add ability to patch template with update (#82)

dotdrop/dotdrop.py

@@ -44,7 +44,7 @@ Usage:
   dotdrop import    [-ldVb]    [-c <path>] [-p <profile>] <path>...
   dotdrop compare   [-Vb]      [-c <path>] [-p <profile>]
                                [-o <opts>] [-C <file>...] [-i <pattern>...]
-  dotdrop update    [-fdVbk]   [-c <path>] [-p <profile>]
+  dotdrop update    [-fdVbkP]  [-c <path>] [-p <profile>]
                                [-i <pattern>...] [<path>...]
   dotdrop listfiles [-VTb]     [-c <path>] [-p <profile>]
   dotdrop detail    [-Vb]      [-c <path>] [-p <profile>] [<key>...]
@@ -63,6 +63,7 @@ Options:
   -T --template           Only template dotfiles.
   -D --showdiff           Show a diff before overwriting.
   -l --inv-link           Invert the value of "link_by_default" when importing.
+  -P --show-patch         Provide a one-liner to manually patch template.
   -f --force              Do not warn if exists.
   -k --key                Treat <path> as a dotfile key.
   -V --verbose            Be verbose.
@@ -213,12 +214,13 @@ def cmd_compare(opts, conf, tmp, focus=[], ignore=[]):
     return same
 
 
-def cmd_update(opts, conf, paths, iskey=False, ignore=[]):
+def cmd_update(opts, conf, paths, iskey=False, ignore=[], showpatch=False):
     """update the dotfile(s) from path(s) or key(s)"""
     ret = True
     updater = Updater(conf, opts['dotpath'], opts['profile'],
                       opts['dry'], opts['safe'], iskey=iskey,
-                      debug=opts['debug'], ignore=[])
+                      debug=opts['debug'], ignore=[],
+                      showpatch=showpatch)
     if not iskey:
         # update paths
         if opts['debug']:
@@ -509,8 +511,9 @@ def main():
             if opts['debug']:
                 LOG.dbg('running cmd: update')
             iskey = args['--key']
-            ret = cmd_update(opts, conf, args['<path>'], iskey=iskey,
-                             ignore=args['--ignore'])
+            ret = cmd_update(opts, conf, args['<path>'],
+                             iskey=iskey, ignore=args['--ignore'],
+                             showpatch=args['--show-patch'])
 
         elif args['detail']:
             # detail files

dotdrop/updater.py

@@ -21,7 +21,7 @@ TILD = '~'
 class Updater:
 
     def __init__(self, conf, dotpath, profile, dry, safe,
-                 iskey=False, debug=False, ignore=[]):
+                 iskey=False, debug=False, ignore=[], showpatch=False):
         self.conf = conf
         self.dotpath = dotpath
         self.profile = profile
@@ -30,6 +30,7 @@ class Updater:
         self.iskey = iskey
         self.debug = debug
         self.ignore = ignore
+        self.showpatch = showpatch
         self.log = Logger()
 
     def update_path(self, path):
@@ -144,6 +145,21 @@ class Updater:
         self.log.warn('{} uses template, update manually'.format(path))
         return True
 
+    def _show_patch(self, tpath, fpath):
+        """provide a way to manually patch the template"""
+        content = self._resolve_template(tpath)
+        tmp = utils.write_to_tmpfile(content)
+        cmds = ['diff', '-u', tmp, fpath, '|', 'patch', tpath]
+        self.log.warn('try patching with: \"{}\"'.format(' '.join(cmds)))
+        return False
+
+    def _resolve_template(self, tpath):
+        """resolve the template to a temporary file"""
+        variables = self.conf.get_variables(self.profile)
+        t = Templategen(variables=variables, base=self.dotpath,
+                        debug=self.debug)
+        return t.generate(tpath)
+
     def _handle_file(self, left, right, compare=True):
         """sync left (deployed file) and right (dotdrop dotfile)"""
         if self._ignore([left, right]):
@@ -151,8 +167,11 @@ class Updater:
         if self.debug:
             self.log.dbg('update for file {} and {}'.format(left, right))
         if self._is_template(right):
+            # dotfile is a template
             if self.debug:
                 self.log.dbg('{} is a template'.format(right))
+            if self.showpatch:
+                self._show_patch(right, left)
             return False
         if compare and filecmp.cmp(left, right, shallow=True):
             # no difference

dotdrop/utils.py

@@ -41,6 +41,14 @@ def run(cmd, raw=True, debug=False, checkerr=False):
     return ret == 0, lines
 
 
+def write_to_tmpfile(content):
+    """write some content to a tmp file"""
+    path = get_tmpfile()
+    with open(path, 'wb') as f:
+        f.write(content)
+    return path
+
+
 def shell(cmd):
     """run a command in the shell (expects a string)"""
     return subprocess.getoutput(cmd)