origin_trials/generate_token.py: Look for default key in script dir.

tools/origin_trials/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]
@@ skipping 17 matching lines @@
 import ed25519
 
 
 # Matches a valid DNS name label (alphanumeric plus hyphens, except at the ends,
 # no longer than 63 ASCII characters)
 DNS_LABEL_REGEX = re.compile(r"^(?!-)[a-z\d-]{1,63}(?<!-)$", re.IGNORECASE)
 
 # This script generates Version 2 tokens.
 VERSION = "\x02"
 
+# Default key file, relative to script_dir.
+DEFAULT_KEY_FILE = 'eftest.key'
+
 def HostnameFromArg(arg):
   """Determines whether a string represents a valid hostname.
 
   Returns the canonical hostname if its argument is valid, or None otherwise.
   """
   if not arg or len(arg) > 255:
     return None
   if arg[-1] == ".":
     arg = arg[:-1]
   if "." not in arg and arg != "localhost":
@@ skipping 43 matching lines @@
   return version + struct.pack(">I",len(data)) + data
 
 def Sign(private_key, data):
   return ed25519.signature(data, private_key[:32], private_key[32:])
 
 def FormatToken(version, signature, data):
   return base64.b64encode(version + signature +
                           struct.pack(">I",len(data)) + data)
 
 def main():
+  default_key_file_absolute = os.path.join(script_dir, DEFAULT_KEY_FILE)
+
   parser = argparse.ArgumentParser(
       description="Generate tokens for enabling experimental APIs")
   parser.add_argument("origin",
                       help="Origin for which to enable the API. This can be "
                            "either a hostname (default scheme HTTPS, default "
                            "port 443) or a URL.",
                       type=OriginFromArg)
   parser.add_argument("trial_name",
                       help="Feature to enable. The current list of "
                            "experimental feature trials can be found in "
                            "RuntimeFeatures.in")
   parser.add_argument("--key-file",
                       help="Ed25519 private key file to sign the token with",
-                      default="eftest.key")
+                      default=default_key_file_absolute)
   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 (seconds since 1970-01-01 "
                                  "00:00:00 UTC) when the token should exipire",
                             type=int)
 
@@ skipping 29 matching lines @@
   print " Origin: %s" % args.origin
   print " Feature: %s" % args.trial_name
   print " Expiry: %d (%s UTC)" % (expiry, datetime.utcfromtimestamp(expiry))
   print
 
   # Output the properly-formatted token.
   print FormatToken(VERSION, signature, token_data)
 
 if __name__ == "__main__":
   main()