check partial chunk result (#73)

* validate result when getting partial chunk and warn on failure
* changelog

1 files changed, 26 insertions, 9 deletions

diff --git a/src/zenstore/cache/cacherpc.cpp b/src/zenstore/cache/cacherpc.cpp
index 5bd73e902..d2625b97c 100644
--- a/src/zenstore/cache/cacherpc.cpp
+++ b/src/zenstore/cache/cacherpc.cpp
@@ -1663,17 +1663,34 @@ CacheRpcHandler::WriteGetCacheChunksResponse([[maybe_unused]] const CacheRequest
 						}
 						Request.Value =
 							Request.Value.GetRange(Request.RequestedOffset, Request.RequestedSize == 0 ? 1u : Request.RequestedSize);
-						uint64_t FragmentLength = Request.Value.DecodeRawSize();
 
-						IoHashStream FragmentHashStream;
-						FragmentHashStream.Append(Request.Key->ChunkId.Hash, sizeof(Request.Key->ChunkId.Hash));
-						FragmentHashStream.Append(&FragmentRawOffset, sizeof(FragmentRawOffset));
-						FragmentHashStream.Append(&FragmentLength, sizeof(FragmentLength));
-						IoHash FragmentHash = FragmentHashStream.GetHash();
+						if (Request.Value)
+						{
+							uint64_t FragmentLength = Request.Value.DecodeRawSize();
+
+							IoHashStream FragmentHashStream;
+							FragmentHashStream.Append(Request.Key->ChunkId.Hash, sizeof(Request.Key->ChunkId.Hash));
+							FragmentHashStream.Append(&FragmentRawOffset, sizeof(FragmentRawOffset));
+							FragmentHashStream.Append(&FragmentLength, sizeof(FragmentLength));
+							IoHash FragmentHash = FragmentHashStream.GetHash();
 
-						Writer.AddHash("FragmentHash", FragmentHash);
-						Writer.AddInteger("FragmentOffset", FragmentRawOffset);
-						RpcResponse.AddAttachment(CbAttachment(Request.Value, FragmentHash));
+							Writer.AddHash("FragmentHash", FragmentHash);
+							Writer.AddInteger("FragmentOffset", FragmentRawOffset);
+							RpcResponse.AddAttachment(CbAttachment(Request.Value, FragmentHash));
+						}
+						else
+						{
+							ZEN_WARN(
+								"Failed to get partial chunk for attachment {}/{}/{} (rawsize: {}, offset: {}, size: {}). Sending full "
+								"chunk",
+								Namespace,
+								Request.Key->Key.Bucket,
+								Request.Key->ChunkId,
+								Request.Value.DecodeRawSize(),
+								Request.RequestedOffset,
+								Request.RequestedSize)
+							RpcResponse.AddAttachment(CbAttachment(Request.Value, Request.Key->ChunkId));
+						}
 					}
 					else
 					{