docker + golang lib / pq“拨号TCP 127.0.0.1:5432：连接：连接被拒绝”

Question

sql.Open() wouldn't error:

if db, err = sql.Open("postgres", url); err != nil {
    return nil, fmt.Errorf("Postgres connect error : (%v)", err)
}

but db.Ping() would error:

if err = db.Ping(); err != nil {
    return nil, fmt.Errorf("Postgres ping error : (%v)", err)
}

and it was simply because the lib/pq connection string wouldn't connect from within a docker container with the seperated connection parameters.

For example:

url := fmt.Sprintf("user=%v password=%v host=%v port=%v dbname=%v",
    rs.conf.Redshift.User,
    rs.conf.Redshift.Password,
    rs.conf.Redshift.Host,
    rs.conf.Redshift.Port,
    rs.conf.Redshift.DB)