How do I propagate failures from upstream wms-servers?

[Trond Michelsen]

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
> 

-- 
Trond Michelsen