tko

TKO

tko = Tekton + ko

This is a WIP tool for generating Tekton tasks from Go types.

The goal is to let developers write Tasks in Go to make it easier to write Tasks with tests that don't depend on Docker / Kubernetes, and rely on code generation to handle the rest.

tko generates a ko-compatible Task + main.go, which can then be applied, published, etc.

Usage

$ tko <package> [<ko flags> | <tko flags>]

See https://ko.build/reference/ko_resolve/ for details on <ko flags>

Writing Tasks

tko expects Tasks to follow a particular format. All Tasks should be Go structs with names ending in Task.

Each Task can declare Params and Results fields to represent Task I/O (name must match, but the struct type can be whatever you choose)

Tasks should be a runnable Go program and implement the tko.Runner interface. In most cases you can use a simple main wrapper:

func main() {
	tko.Execute(context.Background(), new(MyTask))
}

tko.Execute will automatically:

• Generate command line flags matching variables defined in Params.
• Write Result output for data (Tasks are responsible for populating the Results field).

Example

The example directory contains a functioning tko Task.

$ export KO_DOCKER_REPO="ttl.sh/tko-example"
$ tko github.com/wlynch/tko/example
...
Creating Tekton Bundle:
        - Added Task: MyTask to image

Pushed Tekton Bundle to ttl.sh/tko-example/mytask@sha256:042026b6d4ab01f4eb4d403ebfe17f00f25b69753d9132feff35bf7de54ae88b

Use the Task

$ cat run.yaml
apiVersion: tekton.dev/v1beta1
kind: TaskRun
metadata:
  generateName: hello-
spec:
  params:
    - name: A
      value: "foo"
    - name: B
      value: "1"
  taskRef:
    name: "MyTask"
    bundle: ttl.sh/tko-example/mytask:latest
$ kubectl create -f run.yaml
taskrun.tekton.dev/hello-8cbnm created
$ tkn tr logs hello-8cbnm
[unnamed-0] hello foo 1

Get the SBOM

Because the Task is built with ko, an SBOM is automatically generated at build time.

$ tkn bundle list ttl.sh/tko-example/mytask@sha256:042026b6d4ab01f4eb4d403ebfe17f00f25b69753d9132feff35bf7de54ae88b -o yaml
*Warning*: This is an experimental command, it's usage and behavior can change in the next release(s)
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  creationTimestamp: null
  name: MyTask
spec:
  params:
  - name: A
    type: string
  - name: B
    type: string
  results:
  - name: C
    type: string
  - name: D
    type: string
  steps:
  - args:
    - -A
    - $(params.A)
    - -B
    - $(params.B)
    image: ttl.sh/tko-example/example-866e979aaefecbc4e8e26d4fbed651a0@sha256:4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086
    name: ""
    resources: {}
$ cosign download sbom ttl.sh/tko-example/example-866e979aaefecbc4e8e26d4fbed651a0@sha256:4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086
{
  "SPDXID": "SPDXRef-DOCUMENT",
  "name": "sbom-sha256:4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086",
  "spdxVersion": "SPDX-2.2",
  "creationInfo": {
    "created": "2023-02-11T00:09:29Z",
    "creators": [
      "Tool: ko 0.12.0"
    ]
  },
  "dataLicense": "CC0-1.0",
  "documentNamespace": "http://spdx.org/spdxdocs/ko/sha256:4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086",
  "documentDescribes": [
    "SPDXRef-Package-sha256-4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086"
  ],
  "packages": [
    {
      "SPDXID": "SPDXRef-Package-sha256-4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086",
      "name": "sha256:4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086",
      "filesAnalyzed": false,
      "licenseDeclared": "NOASSERTION",
      "licenseConcluded": "NOASSERTION",
      "downloadLocation": "NOASSERTION",
      "copyrightText": "NOASSERTION",
      "externalRefs": [
        {
          "referenceCategory": "PACKAGE_MANAGER",
          "referenceLocator": "pkg:oci/image@sha256:4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086?mediaType=application%2Fvnd.oci.image.manifest.v1%2Bjson",
          "referenceType": "purl"
        }
      ]
    },
    {
      "SPDXID": "SPDXRef-Package-sha256-1cbda2ed63073d3e391d559467f54e6febdb0fd26d1a574f0786f30a01f3bba4",
      "name": "distroless.dev/static@sha256:1cbda2ed63073d3e391d559467f54e6febdb0fd26d1a574f0786f30a01f3bba4",
      "versionInfo": "distroless.dev/static:latest",
      "filesAnalyzed": false,
      "licenseDeclared": "NOASSERTION",
      "licenseConcluded": "NOASSERTION",
      "downloadLocation": "NOASSERTION",
      "copyrightText": "NOASSERTION",
      "checksums": [
        {
          "algorithm": "SHA256",
          "checksumValue": "1cbda2ed63073d3e391d559467f54e6febdb0fd26d1a574f0786f30a01f3bba4"
        }
      ],
      "externalRefs": [
        {
          "referenceCategory": "PACKAGE_MANAGER",
          "referenceLocator": "pkg:oci/image@sha256:1cbda2ed63073d3e391d559467f54e6febdb0fd26d1a574f0786f30a01f3bba4?repository_url=distroless.dev%2Fstatic\u0026tag=latest",
          "referenceType": "purl"
        }
      ]
    },
    {
      "SPDXID": "SPDXRef-Package-github.com.wlynch.tko-(devel)",
      "name": "github.com/wlynch/tko",
      "filesAnalyzed": false,
      "licenseDeclared": "NOASSERTION",
      "licenseConcluded": "NOASSERTION",
      "downloadLocation": "https://github.com/wlynch/tko",
      "copyrightText": "NOASSERTION",
      "externalRefs": [
        {
          "referenceCategory": "PACKAGE_MANAGER",
          "referenceLocator": "pkg:golang/github.com/wlynch/tko@(devel)?type=module",
          "referenceType": "purl"
        }
      ]
    }
  ],
  "relationships": [
    {
      "spdxElementId": "SPDXRef-DOCUMENT",
      "relationshipType": "DESCRIBES",
      "relatedSpdxElement": "SPDXRef-Package-sha256-4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086"
    },
    {
      "spdxElementId": "SPDXRef-Package-sha256-4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086",
      "relationshipType": "DESCENDANT_OF",
      "relatedSpdxElement": "SPDXRef-Package-sha256-1cbda2ed63073d3e391d559467f54e6febdb0fd26d1a574f0786f30a01f3bba4"
    },
    {
      "spdxElementId": "SPDXRef-Package-sha256-4dc3ec2734739c31a31f1485490cc54841941d0bc5ccf4bb764ad77ae6c49086",
      "relationshipType": "CONTAINS",
      "relatedSpdxElement": "SPDXRef-Package-github.com.wlynch.tko-(devel)"
    }
  ]
}