fail-safe symlink function added

common_helper_files/__init__.py

 from .file_functions import read_in_chunks, get_directory_for_filename, create_dir_for_file, human_readable_file_size
 from .git_functions import get_version_string_from_git
-from .fail_safe_file_operations import get_binary_from_file, get_string_list_from_file, write_binary_to_file, get_safe_name, delete_file, get_files_in_dir, get_dirs_in_dir
+from .fail_safe_file_operations import get_binary_from_file, get_string_list_from_file, write_binary_to_file, get_safe_name, delete_file, get_files_in_dir, get_dirs_in_dir, create_symlink
 
-__version__ = '0.1.7'
+__version__ = '0.1.8'
 
 __all__ = [
     'get_directory_for_filename',
@@ -15,6 +15,7 @@ __all__ = [
     'write_binary_to_file',
     'get_safe_name',
     'delete_file',
+    'create_symlink',
     'get_files_in_dir',
     'get_dirs_in_dir',
 ]

common_helper_files/fail_safe_file_operations.py

-import os
-import sys
 import logging
+import os
 import re
+import sys
+from builtins import FileExistsError
 
 from .file_functions import create_dir_for_file
 
@@ -103,6 +104,25 @@ def delete_file(file_path):
         logging.error("Could not delete file: {} {}".format(sys.exc_info()[0].__name__, e))
 
 
+def create_symlink(src_path, dst_path):
+    """
+    Fail-safe symlink operation. Symlinks a file if dest does not exist.
+    Errors are logged. No exception raised.
+
+    :param src_path: src file
+    :type src_path: str
+    :param dst_path: link location
+    :type dst_path: str
+    :return: None
+    """
+    try:
+        os.symlink(src_path, dst_path)
+    except FileExistsError as e:
+        logging.debug("Could not create Link: File exists: {}".format(e))
+    except Exception as e:
+        logging.error("Could not create link: {} {}".format(sys.exc_info()[0].__name__, e))
+
+
 def get_safe_name(file_name, max_size=200, valid_characters='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_+. '):
     """
     removes all problematic characters from a file name

tests/test_fail_safe_file_operations.py

@@ -5,7 +5,8 @@ import unittest
 from common_helper_files import get_binary_from_file, \
     write_binary_to_file, delete_file, get_safe_name, \
     get_files_in_dir, get_string_list_from_file, \
-    get_dirs_in_dir, get_directory_for_filename
+    get_dirs_in_dir, get_directory_for_filename, \
+    create_symlink
 from common_helper_files.fail_safe_file_operations import _get_counted_file_path
 
 
@@ -71,6 +72,13 @@ class Test_FailSafeFileOperations(unittest.TestCase):
         # Test delete none existing file
         delete_file(file_path)
 
+    def test_create_symlink(self):
+        test_file_path = os.path.join(self.tmp_dir.name, 'test_folder', 'test_file')
+        symlink_path = os.path.join(self.tmp_dir.name, 'test_symlink')
+        create_symlink(test_file_path, symlink_path)
+        self.assertEqual(os.readlink(symlink_path), test_file_path)
+        create_symlink(test_file_path, symlink_path)
+
     def test_get_safe_name(self):
         a = "/()=Hello%&World!? Foo"
         self.assertEqual(get_safe_name(a), "HelloWorld_Foo", "result not correct")