Make components policy reconfigurable and more

* Add in dcae policy dependencies and policy decorators into tasks
* Fetch docker logins dynamically
* Add in policy example blueprint
* Add in policy update operation for components

Issue-Id: DCAEGEN2-97
Change-Id: Ib58adfbd7070999c7b8e59ab008f5ff90d4984a7
Signed-off-by: Michael Hwang <mhwang@research.att.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/docker/dockerplugin/discovery.py b/docker/dockerplugin/discovery.py
index 03a51f6..8361c13 100644
--- a/docker/dockerplugin/discovery.py
+++ b/docker/dockerplugin/discovery.py
@@ -38,6 +38,9 @@ class DiscoveryConnectionError(RuntimeError):
 class DiscoveryServiceNotFoundError(RuntimeError):
     pass
 
+class DiscoveryKVEntryNotFoundError(RuntimeError):
+    pass
+
 
 def _wrap_consul_call(consul_func, *args, **kwargs):
     """Wrap Consul call to map errors"""
@@ -84,6 +87,20 @@ def remove_service_component_config(kv_conn, service_component_name):
     kv_delete_func(service_component_name)
 
 
+def get_kv_value(kv_conn, key):
+    """Get a key-value entry's value from Consul
+
+    Raises DiscoveryKVEntryNotFoundError if entry not found
+    """
+    kv_get_func = partial(_wrap_consul_call, kv_conn.kv.get)
+    (index, val) = kv_get_func(key)
+
+    if val:
+        return json.loads(val['Value']) # will raise ValueError if not JSON, let it propagate
+    else:
+        raise DiscoveryKVEntryNotFoundError("{0} kv entry not found".format(key))
+
+
 def _create_rel_key(service_component_name):
     return "{0}:rel".format(service_component_name)