Python 子进程模块 |带密码的 Postgres pg_dump

Question

我有一个数据库，我想用我的 python 代码备份它。

我试图将我的代码基于 this discussion 中的代码使用子进程模块和 pg_dump。我现在的问题是我必须手动输入密码才能获取备份文件。我在某处读到过执行 .pgpass 但我确实想看看是否可以在 subprocess 模块中执行此操作。

我的代码如下:

from subprocess import Popen, PIPE
from pathlib import Path, PureWindowsPath

def backup():
    version = 11
    postgresDir = Path("C:/Program Files/PostgreSQL/{}/bin/".format(version))
    directory = PureWindowsPath(postgresDir)
    filename = 'myBackUp2'  # output filename here
    saveDir = Path("D:/Desktop/{}.tar".format(filename))  # output directory here
    file = PureWindowsPath(saveDir)

    host = 'localhost'
    user = 'postgres'
    port = '5434'
    dbname = 'database_name'  # database name here
    proc = Popen(['pg_dump', '-h', host, '-U', user, '-W', '-p', port,
                   '-F', 't', '-f', str(file), '-d', dbname],
                    cwd=directory, shell=True, stdin=PIPE)
    proc.wait()

backup()

上面的代码有效，我输入密码就创建了备份。我尝试用下面的代码替换 proc.wait() 以消除手动输入密码的需要:

return proc.communicate('{}\n'.format(database_password))

但是我会收到这个错误:

TypeError: a bytes-like object is required, not 'str'

这可以在子流程中完成吗？如果是，怎么办？

Answer 1

使用a password file.

On Microsoft Windows the file is named %APPDATA%\postgresql\pgpass.conf (where %APPDATA% refers to the Application Data subdirectory in the user's profile).

和-w 或--no-password command line option (而不是 -W)

-w

--no-password

Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as a .pgpass file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to enter a password.