Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/google/auth/credentials.py: 60%
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1# Copyright 2016 Google LLC
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7# http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
16"""Interfaces for credentials."""
18import abc
19import os
21from google.auth import _helpers, environment_vars
22from google.auth import exceptions
23from google.auth import metrics
26class Credentials(metaclass=abc.ABCMeta):
27 """Base class for all credentials.
29 All credentials have a :attr:`token` that is used for authentication and
30 may also optionally set an :attr:`expiry` to indicate when the token will
31 no longer be valid.
33 Most credentials will be :attr:`invalid` until :meth:`refresh` is called.
34 Credentials can do this automatically before the first HTTP request in
35 :meth:`before_request`.
37 Although the token and expiration will change as the credentials are
38 :meth:`refreshed <refresh>` and used, credentials should be considered
39 immutable. Various credentials will accept configuration such as private
40 keys, scopes, and other options. These options are not changeable after
41 construction. Some classes will provide mechanisms to copy the credentials
42 with modifications such as :meth:`ScopedCredentials.with_scopes`.
43 """
45 def __init__(self):
46 self.token = None
47 """str: The bearer token that can be used in HTTP headers to make
48 authenticated requests."""
49 self.expiry = None
50 """Optional[datetime]: When the token expires and is no longer valid.
51 If this is None, the token is assumed to never expire."""
52 self._quota_project_id = None
53 """Optional[str]: Project to use for quota and billing purposes."""
54 self._trust_boundary = None
55 """Optional[str]: Encoded string representation of credentials trust
56 boundary."""
57 self._universe_domain = "googleapis.com"
58 """Optional[str]: The universe domain value, default is googleapis.com
59 """
61 @property
62 def expired(self):
63 """Checks if the credentials are expired.
65 Note that credentials can be invalid but not expired because
66 Credentials with :attr:`expiry` set to None is considered to never
67 expire.
68 """
69 if not self.expiry:
70 return False
72 # Remove some threshold from expiry to err on the side of reporting
73 # expiration early so that we avoid the 401-refresh-retry loop.
74 skewed_expiry = self.expiry - _helpers.REFRESH_THRESHOLD
75 return _helpers.utcnow() >= skewed_expiry
77 @property
78 def valid(self):
79 """Checks the validity of the credentials.
81 This is True if the credentials have a :attr:`token` and the token
82 is not :attr:`expired`.
83 """
84 return self.token is not None and not self.expired
86 @property
87 def quota_project_id(self):
88 """Project to use for quota and billing purposes."""
89 return self._quota_project_id
91 @property
92 def universe_domain(self):
93 """The universe domain value."""
94 return self._universe_domain
96 @abc.abstractmethod
97 def refresh(self, request):
98 """Refreshes the access token.
100 Args:
101 request (google.auth.transport.Request): The object used to make
102 HTTP requests.
104 Raises:
105 google.auth.exceptions.RefreshError: If the credentials could
106 not be refreshed.
107 """
108 # pylint: disable=missing-raises-doc
109 # (pylint doesn't recognize that this is abstract)
110 raise NotImplementedError("Refresh must be implemented")
112 def _metric_header_for_usage(self):
113 """The x-goog-api-client header for token usage metric.
115 This header will be added to the API service requests in before_request
116 method. For example, "cred-type/sa-jwt" means service account self
117 signed jwt access token is used in the API service request
118 authorization header. Children credentials classes need to override
119 this method to provide the header value, if the token usage metric is
120 needed.
122 Returns:
123 str: The x-goog-api-client header value.
124 """
125 return None
127 def apply(self, headers, token=None):
128 """Apply the token to the authentication header.
130 Args:
131 headers (Mapping): The HTTP request headers.
132 token (Optional[str]): If specified, overrides the current access
133 token.
134 """
135 headers["authorization"] = "Bearer {}".format(
136 _helpers.from_bytes(token or self.token)
137 )
138 if self._trust_boundary is not None:
139 headers["x-identity-trust-boundary"] = self._trust_boundary
140 if self.quota_project_id:
141 headers["x-goog-user-project"] = self.quota_project_id
143 def before_request(self, request, method, url, headers):
144 """Performs credential-specific before request logic.
146 Refreshes the credentials if necessary, then calls :meth:`apply` to
147 apply the token to the authentication header.
