Update test_model_framework_tensorflow_model.py to use local file as lock.

Author: qiuosier

tests/unitary/with_extras/model/test_model_framework_tensorflow_model.py

@@ -9,8 +9,10 @@
 import base64
 import os
 import shutil
+import time
 import uuid
 from io import BytesIO
+from pathlib import Path
 
 import numpy as np
 import onnxruntime as rt
@@ -35,9 +37,23 @@ def setup_module():
 
 
 class MyTFModel:
-
     mnist = tf.keras.datasets.mnist
-    (x_train, y_train), (x_test, y_test) = mnist.load_data()
+    lock_file = os.path.expanduser("~/.keras/datasets/mnist.npz.downloading")
+    try:
+        time_start = time.time()
+        while os.path.exists(lock_file):
+            time.sleep(10)
+            elapsed = time.time() - time_start
+            if elapsed > 60 * 15:
+                raise TimeoutError(
+                    "Timeout when waiting for MNIST data to finished downloading in another process. "
+                    "Please check internet connection."
+                )
+        Path(lock_file).touch()
+        (x_train, y_train), (x_test, y_test) = mnist.load_data()
+    finally:
+        os.unlink(lock_file)
+
     x_train, x_test = x_train / 255.0, x_test / 255.0
 
     x_train, y_train = x_train[:1000], y_train[:1000]