aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/python/google-auth/py2/google/oauth2/service_account.py
blob: 8f18f26ea17b8ea48e269e90cf96dc58800cc2c0 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
# Copyright 2016 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Service Accounts: JSON Web Token (JWT) Profile for OAuth 2.0

This module implements the JWT Profile for OAuth 2.0 Authorization Grants
as defined by `RFC 7523`_ with particular support for how this RFC is
implemented in Google's infrastructure. Google refers to these credentials
as *Service Accounts*.

Service accounts are used for server-to-server communication, such as
interactions between a web application server and a Google service. The
service account belongs to your application instead of to an individual end
user. In contrast to other OAuth 2.0 profiles, no users are involved and your
application "acts" as the service account.

Typically an application uses a service account when the application uses
Google APIs to work with its own data rather than a user's data. For example,
an application that uses Google Cloud Datastore for data persistence would use
a service account to authenticate its calls to the Google Cloud Datastore API.
However, an application that needs to access a user's Drive documents would
use the normal OAuth 2.0 profile.

Additionally, Google Apps domain administrators can grant service accounts
`domain-wide delegation`_ authority to access user data on behalf of users in
the domain.

This profile uses a JWT to acquire an OAuth 2.0 access token. The JWT is used
in place of the usual authorization token returned during the standard
OAuth 2.0 Authorization Code grant. The JWT is only used for this purpose, as
the acquired access token is used as the bearer token when making requests
using these credentials.

This profile differs from normal OAuth 2.0 profile because no user consent
step is required. The use of the private key allows this profile to assert
identity directly.

This profile also differs from the :mod:`google.auth.jwt` authentication
because the JWT credentials use the JWT directly as the bearer token. This
profile instead only uses the JWT to obtain an OAuth 2.0 access token. The
obtained OAuth 2.0 access token is used as the bearer token.

Domain-wide delegation
----------------------

Domain-wide delegation allows a service account to access user data on
behalf of any user in a Google Apps domain without consent from the user.
For example, an application that uses the Google Calendar API to add events to
the calendars of all users in a Google Apps domain would use a service account
to access the Google Calendar API on behalf of users.

The Google Apps administrator must explicitly authorize the service account to
do this. This authorization step is referred to as "delegating domain-wide
authority" to a service account.

You can use domain-wise delegation by creating a set of credentials with a
specific subject using :meth:`~Credentials.with_subject`.

.. _RFC 7523: https://tools.ietf.org/html/rfc7523
"""

import copy
import datetime

from google.auth import _helpers
from google.auth import _service_account_info
from google.auth import credentials
from google.auth import jwt
from google.oauth2 import _client

_DEFAULT_TOKEN_LIFETIME_SECS = 3600  # 1 hour in seconds
_GOOGLE_OAUTH2_TOKEN_ENDPOINT = "https://oauth2.googleapis.com/token"


class Credentials(
    credentials.Signing, credentials.Scoped, credentials.CredentialsWithQuotaProject
):
    """Service account credentials

    Usually, you'll create these credentials with one of the helper
    constructors. To create credentials using a Google service account
    private key JSON file::

        credentials = service_account.Credentials.from_service_account_file(
            'service-account.json')

    Or if you already have the service account file loaded::

        service_account_info = json.load(open('service_account.json'))
        credentials = service_account.Credentials.from_service_account_info(
            service_account_info)

    Both helper methods pass on arguments to the constructor, so you can
    specify additional scopes and a subject if necessary::

        credentials = service_account.Credentials.from_service_account_file(
            'service-account.json',
            scopes=['email'],
            subject='user@example.com')

    The credentials are considered immutable. If you want to modify the scopes
    or the subject used for delegation, use :meth:`with_scopes` or
    :meth:`with_subject`::

        scoped_credentials = credentials.with_scopes(['email'])
        delegated_credentials = credentials.with_subject(subject)

