Add support for externally provided refresh tokens.

OAuth token cache file (as implemented by oauth2client library) stores refresh
token and can in theory be deployed via Puppet as the credential. But it is
mutated by the library (to store access tokens, rotated each hour), and so it is
not static and managing it via Puppet (or however else) is a big pain.

Instead, now depot_tools accepts --auth-refresh-token-json parameter with a path
to a static JSON file (with minimal body being {"refresh_token": "....."}). It
can be used to pass previously prepared refresh tokens of role accounts. It
will be used for blink DEPS roller account and similar @chromium.org accounts.

R=maruel@chromium.org
BUG=356813

Review URL: https://codereview.chromium.org/1060193005

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@294870 0039d316-1c4b-4281-b951-d872f2087c98

auth.py

@@ -8,6 +8,7 @@ import BaseHTTPServer
 import collections
 import datetime
 import functools
+import hashlib
 import json
 import logging
 import optparse
@@ -62,6 +63,7 @@ AuthConfig = collections.namedtuple('AuthConfig', [
     'save_cookies', # deprecated, will be removed
     'use_local_webserver',
     'webserver_port',
+    'refresh_token_json',
 ])
 
 
@@ -72,6 +74,14 @@ AccessToken = collections.namedtuple('AccessToken', [
 ])
 
 
+# Refresh token passed via --auth-refresh-token-json.
+RefreshToken = collections.namedtuple('RefreshToken', [
+    'client_id',
+    'client_secret',
+    'refresh_token',
+])
+
+
 class AuthenticationError(Exception):
   """Raised on errors related to authentication."""
 
@@ -91,7 +101,8 @@ def make_auth_config(
     use_oauth2=None,
     save_cookies=None,
     use_local_webserver=None,
-    webserver_port=None):
+    webserver_port=None,
+    refresh_token_json=None):
   """Returns new instance of AuthConfig.
 
   If some config option is None, it will be set to a reasonable default value.
@@ -103,7 +114,8 @@ def make_auth_config(
       default(use_oauth2, _should_use_oauth2()),
       default(save_cookies, True),
       default(use_local_webserver, not _is_headless()),
-      default(webserver_port, 8090))
+      default(webserver_port, 8090),
+      default(refresh_token_json, ''))
 
 
 def add_auth_options(parser, default_config=None):
@@ -148,6 +160,10 @@ def add_auth_options(parser, default_config=None):
       default=default_config.webserver_port,
       help='Port a local web server should listen on. Used only if '
           '--auth-no-local-webserver is not set. [default: %default]')
+  parser.auth_group.add_option(
+      '--auth-refresh-token-json',
+      default=default_config.refresh_token_json,
+      help='Path to a JSON file with role account refresh token to use.')
 
 
 def extract_auth_config_from_options(options):
@@ -159,7 +175,8 @@ def extract_auth_config_from_options(options):
       use_oauth2=options.use_oauth2,
       save_cookies=False if options.use_oauth2 else options.save_cookies,
       use_local_webserver=options.use_local_webserver,
-      webserver_port=options.auth_host_port)
+      webserver_port=options.auth_host_port,
+      refresh_token_json=options.auth_refresh_token_json)
 
 
 def auth_config_to_command_options(auth_config):
@@ -181,6 +198,9 @@ def auth_config_to_command_options(auth_config):
       opts.append('--auth-no-local-webserver')
   if auth_config.webserver_port != defaults.webserver_port:
     opts.extend(['--auth-host-port', str(auth_config.webserver_port)])
+  if auth_config.refresh_token_json != defaults.refresh_token_json:
+    opts.extend([
+        '--auth-refresh-token-json', str(auth_config.refresh_token_json)])
   return opts
 
 
@@ -222,6 +242,9 @@ class Authenticator(object):
     self._config = config
     self._lock = threading.Lock()
     self._token_cache_key = token_cache_key
+    self._external_token = None
+    if config.refresh_token_json:
+      self._external_token = _read_refresh_token_json(config.refresh_token_json)
 
   def login(self):
     """Performs interactive login flow if necessary.
@@ -229,24 +252,29 @@ class Authenticator(object):
     Raises:
       AuthenticationError on error or if interrupted.
     """
+    if self._external_token:
+      raise AuthenticationError(
+          'Can\'t run login flow when using --auth-refresh-token-json.')
     return self.get_access_token(
         force_refresh=True, allow_user_interaction=True)
 
   def logout(self):
     """Revokes the refresh token and deletes it from the cache.
 
-    Returns True if actually revoked a token.
+    Returns True if had some credentials cached.
     """
-    revoked = False
     with self._lock:
       self._access_token = None
       storage = self._get_storage()
       credentials = storage.get()
-      if credentials:
-        credentials.revoke(httplib2.Http())
-        revoked = True
+      had_creds = bool(credentials)
+      if credentials and credentials.refresh_token and credentials.revoke_uri:
+        try:
+          credentials.revoke(httplib2.Http())
+        except client.TokenRevokeError as e:
+          logging.warning('Failed to revoke refresh token: %s', e)
       storage.delete()
-    return revoked
+    return had_creds
 
   def has_cached_credentials(self):
     """Returns True if long term credentials (refresh token) are in cache.
@@ -262,8 +290,7 @@ class Authenticator(object):
     it.
     """
     with self._lock:
-      credentials = self._get_storage().get()
-      return credentials and not credentials.invalid
+      return bool(self._get_cached_credentials())
 
   def get_access_token(self, force_refresh=False, allow_user_interaction=False):
     """Returns AccessToken, refreshing it if necessary.
@@ -348,17 +375,57 @@ class Authenticator(object):
 
