Pylint报import-error无法导入machinetranslation.translator模块

问题场景 #

编写翻译功能单元测试时，需要导入同目录下machinetranslation包translator模块内的english_to_french、french_to_english两个函数，编写导入语句后Pylint持续抛出Unable to import 'machinetranslation.translator'pylint(import-error)错误，移除导入路径中的machinetranslation前缀直接导入translator，仍然触发相同报错。

相关代码 #

单元测试文件代码 #

import unittest

from machinetranslation.translator import english_to_french, french_to_english

class TestMyModule(unittest.TestCase):

    def test_english_to_french(self):

        self.assertNotEqual(english_to_french("None"), "")

        self.assertEqual(english_to_french('Hello'), 'Bonjour')

    def test_french_to_english(self):

        self.assertNotEqual(french_to_english("None"), "")

        self.assertEqual(french_to_english('Bonjour'), 'Hello')

if __name__ == '__main__':
    unittest.main()

translator.py模块代码 #

import os
import json
import six
from dotenv import load_dotenv
from google.cloud import translate


#Api key and url


apikey = os.environ['AIzaSyC8ZLEGytCqTMcqvFV0AVh0wCEgBkRlHr4']

url = os.environ['https://console.cloud.google.com/apis/credentials?project=ferrous-amphora-352613']

#Translates english to french
# Initialize Translation client
def english_to_french(english_text="Hello", project_id="ferrous-amphora-352613"):

    client = translate.TranslationServiceClient()

    location = "global"

    parent = f"projects/{'ferrous-amphora-352613'}/locations/{'My First Project'}"

    # Translate text from English to French
    response = client.translate_text(
        request={
            "location": location,
            "parent": parent,
            "contents": [english_text],
            "mime_type": "text/plain",
            "source_language_code": "en-US",
            "target_language_code": "fr",
        }
    )

    # Display the translation for each input text provided
    for translation in response.translations:
        print("Translated text: {}".format(translation.translated_text))



# Translates french to english
# Initialize Translation client
def french_to_english(french_text="Bonjour", project_id="ferrous-amphora-352613"):
    """Translating Text."""

    client = translate.TranslationServiceClient()

    location = "global"

    parent = f"projects/{'ferrous-amphora-352613'}/locations/{'MyFirstProject'}"

    # Translate text from English to French
    response = client.translate_text(
        request={
            "location": location,
            "parent": parent,
            "contents": [french_text],
            "mime_type": "text/plain",
            "source_language_code": "fr",
            "target_language_code": "en",
        }
    )

    # Display the translation for each input text provided
    for translation in response.translations:
        print("Translated text: {}".format(translation.translated_text))


if __name__ == "__main__":
    pass

问题原因与修复方案 #

该问题不是单一原因导致，既包含Pylint配置问题，也存在代码本身的写法错误，分别修复即可：

1. Pylint导入报错修复 #

Pylint默认不会自动将当前项目目录加入Python模块搜索路径，同时如果包目录缺少标识文件也会导致识别失败，按以下步骤排查：

• 确认machinetranslation目录下存在名为__init__.py的空文件，该文件是Python识别目录为可导入包的必要标识，缺少该文件时无论怎么写导入语句都会失败。
• 配置Pylint搜索路径：在项目根目录新建.pylintrc文件，写入以下配置，将当前工作目录加入模块搜索路径：

[MASTER]
init-hook='import sys; sys.path.append(".")'

• 如果使用VS Code等IDE，也可以直接在编辑器的Pylint扩展设置中，给Pylint添加启动参数--init-hook="import sys; sys.path.append('.')"，不需要单独写配置文件。

2. 代码运行时错误修复 #

就算解决Pylint报错，现有代码运行时也会直接抛出异常，需要同步修复以下问题：

• 环境变量读取写法错误：os.environ['key']的作用是读取系统中已配置的、key为传入参数的环境变量，直接把API Key、URL作为key传入会直接触发KeyError。如果不需要读取系统环境变量，直接给变量赋值即可：

# 修正后
apikey = "AIzaSyC8ZLEGytCqTMcqvFV0AVh0wCEgBkRlHr4"
url = "https://console.cloud.google.com/apis/credentials?project=ferrous-amphora-352613"

• 翻译函数无返回值：两个翻译函数目前仅打印翻译结果，没有return语句返回值，单元测试的断言逻辑拿到的永远是None，会直接断言失败。需要在打印逻辑后添加返回值：

# 以english_to_french为例，修改遍历结果部分
for translation in response.translations:
    translated_res = translation.translated_text
    print("Translated text: {}".format(translated_res))
    return translated_res

french_to_english函数按相同逻辑添加返回值即可。

• Google Cloud接口parent参数格式错误：parent参数格式要求为projects/{项目ID}/locations/{服务区域}，你已经将location设为global，parent里的locations值应该和location参数保持一致，不能写自定义的项目名称，修正后写法：

parent = f"projects/{project_id}/locations/global"

内容的提问来源于stack exchange，提问作者MashCode20