy to learn (there is not much of it), and most of the functionality exposed is simply the built in functionality of nginx (async http), plus some libraries, so having the libraries that come with other languages is not that useful as you can't use anything blocking (like with Node) inside Nginx.
justincormack 14y ago
There is an introductory talk (video and slides) from the London Lua meetup group on Nginx and Lua here http://www.londonlua.org/scripting_nginx_with_lua/index.html http://www.londonlua.org/scripting_nginx_with_lua/index.html
- transmit101 14y ago
  This is a very good talk. Thanks for posting.
kyrra 14y ago
So the idea is interesting, but I think adding something like this onto Nginx could lead to problems in the future. For what you're trying to do, I feel like implementing your reverse proxy in Go may prove to be less prone to errors. Go has ReverseProxy stuff already built in: http://golang.org/pkg/net/http/httputil/#ReverseProxy http://golang.org/pkg/net/http/httputil/#ReverseProxy Go already has a pretty strong following doing near exactly what you are doing here with Nginx + Lua. But that would require learning a new language and screwing with infrastructure, which always is a giant pain.
- justincormack 14y ago
  Go is the only other way I would try to do this type of thing. Nginx has the advantage that a lof of people already have it in their stack so adding some bits of Lua incrementally is easy, while with Go you would be adding another piece of infrastructure. I don't think there are any problems, or that it is error prone. Most people are learning a new language with Lua, so take your choice.
- transmit101 14y ago
  I don't know anything about Go but your idea sounds feasible. As another commenter says, there is a large Nginx community and we have a lot of investment in Nginx already. But for somebody starting from scratch it may be worth considering.
- vidarh 14y ago
  Nginx is "battle tested" as one of the most used web servers, particularly as a reverse proxy. Lua is battle tested as an embedded language for just this type of thing. In comparison, Go is a pretty much unknown quantity. I'm curious as to what problems you think that this might lead to that aren't just as likely or more likely with a Go based implementation.
Lasher 14y ago
Different application area but we implemented Lua into a MUD (online RPG) as the scripting interface for all area builder development and it was probably the single most valuable change we ever made. Check out the 'lua coding' section on Aardwolf.com if you want to see some examples. Over 200,000 lines of lua now, millions of prog executions per hour and still as fast as ever.
- bonch 14y ago
  You already posted this comment word for word in the original article.
rotation1 14y ago
Bit off topic but you might want to 301 redirect to the right page instead of just disallowing search engines on your subdomains. This way if someone links to the wrong page you will still get the link juice. I might have misunderstood that first bit though, since it looks like you do redirect anyway.
- transmit101 14y ago
  I can imagine a scenario where we wanted a sub-domain which didn't redirect, but also wasn't crawlable. But I agree the example is a little bit contrived ;)
sciurus 14y ago
It's nice to see how tight the lua integration into nginx is. It reminds me of Apache and mod_perl.
Joe_Knapp 14y ago
Nginx is awesome. This looks like a major improvement also.

61 points by transmit101 14y ago

jot 14y ago

Can you provide us with an idea of how much this improved performance or how many more requests it allowed you to handle? Were there time or cost savings compared to alternative approaches?

transmit101 14y ago
There's no single self-contained solution in the post really, it's more an illustration of a number of useful things that Lua can be used for. I might try to put another post together at some stage though. For us our main goal is to prevent the majority of requests from even reaching the Rails stack. We've done this by introducing full page caching across the site, for both logged in and logged out users. This means that only a small percentage of requests at peak times need to touch Rails or any database at all - everything is served by Nginx. This hasn't been without its challenges. The last section of this post might give a clue as to how we've solved the most difficult ones. I will think about a post tackling this whole subject but I need to think about how to get it across, it's not easy.
- themgt 14y ago
  Yeah, we're using this to map hosts->upstream servers/redirects in a redis DB, and then there's no need for managing vhost files to add/remove/scale sites (or adding/swapping nginx servers). Writing code instead of config files is very powerful
taligent 14y ago
It is non-blocking and executed within Nginx itself so it is supposed to be very fast. The Lua work has been done by Chinese engineers from Taobao and Weibo which obviously get a huge amount of traffic.
- transmit101 14y ago
  I didn't know about the Weibo connection. It is a very fast module, and non-blocking, but just as importantly it provides the flexibility to avoid sending requests from Nginx to slow backend servers (Ruby, Python, whatever) at all. In real-life situations, this is the most important bit. As I said in another thread, we've done some good work to tie this in with our Rails app. We now page cache almost every important request, even for logged in users. This means Rails and our databases are protected from most spikes of traffic. I would like to write a post describing this in more detail, I need to think how to get it across though.

voxx 14y ago

LUA ON THE FRONT PAGE There is a god

slurgfest 14y ago

Is there any reason in principle why this has to be done with Lua and not with other interpreted languages? Once you are writing interpreted code which reads request data and interacts with Redis you are not that far from what a normal Ruby or Python web app does anyway.

