Re: Debugging memory leaks
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- Subject: Re: Debugging memory leaks
- From: Sean Conner <sean@...>
- Date: 2019年5月16日 16:34:41 -0400
It was thus said that the Great nobody once stated:
> On 16/05/2019 20.30, Sean Conner wrote:
> >It was thus said that the Great Sean Conner once stated:
> >>
> >>[1] I wrote a tool last year (not released) that I can
> >>interactively check a Lua state (using a text-based UI). I was
> >>able to integrate it into the event framework, so I was able to
> >>check various tables in real time (as the program was processing
> >>network events) to see what table was growing without bound.
> >>
> >>Attached is a screen shot for those that might be interested.
> >
> >I forgot the screen shot. Sigh.
> >
> >-spc (Included this time ...)
>
> That sounds cool! Can you briefly describe how you get the information
> from the Lua state to the tool? (Apart from invasive hooks everywhere &
> blasting stuff out via sockets, I'd have no idea how to do this…)
No invasive hooks, and use of the standard debug module.
It's interactive at the command line and I typically use it from the stock
Lua interpeter:
[spc]lucy:~>lua
Lua 5.3.5 Copyright (C) 1994-2018 Lua.org, PUC-Rio
> luaview = require "org.flummux.luaview"
> luaview.run()
But because it's a module and *not* an application, you can embed it. So
I added it to the code in question:
-- This is UDP socket that accepts incoming requests. It will
-- then spawn a coroutine to handle sending the data to an HTTP
-- endpoint
nfl.SOCKETS:insert(usock,'r',function() -- [1]
local remote,packet,err = usock:recv()
nfl.spawn(handler,remote,packet)
end)
luaview = require "org.flummux.luaview"
luaview.init() -- intialize the luaview module
-- When a keyboard event is detected, run one step
-- of the luaview module. This give us a real-time
-- interactive view into the current Lua state as the
-- program is running. I can check the global environment,
-- the registry, upvalues, metatables, etc.
nfl.SOCKETS:insert(luaview,'r',function()
if not luaview.step() then
nfl.SOCKETS;remove(luaview)
luaview.close()
end
end)
nfl.server_eventloop()
So it's not a remote, interactive viewer thing---it's purely a local,
interactive thing.
The function luaview.step() just reads the next key from the keyboard and
handles that one key. luaview.run() calls luaview.init(), luaview.step()
(in a loop) and luaview.close(). That's pretty much it to the luaview API.
-spc (Never given it thought of making it remote ... )
[1] My wrapper for select() [2] will attempt to call _tofd() via a
metatable on the second parameter. My other modules, like
org.conman.net (and org.flummux.luaview) support this. If you use
org.conman.fsys, it will add a _tofd() function to the FILE*
metatable in Lua so one can pass in items like io.stdin [3].
[2] Which will use epoll() under Linux, poll() under other Unix systems,
and only if poll() isn't available, select(). The API is the same
across all three implementations.
[3] I'm still unsure if monkey patching like this is a Good Thing or
not.