微软的分布式应用框架 Dapr Helloworld

时间 2019-11-06

标签微软分布式应用框架 dapr helloworld 栏目 Microsoft 繁體版

原文原文链接

Dapr HelloWorld

<a name="XMoC2"></a>javascript

Dapr

Distributed Application Runtime. An event-driven, portable runtime for building microservices on cloud and edge.java

分布式应用运行时、事件驱动、为云和边缘构建微服务提供便携化运行时。node

我如今也不是很懂。git

<a name="MCBci"></a>github

dapr/dapr

GitHubredis

Dapr is a portable, serverless, event-driven runtime that makes it easy for developers to build resilient, stateless and stateful microservices that run on the cloud and edge and embraces the diversity of languages and developer frameworks.docker

Dapr codifies the best practices for building microservice applications into open, independent, building blocks that enable you to build portable applications with the language and framework of your choice. Each building block is independent and you can use one, some, or all of them in your application.express

比上面的介绍多了 stateless or stateful 的标签。学《计算理论》的时候接触过一些状态机。npm

”状态时万恶之源“ 编程

注意提到了多语言和多开发者框架，我认为这是他选择的经过通讯共享信息，即 HTTP 和 GRPC 支持多语言等特性。微软想经过这个设定一个构建微服务应用的规则。从根本上确立你开发的每个应用的独立性。

下面进行一个 QuickStart

环境

Install Docker（微服务已经离不开容器化了）
Install Dapr
Node.js version 8 or greater（这个 Helloworld 是 node 应用）

On MacOS

Install the latest darwin Dapr CLI to /usr/local/bin

curl -fsSL https://raw.githubusercontent.com/dapr/cli/master/install/install.sh | /bin/bash

有条件能够加速

执行初始化（会启动 docker 容器）

$ dapr init
⌛  Making the jump to hyperspace...
Downloading binaries and setting up components
✅  Success! Dapr is up and running

$ docker ps
CONTAINER ID        IMAGE                COMMAND                  CREATED             STATUS              PORTS                        NAMES
b3a5600e672f        redis                "docker-entrypoint.s…"   44 hours ago        Up 44 hours         0.0.0.0:6379->6379/tcp       xenodochial_hofstadter
e5010ba0c33f        daprio/dapr          "./placement"            44 hours ago        Up 44 hours         0.0.0.0:50005->50005/tcp     dapr_placement

HelloWorld

Application Architecture

<br />可以看到暴露两个 endpoint 是 HTTP 访问，一个建立一个查询。

主要看咱们使用 Dapr 的交互。在图中它做为 Runtime

提供 Dapr API 给多语言调用。
提供状态管理 By state stores

Download Code

下载并进入相应文件夹

git clone https://github.com/dapr/samples.git
cd samples/1.hello-world

Cat app.js

// $ cat app.js 
// ------------------------------------------------------------
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
// ------------------------------------------------------------

const express = require('express');
const bodyParser = require('body-parser');
require('isomorphic-fetch');

const app = express();
app.use(bodyParser.json());

const daprPort = process.env.DAPR_HTTP_PORT || 3500;
const stateUrl = `http://localhost:${daprPort}/v1.0/state`;
const port = 3000;

app.get('/order', (_req, res) => {
    fetch(`${stateUrl}/order`)
        .then((response) => {
            return response.json();
        }).then((orders) => {
            res.send(orders);
        });
});

app.post('/neworder', (req, res) => {
    const data = req.body.data;
    const orderId = data.orderId;
    console.log("Got a new order! Order ID: " + orderId);

    const state = [{
        key: "order",
        value: data
    }];

    fetch(stateUrl, {
        method: "POST",
        body: JSON.stringify(state),
        headers: {
            "Content-Type": "application/json"
        }
    }).then((response) => {
        console.log((response.ok) ? "Successfully persisted state" : "Failed to persist state");
    });

    res.status(200).send();
});

app.listen(port, () => console.log(`Node App listening on port ${port}!`));

这是一些路由和 handlers

注意 14-16 行

const daprPort = process.env.DAPR_HTTP_PORT || 3500;
const stateUrl = `http://localhost:${daprPort}/v1.0/state`;
const port = 3000;

3500 是 Dapr 的环境端口，若是你安装时有改动，须要考虑。<br />stateurl 就是 Dapr 提供的 URL 了

Handlers

/neworder

app.post('/neworder', (req, res) => {
    const data = req.body.data;
    const orderId = data.orderId;
    console.log("Got a new order! Order ID: " + orderId);

    const state = [{
        key: "order",
        value: data
    }];

    fetch(stateUrl, {
        method: "POST",
        body: JSON.stringify(state),
        headers: {
            "Content-Type": "application/json"
        }
    }).then((response) => {
        console.log((response.ok) ? "Successfully persisted state" : "Failed to persist state");
    });

    res.status(200).send();
});

