Add scaleset configurations

charms/garm-configurator/charmcraft.yaml

@@ -63,6 +63,50 @@ config:
       description: |
         Juju secret containing the GitHub App private key (PEM format).
         The secret content must have a "value" key with the private key string.
+    name:
+      type: string
+      description: |
+        The name of the scaleset.
+    flavor:
+      type: string
+      description: |
+        The resource flavor to use for runners in the scaleset.
+    os-arch:
+      type: string
+      description: |
+        The CPU architecture for runners in the scaleset.
+    min-idle-runner:
+      type: int
+      default: 0
+      description: |
+        Minimum number of idle runners in the scaleset.
+    max-runner:
+      type: int
+      default: 0
+      description: |
+        Maximum number of runners in the scaleset.
+    labels:
+      type: string
+      description: |
+        Comma-separated list of labels to add to runners.
+    repo:
+      type: string
+      description: |
+        Repository to register runners to. Mutually exclusive with org.
+    org:
+      type: string
+      description: |
+        Organization to register runners to. Mutually exclusive with repo.
+    runner-group:
+      type: string
+      default: default
+      description: |
+        Runner group for org registration. Ignored when repo is set.
+    pre-install-scripts:
+      type: string
+      description: |
+        A Python dict-like string containing key-value pairs of script name
+        to bash script to be run prior to runner installation.
 
 parts:
   charm:

charms/garm-configurator/src/charm_state.py

@@ -19,6 +19,17 @@
 GITHUB_APP_INSTALLATION_ID_CONFIG_NAME = "github-app-installation-id"
 GITHUB_APP_PRIVATE_KEY_CONFIG_NAME = "github-app-private-key"  # nosec
 
+SCALESET_NAME_CONFIG_NAME = "name"
+SCALESET_FLAVOR_CONFIG_NAME = "flavor"
+SCALESET_OS_ARCH_CONFIG_NAME = "os-arch"
+SCALESET_MIN_IDLE_RUNNER_CONFIG_NAME = "min-idle-runner"
+SCALESET_MAX_RUNNER_CONFIG_NAME = "max-runner"
+SCALESET_LABELS_CONFIG_NAME = "labels"
+SCALESET_REPO_CONFIG_NAME = "repo"
+SCALESET_ORG_CONFIG_NAME = "org"
+SCALESET_RUNNER_GROUP_CONFIG_NAME = "runner-group"
+SCALESET_PRE_INSTALL_SCRIPTS_CONFIG_NAME = "pre-install-scripts"
+
 
 class CharmConfigInvalidError(Exception):
     """Raised when charm configuration is invalid.
@@ -176,28 +187,130 @@ def from_charm(cls, charm: ops.CharmBase) -> "GithubAppConfig":
         )
 