149 Args:
150 request (google.auth.transport.Request): The object used to make
151 HTTP requests.
152 method (str): The request's HTTP method or the RPC method being
153 invoked.
154 url (str): The request's URI or the RPC service's URI.
155 headers (Mapping): The request's headers.
156 """
157 # pylint: disable=unused-argument
158 # (Subclasses may use these arguments to ascertain information about
159 # the http request.)
160 if not self.valid:
161 self.refresh(request)
162 metrics.add_metric_header(headers, self._metric_header_for_usage())
163 self.apply(headers)
166class CredentialsWithQuotaProject(Credentials):
167 """Abstract base for credentials supporting ``with_quota_project`` factory"""
169 def with_quota_project(self, quota_project_id):
170 """Returns a copy of these credentials with a modified quota project.
172 Args:
173 quota_project_id (str): The project to use for quota and
174 billing purposes
176 Returns:
177 google.oauth2.credentials.Credentials: A new credentials instance.
178 """
179 raise NotImplementedError("This credential does not support quota project.")
181 def with_quota_project_from_environment(self):
182 quota_from_env = os.environ.get(environment_vars.GOOGLE_CLOUD_QUOTA_PROJECT)
183 if quota_from_env:
184 return self.with_quota_project(quota_from_env)
185 return self
188class CredentialsWithTokenUri(Credentials):
189 """Abstract base for credentials supporting ``with_token_uri`` factory"""
191 def with_token_uri(self, token_uri):
192 """Returns a copy of these credentials with a modified token uri.
194 Args:
195 token_uri (str): The uri to use for fetching/exchanging tokens
197 Returns:
198 google.oauth2.credentials.Credentials: A new credentials instance.
199 """
200 raise NotImplementedError("This credential does not use token uri.")
203class AnonymousCredentials(Credentials):
204 """Credentials that do not provide any authentication information.
206 These are useful in the case of services that support anonymous access or
207 local service emulators that do not use credentials.
208 """
210 @property
211 def expired(self):
212 """Returns `False`, anonymous credentials never expire."""
213 return False
215 @property
216 def valid(self):
217 """Returns `True`, anonymous credentials are always valid."""
218 return True
220 def refresh(self, request):
221 """Raises :class:``InvalidOperation``, anonymous credentials cannot be
222 refreshed."""
223 raise exceptions.InvalidOperation("Anonymous credentials cannot be refreshed.")
225 def apply(self, headers, token=None):
226 """Anonymous credentials do nothing to the request.
228 The optional ``token`` argument is not supported.
230 Raises:
231 google.auth.exceptions.InvalidValue: If a token was specified.
232 """
233 if token is not None:
234 raise exceptions.InvalidValue("Anonymous credentials don't support tokens.")
236 def before_request(self, request, method, url, headers):
237 """Anonymous credentials do nothing to the request."""
240class ReadOnlyScoped(metaclass=abc.ABCMeta):
241 """Interface for credentials whose scopes can be queried.
243 OAuth 2.0-based credentials allow limiting access using scopes as described
244 in `RFC6749 Section 3.3`_.
245 If a credential class implements this interface then the credentials either
246 use scopes in their implementation.
248 Some credentials require scopes in order to obtain a token. You can check
249 if scoping is necessary with :attr:`requires_scopes`::
251 if credentials.requires_scopes:
252 # Scoping is required.
253 credentials = credentials.with_scopes(scopes=['one', 'two'])
255 Credentials that require scopes must either be constructed with scopes::
257 credentials = SomeScopedCredentials(scopes=['one', 'two'])
259 Or must copy an existing instance using :meth:`with_scopes`::
261 scoped_credentials = credentials.with_scopes(scopes=['one', 'two'])
263 Some credentials have scopes but do not allow or require scopes to be set,
264 these credentials can be used as-is.
266 .. _RFC6749 Section 3.3: https://tools.ietf.org/html/rfc6749#section-3.3
267 """
269 def __init__(self):
270 super(ReadOnlyScoped, self).__init__()
271 self._scopes = None
272 self._default_scopes = None
274 @property
275 def scopes(self):
276 """Sequence[str]: the credentials' current set of scopes."""
277 return self._scopes
279 @property
280 def default_scopes(self):
281 """Sequence[str]: the credentials' current set of default scopes."""
282 return self._default_scopes
284 @abc.abstractproperty
285 def requires_scopes(self):
286 """True if these credentials require scopes to obtain an access token.
