Merge pull request #271 from ashwinkumar12345/ism_priority_action

added index priority support for ISM

Author: aetter

docs/ism/policies.md

@@ -101,6 +101,7 @@ ISM supports the following operations:
 - [rollover](#rollover)
 - [notification](#notification)
 - [snapshot](#snapshot)
+- [priority](#priority)
 
 ### force_merge
 
@@ -321,6 +322,26 @@ Parameter | Description | Type | Required | Default
 }
 ```
 
+### index_priority
+
+Set the priority for the index in a specific state. Unallocated shards of indices are recovered in the order of their priority, whenever possible. The indices with higher priority values are recovered first followed by the indices with lower priority values.
+
+The `index_priority` operation has the following parameter:
+
+Parameter | Description | Type | Required | Default
+:--- | :--- |:--- |:--- |:---
+`priority` | The priority for the index as soon as it enters a state. | `number` | Yes | 1
+
+```json
+"actions": [
+  {
+    "index_priority": {
+      "priority": 50
+    }
+  }
+]
+```
+
 ---
 
 ## Transitions