    To add a quota project, use :meth:`with_quota_project`::

        credentials = credentials.with_quota_project('myproject-123')
    """

    def __init__(
        self,
        signer,
        service_account_email,
        token_uri,
        scopes=None,
        default_scopes=None,
        subject=None,
        project_id=None,
        quota_project_id=None,
        additional_claims=None,
        always_use_jwt_access=False,
    ):
        """
        Args:
            signer (google.auth.crypt.Signer): The signer used to sign JWTs.
            service_account_email (str): The service account's email.
            scopes (Sequence[str]): User-defined scopes to request during the
                authorization grant.
            default_scopes (Sequence[str]): Default scopes passed by a
                Google client library. Use 'scopes' for user-defined scopes.
            token_uri (str): The OAuth 2.0 Token URI.
            subject (str): For domain-wide delegation, the email address of the
                user to for which to request delegated access.
            project_id  (str): Project ID associated with the service account
                credential.
            quota_project_id (Optional[str]): The project ID used for quota and
                billing.
            additional_claims (Mapping[str, str]): Any additional claims for
                the JWT assertion used in the authorization grant.
            always_use_jwt_access (Optional[bool]): Whether self signed JWT should
                be always used.

        .. note:: Typically one of the helper constructors
            :meth:`from_service_account_file` or
            :meth:`from_service_account_info` are used instead of calling the
            constructor directly.
        """
        super(Credentials, self).__init__()

        self._scopes = scopes
        self._default_scopes = default_scopes
        self._signer = signer
        self._service_account_email = service_account_email
        self._subject = subject
        self._project_id = project_id
        self._quota_project_id = quota_project_id
        self._token_uri = token_uri
        self._always_use_jwt_access = always_use_jwt_access

        self._jwt_credentials = None

        if additional_claims is not None:
            self._additional_claims = additional_claims
        else:
            self._additional_claims = {}

    @classmethod
    def _from_signer_and_info(cls, signer, info, **kwargs):
        """Creates a Credentials instance from a signer and service account
        info.

        Args:
            signer (google.auth.crypt.Signer): The signer used to sign JWTs.
            info (Mapping[str, str]): The service account info.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.jwt.Credentials: The constructed credentials.

        Raises:
            ValueError: If the info is not in the expected format.
        """
        return cls(
            signer,
            service_account_email=info["client_email"],
            token_uri=info["token_uri"],
            project_id=info.get("project_id"),
            **kwargs
        )

    @classmethod
    def from_service_account_info(cls, info, **kwargs):
        """Creates a Credentials instance from parsed service account info.

        Args:
            info (Mapping[str, str]): The service account info in Google
                format.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.service_account.Credentials: The constructed
                credentials.

        Raises:
            ValueError: If the info is not in the expected format.
        """
        signer = _service_account_info.from_dict(
            info, require=["client_email", "token_uri"]
        )
        return cls._from_signer_and_info(signer, info, **kwargs)

    @classmethod
    def from_service_account_file(cls, filename, **kwargs):
        """Creates a Credentials instance from a service account json file.

        Args:
            filename (str): The path to the service account json file.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.service_account.Credentials: The constructed
                credentials.
        """
        info, signer = _service_account_info.from_filename(
            filename, require=["client_email", "token_uri"]
        )
        return cls._from_signer_and_info(signer, info, **kwargs)

    @property
    def service_account_email(self):
        """The service account email."""
        return self._service_account_email

    @property
    def project_id(self):
        """Project ID associated with this credential."""
        return self._project_id

    @property
    def requires_scopes(self):
        """Checks if the credentials requires scopes.

        Returns:
            bool: True if there are no scopes set otherwise False.
        """
        return True if not self._scopes else False

    @_helpers.copy_docstring(credentials.Scoped)
    def with_scopes(self, scopes, default_scopes=None):
        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            scopes=scopes,
            default_scopes=default_scopes,
            token_uri=self._token_uri,
            subject=self._subject,
            project_id=self._project_id,
            quota_project_id=self._quota_project_id,
            additional_claims=self._additional_claims.copy(),
            always_use_jwt_access=self._always_use_jwt_access,
        )

    def with_always_use_jwt_access(self, always_use_jwt_access):
        """Create a copy of these credentials with the specified always_use_jwt_access value.

