plotly-dash 简单使用（一）

plotly-dash 是一个很不错的dashboard 开发平台，基于python 编写，提供了很便捷的dashboard 开发模型
同时扩展上也比较灵活我们可以编写自己的组件。
以下是一个简单的项目以及集成docker 运行（实际通过gunicorn,uwsgi运行应用）

本地方式运行

使用venv 进行python 环境管理

• 初始化venv 项目

 

python3 -m venv venv

• 激活环境

source   venv/bin/activate

• 添加依赖

pip install dash==1.1.1

pip install dash-daq==0.1.0

• 简单代码

# -*- coding: utf-8 -*-

import dash

import flask

import dash_core_components as dcc

import dash_html_components as html

server = flask.Flask(__name__)

​

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

server = app.server

app.layout = html.Div(children=[

    html.H1(children='Hello Dash'),

​

    html.Div(children='''

        Dash: A web application framework for Python.

    '''),

​

    dcc.Graph(

        id='example-graph',

        figure={

            'data': [

                {'x': [1, 2, 3], 'y': [4, 1, 2], 'type': 'bar', 'name': 'SF'},

                {'x': [1, 2, 3], 'y': [2, 4, 5], 'type': 'bar', 'name': u'Montréal'},

            ],

            'layout': {

                'title': 'Dash Data Visualization'

            }

        }

    )

])

​

if __name__ == '__main__':

    app.run_server(debug=False)

• 启动

python app.py

• 效果

 * Serving Flask app "app" (lazy loading)

 * Environment: production

   WARNING: This is a development server. Do not use it in a production deployment.

   Use a production WSGI server instead.

 * Debug mode: off

 * Running on http://127.0.0.1:8050/ (Press CTRL+C to quit)

 

docker 运行

docker 提供了两种方式的运行，gunicorn以及uwsgi

• docker-compose 文件

version: "3"

services: 

  dash-gunicorn:

     build: ./

     image: dalongrong/dash-demo:gunicorn

     ports: 

     - "5000:5000"

  dash-uwsgi:

     build: 

      context: ./

      dockerfile: Dockerfile-uwsgi

     image: dalongrong/dash-demo:uwsgi

     ports: 

     - "5001:5001"

• gunicorn 方式dockerfile

FROM python:3.5.7-alpine

RUN pip install dash==1.1.1 \

    && pip install dash-daq==0.1.0 \

    && pip install gunicorn

WORKDIR /app

COPY . /app

EXPOSE 5000

ENTRYPOINT [ "gunicorn","-b",":5000","app:server"]

• uwsgi 方式dockerfile

FROM python:3.5.7-alpine

RUN apk add --no-cache uwsgi uwsgi-python3 uwsgi-http

RUN pip install dash==1.1.1 \

    && pip install dash-daq==0.1.0

WORKDIR /app

COPY . /app

EXPOSE 5001

ENTRYPOINT [ "uwsgi","--plugins","http,python3","--http","0.0.0.0:5001","--module","app:server","--pythonpath","/usr/local/lib/python3.5/site-packages"]

• 运行

docker-compose build

docker-compose up -d

• 效果

• 几点说明
  使用uwsgi的时候碰到了pip 包查找的问题，问题如下：

 

 Traceback (most recent call last):

dash-uwsgi_1 | File "./app.py", line 2, in <module>

dash-uwsgi_1 | import dash

dash-uwsgi_1 | ModuleNotFoundError: No module named 'dash'

dash-uwsgi_1 | unable to load app 0 (mountpoint='') (callable not found or import error)

dash-uwsgi_1 | *** no app loaded. going in full dynamic mode ***

解决方法，添加pythonpath 如下：

ENTRYPOINT [ "uwsgi","--plugins","http,python3","--http","0.0.0.0:5001","--module","app:server","--pythonpath","/usr/local/lib/python3.5/site-packages"]

uwsgi 只安装了uwsgi python 无法运行，问题

uwsgi http is ambiguous

问题原因，因为我是通过alpine 的apk 安装的，需要添加http 以及python 的支持,解决方法

RUN apk add --no-cache uwsgi uwsgi-python3 uwsgi-http

注意对于python模块的支持需要uwsgi-python3 因为我们使用的是python3 的基础镜像

说明

plotly-dash 功能很强大，开发模型也比较简单,后边会写一些相关的学习

参考资料

https://stackoverflow.com/questions/35460816/uwsgi-http-is-ambiguous
https://uwsgi-docs.readthedocs.io/en/latest/Python.html
https://dash.plot.ly/installation
https://github.com/rongfengliang/plot_dash_docker_running