A small Lua module for executing processes. It's primarily intended to be used with OpenResty, but will work in regular Lua applications as well. When used with OpenResty, it's completely non-blocking (otherwise it falls back to using LuaSocket and does block).
It's similar to (and inspired by) lua-resty-shell, the primary difference being this module uses sockexec, which doesn't spawn a shell - instead you provide an array of argument strings, which means you don't need to worry about shell escaping/quoting/parsing rules.
This requires your web server to have an active instance of sockexec running.
local exec = require'resty.exec' local prog = exec.new('/tmp/exec.sock')Creates a new prog object, using /tmp/exec.sock for its connection to sockexec.
From there, you can use prog in a couple of different ways:
local res, err = prog('uname') -- res = { stdout = "Linux\n", stderr = nil, exitcode = 0, termsig = nil } -- err = nil ngx.print(res.stdout)This will run uname, with no data on stdin.
Returns a table of output/error codes, with err set to any errors encountered.
prog.argv = { 'uname', '-a' } local res, err = prog() -- res = { stdout = "Linux localhost 3.10.18 #1 SMP Tue Aug 2 21:08:34 PDT 2016 x86_64 GNU/Linux\n", stderr = nil, exitcode = 0, termsig = nil } -- err = nil ngx.print(res.stdout)prog.stdin = 'this is neat!' local res, err = prog('cat') -- res = { stdout = "this is neat!", stderr = nil, exitcode = 0, termsig = nil } -- err = nil ngx.print(res.stdout)local res, err = prog( { argv = 'cat', stdin = 'fun!' } ) -- res = { stdout = "fun!", stderr = nil, exitcode = 0, termsig = nil } -- err = nil ngx.print(res.stdout)Note: here argv is a string, which is fine if your program doesn't need any arguments.
If you set prog.stdout or prog.stderr to a function, it will be called for each chunk of stdout/stderr data received.
Please note that there's no guarantees of stdout/stderr being a complete string, or anything particularly sensible for that matter!
-- set bufsize to some smaller value, the default is 4096 -- this allows data to stream in smaller chunks prog.bufsize = 10 prog.stdout = function(data) ngx.print(data) ngx.flush(true) end local res, err = prog('some-program') Not a problem! You can just do something like:
local res, err = prog('bash','-c','echo $PATH')Or if you want to run an entire script:
prog.stdin = script_data local res, err = prog('bash')Assuming you're running sockexec at /tmp/exec.sock
$ sockexec /tmp/exec.sock Then in your nginx config:
location /uname-1 { content_by_lua_block { local prog = require'resty.exec'.new('/tmp/exec.sock') local data,err = prog('uname') if(err) then ngx.say(err) else ngx.say(data.stdout) end } } location /uname-2 { content_by_lua_block { local prog = require'resty.exec'.new('/tmp/exec.sock') prog.argv = { 'uname', '-a' } local data,err = prog() if(err) then ngx.say(err) else ngx.say(data.stdout) end } } location /cat-1 { content_by_lua_block { local prog = require'resty.exec'.new('/tmp/exec.sock') prog.stdin = 'this is neat!' local data,err = prog('cat') if(err) then ngx.say(err) else ngx.say(data.stdout) end } } location /cat-2 { content_by_lua_block { local prog = require'resty.exec'.new('/tmp/exec.sock') local data,err = prog({argv = 'cat', stdin = 'awesome'}) if(err) then ngx.say(err) else ngx.say(data.stdout) end } } location /slow-print { content_by_lua_block { local prog = require'resty.exec'.new('/tmp/exec.sock') prog.bufsize = 10 prog.stdout = function(v) ngx.print(v) ngx.flush(true) end prog('/usr/local/bin/slow-print') } # look in `/misc` of this repo for `slow-print` } location /shell { content_by_lua_block { local prog = require'resty.exec'.new('/tmp/exec.sock') local data, err = prog('bash','-c','echo $PATH') if(err) then ngx.say(err) else ngx.say(data.stdout) end } } MIT license (see LICENSE)
