Added support for OAuth 2 authentication. Fixes #5940

Initial patch sent by: Florian Sabonchi

docs/en_US/getting_started.rst

@@ -37,6 +37,7 @@ Mode is pre-configured for security.
    change_user_password
    ldap
    kerberos
+   oauth2
 
 
 .. note:: Pre-compiled and configured installation packages are available for

docs/en_US/kerberos.rst

@@ -34,6 +34,7 @@ from *config.py* file and modify the values for the following parameters.
    Please note that if it is not set, it will take the value of
    *default_server* parameter."
 
+
 Keytab file for HTTP Service
 ============================
 
@@ -116,3 +117,13 @@ PostgreSQL Server settings to configure Kerberos Authentication
 
 * Note that, you have to login into pgAdmin with Kerberos authentication to
   then connect to PostgreSQL using Kerberos.
+
+
+Master Password
+===============
+
+In the multi user mode, pgAdmin uses user's login password to encrypt/decrypt the PostgreSQL server password.
+In the Kerberos authentication, the pgAdmin user does not have the password, so we need an encryption key to store
+the PostgreSQL server password for the servers which are not configured to use the Kerberos authentication.
+To accomplish this, set the configuration parameter MASTER_PASSWORD to *True*, so upon setting the master password,
+it will be used as an encryption key while storing the password. If it is False, the server password can not be stored.

docs/en_US/oauth2.rst

@@ -0,0 +1,61 @@
+.. _oauth2:
+
+*****************************************
+`Enabling OAUTH2 Authentication`:index:
+*****************************************
+
+
+To enable OAUTH2 authentication for pgAdmin, you must configure the OAUTH2
+settings in the *config_local.py* or *config_system.py* file (see the
+:ref:`config.py <config_py>` documentation) on the system where pgAdmin is
+installed in Server mode. You can copy these settings from *config.py* file
+and modify the values for the following parameters:
+
+
+.. csv-table::
+   :header: "**Parameter**", "**Description**"
+   :class: longtable
+   :widths: 35, 55
+
+   "AUTHENTICATION_SOURCES", "The default value for this parameter is *internal*.
+   To enable OAUTH2 authentication, you must include *oauth2* in the list of values
+   for this parameter. you can modify the value as follows:
+
+   * [‘oauth2’, ‘internal’]: pgAdmin will display an additional button for authenticating with oauth2"
+    "OAUTH2_NAME", "The name of the Oauth2 provider, ex: Google, Github"
+    "OAUTH2_DISPLAY_NAME", "Oauth2 display name in pgAdmin"
+    "OAUTH2_CLIENT_ID", "Oauth2 Client ID"
+    "OAUTH2_CLIENT_SECRET", "Oauth2 Client Secret"
+    "OAUTH2_TOKEN_URL", "Oauth2 Access Token endpoint"
+    "OAUTH2_AUTHORIZATION_URL", "Endpoint for user authorization"
+    "OAUTH2_API_BASE_URL", "Oauth2 base URL endpoint to make requests simple, ex: *https://api.github.com/*"
+    "OAUTH2_USERINFO_ENDPOINT", "User Endpoint, ex: *user* (for github) and *useinfo* (for google)"
+    "OAUTH2_ICON", "The Font-awesome icon to be placed on the oauth2 button,  ex: fa-github"
+    "OAUTH2_BUTTON_COLOR", "Oauth2 button color"
+    "OAUTH2_AUTO_CREATE_USER", "Set the value to *True* if you want to automatically
+    create a pgAdmin user corresponding to a successfully authenticated Oauth2 user.
+    Please note that password is not stored in the pgAdmin database."
+
+Redirect URL
+============
+
+The redirect url to configure Oauth2 server is *http://<pgAdmin Server URL>/oauth2/authorize*
+
+Master Password
+===============
+
+In the multi user mode, pgAdmin uses user's login password to encrypt/decrypt the PostgreSQL server password.
+In the Oauth2 authentication, the pgAdmin does not store the user's password, so we need an encryption key to store
+the PostgreSQL server password.
+To accomplish this, set the configuration parameter MASTER_PASSWORD to *True*, so upon setting the master password,
+it will be used as an encryption key while storing the password. If it is False, the server password can not be stored.
+
+
+Login Page
+============
+
+After configuration, on restart, you can see the login page with the Oauth2 login button(s).
+
+.. image:: images/oauth2_login.png
+    :alt: Oauth2 login
+    :align: center

docs/en_US/release_notes_5_5.rst

@@ -12,6 +12,7 @@ New features
 | `Issue #1975 <https://redmine.postgresql.org/issues/1975>`_ -  Highlighted long running queries on the dashboards.
 | `Issue #3893 <https://redmine.postgresql.org/issues/3893>`_ -  Added support for Reassign/Drop Owned for login roles.
 | `Issue #3920 <https://redmine.postgresql.org/issues/3920>`_ -  Do not block the query editor window when running a query.
+| `Issue #5940 <https://redmine.postgresql.org/issues/5940>`_ -  Added support for OAuth 2 authentication.
 | `Issue #6559 <https://redmine.postgresql.org/issues/6559>`_ -  Added option to provide maximum width of the column when 'Resize by data?’ option in the preferences is set to True.
 
 Housekeeping