Automatically overwrite dashboard UIDs with a prescribed naming pattern, on the provider side

[sed-i]

Issue

• https://github.com/canonical/observability/blob/main/decision-records/2024-08-29--dashboard-uid-collision.md

Solution

Use shake_256 to generate alt-uid, and always use it, overwriting any pre-existing uid.

In tandem with:

• Add dashboard uid generation helper cos-lib#114
• Autogenerate dashboard_alt_uid on the provider side grafana-agent-operator#224
• Replace GrafanaDashboard with LZMABase64 grafana-agent-k8s-operator#337

Context

Afaict, the only user of the .add_dashboard method is https://github.com/canonical/cos-registration-server-k8s-operator/blob/6e156f0b1367f7cc6ce12d89f6a367bf491fea7f/src/charm.py#L240.

Testing Instructions

First, prepare the charms locally:

1. Copy the grafana_dashboard lib from this PR into grafana-agent-operator from Autogenerate dashboard_alt_uid on the provider side grafana-agent-operator#224.
2. Copy cos-agent lib from Autogenerate dashboard_alt_uid on the provider side grafana-agent-operator#224 into zookeeper.
3. In zookeeper, update deps using the following commands. Then remove all the --hash from requirements.txt:

poetry update
poetry lock
poetry install
poetry export -f requirements.txt --output requirements.tx

4. Pack and deploy all charms as follows:

graph LR
subgraph lxd
zookeeper --- grafana-agent
zookeeper2 --- grafana-agent
end
subgraph microk8s
grafana-agent --- grafana
end

Loading

bundle: kubernetes
applications:
  graf:
    charm: ./grafana-k8s_ubuntu-20.04-amd64.charm
    scale: 1
    trust: true
--- # overlay.yaml
applications:
  graf:
    offers:
      graf:
        endpoints:
        - grafana-dashboard
        acl:
          admin: admin

default-base: [email protected]/stable
saas:
  graf:
    url: microk8s:admin/graf.graf
applications:
  ga2:
    charm: ./grafana-agent_ubuntu-22.04-amd64.charm
  zk:
    charm: ./zookeeper_ubuntu-22.04-amd64.charm
    num_units: 2
  zk2:
    charm: ./zookeeper_ubuntu-22.04-amd64.charm
    num_units: 2
relations:
- - ga2:cos-agent
  - zk:cos-agent
- - ga2:cos-agent
  - zk2:cos-agent
- - ga2:grafana-dashboards-provider
  - graf:grafana-dashboard

Upgrade Notes

To enable automatic uid collision prevention for the dashboards in your charm:

1. If cos-lib (cosl) is pinned in your charm, bump it to 0.0.50 or higher.
2. Fetch-lib cos-agent. You should use 0.13 or higher.
3. Refresh your charm.
4. Refresh grafana-agent to revision 369+.

[sed-i]

I'd appreciate your review, @Guillaumebeuzeboc, @taurus-forever, @jdkandersson, @cbartz, @camille-rodriguez, @slapcat, @facundofc.

[jdkandersson]

I'll delegate to @cbartz who has the best understanding of the issue in our team, thank you for preparing the PR!