Add a way to add other container engines

Add engine adapter module to allow additon of other container engines,
create one common EngineClient that would be called in all other
modules.

Based on patch by Konstantin Yarovoy <konstantin.yarovoy@tietoevry.com>

Change-Id: Ice6467086bd292af086322afc3fc4e869d89eefa

3 files changed, 83 insertions, 60 deletions

diff --git a/kolla/image/build.py b/kolla/image/build.py
index 6377ebe9d..196fab4e0 100644
--- a/kolla/image/build.py
+++ b/kolla/image/build.py
@@ -21,6 +21,7 @@ import time
 
 from kolla.common import config as common_config
 from kolla.common import utils
+from kolla.engine_adapter import engine
 from kolla.image.kolla_worker import KollaWorker
 from kolla.image.utils import LOG
 from kolla.image.utils import Status
@@ -104,10 +105,28 @@ def run_build():
     if conf.debug:
         LOG.setLevel(logging.DEBUG)
 
-    if conf.squash:
-        squash_version = utils.get_docker_squash_version()
-        LOG.info('Image squash is enabled and "docker-squash" version is %s',
-                 squash_version)
+    if conf.engine not in (engine.Engine.DOCKER.value,):
+        LOG.error(f'Unsupported engine name "{conf.engine}", exiting.')
+        sys.exit(1)
+    LOG.info(f'Using engine: {conf.engine}')
+
+    if conf.engine == engine.Engine.DOCKER.value:
+        try:
+            import docker
+            docker.version
+        except ImportError:
+            LOG.error("Error, you have set Docker as container engine, "
+                      "but the Python library is not found."
+                      "Try running 'pip install docker'")
+            sys.exit(1)
+        except AttributeError:
+            LOG.error("Error, Docker Python library is too old, "
+                      "Try running 'pip install docker --upgrade'")
+
+        if conf.squash:
+            squash_version = utils.get_docker_squash_version()
+            LOG.info('Image squash is enabled and "docker-squash" version '
+                     'is %s', squash_version)
 
     kolla = KollaWorker(conf)
     kolla.setup_working_dir()
@@ -133,7 +152,7 @@ def run_build():
 
     if conf.save_dependency:
         kolla.save_dependency(conf.save_dependency)
-        LOG.info('Docker images dependency are saved in %s',
+        LOG.info('Container images dependency are saved in %s',
                  conf.save_dependency)
         return
     if conf.list_images:
diff --git a/kolla/image/kolla_worker.py b/kolla/image/kolla_worker.py
index b1e7ac943..1a665ddd4 100644
--- a/kolla/image/kolla_worker.py
+++ b/kolla/image/kolla_worker.py
@@ -11,7 +11,6 @@
 # limitations under the License.
 
 import datetime
-import docker
 import json
 import os
 import queue
@@ -24,6 +23,7 @@ import time
 import jinja2
 from kolla.common import config as common_config
 from kolla.common import utils
+from kolla.engine_adapter import engine
 from kolla import exception
 from kolla.image.tasks import BuildTask
 from kolla.image.unbuildable import UNBUILDABLE_IMAGES
@@ -42,7 +42,7 @@ PROJECT_ROOT = os.path.abspath(os.path.join(
 class Image(object):
     def __init__(self, name, canonical_name, path, parent_name='',
                  status=Status.UNPROCESSED, parent=None,
-                 source=None, logger=None, docker_client=None):
+                 source=None, logger=None, engine_client=None):
         self.name = name
         self.canonical_name = canonical_name
         self.path = path
@@ -56,7 +56,7 @@ class Image(object):
         self.children = []
         self.plugins = []
         self.additions = []
-        self.dc = docker_client
+        self.engine_client = engine_client
 
     def copy(self):
         c = Image(self.name, self.canonical_name, self.path,
@@ -72,8 +72,9 @@ class Image(object):
             c.additions = list(self.additions)
         return c
 
-    def in_docker_cache(self):
-        return len(self.dc.images(name=self.canonical_name, quiet=True)) == 1
+    def in_engine_cache(self):
+        return len(self.engine_client.images(name=self.canonical_name,
+                                             quiet=True)) == 1
 
     def __repr__(self):
         return ("Image(%s, %s, %s, parent_name=%s,"
@@ -148,16 +149,16 @@ class KollaWorker(object):
         self.maintainer = conf.maintainer
         self.distro_python_version = conf.distro_python_version
 