FraaJad 14y ago
Two reasons: 1. Lua is very easy to embed into C code. Python and Ruby, not even in the same ball park ... 2. This nginx+lua config is often implemented using LuaJIT. Luajit is the fastest dynamic language. it's speed is very close to Java's in many cases. So, very little performance penalty..
- slurgfest 14y ago
  Are there real numbers showing that the Python interpreter's performance would be unsuitable for this purpose? (How about pypy's, since JIT seems to be one of the keywords here?) Or has it been decided (as if a priori) that Lua is the only workable solution?
  - ansible 14y ago
    Is Python unsuitable? No, it can probably be made to work. It is just a question of performance, and effort needed to integrate it. Will a Python implementation run slower and use more memory than a Lua one? Probably. what other requirements were you thinking of that would be helped with a Python implementation? You don't need to be afraid of Lua. It is a nice little language, kind of like a Scheme wrapped in a Python syntax.
justincormack 14y ago
1. Lua is designed to be embedded, it is much easier than trying to embed Ruby or Python into a web server. 2. It is a way off an app as it runs in the same process as the web server. 3. Lua is very small and very fast, so it is fine to use it just for doing tiny things like reading cookies, there is no real overhead (most people use LuaJIT so it is compiled anyway). Remember that the point of many of these examples is to offload from Ruby as it is too slow... Also, Lua is a very nice language, easy to learn (there is not much of it), and most of the functionality exposed is simply the built in functionality of nginx (async http), plus some libraries, so having the libraries that come with other languages is not that useful as you can't use anything blocking (like with Node) inside Nginx.

justincormack 14y ago

There is an introductory talk (video and slides) from the London Lua meetup group on Nginx and Lua here http://www.londonlua.org/scripting_nginx_with_lua/index.html http://www.londonlua.org/scripting_nginx_with_lua/index.html

transmit101 14y ago
This is a very good talk. Thanks for posting.

kyrra 14y ago

So the idea is interesting, but I think adding something like this onto Nginx could lead to problems in the future. For what you're trying to do, I feel like implementing your reverse proxy in Go may prove to be less prone to errors. Go has ReverseProxy stuff already built in: http://golang.org/pkg/net/http/httputil/#ReverseProxy http://golang.org/pkg/net/http/httputil/#ReverseProxy Go already has a pretty strong following doing near exactly what you are doing here with Nginx + Lua. But that would require learning a new language and screwing with infrastructure, which always is a giant pain.

justincormack 14y ago
Go is the only other way I would try to do this type of thing. Nginx has the advantage that a lof of people already have it in their stack so adding some bits of Lua incrementally is easy, while with Go you would be adding another piece of infrastructure. I don't think there are any problems, or that it is error prone. Most people are learning a new language with Lua, so take your choice.
transmit101 14y ago
I don't know anything about Go but your idea sounds feasible. As another commenter says, there is a large Nginx community and we have a lot of investment in Nginx already. But for somebody starting from scratch it may be worth considering.
vidarh 14y ago
Nginx is "battle tested" as one of the most used web servers, particularly as a reverse proxy. Lua is battle tested as an embedded language for just this type of thing. In comparison, Go is a pretty much unknown quantity. I'm curious as to what problems you think that this might lead to that aren't just as likely or more likely with a Go based implementation.

Lasher 14y ago

Different application area but we implemented Lua into a MUD (online RPG) as the scripting interface for all area builder development and it was probably the single most valuable change we ever made. Check out the 'lua coding' section on Aardwolf.com if you want to see some examples. Over 200,000 lines of lua now, millions of prog executions per hour and still as fast as ever.

bonch 14y ago
You already posted this comment word for word in the original article.

rotation1 14y ago

Bit off topic but you might want to 301 redirect to the right page instead of just disallowing search engines on your subdomains. This way if someone links to the wrong page you will still get the link juice. I might have misunderstood that first bit though, since it looks like you do redirect anyway.

transmit101 14y ago
I can imagine a scenario where we wanted a sub-domain which didn't redirect, but also wasn't crawlable. But I agree the example is a little bit contrived ;)

sciurus 14y ago

It's nice to see how tight the lua integration into nginx is. It reminds me of Apache and mod_perl.

Joe_Knapp 14y ago

Nginx is awesome. This looks like a major improvement also.