        Args:
            always_use_jwt_access (bool): Whether always use self signed JWT or not.

        Returns:
            google.auth.service_account.Credentials: A new credentials
                instance.
        """
        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            scopes=self._scopes,
            default_scopes=self._default_scopes,
            token_uri=self._token_uri,
            subject=self._subject,
            project_id=self._project_id,
            quota_project_id=self._quota_project_id,
            additional_claims=self._additional_claims.copy(),
            always_use_jwt_access=always_use_jwt_access,
        )

    def with_subject(self, subject):
        """Create a copy of these credentials with the specified subject.

        Args:
            subject (str): The subject claim.

        Returns:
            google.auth.service_account.Credentials: A new credentials
                instance.
        """
        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            scopes=self._scopes,
            default_scopes=self._default_scopes,
            token_uri=self._token_uri,
            subject=subject,
            project_id=self._project_id,
            quota_project_id=self._quota_project_id,
            additional_claims=self._additional_claims.copy(),
            always_use_jwt_access=self._always_use_jwt_access,
        )

    def with_claims(self, additional_claims):
        """Returns a copy of these credentials with modified claims.

        Args:
            additional_claims (Mapping[str, str]): Any additional claims for
                the JWT payload. This will be merged with the current
                additional claims.

        Returns:
            google.auth.service_account.Credentials: A new credentials
                instance.
        """
        new_additional_claims = copy.deepcopy(self._additional_claims)
        new_additional_claims.update(additional_claims or {})

        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            scopes=self._scopes,
            default_scopes=self._default_scopes,
            token_uri=self._token_uri,
            subject=self._subject,
            project_id=self._project_id,
            quota_project_id=self._quota_project_id,
            additional_claims=new_additional_claims,
            always_use_jwt_access=self._always_use_jwt_access,
        )

    @_helpers.copy_docstring(credentials.CredentialsWithQuotaProject)
    def with_quota_project(self, quota_project_id):

        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            default_scopes=self._default_scopes,
            scopes=self._scopes,
            token_uri=self._token_uri,
            subject=self._subject,
            project_id=self._project_id,
            quota_project_id=quota_project_id,
            additional_claims=self._additional_claims.copy(),
            always_use_jwt_access=self._always_use_jwt_access,
        )

    def _make_authorization_grant_assertion(self):
        """Create the OAuth 2.0 assertion.

        This assertion is used during the OAuth 2.0 grant to acquire an
        access token.

        Returns:
            bytes: The authorization grant assertion.
        """
        now = _helpers.utcnow()
        lifetime = datetime.timedelta(seconds=_DEFAULT_TOKEN_LIFETIME_SECS)
        expiry = now + lifetime

        payload = {
            "iat": _helpers.datetime_to_secs(now),
            "exp": _helpers.datetime_to_secs(expiry),
            # The issuer must be the service account email.
            "iss": self._service_account_email,
            # The audience must be the auth token endpoint's URI
            "aud": _GOOGLE_OAUTH2_TOKEN_ENDPOINT,
            "scope": _helpers.scopes_to_string(self._scopes or ()),
        }

        payload.update(self._additional_claims)

        # The subject can be a user email for domain-wide delegation.
        if self._subject:
            payload.setdefault("sub", self._subject)

        token = jwt.encode(self._signer, payload)

        return token

    @_helpers.copy_docstring(credentials.Credentials)
    def refresh(self, request):
        if self._jwt_credentials is not None:
            self._jwt_credentials.refresh(request)
            self.token = self._jwt_credentials.token
            self.expiry = self._jwt_credentials.expiry
        else:
            assertion = self._make_authorization_grant_assertion()
            access_token, expiry, _ = _client.jwt_grant(
                request, self._token_uri, assertion
            )
            self.token = access_token
            self.expiry = expiry

    def _create_self_signed_jwt(self, audience):
        """Create a self-signed JWT from the credentials if requirements are met.

