python中的并发执行

一. Gevent实例

import gevent
import requests
from gevent import monkey
# socket发送请求以后就会进入等待状态，gevent更改了这个机制
# socket.setblocking(False)  -->发送请求后就不会等待服务器响应
monkey.patch_all()  # 找到内置的socket并更改为gevent自己的东西

def fetch_async(method, url, req_kwargs):
    print(method, url, req_kwargs)
    response = requests.request(method=method, url=url, **req_kwargs)
    print(response.url, response.content)

# ##### 发送请求 #####
gevent.joinall([
    # 这里spawn是3个任务[实际是3个协程]，每个任务都会执行fetch_async函数
    gevent.spawn(fetch_async, method='get', url='https://www.python.org/', req_kwargs={}),
    gevent.spawn(fetch_async, method='get', url='https://www.yahoo.com/', req_kwargs={}),
    gevent.spawn(fetch_async, method='get', url='https://github.com/', req_kwargs={}),
])

二. grequests实例

grequests实际上就是封装了gevent里面的方法，然后配合requests实现异步的IO
grequests = gevent + request
grequests.map() 内部实现

import grequests  # 实际上就是requests + gevent
request_list = [
    # 发送get请求
    grequests.get('https://www.baidu.com/', timeout=10.001),
    grequests.get('https://www.taobao.com/'),
    grequests.get('https://hao.360.cn/')
]
# ##### 执行并获取响应列表 #####
response_list = grequests.map(request_list)  # 实际上内部循环执行gevent内部的joinall()方法
print(response_list)

# ##### 执行并获取响应列表（处理异常） #####
# def exception_handler(request, exception):
# print(request,exception)
#     print("Request failed")

# response_list = grequests.map(request_list, exception_handler=exception_handler)
# print(response_list)

转载至：https://www.cnblogs.com/ftl1012/p/9424822.html

三. 项目中的应用

    def user_batch_import(self, token, file, data):
        v = self._user_role(token, {})
        if "errcode" in v.keys():
            return v

        if 'user[college_id]' not in v:
            return {"errcode": 2, "errmsg": str(v)}

        import xlrd
        show_url = Graphics.upload_image(file, data["context_type"], data["content_type"])
        data_path = Graphics.format_nginx_data_url(show_url)
        book = xlrd.open_workbook(data_path)
        names = book.sheet_names()

        res = None
        for name in names:
            sheet = book.sheet_by_name(name)
            nrows = sheet.nrows  # 行
            if nrows == 0:
                print(nrows)
                continue
            else:
                q = queue.Queue(maxsize=nrows)
                threading.Thread(args=(q,))

                first_line = sheet.row_values(0)
                if first_line != ['编号', '姓名', '邮箱', '密码', '电话', '地址', '角色'] and len(first_line) != 7:
                    return {"errcode": 400, "errmsg": u"不支持此格式顺序的输入；正确格式：['编号', '姓名', '邮箱', '密码', '电话', '地址', '角色']"}

                for temp in range(1, nrows):
                    rows = sheet.row_values(temp, start_colx=0, end_colx=None)

                    if rows[6] == "老师":
                        rows[6] = "TeacherEnrollment"
                    elif rows[6] == "学生":
                        rows[6] = "StudentEnrollment"
                    elif rows[6] == "助教":
                        rows[6] = "TaEnrollment"
                    elif rows[6] == "设计者":
                        rows[6] = "DesignerEnrollment"
                    elif rows[6] == "观察者":
                        rows[6] = "ObserverEnrollment"
                    else:
                        return {"errcode": 400, "errmsg": u"所写角色不存在，可选：【老师， 学生， 助教， 观察者， 设计者】"}

                    query = {"user[name]": rows[1], "pseudonym[unique_id]": rows[2], "pseudonym[password]": rows[3],
                             "user[tel]": rows[4], "user[company]": rows[5], "user[time_zone]": "Beijing",
                             "user[locale]": "zh-Hans", "user[terms_of_use]": True, "user[role_name]": rows[6],
                             "user[college_id]": v["user[college_id]"]}

                    q.put(query)

                res = self._user_batch_import(q)
        return {"errcode": 0, "errmsg": str(res)}

    def _user_batch_import(self, q):
        from app.api.apis import very_email, very_password, very_phone
        header = {"Authorization": "Bearer %s" % AccessToken}
        request_res = []
        while q.qsize() > 0:
            query = q.get()
            if very_email(query["pseudonym[unique_id]"]) and very_phone(query["user[tel]"], "tel") and very_password(
                    query["pseudonym[password]"], "password"):
                pass
            else:
                del query

            response = grequests.post(API_CANVAS_HOST + '/api/v1/accounts/{account_id}/users'.format(account_id=1),
                                      headers=header, data=query)
            request_res.append(response)

        res = grequests.map(request_res)
        return res