This functionality is now available in Tekton's experimental repo: https://github.com/tektoncd/experimental/tree/main/cel
This repo provides an experimental Tekton Custom
Task that, when run, simply
evaluates a CEL expression passed as a
parameter, and fails if the result is false, or a non-boolean value, or if
the expression is invalid or can't be evaluated.
The intention is to demonstrate the kinds of things a Custom Task can do, and to demonstrate how to write a Custom Task.
Install and configure ko.
ko apply -f controller.yaml
This will build and install the controller on your cluster, in the namespace
cel-task.
$ kubectl create -f cel-run.yaml
run.tekton.dev/cel-run-fqqjt created
$ kubectl get runs
NAME SUCCEEDED REASON STARTTIME COMPLETIONTIME
cel-run-fqqjt True ExpressionTrue 2s 2s
If you change the expression in cel-run.yaml to something that evaluates to
false, or an invalid CEL expression, the Task will fail instead.