Fixed clearing of pipeline config params and TF session in convert_model() (#16191)

* Fixed pipeline config params clearing.

* Added clearing of TF session. Added tests.

tools/mo/openvino/tools/mo/front/tf/loader.py

@@ -324,6 +324,9 @@ def load_tf_graph_def(graph_file_name: str = "", is_binary: bool = True, checkpo
 
 def convert_to_pb(argv: argparse.Namespace):
     from openvino.tools.mo.utils.cli_parser import get_model_name
+    env_setup = get_environment_setup("tf")
+    if "tensorflow" in env_setup and env_setup["tensorflow"] >= LooseVersion("2.0.0"):
+        tf.keras.backend.clear_session()
 
     # if this is already binary frozen format .pb, there is no need to create auxiliary binary frozen protobuf
     # the main thing is to differentiate this format from text frozen format and checkpoint

tools/mo/openvino/tools/mo/utils/pipeline_config.py

@@ -75,10 +75,10 @@ class PipelineConfig:
     The class that parses pipeline.config files used to generate TF models generated using Object Detection API.
     The class stores data read from the file in a plain dictionary for easier access using the get_param function.
     """
-    _raw_data_dict = dict()
-    _model_params = dict()
 
     def __init__(self, file_name: str):
+        self._raw_data_dict = dict()
+        self._model_params = dict()
         self._raw_data_dict = SimpleProtoParser().parse_file(file_name)
         if not self._raw_data_dict:
             raise Error('Failed to parse pipeline.config file {}'.format(file_name))

tools/mo/unit_tests/mo/front/tf/ObjectDetectionAPI_test.py

@@ -4,6 +4,7 @@
 import unittest
 from argparse import Namespace
 from unittest.mock import patch
+import os
 
 from generator import generator, generate
 
@@ -331,3 +332,19 @@ class TestObjectDetectionAPIPreprocessor2Replacement(unittest.TestCase):
 
         (flag, resp) = compare_graphs(graph, self.build_ref_graph(False), 'result', check_op_attrs=True)
         self.assertTrue(flag, resp)
+
+
+class TestPipelineConfig(unittest.TestCase):
+    def test_pipeline_config_loading(self):
+        from openvino.tools.mo.utils.pipeline_config import PipelineConfig
+        pipeline_config = PipelineConfig(os.path.join(os.path.dirname(__file__), "test_configs/config1.config"))
+        assert pipeline_config.get_param('ssd_anchor_generator_num_layers') == 6
+        assert pipeline_config.get_param('num_classes') == 90
+        assert pipeline_config.get_param('resizer_image_width') == 300
+        assert pipeline_config.get_param('resizer_image_height') == 300
+
+        pipeline_config = PipelineConfig(os.path.join(os.path.dirname(__file__), "test_configs/config2.config"))
+        assert pipeline_config.get_param('ssd_anchor_generator_num_layers') is None
+        assert pipeline_config.get_param('num_classes') == 10
+        assert pipeline_config.get_param('resizer_image_width') == 640
+        assert pipeline_config.get_param('resizer_image_height') == 640

tools/mo/unit_tests/mo/front/tf/convert_to_pb_test.py

@@ -108,3 +108,59 @@ class ConvertToPBTests(unittest.TestCase):
                             "The test model in frozen binary format must exist")
             # test convert_to_pb - expect no auxiliary model created
             self.assertIsNone(convert_to_pb(self.argv))
+
+    def test_meta_format_session_clearing(self):
+        try:
+            import tensorflow.compat.v1 as tf_v1
+        except ImportError:
+            import tensorflow as tf_v1
+
+        from openvino.tools.mo.utils.versions_checker import get_environment_setup
+        from distutils.version import LooseVersion
+
+        env_setup = get_environment_setup("tf")
+        use_tf2 = False
+        if "tensorflow" in env_setup and env_setup["tensorflow"] >= LooseVersion("2.0.0"):
+            use_tf2 = True
+
+        from tensorflow.python.eager.context import graph_mode
+
+        with tempfile.TemporaryDirectory(dir=self.test_directory) as tmp_dir:
+            with graph_mode():
+                a = tf_v1.get_variable("A", initializer=tf_v1.constant(3, shape=[2]))
+                b = tf_v1.get_variable("B", initializer=tf_v1.constant(5, shape=[2]))
+                tf_v1.add(a, b, name='Add')
+                init_op = tf_v1.global_variables_initializer()
+                saver = tf_v1.train.Saver()
+                with tf_v1.Session() as sess:
+                    sess.run(init_op)
+                    saver.save(sess, os.path.join(tmp_dir, 'model1'))
+            if use_tf2:
+                import tensorflow as tf
+                tf.keras.backend.clear_session()
+
+            with graph_mode():
+                c = tf_v1.get_variable("C", initializer=tf_v1.constant(3, shape=[2]))
+                d = tf_v1.get_variable("D", initializer=tf_v1.constant(5, shape=[2]))
+                tf_v1.add(c, d, name='Add1')
+                init_op = tf_v1.global_variables_initializer()
+                saver = tf_v1.train.Saver()
+                with tf_v1.Session() as sess:
+                    sess.run(init_op)
+                    saver.save(sess, os.path.join(tmp_dir, 'model2'))
+            if use_tf2:
+                import tensorflow as tf
+                tf.keras.backend.clear_session()
+
+            self.argv.input_meta_graph = os.path.join(tmp_dir, 'model1.meta')
+            self.argv.output_dir = tmp_dir
+            path_to_pb = convert_to_pb(self.argv)
+            self.assertTrue(os.path.exists(path_to_pb), "The auxiliary .pb is not generated")
+            self.assertTrue(os.path.getsize(path_to_pb) != 0, "The auxiliary .pb is empty")
+
+            self.argv.input_meta_graph = os.path.join(tmp_dir, 'model2.meta')
+            self.argv.output_dir = tmp_dir
+            self.argv.input_model = None
+            path_to_pb = convert_to_pb(self.argv)
+            self.assertTrue(os.path.exists(path_to_pb), "The auxiliary .pb is not generated")
+            self.assertTrue(os.path.getsize(path_to_pb) != 0, "The auxiliary .pb is empty")

tools/mo/unit_tests/mo/front/tf/test_configs/config1.config

@@ -0,0 +1,17 @@
+model {
+  ssd {
+    num_classes: 90
+    image_resizer {
+      fixed_shape_resizer {
+        height: 300
+        width: 300
+      }
+    }
+    anchor_generator {
+      ssd_anchor_generator {
+        num_layers: 6
+      }
+    }
+  }
+}
+

tools/mo/unit_tests/mo/front/tf/test_configs/config2.config

@@ -0,0 +1,11 @@
+model {
+  ssd {
+    num_classes: 10
+    image_resizer {
+      fixed_shape_resizer {
+        height: 640
+        width: 640
+      }
+    }
+  }
+}