example-app.yaml

#@ load("@ytt:data", "data")

---
apiVersion: v1
kind: Namespace
metadata:
  name: #@ data.values.namespace
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin
  namespace: #@ data.values.namespace
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: admin
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: #@ data.values.developeruser
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/part-of: voting
    app.kubernetes.io/name: ui
    app.kubernetes.io/component: frontend
    app.kubernetes.io/managed-by: tekton
  name: ui
  namespace: #@ data.values.namespace
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ui
  template:
    metadata:
      labels:
        app: ui
    spec:
      containers:
        - image: quay.io/openshift-pipeline/vote-ui:latest
          imagePullPolicy: Always
          name: ui
          ports:
            - containerPort: 8080
              protocol: TCP
            - containerPort: 9090
              protocol: TCP
          env:
            - name: VOTING_API_SERVICE_HOST
              value: "api"
            - name: VOTING_API_SERVICE_PORT
              value: "9000"
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: ui
  name: ui
  namespace: #@ data.values.namespace
spec:
  type: NodePort
  ports:
    - name: 8080-tcp
      port: 8080
      targetPort: 8080
      protocol: TCP
  selector:
    app: ui
---
apiVersion: route.openshift.io/v1
kind: Route
metadata:
  labels:
    app: ui
  name: ui
  namespace: #@ data.values.namespace
spec:
  port:
    targetPort: 8080-tcp
  to:
    kind: Service
    name: ui
    weight: 100
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/part-of: voting
    app.kubernetes.io/name: api
    app.kubernetes.io/component: backend
    app.kubernetes.io/managed-by: tekton3
  name: api
  namespace: #@ data.values.namespace
spec:
  replicas: 1
  selector:
    matchLabels:
      app: api
  template:
    metadata:
      labels:
        app: api
    spec:
      containers:
        - image: quay.io/openshift-pipeline/vote-api:latest
          imagePullPolicy: Always
          name: api
          ports:
            - containerPort: 9000
              protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: api
  name: api
  namespace: #@ data.values.namespace
spec:
  type: ClusterIP
  ports:
    - protocol: TCP
      port: 9000
      targetPort: 9000
  selector:
    app: api

example-pipeline.yaml

#@ load("@ytt:data", "data")

---
apiVersion: v1
kind: Namespace
metadata:
  name: #@ data.values.namespace
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: admin
  namespace: #@ data.values.namespace
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: admin
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: #@ data.values.developeruser
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: api-repo
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  type: git
  params:
    - name: url
      value: http://github.com/openshift-pipelines/vote-api.git
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: api-image
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  type: image
  params:
    - name: url
      value: #@ "image-registry.openshift-image-registry.svc:5000/{}/api:latest".format(data.values.namespace)
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: ui-repo
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  type: git
  params:
    - name: url
      value: http://github.com/openshift-pipelines/vote-ui.git
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: ui-image
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  type: image
  params:
    - name: url
      value: #@ "image-registry.openshift-image-registry.svc:5000/{}/ui:latest".format(data.values.namespace)
---
apiVersion: tekton.dev/v1alpha1
kind: Task
metadata:
  name: apply-manifests
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  inputs:
    resources:
      - {type: git, name: source}
    params:
      - name: manifest_dir
        description: The directory in source that contains yaml manifests
        type: string
        default: "k8s"

  steps:
    - name: apply
      image: quay.io/openshift/origin-cli:latest
      workingDir: /workspace/source
      command: ["/bin/bash", "-c"]
      args:
        - |-
          echo Applying manifests in $(inputs.params.manifest_dir) directory
          oc apply -f $(inputs.params.manifest_dir)
          echo -----------------------------------
---
apiVersion: tekton.dev/v1alpha1
kind: Task
metadata:
  name: update-deployment
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  inputs:
    resources:
      - {type: image, name: image}
    params:
      - name: deployment
        description: The name of the deployment patch the image
        type: string

