server: implemented 'flush' and 'refresh' API

Added test that verifies that when client performs Flush (which happens
at the end of each snapshot and when repository is closed), the
server writes new blobs to the storage.

Fixes #464

internal/server/server.go

@@ -135,12 +135,18 @@ func (s *Server) handleAPIPossiblyNotConnected(f func(ctx context.Context, r *ht
 }
 
 func (s *Server) handleRefresh(ctx context.Context, r *http.Request) (interface{}, *apiError) {
-	log(ctx).Infof("refreshing")
+	if err := s.rep.Refresh(ctx); err != nil {
+		return nil, internalServerError(err)
+	}
+
 	return &serverapi.Empty{}, nil
 }
 
 func (s *Server) handleFlush(ctx context.Context, r *http.Request) (interface{}, *apiError) {
-	log(ctx).Infof("flushing")
+	if err := s.rep.Flush(ctx); err != nil {
+		return nil, internalServerError(err)
+	}
+
 	return &serverapi.Empty{}, nil
 }
 

repo/api_server_repository.go

@@ -118,7 +118,7 @@ func (r *apiServerRepository) Refresh(ctx context.Context) error {
 }
 
 func (r *apiServerRepository) Flush(ctx context.Context) error {
-	return nil
+	return r.cli.Post(ctx, "flush", nil, nil)
 }
 
 func (r *apiServerRepository) Close(ctx context.Context) error {
@@ -126,7 +126,7 @@ func (r *apiServerRepository) Close(ctx context.Context) error {
 		return errors.Wrap(err, "error closing object manager")
 	}
 
-	return nil
+	return r.Flush(ctx)
 }
 
 func (r *apiServerRepository) ContentInfo(ctx context.Context, contentID content.ID) (content.Info, error) {

tests/end_to_end_test/api_server_repository_test.go

@@ -33,6 +33,9 @@ func TestAPIServerRepository(t *testing.T) {
 	e1.RunAndExpectSuccess(t, "repo", "connect", "filesystem", "--path", e.RepoDir, "--override-username", "not-foo", "--override-hostname", "bar")
 	e1.RunAndExpectSuccess(t, "snapshot", "create", sharedTestDataDir1)
 
+	originalPBlobCount := len(e1.RunAndExpectSuccess(t, "blob", "list", "--prefix=p"))
+	originalQBlobCount := len(e1.RunAndExpectSuccess(t, "blob", "list", "--prefix=q"))
+
 	htpasswordFile := filepath.Join(e.ConfigDir, "htpasswd.txt")
 	ioutil.WriteFile(htpasswordFile, htpasswdFileContents, 0755)
 
@@ -81,12 +84,35 @@ func TestAPIServerRepository(t *testing.T) {
 		t.Errorf("invalid number of snapshots for foo@bar")
 	}
 
+	// create very small directory
+	smallDataDir := filepath.Join(sharedTestDataDirBase, "dir-small")
+
+	testenv.CreateDirectoryTree(smallDataDir, testenv.DirectoryTreeOptions{
+		Depth:                  1,
+		MaxSubdirsPerDirectory: 1,
+		MaxFilesPerDirectory:   1,
+		MaxFileSize:            100,
+	}, nil)
+
+	// create snapshot of a very small directory using remote repository client
+	e2.RunAndExpectSuccess(t, "snapshot", "create", smallDataDir)
+
+	// make sure snapshot created by the client resulted in blobs being created by the server
+	// as opposed to buffering it in memory
+	if got, want := len(e.RunAndExpectSuccess(t, "blob", "list", "--prefix=p")), originalPBlobCount; got <= want {
+		t.Errorf("unexpected number of P blobs on the server: %v, wanted > %v", got, want)
+	}
+
+	if got, want := len(e.RunAndExpectSuccess(t, "blob", "list", "--prefix=q")), originalQBlobCount; got <= want {
+		t.Errorf("unexpected number of Q blobs on the server: %v, wanted > %v", got, want)
+	}
+
 	// create snapshot using remote repository client
 	e2.RunAndExpectSuccess(t, "snapshot", "create", sharedTestDataDir2)
 
 	// now should see two snapshots
 	snapshots = e2.ListSnapshotsAndExpectSuccess(t)
-	if got, want := len(snapshots), 2; got != want {
+	if got, want := len(snapshots), 3; got != want {
 		t.Errorf("invalid number of snapshots for foo@bar")
 	}
 }