Set up a read-only user in Postgresql

gistfile1.sql

CREATE ROLE readonly LOGIN PASSWORD 'some_pass';
-- Existing objects
GRANT CONNECT ON DATABASE the_db TO readonly;
GRANT USAGE ON SCHEMA public TO readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO readonly;
GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA public TO readonly;
-- New objects
ALTER DEFAULT PRIVILEGES FOR owner_user IN SCHEMA public GRANT SELECT ON TABLES TO readonly;
ALTER DEFAULT PRIVILEGES FOR owner_user IN SCHEMA public GRANT SELECT ON SEQUENCES TO readonly;
ALTER DEFAULT PRIVILEGES FOR owner_user IN SCHEMA public GRANT EXECUTE ON FUNCTIONS TO readonly;