  steps:
    - name: patch
      image: quay.io/openshift/origin-cli:latest
      command: ["/bin/bash", "-c"]
      args:
        - |-
          oc patch deployment $(inputs.params.deployment) --patch='{"spec":{"template":{"spec":{
            "containers":[{
              "name": "$(inputs.params.deployment)",
              "image":"$(inputs.resources.image.url)"
            }]
          }}}}'
---
apiVersion: tekton.dev/v1alpha1
kind: Pipeline
metadata:
  name: build-and-deploy
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/change-group: "tekton/pipeline"
spec:
  resources:
    - name: api-repo
      type: git
    - name: api-image
      type: image
    - name: ui-repo
      type: git
    - name: ui-image
      type: image

  tasks:
    - name: build-api
      taskRef:
        name: buildah
        kind: ClusterTask
      resources:
        inputs:
          - name: source
            resource: api-repo
        outputs:
          - name: image
            resource: api-image
      params:
        - name: TLSVERIFY
          value: "false"

    - name: apply-api-manifests
      taskRef:
        name: apply-manifests
      resources:
        inputs:
          - name: source
            resource: api-repo
      runAfter:
        - build-api

    - name: update-api-image
      taskRef:
        name: update-deployment
      resources:
        inputs:
          - name: image
            resource: api-image
      params:
        - name: deployment
          value: "api"
      runAfter:
        - apply-api-manifests

    - name: build-ui
      taskRef:
        name: s2i-python-3
        kind: ClusterTask
      resources:
        inputs:
          - name: source
            resource: ui-repo
        outputs:
          - name: image
            resource: ui-image
      params:
        - name: TLSVERIFY
          value: "false"

    - name: apply-ui-manifests
      taskRef:
        name: apply-manifests
      resources:
        inputs:
          - name: source
            resource: ui-repo
      runAfter:
        - build-ui
        - update-api-image

    - name: update-ui-image
      taskRef:
        name: update-deployment
      resources:
        inputs:
          - name: image
            resource: ui-image
      params:
        - name: deployment
          value: "ui"
      runAfter:
        - apply-ui-manifests
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineRun
metadata:
  name: build-and-deploy
  namespace: #@ data.values.namespace
  annotations:
    kapp.k14s.io/versioned: ''
    kapp.k14s.io/change-rule: "upsert after upserting tekton/pipeline"
spec:
  pipelineRef:
    name: build-and-deploy
  resources:
  - name: api-repo
    resourceRef:
      name: api-repo
  - name: api-image
    resourceRef:
      name: api-image
  - name: ui-repo
    resourceRef:
      name: api-repo
  - name: ui-image
    resourceRef:
      name: api-image
  serviceAccountName: pipeline
  timeout: 1h0m0s

Process

Deployed (note /tmp/kapp/kapp is my modified kapp):
```
ytt ytt -f example-app.yaml -f example-pipeline.yaml -f values.yaml | /tmp/kapp/kapp deploy -a tekton-sample -n default  -y -f-
```

Changed in example-app, line 97 to a new value, and executed again:
```
ytt ytt -f example-app.yaml -f example-pipeline.yaml -f values.yaml | /tmp/kapp/kapp deploy -a tekton-sample -n default  -y -f-
```

