[mapserver-users] msDrawRasterLayerLow(): Unable to access file.

[Matt Bartolome]

I've run into a strange problem and can't locate the source of the issue.
I'm running a python/mapscript function with apache2 and django via wsgi on
Ubuntu 12.04, mapserver 6.2. When I run the script using plain python as
the www-data user (the same user as the wsgi daemon) the script works
perfectly fine. When I run it under the wsgi process (through the browser)
it fails with the error:

msDrawMap(): Image handling error. Failed to draw layer named 'imagery_2010'.
msDrawRasterLayerLow(): Unable to access file. Corrupt, empty or
missing file '/mnt/test/imagery/test.ecw' for layer 'imagery_2010'.

At first I thought it was a simple permissions issue (reading the ecw off a
mount point etc). I verified with inotifywait that the file is being opened
by the wsgi script. I have compiled gdal with ECW support and have checked
that the wsgi process is running off the same mapscript python lib. Also,
the same wsgi script will run without error if I change the raster to a
non-ecw file, so it seems that it just doesn't like the ecw under wsgi.

gdalinfo reads the ecw just fine as well. It is only under the wsgi process
where it has problems. I'm stumped... Thanks for your help!

Here is my map file:

MAP

  CONFIG "MS_ERRORFILE" "/tmp/ms_output.txt"
  DEBUG 5
  CONFIG "PROJ_LIB" "/usr/share/proj/"

  PROJECTION
    "init=epsg:900913"
  END
  FONTSET "/test/fontset.txt"
  WEB
    METADATA
      "wms_title"           "WMS"
      "wms_onlineresource"  "
http://localhost:81/cgi-bin/mapserv?map=/test/mapserver-config/plan.map"
      "ows_enable_request"   "*"
      "wms_srs"             "epsg:900913"

    END
  END

  OUTPUTFORMAT
    NAME png
    DRIVER "AGG/PNG"
    MIMETYPE "image/png"
    IMAGEMODE RGB
    EXTENSION "png"
  END

  LAYER
    NAME "imagery_2010"
    TYPE RASTER
    STATUS ON
    DATA "/mnt/test/imagery/test.ecw"

    PROJECTION
      "init=epsg:2230"
    END
    PROCESSING "NODATA=255"
    PROCESSING "RESAMPLE=AVERAGE"
  END
END

Here is the python script:

import mapscript

extent = [-13037387.706571, 3898141.5912883, -13036963.719929,
3898380.4570017]
filename = '/tmp/test.pdf'
raster = '/tmp/test.png'
mapfile = '/test/mapserver-config/plan.map'
map_obj =  mapscript.mapObj(mapfile)
map_obj.width = 800
map_obj.height = 600
map_obj.extent = mapscript.rectObj(*extent)
image = map_obj.draw()
image.save(raster)
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