Pass args in file from task_runner to run_isolated

client/run_isolated.py

 #!/usr/bin/env python
 # Copyright 2012 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 """Runs a command with optional isolated input/output.
 
 Despite name "run_isolated", can run a generic non-isolated command specified as
 args.
 
 If input isolated hash is provided, fetches it, creates a tree of hard links,
 appends args to the command in the fetched isolated and runs it.
 To improve performance, keeps a local cache.
 The local cache can safely be deleted.
 
 Any ${EXECUTABLE_SUFFIX} on the command line will be replaced with ".exe" string
 on Windows and "" on other platforms.
 
 Any ${ISOLATED_OUTDIR} on the command line will be replaced by the location of a
 temporary directory upon execution of the command specified in the .isolated
 file. All content written to this directory will be uploaded upon termination
 and the .isolated file describing this directory will be printed to stdout.
 
 Any ${SWARMING_BOT_FILE} on the command line will be replaced by the value of
 the --bot-file parameter. This file is used by a swarming bot to communicate
 state of the host to tasks. It is written to by the swarming bot's
 on_before_task() hook in the swarming server's custom bot_config.py.
 """
 
 __version__ = '0.8.5'

[M-A Ruel, 2016/10/24 16:26:52]

don't forget to bump.

[aludwin, 2016/10/24 18:32:05]

I haven't changed the file format itself, so is this necessary?

[M-A Ruel, 2016/10/24 18:34:11]

You add a new flag. The API changes.

 
 import base64
 import collections
+import json
 import logging
 import optparse
 import os
 import sys
 import tempfile
 import time
 
 from third_party.depot_tools import fix_encoding
 
 from utils import file_path
@@ skipping 772 matching lines @@
             install_packages_fn, options.use_symlinks)
     return run_tha_test(
         command, options.isolated, None, isolated_cache, options.leak_temp_dir,
         options.json, options.root_dir, options.hard_timeout,
         options.grace_period, options.bot_file, args, install_packages_fn,
         options.use_symlinks)
   except cipd.Error as ex:
     print >> sys.stderr, ex.message
     return 1
 
+def get_args(args):
+  if len(args) == 2 and args[0] == '-f':

[M-A Ruel, 2016/10/24 16:26:52]

then create a temporary optparse with only the -f flag supported. Make sure to
not handle --help though.

+    # If the only args are "-f filename", load those
+    # instead.
+    argfile = args[1]
+    args = []
+    try:
+      f = open(argfile, 'r')
+      args = json.loads(f.read())
+      f.close()
+    except Exception as e:
+      print "Couldn't read arguments: %s"%e
+  return args
 
 if __name__ == '__main__':
   subprocess42.inhibit_os_error_reporting()
   # Ensure that we are always running with the correct encoding.
   fix_encoding.fix_encoding()
   file_path.enable_symlink()
-  sys.exit(main(sys.argv[1:]))
+
+  sys.exit(main(get_args(sys.argv[1:])))