Add experimental framework token generation tool

tools/experiments/generate_token.py

+#!/usr/bin/env python
+# Copyright (c) 2016 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.
+
+"""Utility for generating experimental API tokens
+
+usage: generate_token.py [-h] [--key-file KEY_FILE]
+                         [--expire-days EXPIRE_DAYS |
+                          --expire-timestamp EXPIRE_TIMESTAMP]
+                         hostname api_name
+
+Generate tokens for enabling experimental APIs
+
+positional arguments:
+  hostname              Host for which to enable the API. This can be a bare
+                        hostname (in which case https will be assumed,) or a
+                        valid origin URL (hostname, protocol and port can all
+                        be included.)
+  api_name              API to enable. The current list of experimental APIs
+                        can be found in RuntimeFeatures.in
+
+optional arguments:
+  -h, --help            show this help message and exit
+  --key-file KEY_FILE   Ed25519 private key file to sign the token with
+  --expire-days EXPIRE_DAYS
+                        Days from now when the token should exipire
+  --expire-timestamp EXPIRE_TIMESTAMP
+                        Exact time (milliseconds since 1970-01-01 00:00:00
+                        UTC) when the token should exipire

[miket_OOO, 2016/01/21 21:54:56]

This is up to you, but if this is just a rote copy of --help, then it might not
serve a useful purpose beyond explaining the argparse block below. Consider
omitting.

[iclelland, 2016/01/22 20:31:57]

It is a rote copy, just for anyone reading the code, but I'll omit it, and
replace with a note to call -h for more info.

+"""
+import argparse
+import base64
+import re
+import os
+import sys
+import time
+import urlparse
+
+from third_party import ed25519
+
+def OriginFromArgs(arg):
+  """Constructs the origin for the token from the command line arguments.
+
+  Returns None if this is not possible (neither a valid hostname nor a
+  valid origin URL was provided.)
+  """
+  # Does it look like a hostname?
+  if re.match('^[a-z0-9.-]*$', arg):

[miket_OOO, 2016/01/21 21:54:56]

Make sure we (this tool and dev-console server code) agree on what a hostname
is.

[iclelland, 2016/01/22 20:31:57]

It looks like your regex disallows a '-' as a component, which makes sense.
Updated.

+    return 'https://'+arg
+  # Try to construct an origin URL from the argument
+  origin = urlparse.urlparse(arg)
+  if not origin or not origin.scheme or not origin.netloc:
+    raise argparse.ArgumentTypeError("%s is not a hostname or a URL" % arg)
+  # Strip any other components and return the URL:
+  return urlparse.urlunparse(origin[:2]+('',)*4)

[miket_OOO, 2016/01/21 21:54:56]

whitespace after comma and around binary operator +

[iclelland, 2016/01/22 20:31:57]

Done.

+
+def ExpiryFromArgs(args):
+  if args.expire_timestamp:
+    return int(args.expire_timestamp)
+  return ((int(time.time()) + (int(args.expire_days) * 86400)) * 1000)
+
+def GenerateTokenData(origin, apiName, expiry):
+  return "{0}|{1}|{2}".format(origin, apiName, expiry)
+
+def Sign(private_key, data):
+  return ed25519.signature(data, private_key[:32], private_key[32:])
+
+def FormatToken(signature, data):
+  return base64.b64encode(signature) + "|" + data
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Generate tokens for enabling experimental APIs")
+  parser.add_argument('hostname',
+                      help="Host for which to enable the API. This can be a "
+                           "bare hostname (in which case https will be "
+                           "assumed,) or a valid origin URL (hostname, "
+                           "protocol and port can all be included.)",
+                      type=OriginFromArgs)
+  parser.add_argument('api_name',
+                      help="API to enable. The current list of experimental "
+                           "APIs can be found in RuntimeFeatures.in")
+  parser.add_argument('--key-file',
+                      help='Ed25519 private key file to sign the token with',
+                      default="eftest.key")
+  expiry_group = parser.add_mutually_exclusive_group()
+  expiry_group.add_argument('--expire-days',
+                            help='Days from now when the token should exipire',
+                            type=int,
+                            default=42)
+  expiry_group.add_argument('--expire-timestamp',
+                            help="Exact time (milliseconds since 1970-01-01 "
+                                 "00:00:00 UTC) when the token should exipire",
+                            type=int)
+
+  args = parser.parse_args()
+  expiry = ExpiryFromArgs(args)
+
+  key_file = open(os.path.expanduser(args.key_file))
+  private_key = key_file.read()
+
+  # Validate that the key file read was a proper Ed25519 key -- running the
+  # publickey method on the first half of the key should return the second
+  # half.
+  if (len(private_key) != 64 or
+    ed25519.publickey(private_key[:32]) != private_key[32:]):
+    print("Unable to use the specified private key file.")
+    sys.exit(1)
+
+  token_data = GenerateTokenData(args.hostname, args.api_name, expiry)
+  signature = Sign(private_key, token_data)
+
+  # Verify that that the signature is correct before printing it.
+  try:
+    ed25519.checkvalid(signature, token_data, private_key[32:])
+  except Exception:
+    print "There was an error generating the signature."
+    sys.exit(1)
+
+  print FormatToken(signature, token_data)
+
+if __name__ == "__main__":
+  main()