如何从 Python subprocess.check_output() 捕获异常输出?

2022-01-18 00:00:00 python subprocess bash

问题描述

我正在尝试从 Python 中进行比特币支付.在 bash 中，我通常会这样做:

I'm trying to do a Bitcoin payment from within Python. In bash I would normally do this:

bitcoin sendtoaddress <bitcoin address> <amount>

例如:

bitcoin sendtoaddress 1HoCUcbK9RbVnuaGQwiyaJGGAG6xrTPC9y 1.4214

如果成功，我会得到一个交易 ID 作为输出，但如果我尝试转移一个大于我的比特币余额的金额，我会得到以下输出:

If it is successful I get a transaction id as output, but if I try to transfer an amount larger than my bitcoin balance, I get the following output:

error: {"code":-4,"message":"Insufficient funds"}

在我的 Python 程序中，我现在尝试按如下方式付款:

In my Python program I now try to do the payment as follows:

import subprocess

try:
    output = subprocess.check_output(['bitcoin', 'sendtoaddress', address, str(amount)])
except:
    print "Unexpected error:", sys.exc_info()

如果有足够的余额，它可以正常工作，但如果没有足够的余额，sys.exc_info() 会打印出来:

If there's enough balance it works fine, but if there's not enough balance sys.exc_info() prints out this:

(<class 'subprocess.CalledProcessError'>, CalledProcessError(), <traceback object at 0x7f339599ac68>)

它不包括我在命令行上遇到的错误.所以我的问题是；如何从 Python 中获取输出的错误({code":-4,message":Insufficient fund"})?

It doesn't include the error which I get on the command line though. So my question is; how can I get the outputted error ({"code":-4,"message":"Insufficient funds"}) from within Python?

解决方案

根据subprocess.check_output() docs，错误引发的异常有一个 output 属性，可用于访问错误详细信息:

According to the subprocess.check_output() docs, the exception raised on error has an output attribute that you can use to access the error details:

try:
    subprocess.check_output(...)
except subprocess.CalledProcessError as e:
    print(e.output)

然后您应该能够分析此字符串并使用 json 模块解析错误详细信息:

You should then be able to analyse this string and parse the error details with the json module:

if e.output.startswith('error: {'):
    error = json.loads(e.output[7:]) # Skip "error: "
    print(error['code'])
    print(error['message'])

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