使用setuptools（pip）时如何打印警告和错误

Question

我正在使用setuptools打包代码，以便可以使用以下命令轻松安装

cd project_name && pip install .

在设置过程中，我想警告用户有关预先存在的配置文件，并在系统上打印一些安装后的说明。 例如

/etc/project_name/project.conf exists. Not copying default config file.

我尝试使用print和logging.warning()但使用pip安装时仍然没有出现警告。 我感觉自己缺少明显的东西。

我们正在尝试在Redhat系列> = el6和Ubuntu> = 14.04LTS上支持3.0> python> = 2.6

Answer 1

如果您看一下pip源代码，那么在负责运行安装脚本的函数call_subprocess （ 此处的源代码 ）中，它说：

def call_subprocess(cmd, show_stdout=True, cwd=None, ...
    ...
    # The obvious thing that affects output is the show_stdout=
    # kwarg. show_stdout=True means, let the subprocess write directly to our
    # stdout. Even though it is nominally the default, it is almost never used
    # inside pip (and should not be used in new code without a very good
    # reason); as of 2016-02-22 it is only used in a few places inside the VCS
    # wrapper code. Ideally we should get rid of it entirely, because it
    # creates a lot of complexity here for a rarely used feature.
    #
    # Most places in pip set show_stdout=False. What this means is:
    # - We connect the child stdout to a pipe, which we read.
    # - By default, we hide the output but show a spinner -- unless the
    #   subprocess exits with an error, in which case we show the output.
    # - If the --verbose option was passed (= loglevel is DEBUG), then we show
    #   the output unconditionally. (But in this case we don't want to show
    #   the output a second time if it turns out that there was an error.)

简而言之，只有在以下情况下，您才能看到输出：

• 您的设置退出并出现错误，或者
• 用户使用-v （详细标志）调用pip