`run`¶

The run task executes a bash script.

Basic Example¶

The following (partially-specified) experiment executes the one line script kubectl apply using a YAML manifest at the end of the experiment.

kind: Experiment
...
spec:
  ...
  strategy:
    ...
    actions:
      finish:
      - run: kubectl apply -f https://raw.githubusercontent.com/iter8-tools/iter8/master/samples/mysample/manifest.yaml

Conditional Execution¶

The run task can be executed conditionally, where the condition is specified using the if clause. Supported conditions include WinnerFound(), CandidateWon() and their negations using the not keyword.

kind: Experiment
...
spec:
  ...
  strategy:
    ...
    actions:
      finish: # run the following sequence of tasks at the end of the experiment
      - if: CandidateWon()
        run: "kubectl apply -f https://raw.githubusercontent.com/iter8-tools/iter8/master/samples/knative/quickstart/candidate.yaml"
      - if: not CandidateWon()
        run: "kubectl apply -f https://raw.githubusercontent.com/iter8-tools/iter8/master/samples/knative/quickstart/baseline.yaml"

Secret¶

The run task can be used with a Kubernetes secret provided to it as an input.

kind: Experiment
...
spec:
  ...
  strategy:
    ...
    actions:
      finish: # run the following sequence of tasks at the end of the experiment
      - run: "git clone https://username:@< .Secret 'token' >@@github.com/username/repo.git"
        with:
          # reference to a K8s secret resource in the namespace/name format. If no namespace is specified, the namespace of the secret is assumed to be that of the experiment.
          secret: myns/mysecret

In the above example, a token value is extracted from the given Kubernetes secret, and inserted into the (templated) git clone script. This task requires the secret resource mysecret to be available in the myns namespace, and requires the secret to contain token as a key in its data section.

Placeholders¶

The script to be executed may contain placeholders. Placeholders in this task use @< and >@ as the left and right delimiters respectively. Placeholders are especially handy for specifying data in a Kubernetes secret, supplying the secret as part of the task, and extracting the secret within the script at runtime. See above for an example.

Scratch folder¶

The SCRATCH_DIR environment variable points to a scratch folder. This intended for creating and manipulating files as part of the run script.

kind: Experiment
...
spec:
  ...
  strategy:
    ...
    actions:
      finish: # run the following sequence of tasks at the end of the experiment
      - run: |
          cd $SCRATCH_DIR
          echo "hello" > world.txt

Available commands¶

The Dockerfile used to build the task runner image is here. In addition to the standard linux commands (sed, awk, ...) available in its base image, the task runner also includes the commands kubectl, kustomize, helm, yq, git, curl, and gh.

kind: Experiment
...
spec:
  ...
  strategy:
    ...
    actions:
      finish: # a few things you can do within the run script
      - run: |
          kustomize build hello/world/folder > manifest.yaml
          kubectl apply -f manifest.yaml
          helm upgrade my-app helm/chart --install
          yq -i a=b manifest.yaml
          git clone https://github.com/iter8-tools/iter8.git
          gh pr create
          curl https://iter8.tools -O $SCARCH_DIR/i.html

Inputs¶

Field name	Field type	Description	Required
secret	string	Reference to a K8s secret in the `namespace/name` format. If no namespace is specified, then the namespace is assumed to be that of the experiment.	No

Result¶

The script will be executed. If this script exits with a non-zero error code, the run task and therefore the experiment to which it belongs will fail.

run¶