        Args:
            audience (str): The service URL. ``https://[API_ENDPOINT]/``
        """
        # https://google.aip.dev/auth/4111
        if self._always_use_jwt_access:
            if self._scopes:
                self._jwt_credentials = jwt.Credentials.from_signing_credentials(
                    self, None, additional_claims={"scope": " ".join(self._scopes)}
                )
            elif audience:
                self._jwt_credentials = jwt.Credentials.from_signing_credentials(
                    self, audience
                )
            elif self._default_scopes:
                self._jwt_credentials = jwt.Credentials.from_signing_credentials(
                    self,
                    None,
                    additional_claims={"scope": " ".join(self._default_scopes)},
                )
        elif not self._scopes and audience:
            self._jwt_credentials = jwt.Credentials.from_signing_credentials(
                self, audience
            )

    @_helpers.copy_docstring(credentials.Signing)
    def sign_bytes(self, message):
        return self._signer.sign(message)

    @property
    @_helpers.copy_docstring(credentials.Signing)
    def signer(self):
        return self._signer

    @property
    @_helpers.copy_docstring(credentials.Signing)
    def signer_email(self):
        return self._service_account_email


class IDTokenCredentials(credentials.Signing, credentials.CredentialsWithQuotaProject):
    """Open ID Connect ID Token-based service account credentials.

    These credentials are largely similar to :class:`.Credentials`, but instead
    of using an OAuth 2.0 Access Token as the bearer token, they use an Open
    ID Connect ID Token as the bearer token. These credentials are useful when
    communicating to services that require ID Tokens and can not accept access
    tokens.

    Usually, you'll create these credentials with one of the helper
    constructors. To create credentials using a Google service account
    private key JSON file::

        credentials = (
            service_account.IDTokenCredentials.from_service_account_file(
                'service-account.json'))


    Or if you already have the service account file loaded::

        service_account_info = json.load(open('service_account.json'))
        credentials = (
            service_account.IDTokenCredentials.from_service_account_info(
                service_account_info))


    Both helper methods pass on arguments to the constructor, so you can
    specify additional scopes and a subject if necessary::

        credentials = (
            service_account.IDTokenCredentials.from_service_account_file(
                'service-account.json',
                scopes=['email'],
                subject='user@example.com'))


    The credentials are considered immutable. If you want to modify the scopes
    or the subject used for delegation, use :meth:`with_scopes` or
    :meth:`with_subject`::

        scoped_credentials = credentials.with_scopes(['email'])
        delegated_credentials = credentials.with_subject(subject)

    """

    def __init__(
        self,
        signer,
        service_account_email,
        token_uri,
        target_audience,
        additional_claims=None,
        quota_project_id=None,
    ):
        """
        Args:
            signer (google.auth.crypt.Signer): The signer used to sign JWTs.
            service_account_email (str): The service account's email.
            token_uri (str): The OAuth 2.0 Token URI.
            target_audience (str): The intended audience for these credentials,
                used when requesting the ID Token. The ID Token's ``aud`` claim
                will be set to this string.
            additional_claims (Mapping[str, str]): Any additional claims for
                the JWT assertion used in the authorization grant.
            quota_project_id (Optional[str]): The project ID used for quota and billing.
        .. note:: Typically one of the helper constructors
            :meth:`from_service_account_file` or
            :meth:`from_service_account_info` are used instead of calling the
            constructor directly.
        """
        super(IDTokenCredentials, self).__init__()
        self._signer = signer
        self._service_account_email = service_account_email
        self._token_uri = token_uri
        self._target_audience = target_audience
        self._quota_project_id = quota_project_id

        if additional_claims is not None:
            self._additional_claims = additional_claims
        else:
            self._additional_claims = {}

    @classmethod
    def _from_signer_and_info(cls, signer, info, **kwargs):
        """Creates a credentials instance from a signer and service account
        info.

