How do I propagate failures from upstream wms-servers?

[Fred warnock]

Trond

Man I had hoped that if my name was going to be used for something it'd 
be for good.  That hope has been shattered.

I had to educate myself as to what "Warnocked" means to ensure that I 
was not in some means being implicated here.  *sigh* I'm now an innocent 
pariah.

;)

Fred [Warnock!]

Trond Michelsen wrote:
> No takers? I feel like I'm being Warnocked here :)
> 
> I really hope the silence isn't an indication that the question is too
> stupid. Getting blank images instead of an error message is actually a
> big problem with my server configuration, as I'm caching all responses
> with an image/* content-type.
> 
> On Tue, Nov 06, 2007 at 05:35:17PM +0100, Trond Michelsen wrote:
>> In my mapfile, I have several layers with connectiontype WMS. Once in
>> a while, the WMS-servers that deliver these layers will fail, usually
>> due to high load, and return an application/vnd.ogc.se_xml
>> exception. In these cases, I'd like mapserver to return an exception
>> as well, but instead, mapserver will just log the error message in
>> MS_ERRORFILE, and continue drawing the rest of the layers. If there
>> are no more layers, it will result in a blank image.
>>
>> (BTW: I've also noticed the same behaviour if the remote wms-server
>> answers with an internal server error)
>>
>> Here's the layer definition that I use for testing. exception.cgi will
>> always return a dummy XML exception.
>>
>> LAYER
>>     NAME "exception"
>>     TYPE RASTER
>>     STATUS ON
>>     CONNECTION "http://wms1.oslo.dnmi.no/cgi-bin/exception.cgi"
>>     CONNECTIONTYPE WMS
>>     OFFSITE 255 255 254
>>     METADATA
>>       "wms_srs"               "EPSG:4326"
>>       "wms_name"              "exception"
>>       "wms_server_version"    "1.1.1"
>>       "wms_formatlist"        "image/png"
>>       "wms_format"            "image/png"
>>       "wms_exceptions_format" "application/vnd.ogc.se_xml"
>>     END #metadata
>> END #layer
>>
>> Is there something I can do to force mapserver to fail, and return an
>> exception if it fails to draw any of the wms-layers?
>>
>> I'm using mapserver 4.10
>>
>> $ cgi-bin/mapserv -v
>> MapServer version 4.10.0 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPPORTS=THREADS SUPPORTS=GEOS INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE DEBUG=MSDEBUG
>>
>>
>> -- 
>> Trond Michelsen
>>
>