Fix export issue

PNG came out wrong because of concurrency (?) issues where the SVG file
was converted before being fully generated. The solution was to close
the temporary file between each operation.

lokrez/export.py

@@ -51,11 +51,13 @@ def generate_outfile(
 
         cachedir.mkdir(parents=True, exist_ok=True)
 
-        with tempfile.NamedTemporaryFile(
+        tmpsvg = tempfile.NamedTemporaryFile(
                 suffix=".svg",
                 mode = "w",
+                delete = False,
                 dir = str(cachedir),
-                ) as tmpsvg:
+                )
+        tmpsvg.close()
         try:
             log.info(
                     "Exporting to {} using inkscape" \
@@ -63,7 +65,7 @@ def generate_outfile(
                             )
             import subprocess
 
-                jj2_tpl.stream(context).dump( tmpsvg )
+            jj2_tpl.stream(context).dump( tmpsvg.name )
 
             inkscape_process = subprocess.Popen(
                     [
@@ -97,6 +99,9 @@ def generate_outfile(
             log.warning("Failed to export with inkscape")
             log.debug(e, exc_info=True)
 
+        finally:
+            os.unlink(tmpsvg.name)
+
     # To png, pdf or ps with cairosvg
     # -------------------------------------------------------------------------
     if outfilename.suffix in [ ".png", ".pdf", ".ps" ]: