Pull underlying capabilities up to 00-multus.conf

Using Python, we analyze the content of the master plugin configuration,
and we integrate any capabilities from the underlying chained plugins
declaration. We only pull enabled capabilties from the underlying
(chained) plugin definitions.

Fixes intel#544

Signed-off-by: <Clement.Nussbaumer@Swisscom.com>

images/entrypoint.sh

@@ -302,6 +302,24 @@ if [ "$MULTUS_CONF_FILE" == "auto" ]; then
         MASTER_PLUGIN_NET_NAME="multus-cni-network"
       fi
 
+      capabilities_python_filter_tmpfile=$(mktemp)
+      cat << EOF > $capabilities_python_filter_tmpfile
+import json,sys
+conf = json.load(sys.stdin)
+capabilities = {}
+for capa in [p['capabilities'] for p in conf['plugins'] if 'capabilities' in p]:
+    capabilities.update({capability:enabled for (capability,enabled) in capa.items() if enabled})
+if len(capabilities) > 0:
+    print("""\"capabilities\": """ + json.dumps(capabilities) + ",")
+else:
+    print("")
+EOF
+
+      NESTED_CAPABILITIES_STRING="$(cat $MULTUS_AUTOCONF_DIR/$MASTER_PLUGIN | \
+            python $capabilities_python_filter_tmpfile)"
+      rm $capabilities_python_filter_tmpfile
+      log "Nested capabilities string: $NESTED_CAPABILITIES_STRING" 
+
       MASTER_PLUGIN_LOCATION=$MULTUS_AUTOCONF_DIR/$MASTER_PLUGIN
       MASTER_PLUGIN_JSON="$(cat $MASTER_PLUGIN_LOCATION)"
       log "Using $MASTER_PLUGIN_LOCATION as a source to generate the Multus configuration"
@@ -310,6 +328,7 @@ if [ "$MULTUS_CONF_FILE" == "auto" ]; then
           $CNI_VERSION_STRING
           "name": "$MASTER_PLUGIN_NET_NAME",
           "type": "multus",
+          $NESTED_CAPABILITIES_STRING
           $ISOLATION_STRING
           $LOG_LEVEL_STRING
           $LOG_FILE_STRING