Dapr quickstart

本文使用的demo是官方提供的hello-kubernates项目，代码地址：https://github.com/dapr/quickstarts/tree/master/hello-kubernetes

Step 1    -    dapr初始化

$ dapr init --kubernetes
ℹ️  Note: this installation is recommended for testing purposes. For production environments, please use Helm

⌛  Making the jump to hyperspace...
✅  Deploying the Dapr Operator to your cluster...
✅  Success! Dapr has been installed. To verify, run 'dapr status -k' in your terminal. To get started, go here: https://aka.ms/dapr-getting-started

Step 2 - Create and configure a state store

Dapr can use a number of different state stores (Redis, CosmosDB, DynamoDB, Cassandra, etc) to persist and retrieve state. This demo will use Redis.

本文使用已安装好的redis服务，修改redis.yaml文件中的redis连接信息：

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: statestore
spec:
  type: state.redis
  version: v1
  metadata:
  # These settings will work out of the box if you use `helm install
  # bitnami/redis`.  If you have your own setup, replace
  # `redis-master:6379` with your own Redis master address, and the
  # Redis password with your own Secret's name. For more information,
  # see https://docs.dapr.io/operations/components/component-secrets .
  - name: redisHost
    value: redis-master-0.redis-headless.redis.svc.cluster.local:6379
  - name: redisPassword
    value: <YOUR_REDIS_PASSWORD>
  #  secretKeyRef:
  #    name: redis
  #    key: redis-password
auth:
  secretStore: kubernetes

执行apply安装:

$ kubectl apply -f ./deploy/redis.yaml
component.dapr.io/statestore created

Step 3 - Deploy the Node.js app with the Dapr sidecar

node.yaml

kind: Service
apiVersion: v1
metadata:
  name: nodeapp
  labels:
    app: node
spec:
  selector:
    app: node
  ports:
  - protocol: TCP
    port: 80
    targetPort: 3000
  type: LoadBalancer

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nodeapp
  labels:
    app: node
spec:
  replicas: 1
  selector:
    matchLabels:
      app: node
  template:
    metadata:
      labels:
        app: node
      annotations:
        dapr.io/enabled: "true"
        dapr.io/app-id: "nodeapp"
        dapr.io/app-port: "3000"
    spec:
      containers:
      - name: node
        image: dapriosamples/hello-k8s-node:latest
        ports:
        - containerPort: 3000
        imagePullPolicy: Always

配置中的这三项是dapr的相关内容

# 启动dapr
dapr.io/enabled: "true"    
# dapr中的appId
dapr.io/app-id: "nodeapp"
# 应用的http端口
dapr.io/app-port: "3000"

这个app.js源码如下:

// ------------------------------------------------------------
// 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());

// These ports are injected automatically into the container.
const daprPort = process.env.DAPR_HTTP_PORT; 
const daprGRPCPort = process.env.DAPR_GRPC_PORT;

const stateStoreName = `statestore`;
const stateUrl = `http://localhost:${daprPort}/v1.0/state/${stateStoreName}`;
const port = 3000;

app.get('/order', (_req, res) => {
    fetch(`${stateUrl}/order`)
        .then((response) => {
            if (!response.ok) {
                throw "Could not get state.";
            }

            return response.text();
        }).then((orders) => {
            res.send(orders);
        }).catch((error) => {
            console.log(error);
            res.status(500).send({message: error});
        });
});

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) => {
        if (!response.ok) {
            throw "Failed to persist state.";
        }

        console.log("Successfully persisted state.");
        res.status(200).send();
    }).catch((error) => {
        console.log(error);
        res.status(500).send({message: error});
    });
});

app.get('/ports', (_req, res) => {
    console.log("DAPR_HTTP_PORT: " + daprPort);
    console.log("DAPR_GRPC_PORT: " + daprGRPCPort);
    res.status(200).send({DAPR_HTTP_PORT: daprPort, DAPR_GRPC_PORT: daprGRPCPort })
});

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

注意：neworder接口，这里收到请求后调用Dapr的state接口将数据持久化存储了。

执行apply安装:

$ kubectl apply -f ./deploy/node.yaml

查看是否安装成功：

$ kubectl get svc nodeapp
NAME      TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
nodeapp   NodePort   10.88.0.173   <none>        80:32325/TCP   2h  

我们采用NodePort模式（仅测试使用），将nodeapp ip映射出来：

$ curl -s 10.110.2.74:32325/ports | python -m json.tool
{
    "DAPR_GRPC_PORT": "50001",
    "DAPR_HTTP_PORT": "3500"
}

Step 5 - Deploy the Python app with the Dapr sidecar

python.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pythonapp
  labels:
    app: python
spec:
  replicas: 2
  selector:
    matchLabels:
      app: python
  template:
    metadata:
      labels:
        app: python
      annotations:
        dapr.io/enabled: "true"
        dapr.io/app-id: "pythonapp"
    spec:
      containers:
      - name: python
        image: dapriosamples/hello-k8s-python:latest

这个app.py源码如下:

# ------------------------------------------------------------
# Copyright (c) Microsoft Corporation.
# Licensed under the MIT License.
# ------------------------------------------------------------

import os
import requests
import time

dapr_port = os.getenv("DAPR_HTTP_PORT", 3500)
dapr_url = "http://localhost:{}/v1.0/invoke/nodeapp/method/neworder".format(dapr_port)

n = 0
while True:
    n += 1
    message = {"data": {"orderId": n}}

    try:
        response = requests.post(dapr_url, json=message, timeout=5)
        if not response.ok:
            print("HTTP %d => %s" % (response.status_code,
                                     response.content.decode("utf-8")), flush=True)
    except Exception as e:
        print(e, flush=True)

    time.sleep(1)

可以看到，一直循环调用nodeapp的neworder接口。

执行apply安装:

$ kubectl apply -f ./deploy/python.yaml

查看是否安装成功：

$ kubectl get pods --selector=app=python
NAME                         READY   STATUS    RESTARTS   AGE
pythonapp-6cc7dd7cfc-fg6mg   2/2     Running   0          2h

Step 6 - Observe messages

$ kubectl logs --selector=app=node -c node --tail=-1 -f
Got a new order! Order ID: 146155
Successfully persisted state.
Got a new order! Order ID: 146157
Successfully persisted state.
Got a new order! Order ID: 146159
Successfully persisted state.
Got a new order! Order ID: 146161
Successfully persisted state.
Got a new order! Order ID: 146163
Successfully persisted state.
Got a new order! Order ID: 146154

Step 7 - Confirm successful persistence

$ curl -s http://10.110.2.74:32325/order | python -m json.tool
{
    "orderId": 146398
}

Step 8 - 登录redis验证存储的数据

redis-master-0:/$ redis-cli 
127.0.0.1:6379> auth 123456
OK
127.0.0.1:6379> keys *
1) "nodeapp||order"
2) "bitmap_cat"
3) "mybit"
127.0.0.1:6379> type nodeapp||order
hash
127.0.0.1:6379> hgetall nodeapp||order
1) "data"
2) "{\"orderId\":146856}"
3) "version"
4) "137146"

That is all!