[Access Environment Variables With Postgres] Use environment variables with postgresql #postgres

pg_env_vars.sql

-- Before starting postgres server
-- export ENVNAME='whatever'
-- pg_ctl -D /usr/local/var/postgres [etc...] start

DROP TABLE IF EXISTS env;
DROP TABLE IF EXISTS env_tmp;
CREATE TEMP TABLE env_tmp(e text);
CREATE TEMP TABLE env(k text, v text);

COPY env_tmp ( e ) FROM PROGRAM 'env';

INSERT INTO env
SELECT (regexp_split_to_array(e,'={1,1}'))[1],
  (regexp_match(e, '={1,1}(.*)'))[1]
FROM env_tmp;

SELECT * FROM env WHERE k = 'ENVNAME';