# Stream closed (IOError)

**URL:** <https://www.ruby-forum.com/t/stream-closed-ioerror/150169>\
**Category:** Ruby\
**Created:** [October 5, 2008, 6:21am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169 "2008-10-05T06:21:55Z")\
**Posts on this page:** 17\
**Page:** 1

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 6:21am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/1 "2008-10-05T06:21:55Z")

</div>

This code:

```
    puts "closed?: %s" % @socket.closed?.to_s

    begin
        @socket.close
    rescue Exception => e
        return
    rescue IOError => e
        return
    rescue Errno => e
        return
    end

```

outputs this:

closed?: false  
/Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd/xmpp/stream.rb:231:in  
`ioloop': stream closed (IOError) from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:196:in`loop’  
from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:196:in  
`ioloop’  
from ./bin/xmppd:20  
praxis:trunk rakaur$

Latest stable Ruby (1.8.7-p72). I don’t see how this is possible.  
Google seems mostly silent on the matter unless you speak Japanese.

Any ideas?

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 7:37am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/2 "2008-10-05T07:37:56Z")

</div>

Hi,

In message “Re: stream closed (IOError)”  
on Sun, 5 Oct 2008 12:51:52 +0900, “Eric W.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|This code:  
|  
| puts “closed?: %s” % @socket.closed?.to\_s  
|  
| begin  
| @socket.close  
| rescue Exception =\> e  
| return  
| rescue IOError =\> e  
| return  
| rescue Errno =\> e  
| return  
| end  
|  
|outputs this:  
|  
|closed?: false  
|/Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd/xmpp/stream.rb:231:in  
|`ioloop': stream closed (IOError) | from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:196:in `loop’  
| from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:196:in `ioloop’  
| from ./bin/xmppd:20  
|praxis:trunk rakaur$

It’s hard to tell without full executable script, but at least the  
exception was raised _outside_ of your code snippet. I believe you  
touched @socket after you closed it.

```
          matz.

```

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 4:56pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/3 "2008-10-05T16:56:39Z")

</div>

Line 231 is the @socket.close line. Nothing gets done to the socket  
after this, or if it is, it’s not getting to it because it crashes on  
@socket.close. Nothing should even be touching the entire object after  
this, because it sets a flag saying “I’m dead, please GC me.”

It’s a large program, and the code is available at  
[http://synapse.malkier.net/browser](http://synapse.malkier.net/browser). The socket closing is in  
lib/xmppd/xmpp/stream.rb. The code right there doesn’t have the  
exception catching written in, because I removed the thing that causes  
this to happen, which is this:

```
    # Check for connection timeouts.
    #Timer::Timer.new('check connection timeouts', 60, true) do
    # $connections.each do |c|
    # c.error('connection-timeout') if ($time - c.rtime) >= 

```

30  
# end

I’ll try putting the exception around this. One second.

No, that doesn’t work. Nor does this:

```
    # Check for connection timeouts.
    Timer::Timer.new('check connection timeouts', 60, true) do
        $connections.each do |c|
            next if c.dead? or c.socket.closed?
            c.error('connection-timeout') if ($time - c.rtime) >= 30
        end

```

The socket.closed? returns false, then ONE LINE LATER when I call  
socket.close, the IOError is raised and cannot seem to be rescued.

Ok, I’ve updated the code in svn. Relevant files are  
[http://synapse.malkier.net/browser/trunk/lib/xmppd.rb](http://synapse.malkier.net/browser/trunk/lib/xmppd.rb) (which is where  
the Timer is started),  
[http://synapse.malkier.net/browser/trunk/lib/xmppd/timer.rb](http://synapse.malkier.net/browser/trunk/lib/xmppd/timer.rb) (which is  
the Timers themselves), and  
[http://synapse.malkier.net/browser/trunk/lib/xmppd/xmpp/stream.rb](http://synapse.malkier.net/browser/trunk/lib/xmppd/xmpp/stream.rb)  
(which is where the socket is closing.

This code outputs this:

/Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd/xmpp/stream.rb:230:in  
`ioloop': stream closed (IOError) from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:197:in `loop’  
from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:197:in  
`ioloop’  
from ./bin/xmppd:20

Perhaps it has to do with the timers running in a separate thread?  
Putting begin/rescue in the tread doesn’t catch it, either.

Thanks.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 5:49pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/4 "2008-10-05T17:49:29Z")

</div>

Hi,

In message “Re: stream closed (IOError)”  
on Sun, 5 Oct 2008 23:54:36 +0900, “Eric W.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|Line 231 is the @socket.close line. Nothing gets done to the socket  
|after this, or if it is, it’s not getting to it because it crashes on  
|@socket.close. Nothing should even be touching the entire object after  
|this, because it sets a flag saying “I’m dead, please GC me.”

