dsn2pgpass.py

#!/usr/bin/env python

import fileinput
import urllib.parse


urllib.parse.uses_netloc.append("postgres")
dsn = next(fileinput.input()).strip()
url = urllib.parse.urlparse(dsn)

pgpass = "{hostname}:{port}:{database}:{username}:{password}".format(
    database=url.path[1:],
    username=url.username,
    password=url.password,
    hostname=url.hostname,
    port=url.port
)

pgpass_dsn = "postgres://{username}@{hostname}:{port}/{database}".format(
    database=url.path[1:],
    username=url.username,
    hostname=url.hostname,
    port=url.port    
)

print("""cat >> ~/.pgpass << EOF
{}
EOF""".format(pgpass)
)

print("%sql {}".format(pgpass_dsn))