Outputs¶

Binding outputs can be useful to communicate and reuse computation results between operations.

Supported operations¶

Currently, only script and command operations support outputs.

Lifetime of outputs¶

Once an output has been added in the form of a binding, this binding will be available to all following operations in the same step.

Currently, outputs do not cross the step boundaries.

Matching¶

An output supports an optional match field. The match is used to conditionally create a binding.

In the case of applying a file, for example, the file may contain multiple resources. The match can be used to select the resource to use for creating the binding.

Examples¶

The example below defines invokes a kubectl command to get a configmap from the cluster in json format.

The json output is then parsed and added to the $cm binding and the next operation performs an assertion on it by reading the binding instead of querying the cluster.

Output in script

apiVersion: chainsaw.kyverno.io/v1alpha1
kind: Test
metadata:
  name: example
spec:
  steps:
  # ...
  - try:
    - script:
        content: kubectl get cm quick-start -n $NAMESPACE -o json
        outputs:
        - match:
            (json_parse($stdout)):
              apiVersion: v1
              kind: ConfigMap
          name: cm
          value: (json_parse($stdout))
    - assert:
        resource:
          ($cm):
            metadata:
              (uid != null): true
  # ...

Output in command

apiVersion: chainsaw.kyverno.io/v1alpha1
kind: Test
metadata:
  name: example
spec:
  steps:
  # ...
  - try:
    - command:
        entrypoint: kubectl
        args:
        - get
        - cm
        - quick-start
        - -n
        - $NAMESPACE
        - -o
        - json
        outputs:
        - match:
            (json_parse($stdout)):
              apiVersion: v1
              kind: ConfigMap
          name: cm
          value: (json_parse($stdout))
    - assert:
        resource:
          ($cm):
            metadata:
              (uid != null): true
  # ...