I don’t think we can trust line numbers here, maybe due to bugs. The  
back trace does not make sense at all.

|/Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd/xmpp/stream.rb:230:in  
|`ioloop': stream closed (IOError) | from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:197:in `loop’  
| from /Users/rakaur/Sources/wc/ruby/synapse/trunk/lib/xmppd.rb:197:in `ioloop’  
| from ./bin/xmppd:20

stream.rb:230 is not within ioloop; xmppd:20 does not call ioloop.  
The fact rescue does not catch the exception also suggest the wrong  
line numbers. How about stopping using timer library, as a start?

```
          matz.

```

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 6:04pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/5 "2008-10-05T18:04:23Z")

</div>

On Sun, Oct 5, 2008 at 11:46 AM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> I don’t think we can trust line numbers here, maybe due to bugs. The  
> back trace does not make sense at all.  
> […]  
> stream.rb:230 is not within ioloop; xmppd:20 does not call ioloop.  
> The fact rescue does not catch the exception also suggest the wrong  
> line numbers. How about stopping using timer library, as a start?

Hey matz. Thanks for your help. Everything is within ioloop.  
bin/xmppd:20 is `XMPPd.instance.ioloop`  
When I don’t use the timers, this doesn’t happen. In fact, it doesn’t  
happen until I use that specific Timer to do connection timeouts in  
lib/xmppd.rb.

> ```
> matz.
> 
> ```

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 6:12pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/6 "2008-10-05T18:12:49Z")

</div>

On Sun, Oct 5, 2008 at 12:03 PM, Iñaki Baz C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Not sure if your problem could be related to this post:
> 
> [http://blog.headius.com/2008/02/rubys-threadraise-threadkill-timeoutrb.html](http://blog.headius.com/2008/02/rubys-threadraise-threadkill-timeoutrb.html)

Not sure I grasp everything going on there. I don’t use threads for  
anything EXCEPT running my timers, which use Timeout. This could  
potentially be the culprit, but I have no idea how that helps me.  
Trying to rescue the IOError in my Timer library hasn’t worked,  
either.

matz, any input on this?

Thanks guys.

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 6:36pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/7 "2008-10-05T18:36:43Z")

</div>

Hi,

In message “Re: stream closed (IOError)”  
on Mon, 6 Oct 2008 01:10:05 +0900, “Eric W.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|matz, any input on this?

Since I still can not reproduce the problem, I can not say clearly, but:

- timer callback may touch the socket right after it’s closed.

- you’ve mixed fork and threads, which may not work properly.

- you don’t need timeout.rb. try attached simpler version.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 6:45pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/8 "2008-10-05T18:45:38Z")

</div>

On Sun, Oct 5, 2008 at 12:33 PM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Since I still can not reproduce the problem, I can not say clearly, but:
> 
> - timer callback may touch the socket right after it’s closed.
> - you’ve mixed fork and threads, which may not work properly.
> - you don’t need timeout.rb. try attached simpler version.

Thanks. I should have thought of that to begin with. 🙂

It doesn’t have to do with fork. In all my tests I run it with  
–nofork (which skips forking). The only thing using threads was  
timer.rb.

Googling found me some Japanese posts, but that didn’t help. The rest  
seemed to be fixed by checking socket#closed? first.

Thanks so much.

> ```
> matz.
> 
> ```

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 6:06pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/9 "2008-10-05T18:06:47Z")

</div>

El Domingo, 5 de Octubre de 2008, Eric W.  
escribió:\> On Sun, Oct 5, 2008 at 11:46 AM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> happen until I use that specific Timer to do connection timeouts in  
> lib/xmppd.rb.

Not sure if your problem could be related to this post:

> **[Ruby's Thread#raise, Thread#kill, timeout.rb, and net/protocol.rb libraries...](http://blog.headius.com/2008/02/rubys-threadraise-threadkill-timeoutrb.html)**
>
> (NOTE: Due to an issue migrating my blog from one Google account to another, this URL now points at a \*copy\* of the original post. If you would like to add further comments, please do so there.)I'm taking a break from some bug fixing to bring you...

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 5, 2008, 7:18pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/10 "2008-10-05T19:18:21Z")

</div>

Hi,

In message “Re: stream closed (IOError)”  
on Mon, 6 Oct 2008 01:43:14 +0900, “Eric W.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|Googling found me some Japanese posts, but that didn’t help. The rest  
|seemed to be fixed by checking socket#closed? first.

Show me the URL if you need further info, since I can read some  
Japanese. 😉

```
          matz.

```

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 2:03am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/11 "2008-10-06T02:03:39Z")

</div>

On Sun, Oct 5, 2008 at 12:33 PM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> - you don’t need timeout.rb. try attached simpler version.