-        docker_kwargs = docker.utils.kwargs_from_env()
         try:
-            self.dc = docker.APIClient(version='auto', **docker_kwargs)
-        except docker.errors.DockerException as e:
-            self.dc = None
+            self.engine_client = engine.getEngineClient(self.conf)
+        except engine.getEngineException(self.conf) as e:
+            self.engine_client = None
             if not (conf.template_only or
                     conf.save_dependency or
                     conf.list_images or
                     conf.list_dependencies):
-                LOG.error("Unable to connect to Docker, exiting")
+                LOG.error("Unable to connect to container engine daemon, "
+                          "exiting")
                 LOG.info("Exception caught: {0}".format(e))
                 sys.exit(1)
 
@@ -179,18 +180,18 @@ class KollaWorker(object):
             #                 this is the correct path
             # TODO(SamYaple): Improve this to make this safer
             if os.path.exists(os.path.join(image_path, 'base')):
-                LOG.info('Found the docker image folder at %s', image_path)
+                LOG.info('Found the container image folder at %s', image_path)
                 return image_path
         else:
             raise exception.KollaDirNotFoundException('Image dir can not '
                                                       'be found')
 
     def build_rpm_setup(self, rpm_setup_config):
-        """Generates a list of docker commands based on provided configuration.
+        """Generates a list of engine commands based on provided configuration
 
         :param rpm_setup_config: A list of .rpm or .repo paths or URLs
                                  (can be empty)
-        :return: A list of docker commands
+        :return: A list of engine commands
         """
         rpm_setup = list()
 
@@ -470,7 +471,7 @@ class KollaWorker(object):
             if image.status != Status.MATCHED:
                 continue
             # Skip image if --skip-existing was given and image exists.
-            if (self.conf.skip_existing and image.in_docker_cache()):
+            if (self.conf.skip_existing and image.in_engine_cache()):
                 LOG.debug('Skipping existing image %s', image.name)
                 image.status = Status.SKIPPED
             # Skip image if --skip-parents was given and image has children.
@@ -638,7 +639,7 @@ class KollaWorker(object):
             image = Image(image_name, canonical_name, path,
                           parent_name=parent_name,
                           logger=utils.make_a_logger(self.conf, image_name),
-                          docker_client=self.dc)
+                          engine_client=self.engine_client)
 
             # NOTE(jeffrey4l): register the opts if the section didn't
             # register in the kolla/common/config.py file
@@ -683,7 +684,7 @@ class KollaWorker(object):
         except ImportError:
             LOG.error('"graphviz" is required for save dependency')
             raise
-        dot = graphviz.Digraph(comment='Docker Images Dependency')
+        dot = graphviz.Digraph(comment='Container Images Dependency')
         dot.body.extend(['rankdir=LR'])
         for image in self.images:
             if image.status not in [Status.MATCHED]:
diff --git a/kolla/image/tasks.py b/kolla/image/tasks.py
index cbfecce09..d15ef8d17 100644
--- a/kolla/image/tasks.py
+++ b/kolla/image/tasks.py
@@ -11,7 +11,6 @@
 # limitations under the License.
 
 import datetime
-import docker
 import errno
 import os
 import shutil
@@ -23,6 +22,7 @@ from requests import exceptions as requests_exc
 
 from kolla.common import task  # noqa
 from kolla.common import utils  # noqa
+from kolla.engine_adapter import engine
 from kolla.image.utils import Status
 from kolla.image.utils import STATUS_ERRORS
 
@@ -31,21 +31,18 @@ class ArchivingError(Exception):
     pass
 
 
-class DockerTask(task.Task):
-
-    docker_kwargs = docker.utils.kwargs_from_env()
-
-    def __init__(self):
-        super(DockerTask, self).__init__()
-        self._dc = None
+class EngineTask(task.Task):
+    def __init__(self, conf):
+        super(EngineTask, self).__init__()
+        self._ec = None
+        self.conf = conf
 
     @property
-    def dc(self):
-        if self._dc is not None:
-            return self._dc
-        docker_kwargs = self.docker_kwargs.copy()
-        self._dc = docker.APIClient(version='auto', **docker_kwargs)
-        return self._dc
+    def engine_client(self):
+        if self._ec is not None:
+            return self._ec
+        self._ec = engine.getEngineClient(self.conf)
+        return self._ec
 
 
 class PushIntoQueueTask(task.Task):
@@ -70,11 +67,11 @@ class PushError(Exception):
     pass
 