And got the error:

```
panic: Invalid template version

goroutine 1 [running]:
github.com/k14s/kapp/pkg/kapp/diff.TemplateResource.Version(0x20bbe00, 0xc00002d2c0, 0x0, 0x0, 0x0, 0x203000)
        github.com/k14s/kapp@/pkg/kapp/diff/template_resource.go:45 +0x9b
github.com/k14s/kapp/pkg/kapp/diff.ChangeSetWithTemplates.groupResourcesByTemplate.func2(0x1, 0x0, 0xc0008f6718)
        github.com/k14s/kapp@/pkg/kapp/diff/change_set_with_templates.go:87 +0x6f
sort.insertionSort_func(0xc0008f6798, 0xc0004a1d40, 0x0, 0x2)
        sort/zfuncversion.go:12 +0xb1
sort.quickSort_func(0xc0008f6798, 0xc0004a1d40, 0x0, 0x2, 0x4)
        sort/zfuncversion.go:158 +0x1f3
sort.Slice(0x1cd10a0, 0xc0003c4d00, 0xc0008f6798)
        sort/slice.go:17 +0xf1
github.com/k14s/kapp/pkg/kapp/diff.ChangeSetWithTemplates.groupResourcesByTemplate(0xc0004a4800, 0x1b, 0x20, 0xc000466200, 0xf, 0x10, 0xc00034a540, 0x2, 0x2, 0x1, ...)
        github.com/k14s/kapp@/pkg/kapp/diff/change_set_with_templates.go:86 +0x15a
github.com/k14s/kapp/pkg/kapp/diff.ChangeSetWithTemplates.Calculate(0xc0004a4800, 0x1b, 0x20, 0xc000466200, 0xf, 0x10, 0xc00034a540, 0x2, 0x2, 0x1, ...)
        github.com/k14s/kapp@/pkg/kapp/diff/change_set_with_templates.go:32 +0xd7
github.com/k14s/kapp/pkg/kapp/cmd/app.(*DeployOptions).calculateAndPresentChanges(0xc0002ad440, 0xc0004a4800, 0x1b, 0x20, 0xc000466200, 0xf, 0x10, 0xc000358600, 0x1, 0x1, ...)
        github.com/k14s/kapp@/pkg/kapp/cmd/app/deploy.go:288 +0x3d6
github.com/k14s/kapp/pkg/kapp/cmd/app.(*DeployOptions).Run(0xc0002ad440, 0x0, 0x0)
        github.com/k14s/kapp@/pkg/kapp/cmd/app/deploy.go:136 +0x7a8
github.com/k14s/kapp/pkg/kapp/cmd/app.NewDeployCmd.func1(0xc00042af00, 0xc0004d8720, 0x0, 0x6, 0xc0004dee40, 0xc0000dbbe0)
        github.com/k14s/kapp@/pkg/kapp/cmd/app/deploy.go:48 +0x2a
github.com/k14s/kapp/pkg/kapp/cmd.NewKappCmd.func1.1(0xc00042af00, 0xc0004d8720, 0x0, 0x6, 0x0, 0x0)
        github.com/k14s/kapp@/pkg/kapp/cmd/kapp.go:122 +0xcc
github.com/cppforlife/cobrautil.ReconfigureLeafCmd.func1(0xc00042af00, 0xc0004d8720, 0x0, 0x6, 0x0, 0x0)
        github.com/cppforlife/[email protected]/misc.go:67 +0x135
github.com/cppforlife/cobrautil.WrapRunEForCmd.func1.1(0xc00042af00, 0xc0004d8720, 0x0, 0x6, 0x0, 0x0)
        github.com/cppforlife/[email protected]/misc.go:25 +0xaf
github.com/cppforlife/cobrautil.WrapRunEForCmd.func1.1(0xc00042af00, 0xc0004d8720, 0x0, 0x6, 0x0, 0x0)
        github.com/cppforlife/[email protected]/misc.go:25 +0xaf
github.com/spf13/cobra.(*Command).execute(0xc00042af00, 0xc0004d8660, 0x6, 0x6, 0xc00042af00, 0xc0004d8660)
        github.com/spf13/[email protected]/command.go:762 +0x460
github.com/spf13/cobra.(*Command).ExecuteC(0xc00042a500, 0xc00042a500, 0xc00030b5c0, 0x103b32a)
        github.com/spf13/[email protected]/command.go:852 +0x2ea
github.com/spf13/cobra.(*Command).Execute(...)
        github.com/spf13/[email protected]/command.go:800
main.main()
        github.com/k14s/kapp@/cmd/kapp/kapp.go:27 +0x16f
```

