feat: scaffold garm-configurator charm (ISD-5732)

.github/workflows/charms_lint_and_unit.yaml

@@ -35,6 +35,7 @@ jobs:
         charm:
           - charms/planner-operator
           - charms/webhook-gateway-operator
+          - charms/garm-configurator
     steps:
       - uses: actions/checkout@v6
 

charms/garm-configurator/charmcraft.yaml

@@ -0,0 +1,21 @@
+# This file configures Charmcraft.
+# See https://juju.is/docs/sdk/charmcraft-config for guidance.
+
+name: garm-configurator
+
+type: charm
+
+base: ubuntu@24.04
+platforms:
+  amd64:
+
+summary: Configuration broker charm for GARM scalesets.
+
+description: |
+  Holds configuration for a single GARM scaleset and provider combination,
+  sharing it with the GARM charm via Juju integrations.
+
+parts:
+  charm:
+    source: .
+    plugin: charm

charms/garm-configurator/pyproject.toml

@@ -0,0 +1,86 @@
+# Copyright 2026 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+# Testing tools configuration
+[tool.coverage.run]
+branch = true
+
+[tool.coverage.report]
+show_missing = true
+
+[tool.pytest.ini_options]
+minversion = "6.0"
+log_cli_level = "INFO"
+pythonpath = ["lib", "src"]
+
+# Linting tools configuration
+[tool.ruff]
+target-version = "py310"
+line-length = 99
+
+# enable ruff linters:
+#   S flake8-bandit
+#   B flake8-bugbear
+#   A flake8-builtins
+# CPY flake8-copyright
+# SIM flake8-simplify
+#  TC flake8-type-checking
+#   I isort
+#   N pep8-naming
+#   D pydocstyle
+#   F Pyflakes
+#  UP pyupgrade
+# RUF Ruff-specific rules
+# E/W pycodestyle
+lint.select = ["A", "B", "C", "CPY", "D", "E", "F", "I", "N", "RUF", "S", "SIM", "TC", "UP", "W"]
+lint.ignore = [
+    "B904",
+    "D107",
+    "D203",
+    "D204",
+    "D205",
+    "D213",
+    "D215",
+    "D400",
+    "D404",
+    "D406",
+    "D407",
+    "D408",
+    "D409",
+    "D413",
+    "E501",
+    "S105",
+    "S603",
+    "TC002",
+    "TC006",
+    "UP006",
+    "UP007",
+    "UP035",
+    "UP045",
+]
+lint.per-file-ignores."tests/*" = ["B011", "D100", "D101", "D102", "D103", "D104", "D212", "D415", "D417", "S"]
+lint.flake8-copyright.author = "Canonical Ltd."
+lint.flake8-copyright.min-file-size = 1
+lint.flake8-copyright.notice-rgx = "Copyright\\s\\d{4}([-,]\\d{4})*\\s+"
+lint.mccabe.max-complexity = 10
+lint.pydocstyle.convention = "google"
+
+[tool.codespell]
+skip = "build,lib,venv,icon.svg,.tox,.git,.mypy_cache,.ruff_cache,.coverage,htmlcov,uv.lock,grafana_dashboards"
+
+[tool.mypy]
+check_untyped_defs = true
+disallow_untyped_defs = true
+explicit_package_bases = true
+ignore_missing_imports = true
+namespace_packages = true
+
+[[tool.mypy.overrides]]
+disallow_untyped_defs = false
+module = "tests.*"
+
+[tool.bandit]
+exclude_dirs = ["/venv/"]
+
+[tool.bandit.assert_used]
+skips = ["*/*test.py", "*/test_*.py", "*tests/*.py"]

charms/garm-configurator/requirements.txt

@@ -0,0 +1 @@
+ops==3.7.0

charms/garm-configurator/src/charm.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+# Copyright 2026 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+"""Charm entrypoint for the GARM configurator charm."""
+
+import typing
+
+import ops
+
+
+class GarmConfiguratorCharm(ops.CharmBase):
+    """GARM configurator charm."""
+
+    def __init__(self, *args: typing.Any) -> None:
+        """Initialize the instance.
+
+        Args:
+            args: passthrough to CharmBase.
+        """
+        super().__init__(*args)
+        self.framework.observe(self.on.collect_unit_status, self._on_collect_unit_status)
+
+    def _on_collect_unit_status(self, event: ops.CollectStatusEvent) -> None:
+        """Handle collect-unit-status event.
+
+        Args:
+            event: The collect status event.
+        """
+        event.add_status(ops.ActiveStatus("Ready"))
+
+
+if __name__ == "__main__":
+    ops.main(GarmConfiguratorCharm)

