Merge pull request #790 from dotmesh-io/788-dm-clone-waits-for-commit

#788: Before we transition to active, make sure we finish snapshotting.

pkg/fsm/fsm_discovering.go

@@ -2,6 +2,7 @@ package fsm
 
 import (
 	"github.com/dotmesh-io/dotmesh/pkg/store"
+	"github.com/dotmesh-io/dotmesh/pkg/types"
 
 	log "github.com/sirupsen/logrus"
 )
@@ -47,3 +48,19 @@ func discoveringState(f *FsMachine) StateFn {
 		}
 	}
 }
+
+// If we initiated pull or push, we're only really finished after discovery,
+// otherwise in-memory state won't match on-disk state and we can get race
+// conditions due to that. So this wraps discovery and then only marks transfer
+// as finished when discovery is done.
+func discoveringAfterTransferInitiatorState(f *FsMachine) StateFn {
+	result := discoveringState(f)
+	f.transferUpdates <- types.TransferUpdate{
+		Kind: types.TransferStatus,
+		Changes: types.TransferPollResult{
+			Status:  "finished",
+			Message: "",
+		},
+	}
+	return result
+}

pkg/fsm/fsm_missing.go

@@ -239,14 +239,20 @@ func missingState(f *FsMachine) StateFn {
 					}
 					return backoffState
 				} else {
-					f.innerResponses <- &types.Event{Name: "created"}
-					f.snapshot(&types.Event{Name: "snapshot",
+					responseEvent, nextState := f.snapshot(&types.Event{Name: "snapshot",
 						Args: &types.EventArgs{"metadata": map[string]string{
 							"type":    "dotmesh.initial",
 							"message": "Initial commit",
 							"author":  "admin",
 						}}})
-					return activeState
+					if responseEvent.Name == "snapshotted" {
+						f.innerResponses <- &types.Event{Name: "created"}
+						return activeState
+					} else {
+						// Error snapshotting:
+						f.innerResponses <- responseEvent
+						return nextState
+					}
 				}
 			} else {
 				f.innerResponses <- responseEvent

pkg/fsm/fsm_pull_initiator.go

@@ -309,18 +309,10 @@ func (f *FsMachine) pull(
 		}, backoffState
 	}
 
-	f.transferUpdates <- types.TransferUpdate{
-		Kind: types.TransferStatus,
-		Changes: types.TransferPollResult{
-			Status:  "finished",
-			Message: "",
-		},
-	}
-
 	log.Printf("Successfully received %s => %s for %s", fromSnapshotId, toSnapshotId, toFilesystemId)
 	return &types.Event{
 		Name: "finished-pull",
-	}, discoveringState
+	}, discoveringAfterTransferInitiatorState
 }
 
 func (f *FsMachine) retryPull(

pkg/fsm/fsm_push_initiator.go

@@ -353,19 +353,11 @@ func (f *FsMachine) push(
 
 	pipeReader.Close()
 
-	f.transferUpdates <- types.TransferUpdate{
-		Kind: types.TransferStatus,
-		Changes: types.TransferPollResult{
-			Status:  "finished",
-			Message: "",
-		},
-	}
-
 	// TODO update the transfer record, release the peer state machines
 	return &types.Event{
 		Name: "finished-push",
 		Args: &types.EventArgs{},
-	}, discoveringState
+	}, discoveringAfterTransferInitiatorState
 }
 
 func stash(filesystemId, snapId string, client *dmclient.JsonRpcClient, ctx context.Context) (*types.Event, StateFn) {