[ILM] Relax POST policy route validation (#84203)

* relax policy post route validation

* update comment

Author: jloleysens

x-pack/plugins/index_lifecycle_management/server/routes/api/policies/register_create_route.ts

@@ -23,114 +23,20 @@ async function createPolicy(client: ElasticsearchClient, name: string, phases: a
   return client.ilm.putLifecycle({ policy: name, body }, options);
 }
 
-const minAgeSchema = schema.maybe(schema.string());
-
-const setPrioritySchema = schema.maybe(
-  schema.object({
-    priority: schema.nullable(schema.number()),
-  })
-);
-
-const unfollowSchema = schema.maybe(schema.object({})); // Unfollow has no options
-
-const migrateSchema = schema.maybe(schema.object({ enabled: schema.literal(false) }));
-
-const allocateNodeSchema = schema.maybe(schema.recordOf(schema.string(), schema.string()));
-const allocateSchema = schema.maybe(
-  schema.object({
-    number_of_replicas: schema.maybe(schema.number()),
-    include: allocateNodeSchema,
-    exclude: allocateNodeSchema,
-    require: allocateNodeSchema,
-  })
-);
-
-const forcemergeSchema = schema.maybe(
-  schema.object({
-    max_num_segments: schema.number(),
-    index_codec: schema.maybe(schema.literal('best_compression')),
-  })
-);
-
-const hotPhaseSchema = schema.object({
-  min_age: minAgeSchema,
-  actions: schema.object({
-    set_priority: setPrioritySchema,
-    unfollow: unfollowSchema,
-    rollover: schema.maybe(
-      schema.object({
-        max_age: schema.maybe(schema.string()),
-        max_size: schema.maybe(schema.string()),
-        max_docs: schema.maybe(schema.number()),
-      })
-    ),
-    forcemerge: forcemergeSchema,
-  }),
-});
-
-const warmPhaseSchema = schema.maybe(
-  schema.object({
-    min_age: minAgeSchema,
-    actions: schema.object({
-      migrate: migrateSchema,
-      set_priority: setPrioritySchema,
-      unfollow: unfollowSchema,
-      readonly: schema.maybe(schema.object({})), // Readonly has no options
-      allocate: allocateSchema,
-      shrink: schema.maybe(
-        schema.object({
-          number_of_shards: schema.number(),
-        })
-      ),
-      forcemerge: forcemergeSchema,
-    }),
-  })
-);
-
-const coldPhaseSchema = schema.maybe(
-  schema.object({
-    min_age: minAgeSchema,
-    actions: schema.object({
-      migrate: migrateSchema,
-      set_priority: setPrioritySchema,
-      unfollow: unfollowSchema,
-      allocate: allocateSchema,
-      freeze: schema.maybe(schema.object({})), // Freeze has no options
-      searchable_snapshot: schema.maybe(
-        schema.object({
-          snapshot_repository: schema.string(),
-        })
-      ),
-    }),
-  })
-);
-
-const deletePhaseSchema = schema.maybe(
-  schema.object({
-    min_age: minAgeSchema,
-    actions: schema.object({
-      wait_for_snapshot: schema.maybe(
-        schema.object({
-          policy: schema.string(),
-        })
-      ),
-      delete: schema.maybe(
-        schema.object({
-          delete_searchable_snapshot: schema.maybe(schema.boolean()),
-        })
-      ),
-    }),
-  })
-);
-
-// Per https://www.elastic.co/guide/en/elasticsearch/reference/current/_actions.html
+/**
+ * We intentionally do not deeply validate the posted policy object to avoid erroring on valid ES
+ * policy configuration Kibana UI does not know or should not know about. For instance, the
+ * `force_merge_index` setting of the `searchable_snapshot` action.
+ *
+ * We only specify a rough structure based on https://www.elastic.co/guide/en/elasticsearch/reference/current/_actions.html.
+ */
 const bodySchema = schema.object({
   name: schema.string(),
   phases: schema.object({
-    hot: hotPhaseSchema,
-    warm: warmPhaseSchema,
-    cold: coldPhaseSchema,
-    delete: deletePhaseSchema,
+    hot: schema.any(),
+    warm: schema.maybe(schema.any()),
+    cold: schema.maybe(schema.any()),
+    delete: schema.maybe(schema.any()),
   }),
 });