import psycopg2
from psycopg2.extras import DictCursor
from psycopg2 import IntegrityError

def dbconn(dbname):
    if dbname == 'etdb':
        dbname = 'ET'
        user_name = 'et_user'
    else:
        user_name = dbname[:-2] + '_user'
    return psycopg2.connect(database=dbname,
                        user=user_name,
                        host="debian",
                        cursor_factory=DictCursor)

def with_connection(dbname):
    def decorator(f):
        conn = dbconn(dbname)
        def with_connection_(*args, **kwargs):
            # or use a pool, or a factory function...
            try:
                rv = f(conn, *args, **kwargs)
            except Exception as e:
                print(e)
                conn.rollback()
            else:
                return rv
        return with_connection_
    return decorator

@with_connection('etdb')
def query_db(conn, sqlstr, params=None, one=True):
    with conn.cursor() as c:
        if params:
            c.execute(sqlstr, params)
        else:
            c.execute(sqlstr)
        conn.commit()
        r = c.fetchone() if one else c.fetchall()
    return r