Resty Repl is a powerful alternative to the standard luajit shell ispired by pry. It is written from scratch to provide a number of advanced features, including:
- Full read/write access to locals, upvalues and global variables
- Pretty print for objects
- A Powerful and flexible command system
- Ability to view and replay history
- Ability to see a context and source of the place in code from where repl was started
- Runtime invocation (use Resty Repl as a developer console or debugger)
- Tab completion
- Simple and easy way to debug lua running in the nginx (openresty)
First install luarock
luarocks install lua-resty-repl
Then just drop this snippet anywhere in your code:
require('resty.repl').start()
or run as cli:
resty-repl
But what makes it really nice is that now you can debug your openresty code right from running nginx!
master_process off;
error_log stderr notice;
daemon off;
events {
worker_connections 1024;
}
http {
server {
listen 8080;
lua_code_cache off;
location / {
content_by_lua_block {
require('resty.repl').start()
}
}
}
}
and start debugging:
$ curl -H X-Header:buz 172.17.0.2:8080?foo=bar
nginx -c /tmp/ngx.conf
2016/09/20 16:26:33 [alert] 2257#0: lua_code_cache is off; this will hurt performance in /tmp/ngx.conf:12
nginx: [alert] lua_code_cache is off; this will hurt performance in /tmp/ngx.conf:12
2016/09/20 16:26:33 [notice] 2257#0: using the "epoll" event method
2016/09/20 16:26:33 [notice] 2257#0: openresty/1.11.2.1
2016/09/20 16:26:33 [notice] 2257#0: built by gcc 4.9.2 (Debian 4.9.2-10)
2016/09/20 16:26:33 [notice] 2257#0: OS: Linux 4.4.0-38-generic
2016/09/20 16:26:33 [notice] 2257#0: getrlimit(RLIMIT_NOFILE): 65536:65536
From: content_by_lua(ngx.conf:17) @ line 2
[1] ngx(content)> ngx.req.get_headers()
=> {
accept = "*/*",
host = "172.17.0.2:8080",
["user-agent"] = "curl/7.47.0",
["x-header"] = "buz",
<metatable> = {
__index = <function 1>
}
}
[2] ngx(content)> ngx.req.get_uri_args()
=> {
foo = "bar"
}
[3] ngx(content)> ngx.say 'it works!'
=> 1
[4] ngx(content)> ngx.exit(ngx.OK)
172.17.0.1 - - [20/Sep/2016:16:26:50 +0000] "GET /?foo=bar HTTP/1.1" 200 20 "-" "curl/7.47.0"
Right now it's only compatible with:
- luajit
- lua5.1 (no readline)
- GNU/Linux
- Mac OS
- colorized output
- smarter completion
- full readline support for lua (no ffi environments)
- remote debugger
- command for showing function source
- test suite with resty-cli, luajit and different versions of lua
- better inspect library
resty-repl is released under the MIT License.