ticket #824: If we get an OS error doing os.rename of stitcher.log an…

…d it is the text windows gives when the file is in use, then exit with a more helpful error message.

CHANGES

@@ -90,6 +90,8 @@ gcf 2.9:
    * Bug fix for merging comments when template has a comment child and other does not. (#815)
   * Quiet down errors deleting a failed reservation from EG AMs (harmless). (#811)
   * Remove reference to ION as a real aggregate in the README. ION has been decommissioned. (#797)
+  * Gracefully handle error when 2 stitcher instances are running in the same directory
+    at once on Windows. (#824)
 
  * Scripts
   * Initial commit of `examples/renewSliceAndSlivers.py`. (#798)

src/stitcher.py

@@ -304,7 +304,16 @@ def call(argv, options=None):
         if os.path.exists(dfn):
             os.remove(dfn)
         if os.path.exists(bfn):
-            os.rename(bfn, dfn)
+            try:
+                os.rename(bfn, dfn)
+            except OSError, e:
+                # Issue #824 partial solution
+                if "being used by another process" in str(e):
+                    # On Windows, when another stitcher instance running in same directory, so has stitcher.log open
+                    # WindowsError: [Error 32] The process cannot access the file because it is being used by another process
+                    sys.exit("Error: Is another stitcher process running in this directory? Run stitcher from a different directory, or re-run with the option `--fileDir <separate directory for this run's output files>`")
+                else:
+                    raise
 
     # Then have Omni configure the logger
     try: