Add a wrapper script which modifies the .isolate on the fly.

tools/isolate_driver.py

+#!/usr/bin/env python
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Adaptor script called through build/isolate.gyp.

[Vadim Sh., 2014/03/14 01:51:35]

isolate.gypi (with 'i')?

[M-A Ruel, 2014/03/14 12:51:56]

Done.

+
+Creates a temporary .isolate merged with the original one into a .isolate file
+that can be consumed by tools/swarming_client/isolate.py.
+
+For now it packages all the dynamic libraries found. This is inefficient and
+non-deterministic. In the very near future, it will parse build.ninja, find back
+the root target and find all the dynamic libraries that are marked as a
+dependency to this target.
+"""
+
+import glob
+import os
+import optparse
+import subprocess
+import sys
+
+
+SRC_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+DYNAMIC_LIBRARIES = {
+  'darwin': '*.dylib',
+  'linux2': 'lib/*.so',
+  'win32': '*.dll',
+}
+
+
+def mangle(args, isolate, isolated):
+  # Open the .isolate, edit it, store it in the temporary directory.
+  # All paths are relative to cwd.
+  cwd = os.getcwd()

[Vadim Sh., 2014/03/14 01:51:35]

What is cwd? Does ninja gives any guarantees about it?

[M-A Ruel, 2014/03/14 12:51:56]

ninja guarantees the script will be called from the directory containing the
.isolate file. At least if this assumption breaks, it'll be very visible. :) The
paths in the .isolate file are also relative to its directory.

[Vadim Sh., 2014/03/14 18:01:38]

Please add a comment describing what cwd is expected to be.

+  src_isolate = os.path.relpath(os.path.join(cwd, args[isolate]), SRC_DIR)
+  build_dir = os.path.dirname(args[isolated])
+  temp_isolate = os.path.join(build_dir, 'gen', src_isolate)
+  dynamic_libs = glob.glob(
+      os.path.join(build_dir, DYNAMIC_LIBRARIES[sys.platform]))
+
+  # Mangle it.
+  with open(args[isolate], 'rb') as f:
+    isolate_content = f.read()
+  isolate_content = isolate_content.strip()[:-1]
+  isolate_content += (

[Vadim Sh., 2014/03/14 01:51:35]

that's is very hacky... why not exec it, modify as python and pprint it back? no
one cares about comments and formating in generated files.

[M-A Ruel, 2014/03/14 12:51:56]

There's a few options;
1. Hack the way it's currently done. Note that the step will immediately break
if the hack breaks.
2. Use eval() as you suggested.
3. Use isolate_format.py as a library to load the file and write it back. It's
the safest approach but makes refactoring to isolate_format.py more annoying
afterward.

As a matter of fact, #2 doesn't buy us much from #1. Both are huge ugly hacks.

[Vadim Sh., 2014/03/14 18:01:38]

I think #1 is more fragile than #2. It's a big relieve that try server covers
changes to *.isolate :)

+      "  'variables': {\n"
+      "    'isolate_tracked': [\n"
+      "%s"
+      "    ],\n"
+      "  },\n"
+      "}\n") % ''.join('      %s,\n' % repr(d) for d in dynamic_libs)
+  gen_dir = os.path.dirname(temp_isolate)
+  if not os.path.isdir(gen_dir):
+    os.makedirs(gen_dir)
+  with open(temp_isolate, 'wb') as f:
+    f.write(isolate_content)
+
+  print('Added %d dynamic libs' % len(dynamic_libs))
+  args[isolate] = temp_isolate
+
+
+def main():
+  args = sys.argv[1:]
+  isolate = None
+  isolated = None
+  is_component = False
+  for i, arg in enumerate(args):

[Vadim Sh., 2014/03/14 01:51:35]

why not optparse? It's even imported.

[M-A Ruel, 2014/03/14 12:51:56]

Yeah I thought about using it first and proxying all the flags but it's more
trouble than worth. In practice some flags are tricky to implement (e.g.
--*-variable) as they accept a variable number of arguments. In the end, this
script is what it is: a big hack. So the shorter the better.

[Vadim Sh., 2014/03/14 18:01:38]

Yeah, makes sense.

+    if arg == '--isolate':
+      isolate = i + 1
+    if arg == '--isolated':
+      isolated = i + 1
+    if arg == 'component=shared_library':
+      is_component = True
+  if isolate is None or isolated is None:
+    print >> sys.stderr, 'Internal failure'
+    return 1
+
+  if is_component:
+    mangle(args, isolate, isolated)
+
+  swarming_client = os.path.join(SRC_DIR, 'tools', 'swarming_client')
+  return subprocess.call(
+      [sys.executable, os.path.join(swarming_client, 'isolate.py')] +
+      sys.argv[1:])
+
+
+if __name__ == '__main__':
+  sys.exit(main())