Attempt to address python compatibility issues

Author: nickrabbott

tlslite/tlsconnection.py

@@ -3268,9 +3268,12 @@ def _serverTLS13Handshake(self, settings, clientHello, cipherSuite,
         # log them if necessary
         if self.sslkeylogfile:
             self._log_session_keys([
-                ('EXPORTER_SECRET', clientHello.random, exporter_master_secret),
-                ('CLIENT_TRAFFIC_SECRET_0', clientHello.random, cl_app_traffic),
-                ('SERVER_TRAFFIC_SECRET_0', clientHello.random, sr_app_traffic)
+                ('EXPORTER_SECRET',
+                 clientHello.random, exporter_master_secret),
+                ('CLIENT_TRAFFIC_SECRET_0',
+                 clientHello.random, cl_app_traffic),
+                ('SERVER_TRAFFIC_SECRET_0',
+                 clientHello.random, sr_app_traffic)
             ])
 
 
@@ -4999,7 +5002,10 @@ def _log_session_keys(self, keys):
 
         with open(self.sslkeylogfile, 'a') as ssl_key_log_file:
             ssl_key_log_file.writelines(
-                f"{label} {client_random.hex()} {secret.hex()}\n"
+                "{0} {1} {2}\n".format(
+                    label,
+                    binascii.hexlify(client_random).decode().upper(),
+                    binascii.hexlify(secret).decode().upper())
                 for label, client_random, secret in keys
             )
 

unit_tests/test_tlslite_ssl_key_log_file.py

@@ -48,7 +48,7 @@ def validate_log_file(log_file_name, labels: Dict[str, List[str]]):
 
 class TestSslKeyLogFile(unittest.TestCase):
     def setUp(self):
-        self.temp_log_file = tempfile.NamedTemporaryFile(delete_on_close=False)
+        self.temp_log_file = tempfile.NamedTemporaryFile(delete=False)
         os.environ['SSLKEYLOGFILE'] = self.temp_log_file.name
 
     def tearDown(self):
@@ -86,7 +86,7 @@ def test_tlsv1_2(self):
             self.assertTrue(validate_log_file(self.temp_log_file.name, expected_labels))
             connection.close()
         except TLSRemoteAlert as alert:
-            print(f"TLS Remote Alert: {alert}")
+            print("TLS Remote Alert: {0}".format(alert))
 
     def test_tlsv1_3(self):
         settings = HandshakeSettings()
@@ -105,7 +105,7 @@ def test_tlsv1_3(self):
             self.assertTrue(validate_log_file(self.temp_log_file.name, expected_labels))
             connection.close()
         except TLSRemoteAlert as alert:
-            print(f"TLS Remote Alert: {alert}")
+            print("TLS Remote Alert: {0}".format(alert))
 
 
 if __name__ == "__main__":