cros_extract_deps -j writes JSON, sorted by package name.

cros_extract_deps

 #!/usr/bin/python
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Extract dependency tree out of emerge and make it accessible and useful."""
 
+import json
 import optparse
-import pprint
 import re
 import shutil
 import subprocess
 import sys
 import tempfile
 import time
 
 class ParseException(Exception):
   def __init__(self, reason):
     Exception.__init__(self)
     self.reason = reason
 
   def __str__(self):
     return self.reason
 
 
+class SetEncoder(json.JSONEncoder):
+  """Custom json encoder class, doesn't hate set types."""
+  def default(self, o):
+    if isinstance(o, set):
+      return list(o)
+    return json.JSONEncoder.default(self, o)
+
+
 def GetDepLinesFromPortage(options, packages):
   """Get dependency lines out of emerge.
 
   This calls emerge -p --debug and extracts the 'digraph' lines which detail
   the dependencies."
   """
   # Use a temporary directory for $ROOT, so that emerge will consider all
   # packages regardless of current build status.
   temp_dir = tempfile.mkdtemp()
 
@@ skipping 136 matching lines @@
                     help='Also extract build-time dependencies.')
   parser.add_option('-o', '--output', default=None,
                     help='Output file.')
   (options, packages) = parser.parse_args()
   if not packages:
     parser.print_usage()
     sys.exit(1)
 
   lines = GetDepLinesFromPortage(options, packages)
   deps_map = ParseDepLines(lines)
-  output = pprint.pformat(deps_map)
+  output = json.dumps(deps_map, sort_keys=True, indent=2, cls=SetEncoder)
   if options.output:
     output_file = open(options.output, 'w')
     output_file.write(output)
     output_file.close()
   else:
     print output
 
 
 if __name__ == '__main__':
   main()