Creating Tekton tasks is real fun! Its similarities to pod containers, and how it works make developing and testing super easy. Still, sometimes it is necessary to reuse steps in multiple tasks, like when using reviewdog.
In this post, we will learn how to do this very easily using kustomize, and the repo danielfbm/tekton-tasks-kustomize has a ready-to-use example.
Let's say we want two different tasks golang-test and golangci-lint need to add a reviewdog-report step as seen below:
The most obvious way would be copying and pasting the steps, but for more complex scenarios, where there are n tasks, this becomes error-prone. Using a template engine like helm could help, but learning another templating engine, plus having to change the contents of said tasks also becomes a burden. Instead, kustomize has a set of tools to make this job easier, while enjoying reutilizing tasks from the tektoncd/catalog.
Folder structure
├── overlays └── tasks - tasks will host your tasks files;
- overlays will host your patches, like adding a shared step;
Tasks
Prepare your tasks, for this example, we will use golang-test and golangci-lint, please adjust accordingly.
Snippet
With the tasks ready, it is time to prepare a snippet, which should consist of all the necessary additions, like params, workspaces, results, steps, etc:
spec: params: # since we are splitting the steps, the previous step needs to save the output to a file - name: report-file default: reportfile description: Report file with errors # format of the report file - name: format default: golint description: Format of error input from the task # reviewdog supports many reporter types - name: reporter default: local description: Reporter type for reviewdog https://github.com/reviewdog/reviewdog#reporters # reviewdog needs a diff for precise pull request comments - name: diff default: git diff FETCH_HEAD description: Diff command https://github.com/reviewdog/reviewdog#reporters workspaces: - name: token description: | Workspace which contains a token file for Github Pull Request comments. Must have a token file with the Github API access token steps: - name: reviewdog-report image: golangci/golangci-lint:v1.31-alpine # both have the same workspace name workingDir: $(workspaces.source.path) script: | #!/bin/sh set -ue wget -O - -q https://raw.githubusercontent.com/reviewdog/reviewdog/master/install.sh | sh -s -- -b $(go env GOPATH)/bin export REVIEWDOG_GITHUB_API_TOKEN=$(cat $(workspaces.token.path)/token) cat $(params.reportfile) | reviewdog -f=$(params.format) -diff="$(params.diff)" Patch
With the above snippet, it is time to create our patch. I've tried using the snippet directly using as a patch but was not successful, so I decided to create a JSON6902 patch:
# parameters - op: add path: /spec/params/- value: name: report-file default: reportfile description: Report file with errors - op: add path: /spec/params/- value: name: format default: golint description: Format of error input from the task - op: add path: /spec/params/- value: name: reporter default: local description: Reporter type for reviewdog https://github.com/reviewdog/reviewdog#reporters - op: add path: /spec/params/- value: name: diff default: git diff FETCH_HEAD description: Diff command https://github.com/reviewdog/reviewdog#reporters # workspaces - op: add path: /spec/workspaces/- value: name: token description: | Workspace which contains a token file for Github Pull Request comments. Must have a token file with the Github API access token # steps - op: add path: /spec/steps/- value: name: reviewdog-report image: golangci/golangci-lint:v1.31-alpine # both have the same workspace name workingDir: $(workspaces.source.path) script: | #!/bin/sh set -ue wget -O - -q https://raw.githubusercontent.com/reviewdog/reviewdog/master/install.sh | sh -s -- -b $(go env GOPATH)/bin export REVIEWDOG_GITHUB_API_TOKEN=$(cat $(workspaces.token.path)/token) cat $(params.reportfile) | reviewdog -f=$(params.format) -diff="$(params.diff)" save as reviewdog-step-patch.yaml and create a kustomization.yaml with the following content:
bases: - ../tasks patches: - path: ./reviewdog-step-patch.yaml target: kind: Task More patching
Make sure all kustomization.yaml files are set up correctly and try running kustomize build overlays. You should see the params, workspaces and params added.
But wait! we still need to connect the dots. Without modifying the imported tasks this would still not work.
For the golangci-lint task, it is necessary to save the result to a file as given in the parameter $(params.report-file), and change the default format for the $(params.format) parameter to golangci-lint:
golangci-lint
- op: replace path: /spec/params/11/default value: golangci-lint - op: replace path: /spec/steps/0/script value: | golangci-lint run $(params.flags) > $(params.report-file) Save the file as overlays/golangci-lint-patch.yaml and add it to the overlays/kustomization.yaml.
[...] - path: ./golangci-lint-patch.yaml target: kind: Task name: golangci-lint golang-test
Here is the change for the golang-test task, and changing it into a golint:
- op: replace path: /spec/steps/0/script value: | if [ ! -e $GOPATH/src/$(params.package)/go.mod ];then SRC_PATH="$GOPATH/src/$(params.package)" mkdir -p $SRC_PATH cp -R "$(workspaces.source.path)/$(params.context)"/* $SRC_PATH cd $SRC_PATH fi golint $(params.packages) > $(params.report-file) Add the entry to overlays/kustomization.yaml:
- path: ./golint-patch.yaml target: kind: Task name: golang-test Suffix
If you want to preserve the original tasks and only add new tasks, just change the overlays/kustomization.yaml adding a suffix to the files:
nameSuffix: -review Testing
Apply your tasks into your Kubernetes cluster using kubectl apply -k overlays or kustomize build overlays | kubectl apply -f -
The resulting file tree should be something like:
├── overlays │ ├── golangci-lint-patch.yaml │ ├── golint-patch.yaml │ ├── kustomization.yaml │ └── reviewdog-step-patch.yaml └── tasks ├── golang-test.yaml ├── golangci-lint.yaml └── kustomization.yaml Enjoy your new golang-test-review and golangci-lint-review.
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