Add retry in downloading python saithrift library (#14636)

tests/test_pretest.py

@@ -317,7 +317,15 @@ def test_update_saithrift_ptf(request, ptfhost):
         pytest.skip("No URL specified for python saithrift package")
     pkg_name = py_saithrift_url.split("/")[-1]
     ptfhost.shell("rm -f {}".format(pkg_name))
-    result = ptfhost.get_url(url=py_saithrift_url, dest="/root", module_ignore_errors=True, timeout=60)
+    # Retry download of saithrift library
+    retry_count = 5
+    while retry_count > 0:
+        result = ptfhost.get_url(url=py_saithrift_url, dest="/root", module_ignore_errors=True, timeout=60)
+        if not result["failed"] or "OK" in result["msg"]:
+            break
+        time.sleep(60)
+        retry_count -= 1
+
     if result["failed"] or "OK" not in result["msg"]:
         pytest.skip("Download failed/error while installing python saithrift package")
     ptfhost.shell("dpkg -i {}".format(os.path.join("/root", pkg_name)))