[mapserver-users] MapCache: Disabling WMS requests for fully-seeded caches?

[thomas bonfort]

I'll have a look, but my config that doesn't segfault is using JPEG.
Note that the 404 error code is the way it's supposed to work, if you
inspect the headers and body you should see a image/jpeg mimetype, a
jpeg body, and an X-MapCache-Error header explaining what happened.

--
thomas

On Tue, Nov 29, 2011 at 21:22, John Taranu
<jtaranu at firstbasesolutions.com> wrote:
> Note that setting the default format to PNG doesn't cause a segmentation
> fault:
>
>
>   <default_format>PNG</default_format>
>   <errors>empty_img</errors>
>
> However, in this case mapcache still returns a HTTP 404 instead of a blank
> image.
>
>
>
> -----Original Message-----
> From: Travis Kirstine [mailto:traviskirstine at gmail.com]
> Sent: Tuesday, November 29, 2011 3:21 PM
> To: thomas bonfort
> Cc: John Taranu; mapserver-users at lists.osgeo.org
> Subject: Re: [mapserver-users] MapCache: Disabling WMS requests for
> fully-seeded caches?
>
> Thomas,
>
> Here is the backtrace:
>
> (gdb) run -X
> Starting program: /usr/sbin/httpd -X
> warning: no loadable sections found in added symbol-file system-supplied DSO
> at 0x2aaaaad1b000 [Thread debugging using libthread_db enabled]
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x00002aaaaca4e32b in strstr () from /lib64/libc.so.6
> (gdb) bt
> #0  0x00002aaaaca4e32b in strstr () from /lib64/libc.so.6
> #1  0x00002aaab539737d in mapcache_image_create_empty () from
> /usr/lib64/httpd/modules/mod_mapcache.so
> #2  0x00002aaab53971fe in mapcache_configuration_parse_xml () from
> /usr/lib64/httpd/modules/mod_mapcache.so
> #3  0x00002aaab53a047a in mapcache_configuration_parse () from
> /usr/lib64/httpd/modules/mod_mapcache.so
> #4  0x00002aaab53879e6 in mapcache_add_alias (cmd=0x7fffffffe760, cfg=<value
> optimized out>, alias=0x2aaaaae0f850 "/mapcache",
>    configfile=0x2aaaaae0f860 "/var/www/html/mapcache/mapcache.xml")
> at mod_mapcache.c:502
> #5  0x00002aaaaaad5c4b in ?? ()
> #6  0x00002aaaaaad60d0 in ap_walk_config ()
> #7  0x00002aaaaaad6232 in ap_process_config_tree ()
> #8  0x00002aaaaaac1c51 in main ()
> (gdb)
>
> #################################################################
>
> MapCache snippet:
>
>  <default_format>mixed</default_format>
>
>  <errors>empty_img</errors>
>
> Regards
>
>
>
>
> On 29 November 2011 11:56, thomas bonfort <thomas.bonfort at gmail.com> wrote:
>> I've just tried report_img locally without issues, any chance you can
>> provide a backtrace ?
>>
>> On Tue, Nov 29, 2011 at 17:32, John Taranu
>> <jtaranu at firstbasesolutions.com> wrote:
>>> Hi Thomas,
>>>
>>> Thanks for the suggestion.  Commenting out the source block disables the
> WMS requests.
>>>
>>> However, the error reporting seems to be broken.  Setting
> <errors>empty_img</errors> crashes Apache with a segmentation fault
> (mod_mapcache SVN revision 12828).  Setting <errors>report</errors> throws
> HTTP 404 responses, which is a more reasonable result.
>>>
>>> John
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: thomas bonfort [mailto:thomas.bonfort at gmail.com]
>>> Sent: Tuesday, November 29, 2011 10:33 AM
>>> To: John Taranu
>>> Cc: mapserver-users at lists.osgeo.org
>>> Subject: Re: [mapserver-users] MapCache: Disabling WMS requests for
> fully-seeded caches?
>>>
>>> You can do this by commenting out the <source> block from the tileset
> once the wanted tiles have been created. You'll probably also want set error
> reporting to return blank images from that stage onwards.
>>>
>>> --
>>> thomas
>>>
>>> On Tue, Nov 29, 2011 at 00:09, John Taranu
> <jtaranu at firstbasesolutions.com> wrote:
>>>> We have a fully seeded cache that was fully seeded to a polygon outline.
>>>> The intent is to serve the tileset through a variety of services
>>>> (WMS,
>>>> TMS) using mod-mapcache.
>>>>
>>>>
>>>>
>>>> Tiles that are outside the polygon outline but still within the
>>>> polygon bounding box should be blank tiles.  However, a request for
>>>> one of these tiles results in a call to that tileset’s WMS source.
>>>> This creates considerable overhead by starting up MapServer and
>>>> writing the resulting tile to the cache.  Is there any way to
>>>> disable the WMS calls for these blank tiles, and instead
>>>> short-circuit the request to return a blank?  That is, once a
>>>> tileset has been fully seeded, is it possible to disable any further
>>>> calls to the WMS, so that requests for tiles that are not in the cache
> return a blank?
>>>>
>>>>
>>>> _______________________________________________
>>>> mapserver-users mailing list
>>>> mapserver-users at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>>>>
>>>
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>