 
+class ScalesetConfig(BaseModel):
+    """Scaleset configuration.
+
+    Attributes:
+        name: The name of the scaleset.
+        flavor: The resource flavor for runners.
+        os_arch: The CPU architecture for runners.
+        min_idle_runner: Minimum number of idle runners.
+        max_runner: Maximum number of runners.
+        labels: Comma-separated list of labels for runners.
+        repo: Repository to register runners to.
+        org: Organization to register runners to.
+        runner_group: Runner group for org registration.
+        pre_install_scripts: Script name to bash script pairs for pre-installation.
+    """
+
+    name: str
+    flavor: str
+    os_arch: str
+    min_idle_runner: int
+    max_runner: int
+    labels: str = ""
+    repo: str | None = None
+    org: str | None = None
+    runner_group: str = "default"
+    pre_install_scripts: str | None = None
+
+    @classmethod
+    def from_charm(cls, charm: ops.CharmBase) -> "ScalesetConfig":
+        """Initialize the scaleset config from charm.
+
+        Args:
+            charm: The charm instance.
+
+        Raises:
+            CharmConfigInvalidError: If any configuration is missing or invalid.
+
+        Returns:
+            The parsed scaleset configuration.
+        """
+        required_string_configs = (
+            SCALESET_NAME_CONFIG_NAME,
+            SCALESET_FLAVOR_CONFIG_NAME,
+            SCALESET_OS_ARCH_CONFIG_NAME,
+        )
+        for key in required_string_configs:
+            value = charm.config.get(key)
+            if not value or not str(value).strip():
+                raise CharmConfigInvalidError(f"Missing required configuration: {key}")
+
+        min_idle_runner = int(charm.config.get(SCALESET_MIN_IDLE_RUNNER_CONFIG_NAME, 0))
+        if min_idle_runner < 0:
+            raise CharmConfigInvalidError(
+                f"{SCALESET_MIN_IDLE_RUNNER_CONFIG_NAME} must be non-negative"
+            )
+
+        max_runner = int(charm.config.get(SCALESET_MAX_RUNNER_CONFIG_NAME, 0))
+        if max_runner < 0:
+            raise CharmConfigInvalidError(
+                f"{SCALESET_MAX_RUNNER_CONFIG_NAME} must be non-negative"
+            )
+
+        repo = charm.config.get(SCALESET_REPO_CONFIG_NAME)
+        repo = str(repo).strip() if repo else None
+        org = charm.config.get(SCALESET_ORG_CONFIG_NAME)
+        org = str(org).strip() if org else None
+        runner_group = str(charm.config.get(SCALESET_RUNNER_GROUP_CONFIG_NAME, "default")).strip()
+
+        if repo and org:
+            raise CharmConfigInvalidError(
+                f"{SCALESET_REPO_CONFIG_NAME} and {SCALESET_ORG_CONFIG_NAME} "
+                f"are mutually exclusive"
+            )
+        if not repo and not org:
+            raise CharmConfigInvalidError(
+                f"At least one of {SCALESET_REPO_CONFIG_NAME} or "
+                f"{SCALESET_ORG_CONFIG_NAME} must be provided"
+            )
+
+        labels = charm.config.get(SCALESET_LABELS_CONFIG_NAME)
+        labels = str(labels).strip() if labels else ""
+        pre_install_scripts = charm.config.get(SCALESET_PRE_INSTALL_SCRIPTS_CONFIG_NAME)
+        pre_install_scripts = str(pre_install_scripts) if pre_install_scripts else None
+
+        return cls(
+            name=str(charm.config.get(SCALESET_NAME_CONFIG_NAME)).strip(),
+            flavor=str(charm.config.get(SCALESET_FLAVOR_CONFIG_NAME)).strip(),
+            os_arch=str(charm.config.get(SCALESET_OS_ARCH_CONFIG_NAME)).strip(),
+            min_idle_runner=min_idle_runner,
+            max_runner=max_runner,
+            labels=labels,
+            repo=repo,
+            org=org,
+            runner_group=runner_group,
+            pre_install_scripts=pre_install_scripts,
+        )
+
+
 class CharmState:
     """The charm state.
 
     Attributes:
         provider_config: OpenStack provider configuration.
         github_app_config: GitHub App configuration.
+        scaleset_config: Scaleset configuration.
     """
 
     def __init__(
         self,
         *,
         provider_config: ProviderConfig,
         github_app_config: GithubAppConfig,
+        scaleset_config: ScalesetConfig,
     ) -> None:
         """Initialize the charm state.
 
         Args:
             provider_config: The OpenStack provider configuration.
             github_app_config: The GitHub App configuration.
+            scaleset_config: The scaleset configuration.
         """
         self.provider_config = provider_config
         self.github_app_config = github_app_config
+        self.scaleset_config = scaleset_config
 
     @classmethod
     def from_charm(cls, charm: ops.CharmBase) -> "CharmState":
@@ -214,7 +327,9 @@ def from_charm(cls, charm: ops.CharmBase) -> "CharmState":
         """
         provider_config = ProviderConfig.from_charm(charm)
         github_app_config = GithubAppConfig.from_charm(charm)
+        scaleset_config = ScalesetConfig.from_charm(charm)
         return cls(
             provider_config=provider_config,
             github_app_config=github_app_config,
+            scaleset_config=scaleset_config,
         )

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

@@ -31,6 +31,12 @@ def _valid_config(secret: Secret, private_key_secret: Secret) -> dict:
         "github-app-client-id": "12345",
         "github-app-installation-id": "67890",
         "github-app-private-key": private_key_secret.id,
+        "name": "my-scaleset",
+        "flavor": "m1.large",
+        "os-arch": "amd64",
+        "min-idle-runner": 0,
+        "max-runner": 5,
+        "repo": "myorg/myrepo",
     }
 
