Re: [PATCH] mirrorlist_client timeouts

[Ricky Zhou]

On 2010-05-12 01:59:15 PM, Matt Domsch wrote:
>  >From 1aa19dfed950c209ad5a2ddf48e2b828b50c07ee Mon Sep 17 00:00:00
> 2001
>  From: Matt Domsch <Matt_Domsch(a)dell.com&gt;
>  Date: Wed, 12 May 2010 13:52:51 -0500
>  Subject: [PATCH] mirrorlist_client: a better way to handle socket timeouts
>  
>  blocking sockets, calling recv(), may block forever if the server end
>  doesn't send anything for some reason.  Don't let that happen.  Python
>  has a socket.settimeout() capability.  We'll use that to let any
>  individual operation (except the select()) take up to 5 seconds (they
>  should all be in the microsecond range, so this is very generous), and
>  let select() continue to wait for 60 seconds for the server to respond
>  at all.
>  
>  If a timeout happens, an exception is raised, which is caught by the
>  caller and a HTTP 503 returned to the web client.
>  ---
>   mirrorlist-server/mirrorlist_client.wsgi |   17 ++++++++---------
>   1 files changed, 8 insertions(+), 9 deletions(-)
>  
>  diff --git a/mirrorlist-server/mirrorlist_client.wsgi
> b/mirrorlist-server/mirrorlist_client.wsgi
>  index 15b3a15..3508f19 100755
>  --- a/mirrorlist-server/mirrorlist_client.wsgi
>  +++ b/mirrorlist-server/mirrorlist_client.wsgi
>  @@ -13,14 +13,14 @@ import cStringIO
>   from datetime import datetime, timedelta
>   
>   socketfile = '/var/run/mirrormanager/mirrorlist_server.sock'
>  -request_timeout = 60 # seconds
>  +select_timeout = 60 # seconds
>  +timeout = 5 # seconds
>   
>   def get_mirrorlist(d):
>  -    try:
>  -        s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
>  -        s.connect(socketfile)
>  -    except:
>  -        raise
>  +    # any exceptions or timeouts raised here get handled by the caller
>  +    s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
>  +    s.settimeout(timeout)
>  +    s.connect(socketfile)
>   
>       p = pickle.dumps(d)
>       del d
>  @@ -33,8 +33,7 @@ def get_mirrorlist(d):
>       del p
>   
>       # wait for other end to start writing
>  -    expiry = datetime.utcnow() + timedelta(seconds=request_timeout)
>  -    rlist, wlist, xlist = select.select([s],[],[],request_timeout)
>  +    rlist, wlist, xlist = select.select([s],[],[],select_timeout)
>       if len(rlist) == 0:
>           s.shutdown(socket.SHUT_RD)
>           raise socket.timeout
>  @@ -48,7 +47,7 @@ def get_mirrorlist(d):
>   
>       readlen = 0
>       p = ''
>  -    while readlen < resultsize and datetime.utcnow() < expiry:
>  +    while readlen < resultsize:
>           p += s.recv(resultsize - readlen)
>           readlen = len(p)
>       results = pickle.loads(p)
>  -- 
>  1.7.0.1 
+1

Thanks,
Ricky