Improve graph and session handling in facenet class

bob/ip/tensorflow_extractor/FaceNet.py

@@ -115,23 +115,24 @@ class FaceNet(object):
 
         # code from https://github.com/davidsandberg/facenet
         model_exp = os.path.expanduser(self.model_path)
-        if (os.path.isfile(model_exp)):
-            logger.info('Model filename: %s' % model_exp)
-            with tf.gfile.FastGFile(model_exp, 'rb') as f:
-                graph_def = tf.GraphDef()
-                graph_def.ParseFromString(f.read())
-                tf.import_graph_def(graph_def, name='')
-        else:
-            logger.info('Model directory: %s' % model_exp)
-            meta_file, ckpt_file = get_model_filenames(model_exp)
-
-            logger.info('Metagraph file: %s' % meta_file)
-            logger.info('Checkpoint file: %s' % ckpt_file)
-
-            saver = tf.train.import_meta_graph(
-                os.path.join(model_exp, meta_file))
-            saver.restore(tf.get_default_session(),
-                          os.path.join(model_exp, ckpt_file))
+        with self.graph.as_default():
+            if (os.path.isfile(model_exp)):
+                logger.info('Model filename: %s' % model_exp)
+                with tf.gfile.FastGFile(model_exp, 'rb') as f:
+                    graph_def = tf.GraphDef()
+                    graph_def.ParseFromString(f.read())
+                    tf.import_graph_def(graph_def, name='')
+            else:
+                logger.info('Model directory: %s' % model_exp)
+                meta_file, ckpt_file = get_model_filenames(model_exp)
+
+                logger.info('Metagraph file: %s' % meta_file)
+                logger.info('Checkpoint file: %s' % ckpt_file)
+
+                saver = tf.train.import_meta_graph(
+                    os.path.join(model_exp, meta_file))
+                saver.restore(self.session,
+                              os.path.join(model_exp, ckpt_file))
         # Get input and output tensors
         self.images_placeholder = self.graph.get_tensor_by_name("input:0")
         self.embeddings = self.graph.get_tensor_by_name(self.layer_name)
@@ -142,8 +143,8 @@ class FaceNet(object):
     def __call__(self, img):
         images = self._check_feature(img)
         if self.session is None:
-            self.session = tf.InteractiveSession()
-            self.graph = tf.get_default_graph()
+            self.graph = tf.Graph()
+            self.session = tf.Session(graph=self.graph)
         if self.embeddings is None:
             self.load_model()
         feed_dict = {self.images_placeholder: images,
@@ -152,9 +153,6 @@ class FaceNet(object):
             self.embeddings, feed_dict=feed_dict)
         return features.flatten()
 
-    def __del__(self):
-        tf.reset_default_graph()
-
     @staticmethod
     def get_rcvariable():
         """