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30天学会Python编程:23. Python代码工程化简介

hfteth 2025-07-08 18:15:26 技术文章 3 ℃

23.1 代码规范与风格

23.1.1 PEP8规范要点

23.1.2 自动化检查工具

# 安装检查工具
pip install flake8 pylint black

# 运行检查
flake8 project_dir/
pylint module.py
black --check project_dir/

23.2 单元测试

23.2.1 unittest框架

import unittest

def add(a, b):
    return a + b

class TestMath(unittest.TestCase):
    def test_add(self):
        self.assertEqual(add(2, 3), 5)
        self.assertNotEqual(add(0.1, 0.2), 0.3)  # 浮点精度问题
    
    def test_add_types(self):
        with self.assertRaises(TypeError):
            add("2", 3)

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

23.2.2 pytest高级特性

# test_math.py
import pytest

@pytest.mark.parametrize("a,b,expected", [
    (1, 2, 3),
    (0.1, 0.2, pytest.approx(0.3)),
    (-1, 1, 0)
])
def test_add(a, b, expected):
    from math_utils import add
    assert add(a, b) == expected

# 运行测试: pytest -v test_math.py

23.3 文档生成

23.3.1 docstring规范

def calculate_interest(principal, rate, years):
    """计算复利
    
    Args:
        principal (float): 本金
        rate (float): 年利率(0-1之间)
        years (int): 投资年限
        
    Returns:
        float: 最终金额
        
    Raises:
        ValueError: 当利率不在0-1范围时抛出
    """
    if not 0 <= rate <= 1:
        raise ValueError("利率必须在0到1之间")
    return principal * (1 + rate) ** years

23.3.2 Sphinx文档

# 初始化文档项目
sphinx-quickstart docs

# 配置conf.py
extensions = ['sphinx.ext.autodoc']
autodoc_default_options = {
    'members': True,
    'special-members': '__init__'
}

# 生成API文档
sphinx-apidoc -o docs/source mypackage
make html

23.4 日志管理

23.4.1 logging配置

import logging
from logging.handlers import RotatingFileHandler

def setup_logger():
    logger = logging.getLogger(__name__)
    logger.setLevel(logging.DEBUG)
    
    # 控制台Handler
    console = logging.StreamHandler()
    console.setLevel(logging.INFO)
    
    # 文件Handler(自动轮转)
    file = RotatingFileHandler(
        'app.log', maxBytes=1e6, backupCount=3
    )
    file.setLevel(logging.DEBUG)
    
    # 格式化
    fmt = '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
    formatter = logging.Formatter(fmt)
    console.setFormatter(formatter)
    file.setFormatter(formatter)
    
    # 添加Handler
    logger.addHandler(console)
    logger.addHandler(file)
    
    return logger

logger = setup_logger()
logger.info("系统初始化完成")

23.5 项目结构

23.5.1 标准项目布局

myproject/
├── docs/                   # 文档
├── tests/                  # 测试代码
├── src/                    # 源代码
│   ├── mypackage/          # 主包
│   │   ├── __init__.py
│   │   ├── module1.py
│   │   └── module2.py
│   └── scripts/            # 可执行脚本
├── .gitignore
├── pyproject.toml          # 构建配置
├── README.md
└── requirements.txt        # 依赖列表

23.5.2 模块化设计原则

  1. 单一职责:每个模块/类只做一件事
  2. 低耦合高内聚:模块间依赖最小化
  3. 明确接口:通过__all__暴露公共API
  4. 分层架构:分离业务逻辑与基础设施

23.6 打包与发布

23.6.1 项目打包配置

# pyproject.toml
[build-system]
requires = ["setuptools>=42", "wheel"]
build-backend = "setuptools.build_meta"

[project]
name = "mypackage"
version = "1.0.0"
authors = [{name = "Your Name", email = "you@example.com"}]
description = "A sample Python package"
readme = "README.md"
requires-python = ">=3.8"
classifiers = [
    "Programming Language :: Python :: 3",
    "License :: OSI Approved :: MIT License",
]

[project.urls]
Homepage = "https://github.com/you/mypackage"

23.6.2 发布到PyPI

# 构建包
python -m build

# 检查包
twine check dist/*

# 上传到PyPI
twine upload dist/*

23.7 应用举例

案例1:项目模板

# src/mypackage/core.py
"""核心业务逻辑实现"""
import logging
from typing import List

logger = logging.getLogger(__name__)

class DataProcessor:
    """数据处理引擎"""
    
    def __init__(self, config: dict):
        self.config = config
        self._setup()
    
    def _setup(self):
        """初始化资源"""
        logger.debug("初始化数据处理引擎")
        # 初始化代码...
    
    def process(self, items: List[float]) -> List[float]:
        """处理数据并返回结果"""
        if not items:
            logger.warning("收到空输入列表")
            return []
        
        try:
            result = [x * self.config['factor'] for x in items]
            logger.info(f"处理完成,共{len(result)}条数据")
            return result
        except Exception as e:
            logger.error(f"处理失败: {str(e)}")
            raise

# tests/test_core.py
import pytest
from mypackage.core import DataProcessor

class TestDataProcessor:
    @pytest.fixture
    def processor(self):
        return DataProcessor({'factor': 2})
    
    def test_process(self, processor):
        assert processor.process([1, 2, 3]) == [2, 4, 6]
    
    def test_empty_input(self, processor, caplog):
        result = processor.process([])
        assert result == []
        assert "收到空输入列表" in caplog.text

案例2:CI/CD集成

# .github/workflows/ci.yml
name: Python CI

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ["3.8", "3.9", "3.10"]
    
    steps:
    - uses: actions/checkout@v2
    
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v2
      with:
        python-version: ${{ matrix.python-version }}
    
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        pip install flake8 pytest pytest-cov
        pip install -e .
    
    - name: Lint with flake8
      run: flake8 src tests
    
    - name: Run tests
      run: pytest --cov=src --cov-report=xml tests/
    
    - name: Upload coverage
      uses: codecov/codecov-action@v1

23.8 知识图谱

23.9 学习总结

核心要点

  • 严格遵守PEP8规范
  • 全面覆盖单元测试
  • 完善的文档体系
  • 合理的项目结构

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