这里重点是状态存储，即将 state 经过 stateurl 存储在 Dapr 中。

/order

咱们并非直接经过 res.json 做为 Response 来进行已经持久化的数据的使用，而是经过暴露一个 GET endpoint 经过访问它来验证持久化是否成功。

app.get('/order', (_req, res) => {
    fetch(`${stateUrl}/order`)
        .then((response) => {
            return response.json();
        }).then((orders) => {
            res.send(orders);
        });
});

如今咱们经过状态转移在 Dapr 里实现了 stateless，一样咱们也能够在加上一个 local cache 并经过一个新的 endpoint 访问来使 Node application 变成 stateful

Dapr Run Node.js App

npm install ：经过当前目录下的 package.json , 会安装 express 和 body-parser ，在 app.js 7-8行咱们能够看到这两项。
dapr run --app-id mynode --app-port 3000 --port 3500 node app.js

$ dapr run --app-id mynode --app-port 3000 --port 3500 node app.js
ℹ️  Starting Dapr with id mynode. HTTP Port: 3500. gRPC Port: 55099
✅  You're up and running! Both Dapr and your app logs will appear here.

应该是有后台运行的 CLI 命令，这里是前台打印的日志

== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="starting Dapr Runtime -- version 0.1.0 -- commit 4358565-dirty"
== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="log level set to: info"
== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="standalone mode configured"
== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="dapr id: mynode"
== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="loaded component messagebus (pubsub.redis)"
== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="loaded component statestore (state.redis)"
== DAPR == time="2019-11-06T10:37:41+08:00" level=info msg="application protocol: http. waiting on port 3000"
== APP == Node App listening on port 3000!
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="application discovered on port 3000"
== DAPR == 2019/11/06 10:37:42 redis: connecting to localhost:6379
== DAPR == 2019/11/06 10:37:42 redis: connected to localhost:6379 (localAddr: [::1]:55130, remAddr: [::1]:6379)
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actor runtime started. actor idle timeout: 1h0m0s. actor scan interval: 30s"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actors: starting connection attempt to placement service at localhost:50005"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="http server is running on port 3500"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="gRPC server is running on port 55099"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="local service entry announced"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="dapr initialized. Status: Running. Init Elapsed 945.8297490000001ms"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actors: established connection to placement service at localhost:50005"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actors: placement order received: lock"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actors: placement order received: update"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actors: placement tables updated"
== DAPR == time="2019-11-06T10:37:42+08:00" level=info msg="actors: placement order received: unlock"

⚠️：注意到 Node App 在指定的 3000 端口运行，同时还有状态存储的 redis 在 6379 端口运行

Post and Get

接下来注意，文中的端口是 app.js 里默认的 3500 <a name="B0eiO"></a>

Post

Curl

curl -XPOST -d @sample.json http://localhost:3500/v1.0/invoke/mynode/method/neworder

Vscode

若是你用 vscode ，使用这个插件 Rest Client Plugin<br />而后打开目录下的 sample.http , 能够看到 send request 的选项<br />sample.http

POST http://localhost:3500/v1.0/invoke/mynode/method/neworder
{
  "data": {
    "orderId": "42"
  } 
}

Postman

如图： http://localhost:3500/v1.0/invoke/mynode/method/neworder

Result Update

你能够在你启动的终端中看到新的日志

== APP == Got a new order! Order ID: 42
== APP == Successfully persisted state

Get

Curl

curl http://localhost:3500/v1.0/invoke/mynode/method/order

Vscode

sample.http

GET http://localhost:3500/v1.0/invoke/mynode/method/order

Postman

Terminate

ctrl + c 或者 dapr stop --app-id mynode

^C
ℹ️  terminated signal received: shutting down
✅  Exited Dapr successfully
✅  Exited App successfully

Feature

具备可插入提供程序和至少一次语义的事件驱动的Pub-Sub系统
使用可插入提供程序的输入和输出绑定
具备可插拔数据存储的状态管理
一致的服务到服务发现和调用
选择加入状态模型：强大/最终一致性，首次写入/最后写入获胜
跨平台虚拟演员
限速
使用OpenTelemetry的内置分布式跟踪
使用专用的Operator和CRD在Kubernetes上本地运行
经过HTTP和gRPC支持全部编程语言
来自Azure，AWS，GCP的多云，开放式组件（绑定，发布-订阅，状态）
做为过程或容器化在任何地方运行
轻量级（58MB二进制，4MB物理内存）
做为辅助工具运行-无需特殊的SDK或库
专用的CLI-易于调试的开发人员友好体验
Java，Dotnet，Go，Javascript和Python的客户端

微软的分布式应用框架 Dapr Helloworld

Dapr HelloWorld

Dapr

dapr/dapr

环境

On MacOS

HelloWorld

Application Architecture

Download Code

Cat app.js

Handlers

/neworder

/order

Dapr Run Node.js App

Post and Get

Post

Curl

Vscode

Postman

Result Update

Get

Curl

Vscode

Postman

Terminate

Feature

Refer