SavedModel support in Go.

Change: 146938337

tensorflow/go/session.go

@@ -59,6 +59,44 @@ func NewSession(graph *Graph, options *SessionOptions) (*Session, error) {
 	return s, nil
 }
 
+// LoadSavedModel creates a new Session from a model previously exported to a
+// directory on disk.
+//
+// Exported models contain a set of graphs and variable values. Tags in the
+// model identify a single graph. LoadSessionFromSavedModel initializes a
+// session with the identified graph and with variables initialized to saved
+// values.
+//
+// The tensorflow package currently does not have the ability to export a model
+// to a directory from Go. This function thus currently targets loading models
+// exported in other languages, such as using tf.saved_model.builder in Python.
+// See:
+// https://www.tensorflow.org/code/tensorflow/python/saved_model/
+func LoadSavedModel(exportDir string, tags []string, options *SessionOptions) (*Session, *Graph, error) {
+	status := newStatus()
+	cOpt := options.c()
+	cExportDir := C.CString(exportDir)
+	cTags := make([]*C.char, len(tags))
+	for i := range tags {
+		cTags[i] = C.CString(tags[i])
+	}
+	graph := NewGraph()
+	// TODO(jhseu): Add support for run_options and meta_graph_def.
+	cSess := C.TF_LoadSessionFromSavedModel(cOpt, nil, cExportDir, (**C.char)(unsafe.Pointer(&cTags[0])), C.int(len(cTags)), graph.c, nil, status.c)
+	for i := range cTags {
+		C.free(unsafe.Pointer(cTags[i]))
+	}
+	C.free(unsafe.Pointer(cExportDir))
+	C.TF_DeleteSessionOptions(cOpt)
+
+	if err := status.Err(); err != nil {
+		return nil, nil, err
+	}
+	s := &Session{c: cSess}
+	runtime.SetFinalizer(s, func(s *Session) { s.Close() })
+	return s, graph, nil
+}
+
 // Run the graph with the associated session starting with the supplied inputs.
 // inputs and outputs may be set to nil. Runs, but does not return Tensors
 // for operations specified in targets.

tensorflow/go/session_test.go

@@ -181,3 +181,15 @@ func TestConcurrency(t *testing.T) {
 		t.Errorf("Close() 2: %v", err)
 	}
 }
+
+func TestSavedModel(t *testing.T) {
+	_, graph, err := LoadSavedModel("../cc/saved_model/testdata/half_plus_two/00000123", []string{"serve"}, nil)
+	if err != nil {
+		t.Fatalf("LoadSavedModel(): %v", err)
+	}
+	if op := graph.Operation("y"); op == nil {
+		t.Fatalf("\"y\" not found in graph")
+	}
+	// TODO(jhseu): half_plus_two has a tf.Example proto dependency to run. Add a
+	// more thorough test when the generated protobufs are available.
+}