Source code for swh.auth.keycloak

# Copyright (C) 2020-2021  The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU Affero General Public License version 3, or any later version
# See top-level LICENSE file for more information

import json
from typing import Any, Dict, Optional
from urllib.parse import urlencode

# add ExpiredSignatureError alias to avoid leaking jose import
# in swh-auth client code
from jose.jwt import ExpiredSignatureError  # noqa
from keycloak import KeycloakOpenID

# add KeycloakError alias to avoid leaking keycloak import
# in swh-auth client code
from keycloak.exceptions import KeycloakError  # noqa

from swh.core.config import load_from_envvar


[docs]class KeycloakOpenIDConnect: """ Wrapper class around python-keycloak to ease the interaction with Keycloak for managing authentication and user permissions with OpenID Connect. """ def __init__( self, server_url: str, realm_name: str, client_id: str, realm_public_key: str = "", ): """ Args: server_url: URL of the Keycloak server realm_name: The realm name client_id: The OpenID Connect client identifier realm_public_key: The realm public key (will be dynamically retrieved if not provided) """ self._keycloak = KeycloakOpenID( server_url=server_url, client_id=client_id, realm_name=realm_name, ) self.server_url = server_url self.realm_public_key = realm_public_key @property def realm_name(self): return self._keycloak.realm_name @realm_name.setter def realm_name(self, value): self._keycloak.realm_name = value @property def client_id(self): return self._keycloak.client_id @client_id.setter def client_id(self, value): self._keycloak.client_id = value
[docs] def well_known(self) -> Dict[str, Any]: """ Retrieve the OpenID Connect Well-Known URI registry from Keycloak. Returns: A dictionary filled with OpenID Connect URIS. """ return self._keycloak.well_know()
[docs] def authorization_url(self, redirect_uri: str, **extra_params: str) -> str: """ Get OpenID Connect authorization URL to authenticate users. Args: redirect_uri: URI to redirect to once a user is authenticated extra_params: Extra query parameters to add to the authorization URL """ auth_url = self._keycloak.auth_url(redirect_uri) if extra_params: auth_url += "&%s" % urlencode(extra_params) return auth_url
[docs] def authorization_code( self, code: str, redirect_uri: str, **extra_params: str ) -> Dict[str, Any]: """ Get OpenID Connect authentication tokens using Authorization Code flow. Raises: KeycloakError in case of authentication failures Args: code: Authorization code provided by Keycloak redirect_uri: URI to redirect to once a user is authenticated (must be the same as the one provided to authorization_url): extra_params: Extra parameters to add in the authorization request payload. """ return self._keycloak.token( grant_type="authorization_code", code=code, redirect_uri=redirect_uri, **extra_params, )
[docs] def login( self, username: str, password: str, scope: str = "openid", **extra_params: str ) -> Dict[str, Any]: """ Get OpenID Connect authentication tokens using Direct Access Grant flow. Raises: KeycloakError in case of authentication failures Args: username: an existing username in the realm password: password associated to username extra_params: Extra parameters to add in the authorization request payload. """ return self._keycloak.token( grant_type="password", scope=scope, username=username, password=password, **extra_params, )
[docs] def refresh_token(self, refresh_token: str) -> Dict[str, Any]: """ Request a new access token from Keycloak using a refresh token. Args: refresh_token: A refresh token provided by Keycloak Returns: A dictionary filled with tokens info """ return self._keycloak.refresh_token(refresh_token)
[docs] def decode_token( self, token: str, options: Optional[Dict[str, Any]] = None ) -> Dict[str, Any]: """ Try to decode a JWT token. Args: token: A JWT token to decode options: Options for jose.jwt.decode Returns: A dictionary filled with decoded token content """ if not self.realm_public_key: realm_public_key = self._keycloak.public_key() self.realm_public_key = "-----BEGIN PUBLIC KEY-----\n" self.realm_public_key += realm_public_key self.realm_public_key += "\n-----END PUBLIC KEY-----" return self._keycloak.decode_token( token, key=self.realm_public_key, options=options )
[docs] def logout(self, refresh_token: str) -> None: """ Logout a user by closing its authenticated session. Args: refresh_token: A refresh token provided by Keycloak """ self._keycloak.logout(refresh_token)
[docs] def userinfo(self, access_token: str) -> Dict[str, Any]: """ Return user information from its access token. Args: access_token: An access token provided by Keycloak Returns: A dictionary fillled with user information """ return self._keycloak.userinfo(access_token)
[docs] @classmethod def from_config(cls, **kwargs: Any) -> "KeycloakOpenIDConnect": """Instantiate a KeycloakOpenIDConnect class from a configuration dict. Args: kwargs: configuration dict for the instance, with one keycloak key, whose value is a Dict with the following keys: - server_url: URL of the Keycloak server - realm_name: The realm name - client_id: The OpenID Connect client identifier Returns: the KeycloakOpenIDConnect instance """ cfg = kwargs["keycloak"] return cls( server_url=cfg["server_url"], realm_name=cfg["realm_name"], client_id=cfg["client_id"], )
[docs] @classmethod def from_configfile(cls, **kwargs: Any) -> "KeycloakOpenIDConnect": """Instantiate a KeycloakOpenIDConnect class from the configuration loaded from the SWH_CONFIG_FILENAME envvar, with potential extra keyword arguments if their value is not None. Args: kwargs: kwargs passed to instantiation call Returns: the KeycloakOpenIDConnect instance """ config = dict(load_from_envvar()).get("keycloak", {}) config.update({k: v for k, v in kwargs.items() if v is not None}) return cls.from_config(keycloak=config)
[docs]def keycloak_error_message(keycloak_error: KeycloakError) -> str: """Transform a keycloak exception into an error message. """ try: # keycloak error wrapped in a JSON document msg_dict = json.loads(keycloak_error.error_message.decode()) error_msg = msg_dict["error"] error_desc = msg_dict.get("error_description") if error_desc: error_msg = f"{error_msg}: {error_desc}" return error_msg except Exception: # fallback: return error message string return keycloak_error.error_message