Added TLS 1.3 support to the Python driver

vertica_python/vertica/connection.py

@@ -596,6 +596,68 @@ def balance_load(self, raw_socket: socket.socket) -> socket.socket:
             self._logger.warning(no_load_balancing)
 
         return raw_socket
+    def enable_ssl(self, raw_socket, ssl_options):
+        # Send SSL request and read server response
+        self._logger.debug('=> %s', messages.SslRequest())
+        raw_socket.sendall(messages.SslRequest().get_message())
+        response = raw_socket.recv(1)
+        self._logger.debug('<= SslResponse: %s', response)
+
+        if response == b'S':
+            self._logger.info('Enabling SSL')
+            try:
+                server_host = self.address_list.peek_host()
+                if server_host is None:   # This should not happen
+                    msg = 'Cannot get the connected server host while enabling SSL'
+                    self._logger.error(msg)
+                    raise errors.ConnectionError(msg)
+
+                if isinstance(ssl_options, ssl.SSLContext):
+                    context = ssl_options
+                else:
+                    context = ssl.create_default_context()
+
+                    # Load user-provided certificates if available
+                    cafile = self.options.get('tls_cafile')
+                    certfile = self.options.get('tls_certfile')
+                    keyfile = self.options.get('tls_keyfile')
+
+                    if cafile:
+                        self._logger.info(f'Loading CA file: {cafile}')
+                        context.load_verify_locations(cafile)
+                    if certfile and keyfile:
+                        self._logger.info(f'Loading client cert: {certfile} and key: {keyfile}')
+                        context.load_cert_chain(certfile=certfile, keyfile=keyfile)
+                    else:
+                        self._logger.warning('Client certificate/key not provided; connection may fail if server requires mutual TLS.')
+
+                # Allow automatic negotiation between TLS 1.2 and 1.3
+                context.minimum_version = ssl.TLSVersion.TLSv1_2
+                context.maximum_version = ssl.TLSVersion.TLSv1_3
+
+                # Enable ALPN for Vertica protocol negotiation
+                try:
+                    context.set_alpn_protocols(['http/1.1', 'vertica', 'postgresql'])
+                except NotImplementedError:
+                    self._logger.warning("ALPN not supported on this system; skipping.")
+
+                # Disable hostname verification for testing (not for production)
+                context.check_hostname = True
+                context.verify_mode = ssl.CERT_REQUIRED
+
+                raw_socket = context.wrap_socket(raw_socket, server_hostname=server_host)
+
+            except ssl.CertificateError as e:
+                raise_from(errors.ConnectionError(str(e)), e)
+            except ssl.SSLError as e:
+                raise_from(errors.ConnectionError(str(e)), e)
+        else:
+            err_msg = "SSL requested but not supported by server"
+            self._logger.error(err_msg)
+            raise errors.SSLNotSupported(err_msg)
+
+        return raw_socket
+
 
     def enable_ssl(self,
                    raw_socket: socket.socket,