Charm Tech pulse 2024#8 - Exciting Updates!

Pulse #8 highlights: We’ve got some fantastic new features and improvements for you: added support for user secrets in Harness, improved the ops usage in the Juju Kubernetes charm tutorial, improved configuration, improved ops-scenario API, finished initial implementation in Pebble of health checks as changes and tasks, and more!

The ops library

  • Good news! We’ve added support for user secrets in Harness. Every secret has an owner – the entity creating, updating, sharing, or removing it. Starting with Juju 3.3, the secret owner can be a user with model admin access, in which case, the secret is known as a “user secret”. To add a user secret, you can run juju add-secret, and now in your test, you can simulate this behaviour by calling Harness.add_user_secret.
  • Configuration just got better! We’ve fixed the types related to the model, and we’re making it easier to use secrets in the config. Instead of explicitly calling Model.get_secret after reading the secret ID from the config, we’re planning on providing a direct way to access the secret object. Check out the draft PR here!
  • We’re also working on converting tests in the ops framework from unittest to pytest style. It’s still a work in progress, but we’re aiming to get it done before the next cycle.
  • Unfortunately, we had to revert the previously introduced support for pebble-change-updated notice due to a fan-out issue with its usage in Juju, which was reverted. We’ll give it another shot in the future, possibly in Juju 3.6.


  • Great news for users of the Juju Kubernetes charm tutorial! We’ve made significant improvements to the ops usage, including better import statements, fixing isort version issues, avoiding unnecessary can_connect calls, eliminating SystemExit raises, and more.
  • We’re adding Scenario support for Pebble custom notices and CloudSpec.
  • Helped review Kratos External IDP charm to make it searchable in Charmhub.
  • @tony-meyer has been working hard on removing python-libjuju AllWatcher and identifying gaps in Juju API without it. The Juju team will be removing the AllWatcher in Juju 4.0. The Charm Tech will help out with this by releasing a new python-libjuju version that works with both 4.0 and 3.6, which does not use the AllWatcher. This will make a significant difference, especially for large models where running an AllWatcher can be expensive but all you want to do is deploy and query the state of a single application. This pulse, we’ve looked into what gaps there are in the Juju API in order to make this happen.
  • As mentioned earlier, Juju’s support for the new Pebble change-update notice has also been reverted.


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