Merge pull request #40 from ElrondNetwork/hotfix-caching

Hotfix: hold block copies in the cache

server/provider/interface.go

@@ -24,4 +24,5 @@ type blocksCache interface {
 	Put(key []byte, value interface{}, size int) (evicted bool)
 	Len() int
 	Keys() [][]byte
+	Clear()
 }

server/provider/networkProvider.go

@@ -251,15 +251,17 @@ func (provider *networkProvider) getBlockByNonceCached(nonce uint64) (*data.Bloc
 	if ok {
 		block, ok := blockUntyped.(*data.Block)
 		if ok {
-			return block, true
+			blockCopy := *block
+			return &blockCopy, true
 		}
 	}
 
 	return nil, false
 }
 
 func (provider *networkProvider) cacheBlockByNonce(nonce uint64, block *data.Block) {
-	_ = provider.blocksCache.Put(blockNonceToBytes(nonce), block, 1)
+	blockCopy := *block
+	_ = provider.blocksCache.Put(blockNonceToBytes(nonce), &blockCopy, 1)
 }
 
 // GetBlockByHash gets a block by hash

server/provider/networkProvider_test.go

@@ -122,6 +122,42 @@ func TestNetworkProvider_DoGetBlockByNonce(t *testing.T) {
 
 		require.Equal(t, blocksCacheCapacity, provider.blocksCache.Len())
 	})
+
+	t.Run("the cache holds block copies", func(t *testing.T) {
+		provider.blocksCache.Clear()
+
+		observerFacade.GetBlockByNonceCalled = func(shardID uint32, nonce uint64, options common.BlockQueryOptions) (*data.BlockApiResponse, error) {
+			return &data.BlockApiResponse{
+				Data: data.BlockApiResponsePayload{
+					Block: data.Block{
+						Nonce: nonce,
+						MiniBlocks: []*data.MiniBlock{
+							{Hash: "aaaa"},
+							{Hash: "bbbb"},
+						},
+					},
+				},
+			}, nil
+		}
+
+		block, err := provider.doGetBlockByNonce(7)
+		require.Nil(t, err)
+		require.Equal(t, uint64(7), block.Nonce)
+		require.Len(t, block.MiniBlocks, 2)
+		require.Equal(t, 1, provider.blocksCache.Len())
+
+		// Simulate mutations performed by downstream handling of blocks, i.e. "simplifyBlockWithScheduledTransactions":
+		block.MiniBlocks = []*data.MiniBlock{}
+
+		cachedBlock, err := provider.doGetBlockByNonce(7)
+		require.Nil(t, err)
+		require.Equal(t, uint64(7), cachedBlock.Nonce)
+		// Miniblocks removal (above) does not reflect in the cached data
+		require.Len(t, cachedBlock.MiniBlocks, 2)
+		// ... because the cache holds block copies:
+		require.False(t, &block == &cachedBlock)
+		require.Equal(t, 1, provider.blocksCache.Len())
+	})
 }
 
 func createDefaultArgsNewNetworkProvider() ArgsNewNetworkProvider {

version/constants.go

@@ -5,7 +5,7 @@ const (
 	RosettaVersion = "v1.4.12"
 
 	// RosettaMiddlewareVersion is the version of this package (application)
-	RosettaMiddlewareVersion = "v0.2.2"
+	RosettaMiddlewareVersion = "v0.2.3"
 
 	// NodeVersion is the canonical version of the node runtime
 	// TODO: We should fetch this from node/status.