Daprが提供する主要な機能について理解してみる - Daprの基本とService-to-service invocationについて

$ eksctl create cluster --name dapr-test-cluster \
  --version 1.14 \
  --nodegroup-name dapr-test-cluster-worker \
  --node-type t3.small \
  --nodes 3 \
  --nodes-min 1 \
  --nodes-max 5 \
  --managed

$ kubectl get no
NAME                                               STATUS   ROLES    AGE     VERSION
ip-192-168-51-32.ap-northeast-1.compute.internal   Ready    <none>   2m32s   v1.14.7-eks-1861c5

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

$ dapr --version
CLI version: 0.3.0
Runtime version: 0.3.0

$ dapr init --runtime-version 0.3.0

$ dapr init --kubernetes

$ kubectl get deployment
NAME                    READY   UP-TO-DATE   AVAILABLE   AGE
dapr-operator           1/1     1            1           2m4s
dapr-placement          1/1     1            1           2m4s
dapr-sidecar-injector   1/1     1            1           2m4s

apiVersion: v1
kind: Pod
metadata:
  name: sample-app
spec:
  containers:
  - image: app
    name: main-container
  - image: logger
    name: sidecar-container

apiVersion: v1
kind: Pod
metadata:
  name: sample-app
  annotations:
    # アノテーションを付与する
    dapr.io/enabled: "true"
spec:
  containers:
  - image: nginx
    name: sample-app

kubectl get po sample-app
NAME         READY   STATUS    RESTARTS   AGE
sample-app   2/2     Running   0          28s

$ kubectl get po sample-app -o yaml
apiVersion: v1
kind: Pod
metadata:
  annotations:
    dapr.io/enabled: "true"
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{"dapr.io/enabled":"true"},"name":"sample-app","namespace":"default"},"spec":{"containers":[{"image":"nginx","name":"sample-app"}]}}
    kubernetes.io/psp: eks.privileged
  creationTimestamp: "2019-12-10T17:05:09Z"
  name: sample-app
  namespace: default
  resourceVersion: "4794"
  selfLink: /api/v1/namespaces/default/pods/sample-app
  uid: 38ee7d0f-1b6f-11ea-be00-0aa1afee716c
spec:
  containers:
  - image: nginx
    imagePullPolicy: Always
    name: sample-app
    resources: {}
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: default-token-mrs9r
      readOnly: true
  - args:
    - --mode
    - kubernetes
    - --dapr-http-port
    - "3500"
    - --dapr-grpc-port
    - "50001"
    - --app-port
    - ""
    - --dapr-id
    - sample-app
    - --control-plane-address
    - http://dapr-api.default.svc.cluster.local
    - --protocol
    - http
    - --placement-address
    - dapr-placement.default.svc.cluster.local:80
    - --config
    - ""
    - --enable-profiling
    - "false"
    - --log-level
    - info
    - --max-concurrency
    - "-1"
    command:
    - /daprd
    env:
    - name: HOST_IP
      valueFrom:
        fieldRef:
          apiVersion: v1
          fieldPath: status.podIP
    - name: NAMESPACE
      value: default
    image: docker.io/daprio/dapr:latest
    imagePullPolicy: Always
    name: daprd
    ports:
    - containerPort: 3500
      name: dapr-http
      protocol: TCP
    - containerPort: 50001
      name: dapr-grpc
      protocol: TCP
...

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app-deployment
spec:
  selector:
    matchLabels:
      app: web-app
  replicas: 2
  template:
    metadata:
      labels:
        app: web-app
      annotations:
        dapr.io/enabled: "true"
        dapr.io/id: "web-app"
        dapr.io/port: "80"
    spec:
      containers:
      - name: web-app
        image: nginx:1.7.9
        ports:
        - containerPort: 80

apiVersion: apps/v1
kind: Deployment
metadata:
  name: caller-deployment
spec:
  selector:
    matchLabels:
      app: caller
  replicas: 1
  template:
    metadata:
      labels:
        app: caller
      annotations:
        dapr.io/enabled: "true"
        dapr.io/id: "caller"
    spec:
      containers:
      - name: caller
        image: centos:7
        command: 
        - "tail"
        - "-f"
        - "dev/null"

# calle podを特定する
$ kubectl get po | grep caller
caller-deployment-5887c557cd-7g8zm       2/2     Running   0          13m
$ kubectl exec -it caller-deployment-5887c557cd-7g8zm bash 

# callerコンテナに入り、sidecar経由でサービス呼び出しを行う
$ curl localhost:3500/v1.0/invoke/web-app/method/
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>


$ curl localhost:3500/v1.0/invoke/web-app/method/50x.html
<!DOCTYPE html>
<html>
<head>
<title>Error</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>An error occurred.</h1>
<p>Sorry, the page you are looking for is currently unavailable.<br/>
Please try again later.</p>
<p>If you are the system administrator of this resource then you should check
the <a href="http://nginx.org/r/error_log">error log</a> for details.</p>
<p><em>Faithfully yours, nginx.</em></p>
</body>
</html>