Merge pull request #349 from nspcc-dev/ec-head-part

EC HEAD

Author: roman-khimov

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 ### Added
 - EC rules to container storage policy (#345)
-- GET/RANGE query for EC part object (#345)
+- GET/RANGE/HEAD query for EC part object (#345, #349)
 
 ### Changed
 

object/service.proto

@@ -487,7 +487,17 @@ message HeaderWithSignature {
   neo.fs.v2.refs.Signature signature = 2 [json_name = "signature"];
 }
 
-// Object HEAD response
+// Object HEAD response.
+//
+// The query for a parent object's EC part locally stored on the server is
+// specified as follows:
+//  - `body.address` is an address of the parent;
+//  - `meta_header.x_headers` includes `__NEOFS__EC_RULE_IDX` and
+//    `__NEOFS__EC_PART_IDX` by object attribute format. Rule index MUST NOT
+//    exceed container's `PlacementPolicy.ec_rules` list. Part index MUST NOT
+//    exceed total part number in the indexed rule.
+// In this case, if `body.address` refers to TOMBSTONE or LOCK object (which
+// cannot have EC parts), the query applies to it.
 message HeadResponse {
   // Object HEAD response body
   message Body {

proto-docs/object.md

@@ -650,7 +650,17 @@ DEPRECATED. This field is ignored. |
 <a name="neo.fs.v2.object.HeadResponse"></a>
 
 ### Message HeadResponse
-Object HEAD response
+Object HEAD response.
+
+The query for a parent object's EC part locally stored on the server is
+specified as follows:
+ - `body.address` is an address of the parent;
+ - `meta_header.x_headers` includes `__NEOFS__EC_RULE_IDX` and
+   `__NEOFS__EC_PART_IDX` by object attribute format. Rule index MUST NOT
+   exceed container's `PlacementPolicy.ec_rules` list. Part index MUST NOT
+   exceed total part number in the indexed rule.
+In this case, if `body.address` refers to TOMBSTONE or LOCK object (which
+cannot have EC parts), the query applies to it.
 
 
 | Field | Type | Label | Description |