如何从零开始编写、搭建和部署一个基于Python的Web应用程序

request->"hello world"->response

mkdir todo
cd todo
virtualenv venv
source venv/bin/activate
pip install flask
touch server.py

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

from flask import Flask, jsonify

app = Flask(__name__)

@app.route('/index')
def index():
    return jsonify(msg='hello world')

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8000)

python server.py
* Running on http://0.0.0.0:8000/ (Press CTRL+C to quit)

{
  "msg": "hello world"
}

from flask import Flask, jsonify, request, abort, Response
from time import time
from uuid import uuid4
import json

app = Flask(__name__)

class Todo(object):
    def __init__(self, content):
        self.id = str(uuid4())
        self.content = content #todo内容
        self.created_at = time() #创建时间
        self.is_finished = False #是否完成
        self.finished_at = None #完成时间

    def finish(self):
        self.is_finished = True
        self.finished_at = time()

    def json(self):
        return {
            'id': self.id,
            'content': self.content,
            'created_at': self.created_at,
            'is_finished': self.is_finished,
            'finished_at': self.finished_at
        }

todos = {}
get_todo = lambda tid: todos.get(tid, False)

@app.route('/todo')
def index():
    return jsonify(data=[todo.json() for todo in todos.values()])

@app.route('/todo', methods=['POST'])
def add():
    content = request.form.get('content', None)
    if not content:
        abort(400)
    todo = Todo(content)
    todos[todo.id] = todo
    return Response() #200

@app.route('/todo/<tid>/finish', methods=['PUT'])
def finish(tid):
    todo = get_todo(tid)
    if todo:
        todo.finish()
        todos[todo.id] = todo
        return Response()
    abort(404)

@app.route('/todo/<tid>', methods=['DELETE'])
def delete(tid):
    todo = get_todo(tid)
    if todo:
        todos.pop(tid)
        return Response()
    abort(404)

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8000)

http -f POST http://127.0.0.1:8000/todo content=好好学习
HTTP/1.0 200 OK
Content-Length: 0
Content-Type: text/html; charset=utf-8
Date: Thu, 26 Jan 2017 06:45:37 GMT
Server: Werkzeug/0.11.15 Python/3.5.2

http http://127.0.0.1:8000/todo
HTTP/1.0 200 OK
Content-Length: 203
Content-Type: application/json
Date: Thu, 26 Jan 2017 06:46:16 GMT
Server: Werkzeug/0.11.15 Python/3.5.2

{
    "data": [
        "{\"created_at\": 1485413137.305699, \"id\": \"6f2b28c4-1e83-45b2-8b86-20e28e21cd40\", \"is_finished\": false, \"finished_at\": null, \"content\": \"\\u597d\\u597d\\u5b66\\u4e60\"}"
    ]
}

http -f PUT http://127.0.0.1:8000/todo/6f2b28c4-1e83-45b2-8b86-20e28e21cd40/finish
HTTP/1.0 200 OK
Content-Length: 0
Content-Type: text/html; charset=utf-8
Date: Thu, 26 Jan 2017 06:47:18 GMT
Server: Werkzeug/0.11.15 Python/3.5.2

http http://127.0.0.1:8000/todo
HTTP/1.0 200 OK
Content-Length: 215
Content-Type: application/json
Date: Thu, 26 Jan 2017 06:47:22 GMT
Server: Werkzeug/0.11.15 Python/3.5.2

{
    "data": [
        "{\"created_at\": 1485413137.305699, \"id\": \"6f2b28c4-1e83-45b2-8b86-20e28e21cd40\", \"is_finished\": true, \"finished_at\": 1485413238.650981, \"content\": \"\\u597d\\u597d\\u5b66\\u4e60\"}"
    ]
}

http -f DELETE http://127.0.0.1:8000/todo/6f2b28c4-1e83-45b2-8b86-20e28e21cd40
HTTP/1.0 200 OK
Content-Length: 0
Content-Type: text/html; charset=utf-8
Date: Thu, 26 Jan 2017 06:48:20 GMT
Server: Werkzeug/0.11.15 Python/3.5.2

http http://127.0.0.1:8000/todo
HTTP/1.0 200 OK
Content-Length: 17
Content-Type: application/json
Date: Thu, 26 Jan 2017 06:48:22 GMT
Server: Werkzeug/0.11.15 Python/3.5.2

{
    "data": []
}

from flask import Flask, jsonify, request, abort, Response
from time import time
from bson.objectid import ObjectId
from bson.json_util import dumps
import pymongo

app = Flask(__name__)

mongo = pymongo.MongoClient('127.0.0.1', 27017)
db = mongo.todo

class Todo(object):
    @classmethod
    def create_doc(cls, content):
        return {
            'content': content,
            'created_at': time(),
            'is_finished': False,
            'finished_at': None
        }

@app.route('/todo')
def index():
    todos = db.todos.find({})
    return dumps(todos)

@app.route('/todo', methods=['POST'])
def add():
    content = request.form.get('content', None)
    if not content:
        abort(400)
    db.todos.insert(Todo.create_doc(content))
    return Response() #200

