Changed file opening syntax to use with open(filename, mode) (#1126)

tools/nni_cmd/launcher.py

@@ -125,8 +125,7 @@ def start_rest_server(port, platform, mode, config_file_name, experiment_id=None
     if mode == 'resume':
         cmds += ['--experiment_id', experiment_id]
     stdout_full_path, stderr_full_path = get_log_path(config_file_name)
-    stdout_file = open(stdout_full_path, 'a+')
-    stderr_file = open(stderr_full_path, 'a+')
+    with open(stdout_full_path, 'a+') as stdout_file, open(stderr_full_path, 'a+') as stderr_file:
         time_now = time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time()))
         #add time information in the header of log files
         log_header = LOG_HEADER % str(time_now)

tools/nni_cmd/tensorboard_utils.py

@@ -94,9 +94,7 @@ def start_tensorboard_process(args, nni_config, path_list, temp_nni_path):
     if detect_port(args.port):
         print_error('Port %s is used by another process, please reset port!' % str(args.port))
         exit(1)
-    
-    stdout_file = open(os.path.join(temp_nni_path, 'tensorboard_stdout'), 'a+')
-    stderr_file = open(os.path.join(temp_nni_path, 'tensorboard_stderr'), 'a+')
+    with open(os.path.join(temp_nni_path, 'tensorboard_stdout'), 'a+') as stdout_file, open(os.path.join(temp_nni_path, 'tensorboard_stderr'), 'a+') as stderr_file:
         cmds = ['tensorboard', '--logdir', format_tensorboard_log_path(path_list), '--port', str(args.port)]
         tensorboard_process = Popen(cmds, stdout=stdout_file, stderr=stderr_file)
     url_list = get_local_urls(args.port)