Flask怎么實現(xiàn)異步執(zhí)行任務(wù)？

from flask import Flask
from time import sleep
from concurrent.futures import ThreadPoolExecutor
# DOCS https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.ThreadPoolExecutor
# 創(chuàng)建線程池執(zhí)行器
executor = ThreadPoolExecutor(2)
app = Flask(__name__)
@app.route('/jobs')
def run_jobs():
 # 交由線程去執(zhí)行耗時任務(wù)
 executor.submit(long_task, 'hello', 123)
 return 'long task running.'
# 耗時任務(wù)
def long_task(arg1, arg2):
 print("args: %s %s!" % (arg1, arg2))
 sleep(5)
 print("Task is done!")
if __name__ == '__main__':
 app.run()

pip install celery
pip install redis

from flask import Flask
from celery import Celery
app = Flask(__name__)
# 配置
# 配置消息代理的路徑，如果是在遠(yuǎn)程服務(wù)器上，則配置遠(yuǎn)程服務(wù)器中redis的URL
app.config['CELERY_BROKER_URL'] = 'redis://localhost:6379/0'
# 要存儲 Celery 任務(wù)的狀態(tài)或運行結(jié)果時就必須要配置
app.config['CELERY_RESULT_BACKEND'] = 'redis://localhost:6379/0'
# 初始化Celery
celery = Celery(app.name, broker=app.config['CELERY_BROKER_URL'])
# 將Flask中的配置直接傳遞給Celery
celery.conf.update(app.config)
 

@celery.task
def long_task(arg1, arg2):
 # 耗時任務(wù)的邏輯
 return result

@app.route('/', methods=['GET', 'POST'])
def index():
 task = long_task.delay(1, 2)
delay () 方法是 applyasync () 方法的快捷方式，applyasync () 參數(shù)更多，可以更加細(xì)致的控制耗時任務(wù)，比如想要 long_task () 在一分鐘后再執(zhí)行
@app.route('/', methods=['GET', 'POST'])
def index():
 task = long_task.apply_async(args=[1, 2], countdown=60)

# bind為True，會傳入self給被裝飾的方法
@celery.task(bind=True)
def long_task(self):
 verb = ['Starting up', 'Booting', 'Repairing', 'Loading', 'Checking']
 adjective = ['master', 'radiant', 'silent', 'harmonic', 'fast']
 noun = ['solar array', 'particle reshaper', 'cosmic ray', 'orbiter', 'bit']
 message = ''
 total = random.randint(10, 50)
 for i in range(total):
 if not message or random.random() < 0.25:
 # 隨機(jī)的獲取一些信息
 message = '{0} {1} {2}...'.format(random.choice(verb),
 random.choice(adjective),
 random.choice(noun))
 # 更新Celery任務(wù)狀態(tài)
 self.update_state(state='PROGRESS',
 meta={'current': i, 'total': total,
 'status': message})
 time.sleep(1)
 # 返回字典
 return {'current': 100, 'total': 100, 'status': 'Task completed!',
 'result': 42}

@app.route('/longtask', methods=['POST'])
def longtask():
 # 異步調(diào)用
 task = long_task.apply_async()
 # 返回 202，與Location頭
 return jsonify({}), 202, {'Location': url_for('taskstatus',
 task_id=task.id)}

@app.route('/status/<task_id>')
def taskstatus(task_id):
 task = long_task.AsyncResult(task_id)
 if task.state == 'PENDING': # 在等待
 response = {
 'state': task.state,
 'current': 0,
 'total': 1,
 'status': 'Pending...'
 }
 elif task.state != 'FAILURE': # 沒有失敗
 response = {
 'state': task.state, # 狀態(tài)
 # meta中的數(shù)據(jù)，通過task.info.get()可以獲得
 'current': task.info.get('current', 0), # 當(dāng)前循環(huán)進(jìn)度
 'total': task.info.get('total', 1), # 總循環(huán)進(jìn)度
 'status': task.info.get('status', '')
 }
 if 'result' in task.info:
 response['result'] = task.info['result']
 else:
 # 后端執(zhí)行任務(wù)出現(xiàn)了一些問題
 response = {
 'state': task.state,
 'current': 1,
 'total': 1,
 'status': str(task.info), # 報錯的具體異常
 }
 return jsonify(response)

var options = {
 classname: 'my-class',
 id: 'my-id',
 // 進(jìn)度條要出現(xiàn)的位置
 target: document.getElementById('myDivId')
};
// 初始化進(jìn)度條對象
var nanobar = new Nanobar( options );
nanobar.go( 30 ); // 30% 進(jìn)度條
nanobar.go( 76 ); // 76% 進(jìn)度條
// 100% 進(jìn)度條，進(jìn)度條結(jié)束
nanobar.go(100);

<h2>Long running task with progress updates</h2>
<button id="start-bg-job">Start Long Calculation</button><br><br>
<div id="progress"></div>

// 按鈕點擊事件
$(function() {
 $('#start-bg-job').click(start_long_task);
 });
// 請求 longtask 接口
function start_long_task() {
 // 添加元素在html中
 div = $('<div class="progress"><div></div><div>0%</div><div>...</div><div> </div></div><hr>');
 $('#progress').append(div);
 // 創(chuàng)建進(jìn)度條對象
 var nanobar = new Nanobar({
 bg: '#44f',
 target: div[0].childNodes[0]
 });
 // ajax請求longtask
 $.ajax({
 type: 'POST',
 url: '/longtask',
 // 獲得數(shù)據(jù)，從響應(yīng)頭中獲取Location
 success: function(data, status, request) {
 status_url = request.getResponseHeader('Location');
 // 調(diào)用 update_progress() 方法更新進(jìn)度條
 update_progress(status_url, nanobar, div[0]);
 },
 error: function() {
 alert('Unexpected error');
 }
 });
 }
// 更新進(jìn)度條
function update_progress(status_url, nanobar, status_div) {
 // getJSON()方法是JQuery內(nèi)置方法，這里向Location中對應(yīng)的url發(fā)起請求，即請求「/status/<task_id>」
 $.getJSON(status_url, function(data) {
 // 計算進(jìn)度
 percent = parseInt(data['current'] * 100 / data['total']);
 // 更新進(jìn)度條
 nanobar.go(percent);
 // 更新文字
 $(status_div.childNodes[1]).text(percent + '%');
 $(status_div.childNodes[2]).text(data['status']);
 if (data['state'] != 'PENDING' && data['state'] != 'PROGRESS') {
 if ('result' in data) {
 // 展示結(jié)果
 $(status_div.childNodes[3]).text('Result: ' + data['result']);
 }
 else {
 // 意料之外的事情發(fā)生
 $(status_div.childNodes[3]).text('Result: ' + data['state']);
 }
 }
 else {
 // 2秒后再次運行
 setTimeout(function() {
 update_progress(status_url, nanobar, status_div);
 }, 2000);
 }
 }); 
 } 

redis-server

celery worker -A app.celery --loglevel=info

python app.py