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Scripting Nginx with Lua (2012)

88 points| chx | 11 years ago |londonlua.org | reply

22 comments

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[+] terhechte|11 years ago|reply
I tend to always use OpenResty for a certain set of tasks these days. Notably, when it is mostly about lightweight data processing. I.e. an API that reads from a DB, transforms some fields and returns json, or a simple proxy server that slightly modifies the data (or just returns it). Or, performing simple calculations based on a few inputs.

All this usually just requires a few lines of code and due to the nature of OpenResty, it scales really well and is very lightweight in terms of CPU consumption and memory.

I haven't really used it for anything bigger yet, mostly because then I'd rather prefer Django or Clojure (depending on the tasks) as they have much more functionality / packages for web development.

Particularly the nonblocking IO for db/file/networking operations (out of the box) is neat. Another interesting aspect is that, once you've set up the system, development feels a lot like PHP development, where every lua file can be one page and changing the file results in a direct change on the frontend (if you turn the lua code cache off).

On the other hand, there're some pitfalls, the project is young, it still lacks packages for many, many things (notably, if you want to do crypto, you have to FFI right into the C library, for now. There's a new sha/hmac module, but it's not part of the current OpenResty distribution yet). Also, sometimes it is difficult to find solutions to problems, as it is not widely used as Django or Rails. If you're interested in using it, take some time to read up on LuaJIT as there're several important optimization techniques to really get the best out of it (see below).

All in all, for smaller projects, I love the stack as it is simple, lightweight, and easy to install.

Here're some useful links:

Lua(Jit) Profiler: https://github.com/jgrahamc/lulip/

IDE With Debugger for OpenResty (Pretty cool, you can debug while your browser requests): http://notebook.kulchenko.com/zerobrane/debugging-openresty-...

LuaJIT Performance Guide: http://wiki.luajit.org/Numerical-Computing-Performance-Guide

Lua Performance Guide: http://www.lua.org/gems/sample.pdf

[+] girvo|11 years ago|reply
The whole debug while requesting a page sounds great, that's a feature I adore from Xdebug.
[+] jgrahamc|11 years ago|reply
If you are interested in working on or with OpenResty then CloudFlare is hiring people in London and San Francisco. We employ agentzh and he works on OpenResty at CloudFlare. We use it _extensively_ throughout the CloudFlare stack.

And also we really, really need more people with experience of OpenResty, NGINX, Lua and LuaJIT.

https://www.cloudflare.com/join-our-team

[+] xfalcox|11 years ago|reply
agentzh is a great and helpful guy! We're using openresty in a big enterprise setup (100.000+ employees) and it's great.

Sometimes you just want to get a simple json endpoint with some dynamic data, and you can do that in 4 lines in lua+openresty.

[+] GrinningFool|11 years ago|reply
One of the concerns I have about openresty is that so much of it relies on agentzh. He does amazing work at an insane rate - a rate that I'm a bit concerned (as someone who uses openresty & luajit extensively) can't be sustained in the long term, and is in serious jeopardy if he gets a better offer.
[+] zeitg3ist|11 years ago|reply
If you'd like to go a bit higher level without sacrificing performance, I suggest Lapis, a Lua/Moonscript framework built on top of OpenResty: http://leafo.net/lapis/

(not the author, just a fan!)

[+] egeozcan|11 years ago|reply
Lapis + pgmoon do look like a wonderful combination indeed. I'm also a fan, but my experience is limited to small experiments.
[+] sciurus|11 years ago|reply
At Lonely Planet we've had a good experience using OpenResty directly behind our CDN. We use it to perform rewrites, route requests to the appropriate applications, manage splits for a/b testing, block malicious traffic, gather metrics, and more!

We touch on our use of it a little bit towards the end of http://velocityconf.com/velocityeu2012/public/schedule/detai.... The last slide is still true- we're hiring! Ruby (remote possible), javascript, devops, and more. See http://www.lonelyplanet.com/jobs/

[+] fasteo|11 years ago|reply
I already posted this some time ago, but let me insist on this one:

Openresty (nginx+lua) is probably one of the most underrated technologies we have available nowadays. In my experience, every webapp can offload a ton of work(1) to openresty. The lua code is usually simpler and a lot faster that the equivalent code in the app.

(1) think caching, auth/acl, security filters, stats, logging

[+] domrdy|11 years ago|reply
We've recently switched from a file based URL rewrite system to nginx/lua/redis. Before we'd literally include() the rewrites into our configuration files which made -s reload a pain. All in all the implementation was relatively painless, decreased our server reponse time quite a bit and scales way better than our previous naive approach.
[+] anonfunction|11 years ago|reply
We've just done this at our API focused startup and been really impressed with the performance. OpenResty makes interfacing the server with your business logic and external services a breeze. Nginx and Lua/LuaJIT have been battle tested for years and they are extremely fast and reliable.

Open Source on GitHub: https://github.com/Mashape/mashape-agent