kubevela/docs/examples/application

Definition Docs

Reserved word

Patch

Perform the CUE AND operation with the content declared by 'patch' and workload cr,

you can define the strategy of list merge through comments, example as follows

base model

containers: [{
       name: "x1"
}, {
       name: "x2"
       image:  string
       envs: [{
               name: "OPS"
               value: string
       }, ...]
}, ...]

define patch model

 // +patchKey=name
containers: [{
        name: "x2"
        image:  "test-image"
        envs: [{
                name: "OPS1"
                value: "V-OPS1"
        },{
                name: "OPS"
                value: "V-OPS"
        }, ...]
}, ...]

and the result model after patch is follow

containers: [{
        name: "x1" 
 },{
        name: "x2"
        image:  "test-image"
        envs: [{
                name: "OPS1"
                value: "V-OPS1"
        },{
                name: "OPS"
                value: "V-OPS"
        }, ...]
}, ...]

output

Generate a new cr, which is generally associated with workload cr

ComponentDefinition

The following ComponentDefinition is to generate a deployment

apiVersion: core.oam.dev/v1beta1
kind: ComponentDefinition
metadata:
  name: worker
  annotations:
    definition.oam.dev/description: "Long-running scalable backend worker without network endpoint"
spec:
  workload:
    definition:
      apiVersion: apps/v1
      kind: Deployment
  schematic:
    cue:
      template: |
        output: {
          apiVersion: "apps/v1"
          kind:       "Deployment"
          spec: {
            selector: matchLabels: {
              "app.oam.dev/component": context.name
            }

            template: {
              metadata: labels: {
                "app.oam.dev/component": context.name
              }

              spec: {
                containers: [{
                  name:  context.name
                  image: parameter.image

                  if parameter["cmd"] != _|_ {
                    command: parameter.cmd
                  }
                }]
              }
            }
          }
        }

        parameter: {
          // +usage=Which image would you like to use for your service
          // +short=i
          image: string

          cmd?: [...string]
        }

If defined an application as follows

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: application-sample
spec:
  components:
    - name: myweb
      type: worker
      properties:
        image: "busybox"
        cmd:
        - sleep
        - "1000"

we will get a deployment

apiVersion: apps/v1
kind: Deployment
spec:
  selector:
    matchLabels:
      app.oam.dev/component: myweb
  template:
    metadata:
      labels:
        app.oam.dev/component: myweb
    spec:
      containers:
      - command:
        - sleep
        - "1000"
        image: busybox
        name: myweb

Service Trait Definition

Define a trait Definition that appends service to workload(worker) , as shown below

apiVersion: core.oam.dev/v1beta1
kind: TraitDefinition
metadata:
  annotations:
    definition.oam.dev/description: "service the app"
  name: kservice
spec:
  appliesToWorkloads:
    - deployments.apps
  schematic:
    cue:
      template: |-
        patch: {spec: template: metadata: labels: app: context.name}
        outputs: service: {
          apiVersion: "v1"
          kind: "Service"
          metadata: name: context.name
          spec: {
            selector:  app: context.name
            ports: [
              for k, v in parameter.http {
                port: v
                targetPort: v
              }
            ]
          }
        }
        parameter: {
          http: [string]: int
        }

If add service capability to the application, as follows

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: application-sample
spec:
  components:
    - name: myweb
      type: worker
      properties:
        image: "busybox"
        cmd:
        - sleep
        - "1000"
      traits:
        - type: kservice
          properties:
            http:
              server: 80

we will get a new deployment and service

// origin deployment  template add labels
apiVersion: apps/v1
kind: Deployment
spec:
  selector:
    matchLabels:
      app.oam.dev/component: myweb
  template:
    metadata:
      labels:
        // add label app
        app: myweb
        app.oam.dev/component: myweb
    spec:
      containers:
      - command:
        - sleep
        - "1000"
        image: busybox
        name: myweb
---
apiVersion: v1
kind: Service
metadata:
  name: myweb
spec:
  ports:
  - port: 80
    targetPort: 80
  selector:
    app: myweb         

Scaler Trait Definition

Define a trait Definition that scale workload(worker) replicas

apiVersion: core.oam.dev/v1beta1
kind: TraitDefinition
metadata:
  annotations:
    definition.oam.dev/description: "Manually scale the app"
  name: scaler
spec:
  appliesToWorkloads:
    - deployments.apps
  schematic:
    cue:
      template: |-
        patch: {
          spec: replicas: parameter.replicas
        }
        parameter: {
          //+short=r
          replicas: *1 | int
        }

If add scaler capability to the application, as follows

  components:
    - name: myweb
      type: worker
      properties:
        image: "busybox"
        cmd:
        - sleep
        - "1000"
      traits:
        - type: kservice
          properties:
            http:
              server: 80           
        - type: scaler
          properties:
            replicas: 10

The deployment replicas will be scale to 10

apiVersion: apps/v1
kind: Deployment
spec:
  selector:
    matchLabels:
      app.oam.dev/component: myweb
  // scale to 10    
  replicas: 10    
  template:
    metadata:
      labels:
        // add label app
        app: myweb
        app.oam.dev/component: myweb
    spec:
      containers:
      - command:
        - sleep
        - "1000"
        image: busybox
        name: myweb

Sidecar Trait Definition

Define a trait Definition that append containers to workload(worker)

apiVersion: core.oam.dev/v1beta1
kind: TraitDefinition
metadata:
  annotations:
    definition.oam.dev/description: "add sidecar to the app"
  name: sidecar
spec:
  appliesToWorkloads:
    - deployments.apps
  schematic:
    cue:
      template: |-
        patch: {
          // +patchKey=name
          spec: template: spec: containers: [parameter]
        }
        parameter: {
          name: string
          image: string
          command?: [...string]
        }

If add sidercar capability to the application, as follows

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: application-sample
spec:
  components:
    - name: myweb
      type: worker
      properties:
        image: "busybox"
        cmd:
        - sleep
        - "1000"
      traits:
        - type: scaler
          properties:
            replicas: 10
        - type: sidecar
          properties:
            name: "sidecar-test"
            image: "nginx"
        - type: kservice
          properties:
            http:
              server: 80

The deployment updated as follows

apiVersion: apps/v1
kind: Deployment
spec:
  selector:
    matchLabels:
      app.oam.dev/component: myweb
  // scale to 10    
  replicas: 10    
  template:
    metadata:
      labels:
        // add label app
        app: myweb
        app.oam.dev/component: myweb
    spec:
      containers:
      - command:
        - sleep
        - "1000"
        image: busybox
        name: myweb
      - name: sidecar-test
        image: nginx