canonical_service_mesh.utils

Helper utilities for Charmed Service Mesh.

Submodules

Functions

charm_kubernetes_label(→ str)

Generate a Kubernetes-compliant label value.

generate_telemetry_labels(→ dict[str, str])

Generate telemetry labels for the application.

get_peer_identity_for_juju_application(→ str)

Return a Juju application's peer identity.

get_peer_identity_for_service_account(→ str)

Return a ServiceAccount's peer identity.

Package Contents

canonical_service_mesh.utils.charm_kubernetes_label(model_name: str, app_name: str, prefix: str = '', suffix: str = '', max_length: int = 63, separator: str = '.') → str

Generate a Kubernetes-compliant label value.

Returns a label in the form {prefix}{model_name}{separator}{app_name}{suffix}. If the label exceeds max_length characters, model_name and app_name are truncated and a hash is appended to ensure uniqueness.

See https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#syntax-and-character-set

Parameters:

  • model_name – The name of the model (must be at least 1 character).

  • app_name – The name of the application (must be at least 1 character).

  • prefix – An optional prefix to prepend.

  • suffix – An optional suffix to append.

  • max_length – The maximum length of the label string.

  • separator – The separator between model_name and app_name.

Returns:

The generated label string, at most max_length characters long.

Raises:

ValueError – If model_name or app_name is empty, or if the fixed portion is too long.

canonical_service_mesh.utils.generate_telemetry_labels(app_name: str, model_name: str) → dict[str, str]

Generate telemetry labels for the application.

The label key includes model_name and app_name, truncated to fit within Kubernetes’ 63-character limit while maintaining uniqueness via a hash.

Parameters:

  • app_name – The application name.

  • model_name – The model (namespace) name.

Returns:

A dictionary with a single telemetry label.

canonical_service_mesh.utils.get_peer_identity_for_juju_application(app_name: str, namespace: str) → str

Return a Juju application’s peer identity.

Format is defined by principals in the Istio AuthorizationPolicy Source reference. Relies on the Juju convention that each application gets a ServiceAccount of the same name.

Parameters:

  • app_name – The name of the Juju application.

  • namespace – The Kubernetes namespace of the application.

Returns:

The SPIFFE identity string for the application.

canonical_service_mesh.utils.get_peer_identity_for_service_account(service_account: str, namespace: str) → str

Return a ServiceAccount’s peer identity.

Format: cluster.local/ns/{namespace}/sa/{service_account}

Parameters:

  • service_account – The Kubernetes ServiceAccount name.

  • namespace – The Kubernetes namespace.

Returns:

The SPIFFE identity string for the service account.