   def _get_storage(self):
     """Returns oauth2client.Storage with cached tokens."""
+    # Do not mix cache keys for different externally provided tokens.
+    if self._external_token:
+      token_hash = hashlib.sha1(self._external_token.refresh_token).hexdigest()
+      cache_key = '%s:refresh_tok:%s' % (self._token_cache_key, token_hash)
+    else:
+      cache_key = self._token_cache_key
     return multistore_file.get_credential_storage_custom_string_key(
-        OAUTH_TOKENS_CACHE, self._token_cache_key)
+        OAUTH_TOKENS_CACHE, cache_key)
+
+  def _get_cached_credentials(self):
+    """Returns oauth2client.Credentials loaded from storage."""
+    storage = self._get_storage()
+    credentials = storage.get()
+
+    # Is using --auth-refresh-token-json?
+    if self._external_token:
+      # Cached credentials are valid and match external token -> use them. It is
+      # important to reuse credentials from the storage because they contain
+      # cached access token.
+      valid = (
+          credentials and not credentials.invalid and
+          credentials.refresh_token == self._external_token.refresh_token and
+          credentials.client_id == self._external_token.client_id and
+          credentials.client_secret == self._external_token.client_secret)
+      if valid:
+        return credentials
+      # Construct new credentials from externally provided refresh token,
+      # associate them with cache storage (so that access_token will be placed
+      # in the cache later too).
+      credentials = client.OAuth2Credentials(
+          access_token=None,
+          client_id=self._external_token.client_id,
+          client_secret=self._external_token.client_secret,
+          refresh_token=self._external_token.refresh_token,
+          token_expiry=None,
+          token_uri='https://accounts.google.com/o/oauth2/token',
+          user_agent=None,
+          revoke_uri=None)
+      credentials.set_store(storage)
+      storage.put(credentials)
+      return credentials
+
+    # Not using external refresh token -> return whatever is cached.
+    return credentials if (credentials and not credentials.invalid) else None
 
   def _load_access_token(self):
     """Returns cached AccessToken if it is not expired yet."""
-    credentials = self._get_storage().get()
-    if not credentials or credentials.invalid:
-      return None
-    if not credentials.access_token or credentials.access_token_expired:
+    creds = self._get_cached_credentials()
+    if not creds or not creds.access_token or creds.access_token_expired:
       return None
-    return AccessToken(str(credentials.access_token), credentials.token_expiry)
+    return AccessToken(str(creds.access_token), creds.token_expiry)
 
   def _create_access_token(self, allow_user_interaction=False):
     """Mints and caches a new access token, launching OAuth2 dance if necessary.
@@ -379,11 +446,9 @@ class Authenticator(object):
       LoginRequiredError if user interaction is required, but
           allow_user_interaction is False.
     """
-    storage = self._get_storage()
-    credentials = None
+    credentials = self._get_cached_credentials()
 
     # 3-legged flow with (perhaps cached) refresh token.
-    credentials = storage.get()
     refreshed = False
     if credentials and not credentials.invalid:
       try:
@@ -391,11 +456,15 @@ class Authenticator(object):
         refreshed = True
       except client.Error as err:
         logging.warning(
-            'OAuth error during access token refresh: %s. '
+            'OAuth error during access token refresh (%s). '
             'Attempting a full authentication flow.', err)
 
     # Refresh token is missing or invalid, go through the full flow.
     if not refreshed:
+      # Can't refresh externally provided token.
+      if self._external_token:
+        raise AuthenticationError(
+            'Token provided via --auth-refresh-token-json is no longer valid.')
       if not allow_user_interaction:
         raise LoginRequiredError(self._token_cache_key)
       credentials = _run_oauth_dance(self._config)
@@ -403,6 +472,7 @@ class Authenticator(object):
     logging.info(
         'OAuth access_token refreshed. Expires in %s.',
         credentials.token_expiry - datetime.datetime.utcnow())
+    storage = self._get_storage()
     credentials.set_store(storage)
     storage.put(credentials)
     return AccessToken(str(credentials.access_token), credentials.token_expiry)
@@ -424,6 +494,23 @@ def _is_headless():
   return sys.platform == 'linux2' and not os.environ.get('DISPLAY')
 
 
+def _read_refresh_token_json(path):
+  """Returns RefreshToken by reading it from the JSON file."""
+  try:
+    with open(path, 'r') as f:
+      data = json.load(f)
+      return RefreshToken(
+          client_id=str(data.get('client_id', OAUTH_CLIENT_ID)),
+          client_secret=str(data.get('client_secret', OAUTH_CLIENT_SECRET)),
+          refresh_token=str(data['refresh_token']))
+  except (IOError, ValueError) as e:
+    raise AuthenticationError(
+        'Failed to read refresh token from %s: %s' % (path, e))
+  except KeyError as e:
+    raise AuthenticationError(
+        'Failed to read refresh token from %s: missing key %s' % (path, e))
+
+
 def _needs_refresh(access_token):
   """True if AccessToken should be refreshed."""
   if access_token.expires_at is not None:

tests/git_cl_test.py

@@ -96,6 +96,7 @@ class TestGitCl(TestCase):
     self.mock(git_cl.upload, 'RealMain', self.fail)
     self.mock(git_cl.watchlists, 'Watchlists', WatchlistsMock)
     self.mock(git_cl.auth, 'get_authenticator_for_host', AuthenticatorMock)
+    self.mock(git_cl.auth, '_should_use_oauth2', lambda: False)
     # It's important to reset settings to not have inter-tests interference.
     git_cl.settings = None