学习日记-2019529

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Flask脚本服务搭建、基于上下文环境的处理、Python从列表中随机抽取若干元素、Python中format格式化输出、Python多进程

【来源】https://www.u3v3.com/

学习日记 2019/5/29

Flask脚本服务搭建

flasky.py

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import os
from dotenv import load_dotenv

dotenv_path = os.path.join(os.path.dirname(__file__), '.env')
if os.path.exists(dotenv_path):
    load_dotenv(dotenv_path)

COV = None
if os.environ.get('FLASK_COVERAGE'):
    import coverage
    COV = coverage.coverage(branch=True, include='app/*')
    COV.start()

import sys
import click
from flask_migrate import Migrate, upgrade
from app import create_app, db
from app.models import User, Follow, Role, Permission, Post, Comment

app = create_app(os.getenv('FLASK_CONFIG') or 'default')
migrate = Migrate(app, db)


@app.shell_context_processor
def make_shell_context():
    return dict(db=db, User=User, Follow=Follow, Role=Role,
                Permission=Permission, Post=Post, Comment=Comment)


@app.cli.command()
@click.option('--coverage/--no-coverage', default=False,
              help='Run tests under code coverage.')
def test(coverage):
    """Run the unit tests."""
    if coverage and not os.environ.get('FLASK_COVERAGE'):
        import subprocess
        os.environ['FLASK_COVERAGE'] = '1'
        sys.exit(subprocess.call(sys.argv))

    import unittest
    tests = unittest.TestLoader().discover('tests')
    unittest.TextTestRunner(verbosity=2).run(tests)
    if COV:
        COV.stop()
        COV.save()
        print('Coverage Summary:')
        COV.report()
        basedir = os.path.abspath(os.path.dirname(__file__))
        covdir = os.path.join(basedir, 'tmp/coverage')
        COV.html_report(directory=covdir)
        print('HTML version: file://%s/index.html' % covdir)
        COV.erase()


@app.cli.command()
@click.option('--length', default=25,
              help='Number of functions to include in the profiler report.')
@click.option('--profile-dir', default=None,
              help='Directory where profiler data files are saved.')
def profile(length, profile_dir):
    """Start the application under the code profiler."""
    from werkzeug.contrib.profiler import ProfilerMiddleware
    app.wsgi_app = ProfilerMiddleware(app.wsgi_app, restrictions=[length],
                                      profile_dir=profile_dir)
    app.run()


@app.cli.command()
def deploy():
    """Run deployment tasks."""
    # migrate database to latest revision
    upgrade()

    # create or update user roles
    Role.insert_roles()

    # ensure all users are following themselves
    User.add_self_follows()

if __name__ == '__main__':
    app.cli()

运行文件

python flasky.py

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(microvenv) [root@iz2ze8rern8nx1sglo8ub1z microblog]# python flasky.py
Usage: flasky.py [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  deploy   Run deployment tasks.
  profile  Start the application under the code...
  test     Run the unit tests.#新添加的内容

python flasky.py test

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(microvenv) [root@iz2ze8rern8nx1sglo8ub1z microblog]# python flasky.py test
test_password_setter (test_user_model.UserModelTestCase) ... ok

----------------------------------------------------------------------
Ran 1 test in 0.447s

OK

基于上下文环境的处理

在 create_app内做Flask相关的初始化，将这部分资源处理置于独立的模块中, 使用的时候直接引入, 在模块第一次引入的时候就完成了资源的连接处理, 但总有一些还是需要运行前要执行的内容, 比如应用参数设置。

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def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])
    config[config_name].init_app(app)

    bootstrap.init_app(app)
    mail.init_app(app)
    moment.init_app(app)
    db.init_app(app)
    login_manager.init_app(app)
    pagedown.init_app(app)

    if app.config['SSL_REDIRECT']:
        from flask_sslify import SSLify
        sslify = SSLify(app)

    from .main import main as main_blueprint
    app.register_blueprint(main_blueprint)

    from .auth import auth as auth_blueprint
    app.register_blueprint(auth_blueprint, url_prefix='/auth')

    from .api import api as api_blueprint
    app.register_blueprint(api_blueprint, url_prefix='/api/v1')

    return app

Python从列表中随机抽取若干元素

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import random
x = [283,238,46,57,82,976]
random.choice(x)
random.sample(x,3)
#从某个范围内获取若干个
random.sample(range(100000),30)
#选取随机字符
random.choice('abcdrfgsfffgr')
#生成随机整数
random.randint(100,200)
#生成随机偶数
random.randrange(0,99,2)
#生成0-1随机浮点数
random.random()

Python中format格式化输出

通过key名填充字符

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print('My Name is {name},Age is {age}'.format(name=name,age=age))

通过字典的方式作参数传递

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params = {'name':name,'age':age}
print('My Name is {name},Age is {age}'.format(**params))

将tuple作为可变参数传递特性

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params=('Tony',18)
print('My Name is {0},Age is {1},And Your Age is {1}'.format(*params))

字符对齐

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print('{:>10},{:>10}'.format('tony',18))#左对齐
#右对齐<
#居中对齐^

数字格式化

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#十进制转
#二进制
print('{:b}'.format(x))
#八进制
print('{:o}'.format(x))
#十六进制
print('{:x}'.format(x))

浮点数精度控制

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pi = 3.1415926
print('{:.2f}'.format(pi))#保留两位小数3.14

三层{}可以转义

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print('{{{0:.2f}}}'.format(pi))#{3.14}

Python多进程

  • 进程创建

unix下使用fork方式创建子进程

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Process 24896 start ... 
This is Father process,And Its child pid is 24897
This is child process and my pid is 24897,my father process is 1
#子进程fork的结果总是0，可以用来作为区分父子进程的标志

变量在多进程之间并没有什么影响

windows下实现多进程用到了multiprocessing

pro = Process(target=pro_do,args=("test","dev"))

pro.start()

是否阻塞方式执行，如果有则阻塞，否则非阻塞

pro.join()

可以通过Pool进程池创建多个进程，可以指定启动的子进程数量

  • 进程间通信

父进程可以指定子进程执行的方法及参数，达到父进程向子进程单项通信

子进程可以通过Queue方式向父进程通信write_queue，read_queue

两个进程间的通信可以使用Pipe形式send_pipe，recv_pipe