287 """
288 return False
290 def has_scopes(self, scopes):
291 """Checks if the credentials have the given scopes.
293 .. warning: This method is not guaranteed to be accurate if the
294 credentials are :attr:`~Credentials.invalid`.
296 Args:
297 scopes (Sequence[str]): The list of scopes to check.
299 Returns:
300 bool: True if the credentials have the given scopes.
301 """
302 credential_scopes = (
303 self._scopes if self._scopes is not None else self._default_scopes
304 )
305 return set(scopes).issubset(set(credential_scopes or []))
308class Scoped(ReadOnlyScoped):
309 """Interface for credentials whose scopes can be replaced while copying.
311 OAuth 2.0-based credentials allow limiting access using scopes as described
312 in `RFC6749 Section 3.3`_.
313 If a credential class implements this interface then the credentials either
314 use scopes in their implementation.
316 Some credentials require scopes in order to obtain a token. You can check
317 if scoping is necessary with :attr:`requires_scopes`::
319 if credentials.requires_scopes:
320 # Scoping is required.
321 credentials = credentials.create_scoped(['one', 'two'])
323 Credentials that require scopes must either be constructed with scopes::
325 credentials = SomeScopedCredentials(scopes=['one', 'two'])
327 Or must copy an existing instance using :meth:`with_scopes`::
329 scoped_credentials = credentials.with_scopes(scopes=['one', 'two'])
331 Some credentials have scopes but do not allow or require scopes to be set,
332 these credentials can be used as-is.
334 .. _RFC6749 Section 3.3: https://tools.ietf.org/html/rfc6749#section-3.3
335 """
337 @abc.abstractmethod
338 def with_scopes(self, scopes, default_scopes=None):
339 """Create a copy of these credentials with the specified scopes.
341 Args:
342 scopes (Sequence[str]): The list of scopes to attach to the
343 current credentials.
345 Raises:
346 NotImplementedError: If the credentials' scopes can not be changed.
347 This can be avoided by checking :attr:`requires_scopes` before
348 calling this method.
349 """
350 raise NotImplementedError("This class does not require scoping.")
353def with_scopes_if_required(credentials, scopes, default_scopes=None):
354 """Creates a copy of the credentials with scopes if scoping is required.
356 This helper function is useful when you do not know (or care to know) the
357 specific type of credentials you are using (such as when you use
358 :func:`google.auth.default`). This function will call
359 :meth:`Scoped.with_scopes` if the credentials are scoped credentials and if
360 the credentials require scoping. Otherwise, it will return the credentials
361 as-is.
363 Args:
364 credentials (google.auth.credentials.Credentials): The credentials to
365 scope if necessary.
366 scopes (Sequence[str]): The list of scopes to use.
367 default_scopes (Sequence[str]): Default scopes passed by a
368 Google client library. Use 'scopes' for user-defined scopes.
370 Returns:
371 google.auth.credentials.Credentials: Either a new set of scoped
372 credentials, or the passed in credentials instance if no scoping
373 was required.
374 """
375 if isinstance(credentials, Scoped) and credentials.requires_scopes:
376 return credentials.with_scopes(scopes, default_scopes=default_scopes)
377 else:
378 return credentials
381class Signing(metaclass=abc.ABCMeta):
382 """Interface for credentials that can cryptographically sign messages."""
384 @abc.abstractmethod
385 def sign_bytes(self, message):
386 """Signs the given message.
388 Args:
389 message (bytes): The message to sign.
391 Returns:
392 bytes: The message's cryptographic signature.
393 """
394 # pylint: disable=missing-raises-doc,redundant-returns-doc
395 # (pylint doesn't recognize that this is abstract)
396 raise NotImplementedError("Sign bytes must be implemented.")
398 @abc.abstractproperty
399 def signer_email(self):
400 """Optional[str]: An email address that identifies the signer."""
401 # pylint: disable=missing-raises-doc
402 # (pylint doesn't recognize that this is abstract)
403 raise NotImplementedError("Signer email must be implemented.")
405 @abc.abstractproperty
406 def signer(self):
407 """google.auth.crypt.Signer: The signer used to sign bytes."""
408 # pylint: disable=missing-raises-doc
409 # (pylint doesn't recognize that this is abstract)
410 raise NotImplementedError("Signer must be implemented.")