Argo Events入门实践

wzdushu@gmail.com (wanzi) — Wed, 07 Jul 2021 16:22:42 +0800

前面我们介绍了Argo Workflow如何安装与触发任务，这一篇主要介绍一个新工具：

ArgoEvents是什么？

Argo Events是一个事件驱动的 Kubernetes 工作流自动化框架。它支持20 多种不同的事件（例如 webhook、S3 drop、cronjob、消息队列-例如 Kafka、GCP PubSub、SNS、 SQS等）

特性：

支持来自20多个事件源和10多个触发器的事件。
能够为工作流自动化定制业务级约束逻辑。
管理从简单、线性、实时到复杂、多源事件的所有内容。
符合CloudEvents。

组件：

EventSource(类似Gateway,把消息发送给eventbus)
EventBus(事件消息队列，基于高性能分布式消息中间件NATS实现，不过看NATS官网到2023年后不再维护了，估计后期架构也会调整)
EventSensor(订阅消息队列，事件参数化并对事件过滤)

ArgoEvents部署安装

argo-events部署：

1
2

kubectl create ns argo-events
kubectl apply -n argo-events -f https://raw.githubusercontent.com/argoproj/argo-events/v1.2.3/manifests/install.yaml

argo-eventbus部署:

`1`	`kubectl apply -n argo-events -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/eventbus/native.yaml`

RBAC账户授权

创建operate-workflow-sa账户

授权operate-workflow-sa可以在argo-events namespace下创建argo workflow任务，这个对于后边EventSensor自动化创建workflow会用到。

apiVersion: v1
kind: ServiceAccount
metadata:
  namespace: argo-events
  name: operate-workflow-sa
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: operate-workflow-role
  namespace: argo-events
rules:
  - apiGroups:
      - argoproj.io
    verbs:
      - "*"
    resources:
      - workflows
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: operate-workflow-role-binding
  namespace: argo-events
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: operate-workflow-role
subjects:
  - kind: ServiceAccount
    name: operate-workflow-sa
    namespace: argo-events

创建workflow-pods-sa账户

授权workflow-pods-sa可以在argo-events下通过workflow自动创建pod

apiVersion: v1
kind: ServiceAccount
metadata:
  namespace: argo-events
  name: workflow-pods-sa
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: workflow-pods-role
rules:
  - apiGroups:
      - ""
    verbs:
      - "*"
    resources:
      - pods
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: workflow-pods-role-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: workflow-pods-role
subjects:
  - kind: ServiceAccount
    name: workflow-pods-sa
    namespace: argo-events

ArgoEvents自动化触发任务

启动一个event-sources接受请求：

`1`	`kubectl apply -n argo-events -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/event-sources/webhook.yaml`

注意：这里event-sources里name为example，对于实际生产环境下边创建sensor需要指定这里的名称

创建 webhook方式sensor消费请求：

apiVersion: argoproj.io/v1alpha1
kind: Sensor
metadata:
  name: webhook
spec:
  template:
    serviceAccountName: operate-workflow-sa
  dependencies:
    - name: test-dep
      eventSourceName: webhook
      eventName: example
  triggers:
    - template:
        name: webhook-workflow-trigger
        k8s:
          group: argoproj.io
          version: v1alpha1
          resource: workflows
          operation: create
          source:
            resource:
              apiVersion: argoproj.io/v1alpha1
              kind: Workflow
              metadata:
                generateName: webhook-
              spec:
                serviceAccountName: workflow-pods-sa
                entrypoint: whalesay
                arguments:
                  parameters:
                  - name: message
                    # the value will get overridden by event payload from test-dep
                    value: hello world
                templates:
                - name: whalesay
                  inputs:
                    parameters:
                    - name: message
                  container:
                    image: docker/whalesay:latest
                    command: [cowsay]
                    args: ["{{inputs.parameters.message}}"]
          parameters:
            - src:
                dependencyName: test-dep
              dest: spec.arguments.parameters.0.value

参考：https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/sensors/webhook.yaml

forward本地请求到远端：

`1`	`kubectl -n argo-events port-forward <name-of-event-source-pod> <local port>:12000`

往event-sources筛数据：

`1`	`curl -d '{"message":"ok"}' -H "Content-Type: application/json" -X POST http://localhost:12000/example`

至此，通过ArgoEvents就可以自动化创建workflow任务了

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