TaskRun resource output

apiVersion: tekton.dev/v1alpha1
kind: TaskRun
metadata:
  annotations:
    kapp.k14s.io/identity: v1;tekton-sample/tekton.dev/Task/apply-manifests;tekton.dev/v1alpha1
    kapp.k14s.io/nonce: "1582739835959499000"
    kapp.k14s.io/original: '{"apiVersion":"tekton.dev/v1alpha1","kind":"Task","metadata":{"labels":{"kapp.k14s.io/app":"1582739791109138000","kapp.k14s.io/association":"v1.84b72e873db941ac9c96fc2056ed1778"},"name":"apply-manifests","namespace":"tekton-sample"},"spec":{"inputs":{"params":[{"default":"k8s","description":"The
      directory in source that contains yaml manifests","name":"manifest_dir","type":"string"}],"resources":[{"name":"source","type":"git"}]},"steps":[{"args":["echo
      Applying manifests in $(inputs.params.manifest_dir) directory\noc apply -f $(inputs.params.manifest_dir)\necho
      -----------------------------------"],"command":["/bin/bash","-c"],"image":"quay.io/openshift/origin-cli:latest","name":"apply","workingDir":"/workspace/source"}]}}'
    kapp.k14s.io/original-diff: |
      - type: test
        path: /metadata/annotations
        value: {}
      - type: remove
        path: /metadata/annotations
      - type: test
        path: /spec/steps/0/resources
        value: {}
      - type: remove
        path: /spec/steps/0/resources
    kapp.k14s.io/original-diff-full: ""
    kapp.k14s.io/original-diff-md5: 35806250b5c519f4774c2cf9216b956d
    kapp.k14s.io/versioned: ""
  creationTimestamp: "2020-02-26T17:58:34Z"
  generation: 1
  labels:
    app.kubernetes.io/managed-by: tekton-pipelines
    kapp.k14s.io/app: "1582739791109138000"
    kapp.k14s.io/association: v1.84b72e873db941ac9c96fc2056ed1778
    tekton.dev/pipeline: build-and-deploy
    tekton.dev/pipelineRun: build-and-deploy-ver-2
    tekton.dev/pipelineTask: apply-api-manifests
    tekton.dev/task: apply-manifests
  name: build-and-deploy-ver-2-apply-api-manifests-k5ckt
  namespace: tekton-sample
  ownerReferences:
  - apiVersion: tekton.dev/v1alpha1
    blockOwnerDeletion: true
    controller: true
    kind: PipelineRun
    name: build-and-deploy-ver-2
    uid: 98e5fddb-dfb4-4c01-8961-98293c4d6ac3
  resourceVersion: "80380"
  selfLink: /apis/tekton.dev/v1alpha1/namespaces/tekton-sample/taskruns/build-and-deploy-ver-2-apply-api-manifests-k5ckt
  uid: af8ad901-0b0c-4b10-93bd-111e24d09b36
spec:
  inputs:
    resources:
    - name: source
      resourceRef:
        name: api-repo
  outputs: {}
  serviceAccountName: pipeline
  taskRef:
    kind: Task
    name: apply-manifests
  timeout: 1h0m0s
status:
  completionTime: "2020-02-26T17:58:50Z"
  conditions:
  - lastTransitionTime: "2020-02-26T17:58:50Z"
    message: All Steps have completed executing
    reason: Succeeded
    status: "True"
    type: Succeeded
  podName: build-and-deploy-ver-2-apply-api-manifests-k5ckt-pod-x7d4c
  resourcesResult:
  - digest: ""
    key: commit
    name: ""
    resourceRef: {}
    value: 374d1daa9ee175fcf590cb62402ed43076973b0d
  startTime: "2020-02-26T17:58:34Z"
  steps:
  - container: step-apply
    imageID: quay.io/openshift/origin-cli@sha256:9bbc48ded57e662103f226217855caf107b957fbb4febb7da650bfe25d307f7b
    name: apply
    terminated:
      containerID: cri-o://a65487cf28816569b72cf8b573407a7539996ee938de909d8e29858c3a4f2248
      exitCode: 0
      finishedAt: "2020-02-26T17:58:50Z"
      reason: Completed
      startedAt: "2020-02-26T17:58:49Z"
  - container: step-git-source-api-repo-hlj9j
    imageID: quay.io/openshift-pipeline/tektoncd-pipeline-git-init@sha256:0956ae04297fe4740af495ec1d6d51bd7fbd79686f5d5a4ea09ca44c4e9838cf
    name: git-source-api-repo-hlj9j
    terminated:
      containerID: cri-o://432b03d52573f2217a750de8bef5e1052a0acc9e6cc0d6647249b00ba685b081
      exitCode: 0
      finishedAt: "2020-02-26T17:58:48Z"
      message: '[{"name":"","digest":"","key":"commit","value":"374d1daa9ee175fcf590cb62402ed43076973b0d","resourceRef":{}}]'
      reason: Completed
      startedAt: "2020-02-26T17:58:47Z"

values.yaml

#@data/values
---
namespace: tekton-sample
developeruser: developer