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This queue is for tickets about the Plack-Middleware-AutoRefresh CPAN distribution.

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The Basics
Id: 56119
Status: resolved
Priority: 0/
Queue: Plack-Middleware-AutoRefresh

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Owner: Nobody in particular
Requestors: the.ashleydev+rt.cpan.org [...] gmail.com
Cc:
AdminCc:

Bug Information
Severity: Unimportant
Broken in: (no value)
Fixed in: (no value)



Subject: all file descriptors are eventually leaked if the files to be 'auto-refreshed' never change
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The inserted .js that the AutoRefresh middleware inserts into the webpage opens a new connection to the server every 1500ms, and Plack::Middleware::AutoRefresh keeps this tcp session open (on the server side) until there is a change of files in the watched directory. So you leak an fd every 1500ms. If no files change before you run out of TCP connection file descriptors, then Plack::Server::AnyEvent wedges in a tight (CPU-intensive) run-loop because accept() fails to block when it cant allocate any new file-descriptors. #---------------------------------------- # Steps to recreate: #---------------------------------------- #save this file: #------------- app.psgi ----------------- #!/usr/bin/perl use Plack::Builder; builder { enable 'Plack::Middleware::AutoRefresh'; sub { [ 200, [ 'content-type' => 'text/html' ], [ '<html><head></head><body>hello world</body></html>' ] ] } }; #---------------------------------------- MacOS 10.6 prompt> ls app.psgi MacOS 10.6 prompt> plackup -s Plack::Server::AnyEvent Accepting requests at http://0.0.0.0:5000/ 127.0.0.1 - - [30/Mar/2010 11:05:53] "GET / HTTP/1.1" 200 3164 "-" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6" #--------------------------------------- # load localhost:5000 in your browser (I used firefox 3.6) #--------------------------------------- # Watch the output of lsof and see another fd leaked each 1500ms in (CLOSE_WAIT) state: #--------------------------------------- MacOS 10.6 prompt> lsof | grep perl # ... localhost:commplex-main->localhost:55086 (CLOSE_WAIT) perl5.10. 59853 ashleydev 16u IPv4 0x1b2702d4 0t0 TCP localhost:commplex-main->localhost:55089 (CLOSE_WAIT) perl5.10. 59853 ashleydev 17u IPv4 0x1af4ba8c 0t0 TCP localhost:commplex-main->localhost:55092 (CLOSE_WAIT) perl5.10. 59853 ashleydev 18u IPv4 0x19605abc 0t0 TCP localhost:commplex-main->localhost:55097 (CLOSE_WAIT) perl5.10. 59853 ashleydev 19u IPv4 0x1661f274 0t0 TCP localhost:commplex-main->localhost:55102 (CLOSE_WAIT) perl5.10. 59853 ashleydev 20u IPv4 0x19609274 0t0 TCP localhost:commplex-main->localhost:55105 (CLOSE_WAIT) perl5.10. 59853 ashleydev 21u IPv4 0x1960ea8c 0t0 TCP localhost:commplex-main->localhost:55109 (CLOSE_WAIT) perl5.10. 59853 ashlyedev 22u IPv4 0x19612b4c 0t0 TCP localhost:commplex-main->localhost:55112 (CLOSE_WAIT) perl5.10. 59853 ashleydev 23u IPv4 0x09f5cabc 0t0 TCP localhost:commplex-main->localhost:55115 (CLOSE_WAIT) #--------------------------------------- # if you `touch app.psgi` you will see all of those `CLOSE_WAIT` tcp connections go away. However if you let it sit there for a day, then when all the file descriptors are used up, the plackup server will wedge, not accept'ing anymore connections and will run up the CPU in a tight select() loop. # solution: I hesitate to provide one since I'm not so well acquainted with the code yet, but I'd assume there's a way have it work without the inserted .js open a new tcp connection and keep it open when there are no changes on the web-server to push.
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Version 0.08 was just uploaded to cpan. It should fix the bug. The plack server now only retains one blocked session for each unique client. This release also makes the js code a bit more robust. It should handle server restarts much better now. Thanks for your bug report! Please let me know if this doesn't solve the problem on your system.
Subject: Re: [rt.cpan.org #56119] all file descriptors are eventually leaked if the files to be 'auto-refreshed' never change
Date: Tue, 30 Mar 2010 19:39:18 -0700
To: bug-Plack-Middleware-AutoRefresh [...] rt.cpan.org
From: Ashley Dev  <the.ashleydev [...] gmail.com>
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Wow, that was fast! On Mar 30, 2010, at 3:52 PM, Mark Grimes via RT wrote: Show quoted text
> <URL: https://rt.cpan.org/Ticket/Display.html?id=56119 > > > Version 0.08 was just uploaded to cpan. It should fix the bug. The plack > server now only retains one blocked session for each unique client. > > This release also makes the js code a bit more robust. It should handle > server restarts much better now. > > Thanks for your bug report! Please let me know if this doesn't solve the > problem on your system.
I really wish follow-up emails didn't reopen resolved tickets in rt.


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