Implement gitignore functionality in SnapshotProvider

lib/tfw/components/snapshot_provider.py

@@ -5,14 +5,14 @@ import re
 from subprocess import run, CalledProcessError, PIPE
 from getpass import getuser
 from os.path import isdir
+from os.path import join as joinpath
 from uuid import uuid4
 
 from dateutil import parser as dateparser
 
 
-# TODO: gitignore
 class SnapshotProvider:
-    def __init__(self, directory, git_dir):
+    def __init__(self, directory, git_dir, exclude_unix_patterns=None):
         self._classname = self.__class__.__name__
         author = f'{getuser()} via TFW {self._classname}'
         self.gitenv = {
@@ -27,6 +27,8 @@ class SnapshotProvider:
 
         self._init_repo()
         self.__last_valid_branch = self._branch
+        if exclude_unix_patterns:
+            self.exclude = exclude_unix_patterns
 
     def _init_repo(self):
         self._check_environment()
@@ -105,6 +107,24 @@ class SnapshotProvider:
             kwargs['env'] = self.gitenv
         return run(*args, **kwargs)
 
+    @property
+    def exclude(self):
+        with open(self._exclude_path, 'r') as ofile:
+            return ofile.read()
+
+    @exclude.setter
+    def exclude(self, exclude_patterns):
+        with open(self._exclude_path, 'w') as ifile:
+            ifile.write('\n'.join(exclude_patterns))
+
+    @property
+    def _exclude_path(self):
+        return joinpath(
+            self.gitenv['GIT_DIR'],
+            'info',
+            'exclude'
+        )
+
     def take_snapshot(self):
         if self._head_detached:
             self._checkout_new_branch_from_head()