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.