MetadataAware mixin added to Core Library

Added a mixin class 'MetadataAware' which contains logic to retrieve
metadata attributes from the object of class which inherits it and
from all objects owning this one. Metadata attrbiutes applied to
objects which are deeper in the stack ovewrite ones from objects which
are higher.

The mixin can also validate if the attribute may be applied to the
objects of the given resource type; the type is defined by its
overridable abstract method 'getResourceType'. This check uses
MetadefBrowser class to retrieve the meta definition namespaces of the
needed resource type.

Instance and CinderVolume classes now inherit this mixin.

Change-Id: I43a081fe2a88e666f61de04b8a2789e1b8e96e38
Targets-blueprint: metadata-assignment-and-propagation

meta/io.murano/Classes/resources/CinderVolume.yaml

@@ -13,10 +13,13 @@
 Namespaces:
   std: io.murano
   =: io.murano.resources
+  sys: io.murano.system
 
 Name: CinderVolume
 
-Extends: Volume
+Extends:
+  - Volume
+  - MetadataAware
 
 Properties:
   name:
@@ -53,6 +56,7 @@ Methods:
     Body:
     - $properties:
         size: $.size
+        metadata: $this.getMetadata($this.getRegion())
 
     - If: $.availabilityZone != null
       Then:
@@ -86,7 +90,7 @@ Methods:
     - Return:
         resources:
           format('vol-{0}', id($)):
-            type: 'OS::Cinder::Volume'
+            type: $this.getResourceType()
             properties: $properties
         outputs:
           format('vol-{0}-id', id($)):
@@ -133,3 +137,8 @@ Methods:
     Body:
       Return:
         get_resource: format('vol-{0}', id($))
+
+
+  getResourceType:
+    Body:
+      - Return: 'OS::Cinder::Volume'

meta/io.murano/Classes/resources/Instance.yaml

@@ -17,7 +17,9 @@ Namespaces:
 
 
 Name: Instance
-Extends: std:CloudResource
+Extends:
+  - std:CloudResource
+  - MetadataAware
 
 Properties:
   name:
@@ -138,6 +140,7 @@ Methods:
           user_data: $preparedUserData.data
           user_data_format: $preparedUserData.format
           key_name: $.keyname
+          metadata: $this.getMetadata($region)
 
       - If: len($.blockDevices) > 0
         Then:
@@ -149,7 +152,7 @@ Methods:
       - $template:
           resources:
             $.name:
-              type: 'OS::Nova::Server'
+              type: $this.getResourceType()
               properties: $properties
 
           outputs:
@@ -382,3 +385,7 @@ Methods:
     Body:
       Return:
         get_resource: $.name
+
+  getResourceType:
+    Body:
+      - Return: 'OS::Nova::Server'

meta/io.murano/Classes/resources/MetadataAware.yaml

@@ -0,0 +1,64 @@
+#  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.
+
+Namespaces:
+  =: io.murano.resources
+  std: io.murano
+  sys: io.murano.system
+
+Name: MetadataAware
+
+Properties:
+  checkApplicability:
+    Contract: $.bool().notNull()
+    Default: true
+
+Methods:
+  .init:
+    Body:
+      - $this._metadefBrowsers: {}
+
+  getMetadefBrowser:
+    Arguments:
+      - region:
+          Contract: $.class(std:CloudRegion).notNull()
+    Body:
+      - $browser: $this._metadefBrowsers.get($region.name)
+      - If: $browser = null
+        Then:
+          - $browser: new(sys:MetadefBrowser, $region)
+          - $this._metadefBrowsers[$region.name]: $browser
+      - Return: $browser
+
+  getMetadata:
+    Arguments:
+      - region:
+          Contract: $.class(std:CloudRegion).notNull()
+    Body:
+      - $thisMeta: metadata($this) or {}
+      - $parentsMeta: {}
+      - $p: $this.find(std:Object)
+      - While: $p != null
+        Do:
+          - $pmeta: metadata($p) or {}
+          - $pmeta: dict($pmeta.items().where(not $[0] in $parentsMeta.keys()))
+          - $parentsMeta: $parentsMeta.set($pmeta)
+          - $p: $p.find(std:Object)
+      - $resourceType: $this.getResourceType()
+      - If: $this.checkApplicability and $resourceType
+        Then:
+          - $browser: $this.getMetadefBrowser($region)
+          - $parentsMeta: dict($parentsMeta.items().where($browser.canBeAppliedTo($[0], $resourceType)))
+      - Return: $parentsMeta.set($thisMeta)
+
+  getResourceType:
+

meta/io.murano/manifest.yaml

@@ -57,6 +57,7 @@ Classes:
   io.murano.resources.ExistingCinderVolume: resources/ExistingCinderVolume.yaml
   io.murano.resources.CinderVolumeBackup: resources/CinderVolumeBackup.yaml
   io.murano.resources.CinderVolumeSnapshot: resources/CinderVolumeSnapshot.yaml
+  io.murano.resources.MetadataAware: resources/MetadataAware.yaml
 
   io.murano.system.Agent: system/Agent.yaml
   io.murano.system.AgentListener: system/AgentListener.yaml

releasenotes/notes/metadata-aware-mixin-41777dd8d1802908.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - Added a MetadataAware mixin class capable to retrieve the metadata
+    attributes from the implementing objects and all its parents.