public URI getAuthorizationEndpoint() throws GuacamoleException {
        return environment.getRequiredProperty(OPENID_AUTHORIZATION_ENDPOINT);
    }
Returns the authorization endpoint (URI) of the OpenID service as
configured with guacamole.properties.

@return
    The authorization endpoint of the OpenID service, as configured with
    guacamole.properties.

@throws GuacamoleException
    If guacamole.properties cannot be parsed, or if the authorization
    endpoint property is missing.
extensions/guacamole-auth-sso/modules/guacamole-auth-sso-openid/src/main/java/org/apache/guacamole/auth/openid/conf/ConfigurationService.java