canonical_service_mesh

A shared utility library for the Charmed Service Mesh ecosystem.

Purpose

The Charmed Service Mesh ecosystem will contain charms that integrate service mesh technologies into the Juju ecosystem. These charms and their interface libraries share a significant amount of common code: Pydantic models for Kubernetes resource creation and service mesh CRD resources, lightkube-based resource management, label generation and authorization policies etc.

This package is the single home for all of that shared utility code. By centralizing it here, every charm and interface library depends on one well-maintained package instead of copying code between repositories or pulling from multiple helper packages.

Ecosystem

The ecosystem has three layers:

1. This package (canonical_service_mesh) provides models, resource managers, and helpers. It has no knowledge of Juju relations or charm lifecycle, which keeps it testable and reusable.
2. Interface libraries (via the charmlibs monorepo) define the relation databag schemas and the interface classes. They import from this package.
3. Charms contain purely the charm specific logic and consume the interface and the canonical_service_mesh libraries.

Package structure

enums

Shared enumerations used across the ecosystem.

models

Pydantic models for Kubernetes and service mesh resources. The top-level models module contains generic Kubernetes Gateway API resource models. The models.istio subpackage contains Istio-specific CRD specs for authorization policies and request authentication.

utils

Helper functions for Kubernetes label generation, Juju identity resolution, and service mesh specific operations like label ConfigMap reconciliation and policy resource construction.

k8s

Kubernetes resource management built on lightkube. The k8s.resource_manager subpackage provides declarative resource lifecycle management with label-based ownership, policy resource management, and batch operations. The k8s.types subpackage defines lightkube type aliases and custom resource definitions.