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

2 files changed, 57 insertions, 0 deletions

diff --git a/kolla/engine_adapter/__init__.py b/kolla/engine_adapter/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/kolla/engine_adapter/__init__.py
diff --git a/kolla/engine_adapter/engine.py b/kolla/engine_adapter/engine.py
new file mode 100644
index 000000000..184bb3856
--- /dev/null
+++ b/kolla/engine_adapter/engine.py
@@ -0,0 +1,57 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from distutils.version import StrictVersion
+from enum import Enum
+from kolla.image.utils import LOG
+
+try:
+    import docker
+except (ImportError):
+    LOG.debug("Docker python library was not found")
+
+
+class Engine(Enum):
+
+    DOCKER = "docker"
+
+
+class UnsupportedEngineError(ValueError):
+
+    def __init__(self, engine_name):
+        super().__init__()
+        self.engine_name = engine_name
+
+    def __str__(self):
+        return f'Unsupported engine name given: "{self.engine_name}"'
+
+
+def getEngineException(conf):
+    if conf.engine == Engine.DOCKER.value:
+        return (docker.errors.DockerException)
+    else:
+        raise UnsupportedEngineError(conf.engine)
+
+
+def getEngineClient(conf):
+    if conf.engine == Engine.DOCKER.value:
+        kwargs_env = docker.utils.kwargs_from_env()
+        return docker.APIClient(version='auto', **kwargs_env)
+    else:
+        raise UnsupportedEngineError(conf.engine)
+
+
+def getEngineVersion(conf):
+    if conf.engine == Engine.DOCKER.value:
+        return StrictVersion(docker.version)
+    else:
+        raise UnsupportedEngineError(conf.engine)