charms/garm-configurator/tests/unit/test_charm.py

@@ -0,0 +1,42 @@
+# Copyright 2026 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+"""Unit tests for GarmConfiguratorCharm."""
+
+import ops
+from scenario import Context, State
+
+from charm import GarmConfiguratorCharm
+
+
+def test_charm_reaches_active_on_install():
+    """
+    arrange: A fresh charm context.
+    act: Run the install event.
+    assert: Unit status is Active.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    out = ctx.run(ctx.on.install(), State())
+    assert out.unit_status == ops.ActiveStatus("Ready")
+
+
+def test_charm_reaches_active_on_config_changed():
+    """
+    arrange: A fresh charm context.
+    act: Run the config-changed event.
+    assert: Unit status is Active.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    out = ctx.run(ctx.on.config_changed(), State())
+    assert out.unit_status == ops.ActiveStatus("Ready")
+
+
+def test_charm_collect_unit_status_emits_active():
+    """
+    arrange: A fresh charm context.
+    act: Run the collect-unit-status event directly.
+    assert: Unit status is Active.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    out = ctx.run(ctx.on.collect_unit_status(), State())
+    assert out.unit_status == ops.ActiveStatus("Ready")

charms/garm-configurator/tox.toml

@@ -0,0 +1,51 @@
+env_list = ["lint", "complexity", "static", "unit", "coverage-report"]
+
+[env_run_base]
+package = "skip"
+set_env = { PYTHONPATH = "{tox_root}/lib:{tox_root}/src:{tox_root}/tests", PYTHONBREAKPOINT = "pdb.set_trace", PY_COLORS = "1" }
+pass_env = ["PYTHONPATH", "CHARM_BUILD_DIR", "MODEL_SETTINGS"]
+
+[env.lint]
+description = "Check code against coding style standards"
+deps = ["ruff", "codespell"]
+commands = [
+  ["codespell", "{tox_root}"],
+  ["ruff", "check", "src"],
+  ["ruff", "format", "--check", "--diff", "src"],
+]
+
+[env.complexity]
+description = "Check cyclomatic complexity"
+deps = ["ruff"]
+commands = [["ruff", "check", "--select", "C90", "src"]]
+
+[env.static]
+description = "Run static type checks"
+deps = ["mypy", "bandit[toml]", "-r requirements.txt"]
+commands = [
+  ["mypy", "src"],
+  ["bandit", "-c", "pyproject.toml", "-r", "src"],
+]
+
+[env.unit]
+description = "Run unit tests"
+deps = ["pytest", "coverage[toml]", "ops-scenario==8.7.0", "-r requirements.txt"]
+commands = [
+  [
+    "coverage",
+    "run",
+    "--source=src",
+    "-m",
+    "pytest",
+    "--tb",
+    "native",
+    "-v",
+    "-s",
+    { replace = "posargs", default = ["tests/unit"], extend = true },
+  ],
+]
+
+[env.coverage-report]
+description = "Report coverage results"
+deps = ["coverage[toml]"]
+commands = [["coverage", "report"]]

charms/tests/integration/test_garm_configurator.py

@@ -0,0 +1,63 @@
+# Copyright 2026 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+"""Integration tests for the garm-configurator charm."""
+
+import logging
+
+import jubilant
+import pytest
+
+from tests.conftest import CHARM_FILE_PARAM
+
+logger = logging.getLogger(__name__)
+
+
+@pytest.fixture(name="garm_configurator_charm_file", scope="module")
+def garm_configurator_charm_file_fixture(pytestconfig: pytest.Config) -> str:
+    """Return the path to the built garm-configurator charm file."""
+    charm = pytestconfig.getoption(CHARM_FILE_PARAM)
+    if not charm:
+        pytest.skip(
+            f"missing required {CHARM_FILE_PARAM} option for garm-configurator integration tests"
+        )
+    if len(charm) > 1:
+        configurator_charms = [f for f in charm if "configurator" in f]
+        if not configurator_charms:
+            pytest.skip(
+                f"no garm-configurator charm file found in {CHARM_FILE_PARAM} option"
+            )
+        return configurator_charms[0]
+    return charm[0]
+
+
+@pytest.fixture(name="garm_configurator_app", scope="module")
+def deploy_garm_configurator_app_fixture(
+    juju: jubilant.Juju,
+    garm_configurator_charm_file: str,
+) -> str:
+    """Deploy the garm-configurator application standalone with no relations.
+
+    Returns the application name once the app reaches Active.
+    """
+    app_name = "garm-configurator"
+    juju.deploy(charm=garm_configurator_charm_file, app=app_name)
+    juju.wait(
+        lambda status: jubilant.all_active(status, app_name),
+        timeout=5 * 60,
+        delay=10,
+    )
+    return app_name
+
+
+def test_garm_configurator_deploys_active(
+    juju: jubilant.Juju,
+    garm_configurator_app: str,
+) -> None:
+    """
+    arrange: garm-configurator charm deployed with no relations wired.
+    act: Check the application status.
+    assert: Application is in Active state.
+    """
+    status = juju.status()
+    assert jubilant.all_active(status, garm_configurator_app)

tox.ini

@@ -55,6 +55,22 @@ commands =
            {[vars]tests_path}/integration/test_planner.py \
            {posargs}
 
+[testenv:garm-configurator-integration]
+pass_env =
+    PYTEST_ADDOPTS
+description = Run garm-configurator charm integration tests
+deps =
+    pytest
+    pytest-operator
+    -r {[vars]tests_path}/integration/requirements.txt
+commands =
+    pytest -v \
+           -s \
+           --tb native \
+           --log-cli-level=INFO \
+           {[vars]tests_path}/integration/test_garm_configurator.py \
+           {posargs}
+
 [testenv:charms-integration]
 pass_env =
     PYTEST_ADDOPTS