@app.route('/todo/<tid>/finish', methods=['PUT'])
def finish(tid):
    result = db.todos.update_one(
        {'_id': ObjectId(tid)},
        {
            '$set': {
                'is_finished': True,
                'finished_at': time()
            }
        }    
    )
    if result.matched_count == 0:
        abort(404)
    return Response()

@app.route('/todo/<tid>', methods=['DELETE'])
def delete(tid):
    result = db.todos.delete_one(
        {'_id': ObjectId(tid)}  
    )
    if result.matched_count == 0:
        abort(404)
    return Response()

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8000)

import requests

for i in range(10000):
    requests.post('http://127.0.0.1:8000/todo', {'content': str(i)})

@app.route('/todo')
def index():
    start = request.args.get('start', '')
    start = int(start) if start.isdigit() else 0
    todos = db.todos.find().sort([('created_at', -1)]).limit(10).skip(start)
    return dumps(todos)

wrk -c 100 -t 12 -d 5s http://127.0.0.1:8000/todo
Running 5s test @ http://127.0.0.1:8000/todo
  12 threads and 100 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     1.22s   618.29ms   1.90s    48.12%
    Req/Sec    14.64     10.68    40.00     57.94%
  220 requests in 5.09s, 338.38KB read
  Socket errors: connect 0, read 0, write 0, timeout 87
Requests/sec:     43.20
Transfer/sec:     66.45KB

db.todos.ensureIndex({'created_at': -1})

> db.todos.find().sort({'created_at': -1}).limit(10).explain()
/* 1 */
{
    "queryPlanner" : {
        "plannerVersion" : 1,
        "namespace" : "todo.todos",
        "indexFilterSet" : false,
        "parsedQuery" : {},
        "winningPlan" : {
            "stage" : "LIMIT",
            "limitAmount" : 10,
            "inputStage" : {
                "stage" : "FETCH",
                "inputStage" : {
                    "stage" : "IXSCAN",
                    "keyPattern" : {
                        "created_at" : -1.0
                    },
                    "indexName" : "created_at_-1",
                    "isMultiKey" : false,
                    "multiKeyPaths" : {
                        "created_at" : []
                    },
                    "isUnique" : false,
                    "isSparse" : false,
                    "isPartial" : false,
                    "indexVersion" : 2,
                    "direction" : "forward",
                    "indexBounds" : {
                        "created_at" : [ 
                            "[MaxKey, MinKey]"
                        ]
                    }
                }
            }
        },
        "rejectedPlans" : []
    },
    "serverInfo" : {
        "host" : "841bf506b6ec",
        "port" : 27017,
        "version" : "3.4.1",
        "gitVersion" : "5e103c4f5583e2566a45d740225dc250baacfbd7"
    },
    "ok" : 1.0
}

wrk -c 100 -t 12 -d 5s http://127.0.0.1:8000/todo
Running 5s test @ http://127.0.0.1:8000/todo
  12 threads and 100 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   310.32ms   47.51ms 357.47ms   94.57%
    Req/Sec    26.88     14.11    80.00     76.64%
  1511 requests in 5.06s, 2.27MB read
Requests/sec:    298.34
Transfer/sec:    458.87KB

gunicorn --workers=9 server:app --bind 127.0.0.1:8000

    def __call__(self, environ, start_response):
        """Shortcut for :attr:`wsgi_app`."""
        return self.wsgi_app(environ, start_response)

gunicorn --workers=9 server:app --bind 127.0.0.1:8000
[2017-01-27 11:20:01 +0800] [5855] [INFO] Starting gunicorn 19.6.0
[2017-01-27 11:20:01 +0800] [5855] [INFO] Listening at: http://127.0.0.1:8000 (5855)
[2017-01-27 11:20:01 +0800] [5855] [INFO] Using worker: sync
[2017-01-27 11:20:01 +0800] [5889] [INFO] Booting worker with pid: 5889
[2017-01-27 11:20:01 +0800] [5890] [INFO] Booting worker with pid: 5890
[2017-01-27 11:20:01 +0800] [5891] [INFO] Booting worker with pid: 5891
[2017-01-27 11:20:01 +0800] [5892] [INFO] Booting worker with pid: 5892
[2017-01-27 11:20:02 +0800] [5893] [INFO] Booting worker with pid: 5893
[2017-01-27 11:20:02 +0800] [5894] [INFO] Booting worker with pid: 5894
[2017-01-27 11:20:02 +0800] [5895] [INFO] Booting worker with pid: 5895
[2017-01-27 11:20:02 +0800] [5896] [INFO] Booting worker with pid: 5896
[2017-01-27 11:20:02 +0800] [5897] [INFO] Booting worker with pid: 5897

wrk -c 100 -t 12 -d 5s http://127.0.0.1:8000/todo
Running 5s test @ http://127.0.0.1:8000/todo
  12 threads and 100 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   109.30ms   16.10ms 251.01ms   90.31%
    Req/Sec    72.47     10.48   100.00     78.89%
  4373 requests in 5.07s, 6.59MB read
Requests/sec:    863.35
Transfer/sec:      1.30MB

