[Enhancement] Add error handler when getting host failed (#1374)

* [Enhancement] Add error handler when getting host failed
Signed-off-by: del-zhenwu <zhenxiang.li@zilliz.com>

* [Enhancement] Add error handler when getting host failed
Signed-off-by: del-zhenwu <zhenxiang.li@zilliz.com>

* [Enhancement] Add error handler when getting host failed
Signed-off-by: del-zhenwu <zhenxiang.li@zilliz.com>

* [Enhancement] Add error handler when getting host failed
Signed-off-by: del-zhenwu <zhenxiang.li@zilliz.com>

mmcv/runner/utils.py

@@ -3,6 +3,7 @@ import os
 import random
 import sys
 import time
+import warnings
 from getpass import getuser
 from socket import gethostname
 
@@ -13,7 +14,18 @@ import mmcv
 
 
 def get_host_info():
-    return f'{getuser()}@{gethostname()}'
+    """Get hostname and username.
+
+    Return empty string if exception raised, e.g. ``getpass.getuser()`` will
+    lead to error in docker container
+    """
+    host = ''
+    try:
+        host = f'{getuser()}@{gethostname()}'
+    except Exception as e:
+        warnings.warn(f'Host or user not found: {str(e)}')
+    finally:
+        return host
 
 
 def get_time_str():