readFileSync() Function

The readFileSync() function will read a local file in the jsPolicy container and return the contents as a string. If the file cannot be found undefined will be returned.

Example#

This example shows how you can directly access the Kubernetes API within a policy, without calling any of the predefined jsPolicy functions except readFileSync and fetchSync.

apiVersion: policy.jspolicy.com/v1beta1
kind: JsPolicy
metadata:
  name: "read-file-policy.example.com"
spec:
  operations: ["CREATE"]
  resources: ["pods"]
  javascript: |
    // read service account token.
    const token = readFileSync("/var/run/secrets/kubernetes.io/serviceaccount/token");
  
    // retrieve all namespaces from the kube service directly, isn't that cool?
    const res = fetchSync("https://kubernetes.default/api/v1/namespaces", {
      "method": "GET",
      "insecure": true,
      "headers": {
        "Authorization": "bearer " + token
      }
    })
    if (res.ok) {
      const namespaceList = res.json();
      namespaceList.items.forEach(namespace => {
        print(namespace.metadata.name);
      });
    } else {
      print("Something went wrong (" + res.status + "): " + res.text());
    }