Move Git storage to the main thread

Closes #29

Makefile

@@ -104,6 +104,7 @@ watch: depends .clean-test
 .PHONY: run
 run: depends-dev .env
 	git init data
+	cd data && touch README && git commit -am "Add initial files"
 ifdef DEBUG
 	$(HONCHO) run $(PYTHON) manage.py run
 else

api/routes/_common.py

@@ -1,9 +1,9 @@
 import os
 import pprint
+import contextlib
 import logging
-from multiprocessing import Process
 
-from sh import git as _git, ErrorReturnCode  # pylint: disable=no-name-in-module
+from sh import git, ErrorReturnCode  # pylint: disable=no-name-in-module
 import requests
 from flask import current_app, request
 
@@ -19,30 +19,36 @@
 log = logging.getLogger(__name__)
 
 
-def sync(obj):
-    """Store updated metrics in version control."""
+def sync(model):
+    """Store all changes in version control."""
+    remote = current_app.config['ENV'] == 'prod'
 
-    def run(_sync=False):  # pragma: no cover (separate process)
-        git = _git.bake(git_dir=os.path.join(DATA, ".git"), work_tree=DATA)
+    message = str(model)  # YORM models can't be used in a different directory
 
+    with location(DATA):
         git.add(all=True)
+        git.stash()
+        if remote:
+            git.pull()
         try:
-            git.commit(message=str(obj))
+            git.stash('apply')
+            git.add(all=True)
+            git.commit(message=message)
         except ErrorReturnCode:
-            commit = False
+            log.warning("No changes to save")
         else:
-            commit = True
-
-        if _sync:
-            if commit:
-                git.push(force=True)
-            git.pull()
-
-    _sync = current_app.config['ENV'] == 'prod'
-    process = Process(target=run, args=[_sync])
-    process.start()
-
-    return obj
+            log.info("Saved model: %s", message)
+            if remote:
+                git.push()
+
+
+@contextlib.contextmanager
+def location(dirpath):
+    """Change to a directory, temporarily."""
+    cwd = os.getcwd()
+    os.chdir(dirpath)
+    yield
+    os.chdir(cwd)
 
 
 def track(obj):