https://github.com/vpetersson/munin_pgpool
Work around patch for munin/pgpool_connections | /var/log/azumakuniyuki 2013
Python 3 対応
https://github.com/kurita0/munin_pgpool/blob/python3-support/pgpool_connections
subprocess.check_output のパラメータに text=True を追加したのでPython 3.7以降
https://docs.python.org/3/library/subprocess.html
SyntaxError: Missing parentheses in call to 'print' と言われました - Qiita