 
@@ -72,6 +78,9 @@ def test_charm_active_with_valid_config():
             _MISSING_CONFIG_SENTINEL,
             id="missing-github-app-private-key",
         ),
+        pytest.param("name", _MISSING_CONFIG_SENTINEL, id="missing-name"),
+        pytest.param("flavor", "", id="empty-flavor"),
+        pytest.param("os-arch", "   ", id="whitespace-only-os-arch"),
     ],
 )
 def test_charm_blocked_missing_or_empty_config(config_key: str, override_value: object):
@@ -193,3 +202,102 @@ def test_charm_blocked_github_app_private_key_secret_not_found():
     assert out.unit_status == ops.BlockedStatus(
         "github-app-private-key secret is invalid or missing 'value' key"
     )
+
+
+def test_charm_blocked_negative_min_idle_runner():
+    """
+    arrange: min-idle-runner is negative.
+    act: Run config-changed.
+    assert: Unit status is Blocked.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    secret = _make_secret()
+    pk_secret = _make_private_key_secret()
+    config = _valid_config(secret, pk_secret)
+    config["min-idle-runner"] = -1
+    state = State(config=config, secrets=[secret, pk_secret])
+    out = ctx.run(ctx.on.config_changed(), state)
+    assert out.unit_status == ops.BlockedStatus("min-idle-runner must be non-negative")
+
+
+def test_charm_blocked_negative_max_runner():
+    """
+    arrange: max-runner is negative.
+    act: Run config-changed.
+    assert: Unit status is Blocked.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    secret = _make_secret()
+    pk_secret = _make_private_key_secret()
+    config = _valid_config(secret, pk_secret)
+    config["max-runner"] = -5
+    state = State(config=config, secrets=[secret, pk_secret])
+    out = ctx.run(ctx.on.config_changed(), state)
+    assert out.unit_status == ops.BlockedStatus("max-runner must be non-negative")
+
+
+def test_charm_blocked_neither_repo_nor_org():
+    """
+    arrange: Neither repo nor org is set.
+    act: Run config-changed.
+    assert: Unit status is Blocked.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    secret = _make_secret()
+    pk_secret = _make_private_key_secret()
+    config = _valid_config(secret, pk_secret)
+    del config["repo"]
+    state = State(config=config, secrets=[secret, pk_secret])
+    out = ctx.run(ctx.on.config_changed(), state)
+    assert out.unit_status == ops.BlockedStatus("At least one of repo or org must be provided")
+
+
+def test_charm_blocked_repo_and_org_both_set():
+    """
+    arrange: Both repo and org are set.
+    act: Run config-changed.
+    assert: Unit status is Blocked.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    secret = _make_secret()
+    pk_secret = _make_private_key_secret()
+    config = _valid_config(secret, pk_secret)
+    config["org"] = "myorg"
+    state = State(config=config, secrets=[secret, pk_secret])
+    out = ctx.run(ctx.on.config_changed(), state)
+    assert out.unit_status == ops.BlockedStatus("repo and org are mutually exclusive")
+
+
+def test_charm_active_with_org_and_runner_group():
+    """
+    arrange: org and runner-group are set (no repo).
+    act: Run config-changed.
+    assert: Unit status is Active.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    secret = _make_secret()
+    pk_secret = _make_private_key_secret()
+    config = _valid_config(secret, pk_secret)
+    del config["repo"]
+    config["org"] = "myorg"
+    config["runner-group"] = "my-group"
+    state = State(config=config, secrets=[secret, pk_secret])
+    out = ctx.run(ctx.on.config_changed(), state)
+    assert out.unit_status == ops.ActiveStatus("Ready")
+
+
+def test_charm_active_with_org_only():
+    """
+    arrange: Only org is set (no repo, no runner-group).
+    act: Run config-changed.
+    assert: Unit status is Active.
+    """
+    ctx = Context(GarmConfiguratorCharm)
+    secret = _make_secret()
+    pk_secret = _make_private_key_secret()
+    config = _valid_config(secret, pk_secret)
+    del config["repo"]
+    config["org"] = "myorg"
+    state = State(config=config, secrets=[secret, pk_secret])
+    out = ctx.run(ctx.on.config_changed(), state)
+    assert out.unit_status == ops.ActiveStatus("Ready")

charms/tests/integration/test_garm_configurator.py

@@ -71,6 +71,10 @@ def deploy_garm_configurator_app_fixture(
             "github-app-client-id": "12345",
             "github-app-installation-id": "67890",
             "github-app-private-key": private_key_secret_uri,
+            "name": "test-scaleset",
+            "flavor": "m1.large",
+            "os-arch": "amd64",
+            "repo": "myorg/myrepo",
         },
     )
     juju.wait(

docs/changelog.md

@@ -8,6 +8,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 Each revision is versioned by the date of the revision.
 
+## 2026-06-03
+
+- add GARM Scaleset configurations for the GARM configurator charm.
+
 ## 2026-06-02
 
 - add OpenStack and GitHub creds/configs for the GARM configurator charm.