Make sure that read-only files can be copied (fix #375)

sigal/utils.py

@@ -50,7 +50,13 @@ def copy(src, dst, symlink=False, rellink=False):
     if rellink:  # relative symlink from dst
         func(os.path.relpath(src, os.path.dirname(dst)), dst)
     else:
-        func(src, dst)
+        try:
+            func(src, dst)
+        except PermissionError:
+            # this can happen if the file is not writable, so we try to remove
+            # it first
+            os.remove(dst)
+            func(src, dst)
 
 
 def check_or_create_dir(path):

tests/test_utils.py

@@ -1,4 +1,5 @@
 import os
+from pathlib import Path
 from sigal import utils
 
 CURRENT_DIR = os.path.dirname(__file__)
@@ -33,6 +34,15 @@ def test_copy(tmpdir):
     assert os.path.join(os.path.dirname(CURRENT_DIR)), os.readlink(dst) == src
     # get absolute path of the current dir plus the relative dir
 
+    src = str(tmpdir.join('foo.txt'))
+    dst = str(tmpdir.join('bar.txt'))
+    p = Path(src)
+    p.touch()
+    p.chmod(0o444)
+    utils.copy(src, dst)
+    utils.copy(src, dst)
+
+
 def test_check_or_create_dir(tmpdir):
     path = str(tmpdir.join('new_directory'))
     utils.check_or_create_dir(path)