Fixed a race condition within geotransform2mapinfo() and...

Fixed a race condition within geotransform2mapinfo() and mapinfo2geotransform() when running in multiprocessing.
Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>

HISTORY.rst

@@ -2,7 +2,13 @@
 History
 =======
 
-0.15.1 (2020-08-26)
+0.15.2 (2020-08-27)
+-------------------
+
+* Fixed a race condition within geotransform2mapinfo() and mapinfo2geotransform() when running in multiprocessing.
+
+
+0.15.1 (2020-08-27)
 -------------------
 
 * Fixed exceptions caused by WKT2 strings passed to GDAL<3.

py_tools_ds/geo/map_info.py

@@ -26,6 +26,7 @@ import math
 import warnings
 import os
 from typing import Union  # noqa F401  # flake8 issue
+from tempfile import TemporaryDirectory
 
 from pyproj import CRS
 import numpy as np
@@ -140,6 +141,7 @@ class Geocoding(object):
                         'Geographic Lat/Lon' if proj4['proj'] == 'longlat' else \
                         'UTM' if proj4['proj'] == 'utm' else proj4['proj']
                     # FIXME there is no 'datum' key in case of, e.g., LAEA projection  # still true?
+                    #       -> use CRS.datum.name instead?
                     self.datum = 'WGS-84' if proj4['datum'] == 'WGS84' else proj4['datum']  # proj4['ellps']?
                     self.units = proj4['unit'] if 'unit' in proj4 else self.units
 
@@ -248,24 +250,22 @@ def geotransform2mapinfo(gt, prj):
         return Geocoding(gt=gt, prj=prj).to_mapinfo()
 
     except KeyError:  # KeyError: 'datum' - in case of, e.g., ETRS/LAEA projection
-        fn_bsq = "py_tools_ds__geotransform2mapinfo_temp.bsq"
-        fn_hdr = os.path.splitext(fn_bsq)[0] + '.hdr'
-        fdir = os.path.join(os.path.abspath(os.curdir))
+        if int(gdal.__version__[0]) < 3:
+            # noinspection PyTypeChecker
+            prj = CRS(prj).to_wkt(version="WKT1_GDAL")
 
-        try:
-            if int(gdal.__version__[0]) < 3:
-                # noinspection PyTypeChecker
-                prj = CRS(prj).to_wkt(version="WKT1_GDAL")
+        with TemporaryDirectory() as fdir:
+            fn = "py_tools_ds__geotransform2mapinfo_temp"
+            fP_bsq = os.path.join(fdir, fn + '.bsq')
+            fP_hdr = os.path.join(fdir, fn + '.hdr')
 
-            ds_out = gdal.GetDriverByName('ENVI').Create(fn_bsq, 2, 2, 1, gdal.GDT_Int32)
+            ds_out = gdal.GetDriverByName('ENVI').Create(fP_bsq, 2, 2, 1, gdal.GDT_Int32)
             ds_out.SetGeoTransform(gt)
             ds_out.SetProjection(prj)
             ds_out.FlushCache()
+            del ds_out
 
-            # noinspection PyUnusedLocal
-            ds_out = None
-
-            with open(fn_hdr, 'r') as inF:
+            with open(fP_hdr, 'r') as inF:
                 content = inF.read()
                 if 'map info' in content:
                     res = re.search("map info = {(.*?)}", content, re.I).group(1)
@@ -279,11 +279,6 @@ def geotransform2mapinfo(gt, prj):
                 else:
                     map_info = ['Arbitrary', 1.0, 1.0, 0.0, 0.0, 1.0, 1.0]
 
-        finally:
-            for fn in [fn_bsq, fn_hdr]:
-                if os.path.exists(os.path.join(fdir, fn)):
-                    gdal.Unlink(os.path.join(fdir, fn))
-
         return map_info
 
 
@@ -298,36 +293,29 @@ def mapinfo2geotransform(map_info):
         return Geocoding(mapinfo=map_info).to_geotransform()
 
     except (KeyError, ValueError):  # KeyError: 'datum' - in case of, e.g., ETRS/LAEA projection
-        fn_bsq = "py_tools_ds__geotransform2mapinfo_temp.bsq"
-        fn_hdr = os.path.splitext(fn_bsq)[0] + '.hdr'
-        fdir = os.path.join(os.path.abspath(os.curdir))
+        with TemporaryDirectory() as fdir:
+            fn = "py_tools_ds__mapinfo2geotransform_temp"
+            fP_bsq = os.path.join(fdir, fn + '.bsq')
+            fP_hdr = os.path.join(fdir, fn + '.hdr')
 
-        try:
-            ds_out = gdal.GetDriverByName('ENVI').Create(fn_bsq, 2, 2, 1)
+            ds_out = gdal.GetDriverByName('ENVI').Create(fP_bsq, 2, 2, 1)
             ds_out.GetRasterBand(1).WriteArray(np.array([[1, 2], [2, 3]]))
             ds_out.FlushCache()
+            del ds_out
 
-            # noinspection PyUnusedLocal
-            ds_out = None
-
-            with open(fn_hdr, 'r') as InHdr:
+            with open(fP_hdr, 'r') as InHdr:
                 lines = InHdr.readlines()
 
             lines.append('map info = { %s }\n' % ', '.join([str(i) for i in map_info]))
 
-            with open(fn_hdr, 'w') as OutHdr:
+            with open(fP_hdr, 'w') as OutHdr:
                 OutHdr.writelines(lines)
 
-            ds = gdal.Open(fn_bsq)
+            ds = gdal.Open(fP_bsq)
             gt = ds.GetGeoTransform()
             del ds
 
-            return gt
-
-        finally:
-            for fn in [fn_bsq, fn_hdr]:
-                if os.path.exists(os.path.join(fdir, fn)):
-                    gdal.Unlink(os.path.join(fdir, fn))
+        return gt
 
 
 def get_corner_coordinates(gdal_ds=None, gt=None, cols=None, rows=None):

py_tools_ds/version.py

@@ -19,5 +19,5 @@
 # You should have received a copy of the GNU Lesser General Public License along
 # with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-__version__ = '0.15.1'
-__versionalias__ = '20200827_01'
+__version__ = '0.15.2'
+__versionalias__ = '20200827_02'