[2017-01-27 11:20:01 +0800] [5855] [INFO] Using worker: sync

Async Workers
The asynchronous workers available are based on Greenlets (via Eventlet and Gevent). Greenlets are an implementation of cooperative multi-threading for Python. In general, an application should be able to make use of these worker classes with no changes.

gunicorn --workers=9 --worker-class="meinheld.gmeinheld.MeinheldWorker" server:app --bind 127.0.0.1:8000
[2017-01-27 11:47:01 +0800] [7497] [INFO] Starting gunicorn 19.6.0
[2017-01-27 11:47:01 +0800] [7497] [INFO] Listening at: http://127.0.0.1:8000 (7497)
[2017-01-27 11:47:01 +0800] [7497] [INFO] Using worker: meinheld.gmeinheld.MeinheldWorker
[2017-01-27 11:47:01 +0800] [7531] [INFO] Booting worker with pid: 7531
[2017-01-27 11:47:01 +0800] [7532] [INFO] Booting worker with pid: 7532
[2017-01-27 11:47:01 +0800] [7533] [INFO] Booting worker with pid: 7533
[2017-01-27 11:47:01 +0800] [7534] [INFO] Booting worker with pid: 7534
[2017-01-27 11:47:01 +0800] [7535] [INFO] Booting worker with pid: 7535
[2017-01-27 11:47:01 +0800] [7536] [INFO] Booting worker with pid: 7536
[2017-01-27 11:47:01 +0800] [7537] [INFO] Booting worker with pid: 7537
[2017-01-27 11:47:01 +0800] [7538] [INFO] Booting worker with pid: 7538
[2017-01-27 11:47:01 +0800] [7539] [INFO] Booting worker with pid: 7539

wrk -c 100 -t 12 -d 5s http://127.0.0.1:8000/todo
Running 5s test @ http://127.0.0.1:8000/todo
  12 threads and 100 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    84.53ms   39.90ms 354.42ms   72.11%
    Req/Sec    94.52     20.84   150.00     70.28%
  5684 requests in 5.04s, 8.59MB read
Requests/sec:   1128.72
Transfer/sec:      1.71MB

      server {
          listen 8888;

          location / {
               proxy_pass http://127.0.0.1:8000;
               proxy_redirect     off;
               proxy_set_header Host $host;
               proxy_set_header X-Real-IP $remote_addr;
               proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
          }
      }

wrk -c 1000 -t 12 -d 5s http://127.0.0.1:8888/todo
Running 5s test @ http://127.0.0.1:8888/todo
  12 threads and 1000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   239.50ms  235.76ms   1.93s    91.13%
    Req/Sec    83.07     76.77   434.00     76.78%
  4548 requests in 5.10s, 6.52MB read
  Socket errors: connect 0, read 297, write 0, timeout 36
  Non-2xx or 3xx responses: 289
Requests/sec:    892.04
Transfer/sec:      1.28MB

rds = redis.StrictRedis('127.0.0.1', 6379)

@app.route('/todo')
def index():
    start = request.args.get('start', '')
    start = int(start) if start.isdigit() else 0
    data = rds.get('todos')
    if data and start == 0:
        return data
    todos = db.todos.find().sort([('created_at', -1)]).limit(10).skip(start)
    data = dumps(todos)
    rds.set('todos', data, 3600)
    return data

wrk -c 1000 -t 12 -d 5s http://127.0.0.1:8888/todo
Running 5s test @ http://127.0.0.1:8888/todo
  12 threads and 1000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    68.33ms   95.27ms   1.34s    93.69%
    Req/Sec   277.32    258.20     1.60k    77.33%
  15255 requests in 5.10s, 22.77MB read
  Socket errors: connect 0, read 382, write 0, timeout 0
  Non-2xx or 3xx responses: 207
Requests/sec:   2992.79
Transfer/sec:      4.47MB

[program:gunicorn]
command=gunicorn --workers=9 --worker-class="meinheld.gmeinheld.MeinheldWorker" server:app --bind 127.0.0.1:8000
autostart=true
autorestart=true
stdout_logfile=access.log
stderr_logfile=error.log

supervisord -c supervisord.conf

docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                     PORTS                                                NAMES
cdca11112543        nginx               "nginx -g 'daemon off"   2 days ago          Exited (128) 2 days ago                                                         nginx
83119f92104a        cassandra           "/docker-entrypoint.s"   2 days ago          Exited (0) 2 days ago                                                           cassandra
841bf506b6ec        mongo               "/entrypoint.sh mongo"   2 days ago          Exited (1) 2 minutes ago   0.0.0.0:27017->27017/tcp, 0.0.0.0:28017->28017/tcp   mongo
b110a4530c4a        python:latest       "python3"                2 days ago          Exited (0) 46 hours ago                                                         python
b522b2a8313b        phpfpm              "docker-php-entrypoin"   4 days ago          Exited (0) 4 days ago                                                           php-fpm
f8630d4b48d7        spotify/kafka       "supervisord -n"         2 weeks ago         Exited (0) 6 days ago                                                           kafka