 
-class PushTask(DockerTask):
-    """Task that pushes an image to a docker repository."""
+class PushTask(EngineTask):
+    """Task that pushes an image to a container image repository."""
 
     def __init__(self, conf, image):
-        super(PushTask, self).__init__()
+        super(PushTask, self).__init__(conf)
         self.conf = conf
         self.image = image
         self.logger = image.logger
@@ -89,9 +86,10 @@ class PushTask(DockerTask):
         try:
             self.push_image(image)
         except requests_exc.ConnectionError:
-            self.logger.exception('Make sure Docker is running and that you'
-                                  ' have the correct privileges to run Docker'
-                                  ' (root)')
+            self.logger.exception('Make sure container engine daemon is '
+                                  'running and that you have the correct '
+                                  'privileges to run the '
+                                  'container engine (root)')
             image.status = Status.CONNECTION_ERROR
         except PushError as exception:
             self.logger.error(exception)
@@ -110,7 +108,8 @@ class PushTask(DockerTask):
     def push_image(self, image):
         kwargs = dict(stream=True, decode=True)
 
-        for response in self.dc.push(image.canonical_name, **kwargs):
+        for response in self.engine_client.push(
+                image.canonical_name, **kwargs):
             if 'stream' in response:
                 self.logger.info(response['stream'])
             elif 'errorDetail' in response:
@@ -120,11 +119,11 @@ class PushTask(DockerTask):
         image.status = Status.BUILT
 
 
-class BuildTask(DockerTask):
+class BuildTask(EngineTask):
     """Task that builds out an image."""
 
     def __init__(self, conf, image, push_queue):
-        super(BuildTask, self).__init__()
+        super(BuildTask, self).__init__(conf)
         self.conf = conf
         self.image = image
         self.push_queue = push_queue
@@ -145,8 +144,9 @@ class BuildTask(DockerTask):
         followups = []
         if self.conf.push and self.success:
             followups.extend([
-                # If we are supposed to push the image into a docker
-                # repository, then make sure we do that...
+                # If we are supposed to push the image into a
+                # container image repository,
+                # then make sure we do that...
                 PushIntoQueueTask(
                     PushTask(self.conf, self.image),
                     self.push_queue),
@@ -348,15 +348,16 @@ class BuildTask(DockerTask):
 
         buildargs = self.update_buildargs()
         try:
-            for stream in self.dc.build(path=image.path,
-                                        tag=image.canonical_name,
-                                        nocache=not self.conf.cache,
-                                        rm=True,
-                                        decode=True,
-                                        network_mode=self.conf.network_mode,
-                                        pull=pull,
-                                        forcerm=self.forcerm,
-                                        buildargs=buildargs):
+            for stream in \
+                self.engine_client.build(path=image.path,
+                                         tag=image.canonical_name,
+                                         nocache=not self.conf.cache,
+                                         rm=True,
+                                         decode=True,
+                                         network_mode=self.conf.network_mode,
+                                         pull=pull,
+                                         forcerm=self.forcerm,
+                                         buildargs=buildargs):
                 if 'stream' in stream:
                     for line in stream['stream'].split('\n'):
                         if line:
@@ -369,11 +370,13 @@ class BuildTask(DockerTask):
                             self.logger.error('%s', line)
                     return
 
-            if image.status != Status.ERROR and self.conf.squash:
+            if image.status != Status.ERROR and self.conf.squash and \
+               self.conf.engine == engine.Engine.DOCKER.value:
                 self.squash()
-        except docker.errors.DockerException:
+        except engine.getEngineException(self.conf):
             image.status = Status.ERROR
-            self.logger.exception('Unknown docker error when building')
+            self.logger.exception('Unknown container engine '
+                                  'error when building')
         except Exception:
             image.status = Status.ERROR
             self.logger.exception('Unknown error when building')
@@ -385,9 +388,9 @@ class BuildTask(DockerTask):
 
     def squash(self):
         image_tag = self.image.canonical_name
-        image_id = self.dc.inspect_image(image_tag)['Id']
+        image_id = self.engine_client.inspect_image(image_tag)['Id']
 
-        parent_history = self.dc.history(self.image.parent_name)
+        parent_history = self.engine_client.history(self.image.parent_name)
         parent_last_layer = parent_history[0]['Id']
         self.logger.info('Parent lastest layer is: %s' % parent_last_layer)