enable the kolla build system to use out of tree docker files

- This change introduces a docker-dir config option to enable
  specifying an out of tree additional docker file
  root dir for use with  kolla build.
- This change allows kolla's build system to be reused by non kolla
  or external project to build arbitrary docker images using jinja2
  templatized docker files.

Co-Authored-By: Michal (inc0) Jastrzebski <inc007@gmail.com>
Change-Id: Idbba02a8910866ef1b838e5cbac3ab230551b7e5

kolla/common/config.py

@@ -246,6 +246,9 @@ _CLI_OPTS = [
                help='Time in seconds after which any operation times out'),
     cfg.MultiOpt('template-override', types.String(),
                  help='Path to template override file'),
+    cfg.MultiOpt('docker-dir', types.String(),
+                 help='Path to additional docker file template directory',
+                 short='D', default=[]),
     cfg.StrOpt('logs-dir', help='Path to logs directory'),
     cfg.BoolOpt('pull', default=True,
                 help='Attempt to pull a newer version of the base image'),

kolla/image/build.py

@@ -643,6 +643,18 @@ class KollaWorker(object):
                 os.path.join(self.working_dir, "base", "apt_preferences")
             )
 
+    def copy_dir(self, src, dest):
+        if not os.path.isdir(dest):
+            shutil.copytree(src, dest)
+        else:
+            for file in os.listdir(src):
+                src_path = os.path.join(src, file)
+                dest_path = os.path.join(dest, file)
+                if os.path.isdir(src_path):
+                    self.copy_dir(src_path, dest_path)
+                else:
+                    shutil.copy2(src_path, dest_path)
+
     def setup_working_dir(self):
         """Creates a working directory for use while building."""
         if self.conf.work_dir:
@@ -653,7 +665,9 @@ class KollaWorker(object):
                 '%Y-%m-%d_%H-%M-%S_')
             self.temp_dir = tempfile.mkdtemp(prefix='kolla-' + ts)
             self.working_dir = os.path.join(self.temp_dir, 'docker')
-        shutil.copytree(self.images_dir, self.working_dir)
+        self.copy_dir(self.images_dir, self.working_dir)
+        for dir in self.conf.docker_dir:
+            self.copy_dir(dir, self.working_dir)
         self.copy_apt_files()
         LOG.debug('Created working dir: %s', self.working_dir)
 

releasenotes/notes/additional-docker-dir-7121c33da7eec160.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Kolla now supports additional dockerfile directory building if they
+    follow Kolla template standard. To add custom docker directory run
+    kolla-build --docker-dir /path/to/custom/dockerfiles