cgitize.cgit: factor out setup_git_auth

3 files changed, 72 insertions, 37 deletions

diff --git a/cgitize/cgit.py b/cgitize/cgit.py
index 167456f..7c6e6f6 100644
--- a/cgitize/cgit.py
+++ b/cgitize/cgit.py
@@ -3,49 +3,14 @@
 # For details, see https://github.com/egor-tensin/cgitize.
 # Distributed under the MIT License.
 
-from contextlib import contextmanager
 import logging
 import os
-import os.path
 import shutil
-import stat
 
 from cgitize.git import Git
 from cgitize.utils import chdir
 
 
-@contextmanager
-def setup_git_auth(repo):
-    if not repo.url_auth:
-        yield
-        return
-    config_path = os.path.expanduser('~/.gitconfig')
-    exists = os.path.exists(config_path)
-    if exists:
-        old_permissions = stat.S_IMODE(os.stat(config_path).st_mode)
-        new_permissions = stat.S_IRUSR | stat.S_IWUSR # 0x600
-        os.chmod(config_path, new_permissions)
-        with open(config_path, encoding='utf-8', mode='r') as fd:
-            old_contents = fd.read()
-    else:
-        old_contents = ''
-    new_contents = f'''{old_contents}
-[url "{repo.clone_url_with_auth}"]
-    insteadOf = {repo.clone_url}
-'''
-    with open(config_path, encoding='utf-8', mode='w') as fd:
-        fd.write(new_contents)
-    try:
-        yield
-    finally:
-        if exists:
-            with open(config_path, encoding='utf-8', mode='w') as fd:
-                fd.write(old_contents)
-            os.chmod(config_path, old_permissions)
-        else:
-            os.unlink(config_path)
-
-
 class CGitServer:
     def __init__(self, clone_url):
         self.clone_url = clone_url
@@ -150,14 +115,14 @@ class CGitRepositories:
             except Exception as e:
                 logging.exception(e)
                 return False
-        with setup_git_auth(repo):
+        with Git.setup_auth(repo):
             return Git.check('clone', '--mirror', '--quiet', repo.clone_url, repo_dir)
 
     def _update_existing(self, repo):
         logging.info("Updating repository '%s'", repo.repo_id)
         repo_dir = self.get_repo_dir(repo)
         with chdir(repo_dir):
-            with setup_git_auth(repo):
+            with Git.setup_auth(repo):
                 if not Git.check('remote', 'update', '--prune'):
                     return False
             # In case the local repository is not a bare repository, but a
diff --git a/cgitize/git.py b/cgitize/git.py
index 87554dd..a2be8df 100644
--- a/cgitize/git.py
+++ b/cgitize/git.py
@@ -3,6 +3,7 @@
 # For details, see https://github.com/egor-tensin/cgitize.
 # Distributed under the MIT License.
 
+from contextlib import contextmanager
 import os
 
 import cgitize.utils as utils
@@ -12,6 +13,33 @@ GIT_ENV = os.environ.copy()
 GIT_ENV['GIT_SSH_COMMAND'] = 'ssh -oBatchMode=yes -oLogLevel=QUIET -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null'
 
 
+class Config:
+    def __init__(self, path):
+        self.path = path
+
+    def exists(self):
+        return os.path.exists(self.path)
+
+    def open(self, mode='r'):
+        return open(self.path, mode=mode, encoding='utf-8')
+
+    def read(self):
+        with self.open(mode='r') as fd:
+            return fd.read()
+
+    def write(self, contents):
+        with self.open(mode='w') as fd:
+            fd.write(contents)
+
+    @contextmanager
+    def backup(self):
+        old_contents = self.read()
+        try:
+            yield old_contents
+        finally:
+            self.write(old_contents)
+
+
 class Git:
     EXE = 'git'
 
@@ -22,3 +50,23 @@ class Git:
     @staticmethod
     def capture(*args, **kwargs):
         return utils.try_run_capture(Git.EXE, *args, env=GIT_ENV, **kwargs)
+
+    @staticmethod
+    def get_global_config():
+        return Config(os.path.expanduser('~/.gitconfig'))
+
+    @staticmethod
+    @contextmanager
+    def setup_auth(repo):
+        if not repo.url_auth:
+            yield
+            return
+        config = Git.get_global_config()
+        with utils.protected_file(config.path):
+            with config.backup() as old_contents:
+                new_contents = f'''{old_contents}
+[url "{repo.clone_url_with_auth}"]
+    insteadOf = {repo.clone_url}
+'''
+                config.write(new_contents)
+                yield
diff --git a/cgitize/utils.py b/cgitize/utils.py
index 0bfa855..152684f 100644
--- a/cgitize/utils.py
+++ b/cgitize/utils.py
@@ -6,6 +6,7 @@
 from contextlib import contextmanager
 import logging
 import os
+import stat
 import subprocess
 import sys
 
@@ -69,3 +70,24 @@ def chdir(new_cwd):
         yield
     finally:
         os.chdir(old_cwd)
+
+
+@contextmanager
+def protected_file(path):
+    # 0600:
+    new_permissions = stat.S_IRUSR | stat.S_IWUSR
+    if os.path.exists(path):
+        old_permissions = stat.S_IMODE(os.stat(path).st_mode)
+        os.chmod(path, new_permissions)
+        try:
+            yield
+        finally:
+            os.chmod(path, old_permissions)
+    else:
+        with open(path, mode='w'):
+            pass
+        os.chmod(path, new_permissions)
+        try:
+            yield
+        finally:
+            os.unlink(path)