        Args:
            signer (google.auth.crypt.Signer): The signer used to sign JWTs.
            info (Mapping[str, str]): The service account info.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.jwt.IDTokenCredentials: The constructed credentials.

        Raises:
            ValueError: If the info is not in the expected format.
        """
        kwargs.setdefault("service_account_email", info["client_email"])
        kwargs.setdefault("token_uri", info["token_uri"])
        return cls(signer, **kwargs)

    @classmethod
    def from_service_account_info(cls, info, **kwargs):
        """Creates a credentials instance from parsed service account info.

        Args:
            info (Mapping[str, str]): The service account info in Google
                format.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.service_account.IDTokenCredentials: The constructed
                credentials.

        Raises:
            ValueError: If the info is not in the expected format.
        """
        signer = _service_account_info.from_dict(
            info, require=["client_email", "token_uri"]
        )
        return cls._from_signer_and_info(signer, info, **kwargs)

    @classmethod
    def from_service_account_file(cls, filename, **kwargs):
        """Creates a credentials instance from a service account json file.

        Args:
            filename (str): The path to the service account json file.
            kwargs: Additional arguments to pass to the constructor.

        Returns:
            google.auth.service_account.IDTokenCredentials: The constructed
                credentials.
        """
        info, signer = _service_account_info.from_filename(
            filename, require=["client_email", "token_uri"]
        )
        return cls._from_signer_and_info(signer, info, **kwargs)

    def with_target_audience(self, target_audience):
        """Create a copy of these credentials with the specified target
        audience.

        Args:
            target_audience (str): The intended audience for these credentials,
            used when requesting the ID Token.

        Returns:
            google.auth.service_account.IDTokenCredentials: A new credentials
                instance.
        """
        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            token_uri=self._token_uri,
            target_audience=target_audience,
            additional_claims=self._additional_claims.copy(),
            quota_project_id=self.quota_project_id,
        )

    @_helpers.copy_docstring(credentials.CredentialsWithQuotaProject)
    def with_quota_project(self, quota_project_id):
        return self.__class__(
            self._signer,
            service_account_email=self._service_account_email,
            token_uri=self._token_uri,
            target_audience=self._target_audience,
            additional_claims=self._additional_claims.copy(),
            quota_project_id=quota_project_id,
        )

    def _make_authorization_grant_assertion(self):
        """Create the OAuth 2.0 assertion.

        This assertion is used during the OAuth 2.0 grant to acquire an
        ID token.

        Returns:
            bytes: The authorization grant assertion.
        """
        now = _helpers.utcnow()
        lifetime = datetime.timedelta(seconds=_DEFAULT_TOKEN_LIFETIME_SECS)
        expiry = now + lifetime

        payload = {
            "iat": _helpers.datetime_to_secs(now),
            "exp": _helpers.datetime_to_secs(expiry),
            # The issuer must be the service account email.
            "iss": self.service_account_email,
            # The audience must be the auth token endpoint's URI
            "aud": _GOOGLE_OAUTH2_TOKEN_ENDPOINT,
            # The target audience specifies which service the ID token is
            # intended for.
            "target_audience": self._target_audience,
        }

        payload.update(self._additional_claims)

        token = jwt.encode(self._signer, payload)

        return token

    @_helpers.copy_docstring(credentials.Credentials)
    def refresh(self, request):
        assertion = self._make_authorization_grant_assertion()
        access_token, expiry, _ = _client.id_token_jwt_grant(
            request, self._token_uri, assertion
        )
        self.token = access_token
        self.expiry = expiry

    @property
    def service_account_email(self):
        """The service account email."""
        return self._service_account_email

    @_helpers.copy_docstring(credentials.Signing)
    def sign_bytes(self, message):
        return self._signer.sign(message)

    @property
    @_helpers.copy_docstring(credentials.Signing)
    def signer(self):
        return self._signer

    @property
    @_helpers.copy_docstring(credentials.Signing)
    def signer_email(self):
        return self._service_account_email