add path_prefix_from_file option, adding security by obscurity. This …

tensorboard/plugins/core/core_plugin.py

@@ -533,6 +533,18 @@ def define_flags(self, parser):
 optional and has no effect. The path_prefix can be leveraged for path
 based routing of an ELB when the website base_url is not available e.g.
 "example.site.com/path/to/tensorboard/".\
+""",
+        )
+
+parser.add_argument(
+            "--path_prefix_from_file",
+            metavar="PATH",
+            type=str,
+            default="",
+            help="""\
+Read the path_prefix from the specified file; avoids the path being
+visible by ps or top - and, thus, is useful to improve security on
+multi-user systems.\
 """,
         )
 
@@ -711,6 +723,16 @@ def fix_flags(self, flags):
                 "--detect_file_replacement=true"
             )
 
+	if flags.path_prefix_from_file and flags.path_prefix is None:
+            try:
+                with open(flags.path_prefix_from_file, 'r') as f:
+                    flags.path_prefix = (f.read()).rstrip()
+                    print("NOTE: using path_prefix=" +  flags.path_prefix + " as read from file")
+            except IOError:
+                raise FlagsError("Cannot read prefix_from_file")
+        elif:
+	    print("NOTE: Skipping prefix_from_file input due to overwrite by path_prefix")    
+
         flags.path_prefix = flags.path_prefix.rstrip("/")
         if flags.path_prefix and not flags.path_prefix.startswith("/"):
             raise FlagsError(