Minimal example how to create a read only group and a time limited user in Redshift. In the example the password is defined with MD5 hash. To generate the actual value you need to concatenate the word md5 with the md5 hash of a composite string, the concatenation of the actual password and the username. For reference the password at this example…

readonly.sql

CREATE GROUP read_only;

REVOKE ALL PRIVILEGES ON ALL TABLES IN SCHEMA public FROM GROUP read_only;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO GROUP read_only;

CREATE USER
  time_limited_reader
  WITH
    PASSWORD 'md5b3d32f5a247d71dd338a1effa3976ede'
    IN GROUP read_only
    VALID UNTIL '2016-07-19'
;