add chunking function to RPCs

Author: tyler-french

server/remote_cache/capabilities_server/BUILD

@@ -11,6 +11,7 @@ go_library(
         "//proto:semver_go_proto",
         "//server/environment",
         "//server/real_environment",
+        "//server/remote_cache/chunking",
         "//server/remote_cache/config",
         "//server/remote_cache/digest",
         "//server/util/bazel_request",

server/remote_cache/capabilities_server/capabilities_server.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/buildbuddy-io/buildbuddy/server/environment"
 	"github.com/buildbuddy-io/buildbuddy/server/real_environment"
+	"github.com/buildbuddy-io/buildbuddy/server/remote_cache/chunking"
 	"github.com/buildbuddy-io/buildbuddy/server/remote_cache/digest"
 	"github.com/buildbuddy-io/buildbuddy/server/util/bazel_request"
 
@@ -64,8 +65,10 @@ func (s *CapabilitiesServer) GetCapabilities(ctx context.Context, req *repb.GetC
 	}
 	if s.supportCAS {
 		splitSpliceEnabled := false
+		chunkingEnabled := false
 		if efp := s.env.GetExperimentFlagProvider(); efp != nil {
 			splitSpliceEnabled = efp.Boolean(ctx, "cache.split_splice_enabled", false)
+			chunkingEnabled = chunking.Enabled(ctx, efp)
 		}
 
 		c.CacheCapabilities = &repb.CacheCapabilities{
@@ -88,6 +91,13 @@ func (s *CapabilitiesServer) GetCapabilities(ctx context.Context, req *repb.GetC
 			SplitBlobSupport:                splitSpliceEnabled,
 			SpliceBlobSupport:               splitSpliceEnabled,
 		}
+
+		if chunkingEnabled {
+			c.CacheCapabilities.FastCdc_2020Params = &repb.FastCdc2020Params{
+				AvgChunkSizeBytes: uint64(chunking.MaxChunkSizeBytes() / 4),
+				Seed:              0,
+			}
+		}
 	}
 	if s.supportRemoteExec {
 		c.ExecutionCapabilities = &repb.ExecutionCapabilities{

server/remote_cache/chunking/chunking.go

@@ -176,7 +176,8 @@ type Manifest struct {
 
 func (cm *Manifest) ToSplitBlobResponse() *repb.SplitBlobResponse {
 	return &repb.SplitBlobResponse{
-		ChunkDigests: cm.ChunkDigests,
+		ChunkDigests:     cm.ChunkDigests,
+		ChunkingFunction: repb.ChunkingFunction_FAST_CDC_2020,
 	}
 }
 
@@ -190,10 +191,11 @@ func (cm *Manifest) ToFindMissingBlobsRequest() *repb.FindMissingBlobsRequest {
 
 func (cm *Manifest) ToSpliceBlobRequest() *repb.SpliceBlobRequest {
 	return &repb.SpliceBlobRequest{
-		BlobDigest:     cm.BlobDigest,
-		ChunkDigests:   cm.ChunkDigests,
-		InstanceName:   cm.InstanceName,
-		DigestFunction: cm.DigestFunction,
+		BlobDigest:       cm.BlobDigest,
+		ChunkDigests:     cm.ChunkDigests,
+		InstanceName:     cm.InstanceName,
+		DigestFunction:   cm.DigestFunction,
+		ChunkingFunction: repb.ChunkingFunction_FAST_CDC_2020,
 	}
 }
 

server/remote_cache/content_addressable_storage_server/content_addressable_storage_server.go

@@ -1167,6 +1167,10 @@ func (s *ContentAddressableStorageServer) SpliceBlob(ctx context.Context, req *r
 		return nil, status.UnimplementedErrorf("SpliceBlob RPC is not currently enabled")
 	}
 
+	if cf := req.GetChunkingFunction(); cf != repb.ChunkingFunction_FAST_CDC_2020 {
+		return nil, status.InvalidArgumentErrorf("unsupported chunking function %v, only FAST_CDC_2020 is supported", cf)
+	}
+
 	if req.GetBlobDigest() == nil {
 		return nil, status.UnimplementedError("SpliceBlob with no blob_digest is not supported")
 	}
@@ -1204,6 +1208,11 @@ func (s *ContentAddressableStorageServer) SplitBlob(ctx context.Context, req *re
 		return nil, status.UnimplementedErrorf("SplitBlob RPC is not currently enabled")
 	}
 
+	cf := req.GetChunkingFunction()
+	if cf != repb.ChunkingFunction_UNKNOWN && cf != repb.ChunkingFunction_FAST_CDC_2020 {
+		return nil, status.InvalidArgumentErrorf("unsupported chunking function %v", cf)
+	}
+
 	if req.GetBlobDigest() == nil {
 		return nil, status.InvalidArgumentError("blob_digest is required")
 	}