Mutate

Source: hello-pepr-mutate

Pepr Mutate() action is used to modify Kubernetes objects during admission. Mutations allow you to enforce defaults, apply standard labels/annotations, or clean up unwanted metadata before the resource is persisted.

When should you use Mutate?

Use Mutate() when you need to:

Apply default labels or annotations to resources as they are created.
Remove unwanted metadata automatically (labels, annotations, fields).
Normalize user input so objects follow your standards.
Enforce consistent cluster hygiene by modifying objects before they are stored.
Transform objects while still allowing them through.

Code Snippet Examples

This example mutates Secret resources and logs different lifecycle events: create, update, delete, and create-or-update.

View full example on Github

Create Event

When(a.Secret)
  .IsCreated()
  .InNamespace(name)
  .WithName("create-yay")
  .Mutate(function createYay() {
    Log.info("Mutate: create-yay");
  });

Example pod log output:

{"level":30,"time":<timestamp>,"pid":<pid>,"hostname":"pepr-<hostname>","msg":"Mutate: create-yay"}

Create or Update Event

When(a.Secret)
  .IsCreatedOrUpdated()
  .InNamespace(name)
  .WithName("cou-create-yay")
  .Mutate(function couCreateYay() {
    Log.info("Mutate: cou-create-yay");
  });

Example pod log output:

{"level":30,"time":<timestamp>,"pid":<pid>,"hostname":"pepr-<hostname>","msg":"Mutate: cou-create-yay"}

Update Event

When(a.Secret)
  .IsUpdated()
  .InNamespace(name)
  .WithName("update-yay")
  .Mutate(function updateYay() {
    Log.info("Mutate: update-yay");
  });

Example pod log output:

{"level":30,"time":<timestamp>,"pid":<pid>,"hostname":"pepr-<hostname>","msg":"Mutate: update-yay"}

Delete Event

When(a.Secret)
  .IsDeleted()
  .InNamespace(name)
  .WithName("delete-yay")
  .Mutate(function deleteYay() {
    Log.info("Mutate: delete-yay");
  });

Example pod log output:

{"level":30,"time":<timestamp>,"pid":<pid>,"hostname":"pepr-<hostname>","msg":"Mutate: delete-yay"}

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