set permissions on output to readable for all

dump_hotfilm.py

@@ -132,6 +132,8 @@ def finish(self, minutes: int):
         logger.info("file finished with %d mins, renaming: %s",
                     minutes, fpath)
         fpath = Path(self.tfile.name).rename(fpath)
+        # the files should not need to be writable
+        fpath.chmod(0o444)
         self.tfile = None
         self.path = None
         self.when = None

test_dump_hotfilm.py

@@ -289,6 +289,8 @@ def test_netcdf_output():
     logger.debug("dumping: %s", " ".join(args))
     main(args)
     assert xout.exists() and xout.stat().st_size > 0
+    # make sure we get permissions ugo=r also
+    assert xout.stat().st_mode & 0o444 == 0o444
     # hardcode for now, but might need to be configurable.  it should also be
     # feasible to just open both files with xarray and compare the datasets.
     nc_compare = Path("/opt/local/bin/nc_compare")