While simpler version, this causes the same error…

> ```
> matz.
> 
> ```

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 1:48am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/12 "2008-10-06T01:48:26Z")

</div>

On Sun, Oct 5, 2008 at 1:15 PM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Show me the URL if you need further info, since I can read some  
> Japanese. 😉

I’m not sure if these are relevant, since Google now shows lots of  
this thread. 🙂

[http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/7000](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/7000)  
[http://133.44.98.95/cgi-bin/vframe.rb/ruby/ruby-list/31677?31634-32001](http://133.44.98.95/cgi-bin/vframe.rb/ruby/ruby-list/31677?31634-32001)  
[http://www.rubyist.net/~nobu/t/20031028.html](http://www.rubyist.net/~nobu/t/20031028.html)  
[http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/31645](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/31645)

> ```
> matz.
> 
> ```

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 2:31am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/13 "2008-10-06T02:31:08Z")

</div>

Hi,

In message “Re: stream closed (IOError)”  
on Mon, 6 Oct 2008 04:56:21 +0900, “Eric W.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|On Sun, Oct 5, 2008 at 12:33 PM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:  
|\> \* you don’t need timeout.rb. try attached simpler version.  
|  
|While simpler version, this causes the same error…

Hmm, let’s step forward one by one. You have two timers, which one is  
causing the problem? What if wrapping timer callbacks with begin and  
rescue?

```
          matz.

```

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 2:35am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/14 "2008-10-06T02:35:49Z")

</div>

On Sun, Oct 5, 2008 at 4:44 PM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> Hmm, let’s step forward one by one. You have two timers, which one is  
> causing the problem? What if wrapping timer callbacks with begin and  
> rescue?

I’ve tried wrapping the start method in timer.rb, wrapping the Timer  
callbacks outside of “Timer.new” and inside of “Timer.new” (ie, part  
of the callback), and none of these rescue it. When I wrap the call to  
ioloop (which is the ENTIRE program, basically) it catches it… which  
doesn’t really narrow it down much.

I’m trying as I’m writing this, so bare with me for a moment…  
wrapping c.read in lib/xmppd.rb catches it… wrapping parse in  
Stream#read with it does NOT catch it. So it’s somewhere between  
Stream#read’s call to Stream#parse.

> ```
> matz.
> 
> ```

I’ll keep playing with this, but I don’t know that I’m getting very  
far… I still think it has something to do with threads.

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 3:04am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/15 "2008-10-06T03:04:30Z")

</div>

On Sun, Oct 5, 2008 at 5:08 PM, Eric W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I’ll keep playing with this, but I don’t know that I’m getting very  
> far… I still think it has something to do with threads.

Yeah, that’s as far as I can get. Wrapping different parts of  
Stream#read doesn’t catch it.

This seems impossible unless it’s something to do with threads, which  
I know next to nothing about. 🙂

I was going to try with ruby1.9, but the IDN gem doesn’t work.

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 12:49pm UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/16 "2008-10-06T12:49:10Z")

</div>

On Oct 5, 2008, at 9:21 PM, Yukihiro M. wrote:

> According to the third URL, “stream closed” error was raised when fd  
> (IO object) is closed while a thread is waiting for that fd,  
> i.e. you’ve closed a socket which other thread (timer callback) is  
> blocking on.

I think it was happening because the timer would kill off the socket,  
and then select() would be trying to check it in the main thread (no  
clue what was up with the error reporting, thread confusion!). I  
worked around this by just moving the timeout check from a Timer to  
manually doing it in the ioloop, before the dead connections are  
removed. Now it never gets to select(), and it works just fine. Thanks  
for your personal attention in helping me figure this out, matz. 🙂

> ```
> matz.
> 
> ```

– Eric W.

---

<div class="post-metadata">

**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [October 6, 2008, 3:24am UTC](https://www.ruby-forum.com/t/stream-closed-ioerror/150169/17 "2008-10-06T03:24:25Z")

</div>

Hi,

In message “Re: stream closed (IOError)”  
on Mon, 6 Oct 2008 04:44:37 +0900, “Eric W.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|On Sun, Oct 5, 2008 at 1:15 PM, Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:  
|\> Show me the URL if you need further info, since I can read some  
|\> Japanese. 😉  
|  
|I’m not sure if these are relevant, since Google now shows lots of  
|this thread. 🙂  
|  
|[http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/7000](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-dev/7000)

It’s about the already fixed bugs.

|[http://133.44.98.95/cgi-bin/vframe.rb/ruby/ruby-list/31677?31634-32001](http://133.44.98.95/cgi-bin/vframe.rb/ruby/ruby-list/31677?31634-32001)

It’s related to dRuby.

|[http://www.rubyist.net/~nobu/t/20031028.html](http://www.rubyist.net/~nobu/t/20031028.html)

Exceptions “closed steam” and “stream closed” are different. A good  
hint, I believe.

|[http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/31645](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/31645)

It’s related to dRuby.

According to the third URL, “stream closed” error was raised when fd  
(IO object) is closed while a thread is waiting for that fd,  
i.e. you’ve closed a socket which other thread (timer callback) is  
blocking on.

```
          matz.

```