feat(garm): apply configurator runner options via per-scaleset GARM templates (ISD-5728)

charms/garm-configurator/charmcraft.yaml

@@ -107,6 +107,34 @@ config:
       description: |
         A Python dict-like string containing key-value pairs of script name
         to bash script to be run prior to runner installation.
+    dockerhub-mirror:
+      type: string
+      description: |
+        Optional Docker registry mirror URL for runners. Must be a valid http(s) address.
+    runner-http-proxy:
+      type: string
+      description: |
+        HTTP proxy that aproxy forwards to. Must be a valid http(s) URL.
+    aproxy-exclude-addresses:
+      type: string
+      description: |
+        Comma-separated IPv4 addresses/CIDRs to exclude from aproxy forwarding.
+    aproxy-redirect-ports:
+      type: string
+      description: |
+        Comma-separated ports or port ranges (e.g. 80,443,8000-9000) to forward to aproxy.
+    otel-collector-endpoint:
+      type: string
+      description: |
+        The OTEL exporter address for the otel-collector to connect to. Must be a valid http(s) URL.
+    pre-job-script:
+      type: string
+      description: |
+        A bash script appended to the end of the runner pre-job script.
+
+provides:
+  garm-configurator:
+    interface: garm_configurator_v0
 
 requires:
   image:

charms/garm-configurator/src/charm.py

@@ -4,12 +4,15 @@
 
 """Charm entrypoint for the GARM configurator charm."""
 
+import json
 import typing
 
 import ops
 
 from charm_state import IMAGE_RELATION_NAME, CharmConfigInvalidError, CharmState
 
+GARM_CONFIGURATOR_RELATION_NAME = "garm-configurator"
+
 
 class GarmConfiguratorCharm(ops.CharmBase):
     """GARM configurator charm."""
@@ -24,6 +27,7 @@ def __init__(self, *args: typing.Any) -> None:
         for event in [
             self.on.config_changed,
             self.on.secret_changed,
+            self.on[GARM_CONFIGURATOR_RELATION_NAME].relation_changed,
             self.on[IMAGE_RELATION_NAME].relation_joined,
             self.on[IMAGE_RELATION_NAME].relation_changed,
             self.on[IMAGE_RELATION_NAME].relation_broken,
@@ -58,6 +62,37 @@ def _reconcile(self, event: ops.EventBase) -> None:
                 }
             )
 
+        rc = state.runner_config
+        relation_data = {
+            "name": state.scaleset_config.name,
+            "provider_name": state.provider_name,
+            "credentials_name": state.credentials_name,
+            "image_id": str(state.image_id),
+            "flavor": state.scaleset_config.flavor,
+            "os_arch": state.scaleset_config.os_arch,
+            "min_idle_runner": str(state.scaleset_config.min_idle_runner),
+            "max_runner": str(state.scaleset_config.max_runner),
+            "labels": (
+                state.scaleset_config.labels
+                if isinstance(state.scaleset_config.labels, str)
+                else ",".join(state.scaleset_config.labels)
+            ),
+            "runner_group": state.scaleset_config.runner_group,
+            "pre_install_scripts": json.dumps(
+                {"pre_install.sh": state.scaleset_config.pre_install_scripts}
+                if state.scaleset_config.pre_install_scripts
+                else {}
+            ),
+            "dockerhub_mirror": rc.dockerhub_mirror or "",
+            "runner_http_proxy": rc.runner_http_proxy or "",
+            "aproxy_exclude_addresses": rc.aproxy_exclude_addresses or "",
+            "aproxy_redirect_ports": rc.aproxy_redirect_ports or "",
+            "otel_collector_endpoint": rc.otel_collector_endpoint or "",
+            "pre_job_script": rc.pre_job_script or "",
+        }
+        for garm_relation in self.model.relations[GARM_CONFIGURATOR_RELATION_NAME]:
+            garm_relation.data[self.unit].update(relation_data)
+
         if relation is None:
             self.unit.status = ops.WaitingStatus("Waiting for image builder relation")
         elif state.image_id is None:

charms/garm-configurator/src/charm_state.py

@@ -3,6 +3,9 @@
 
 """State of the GARM configurator charm."""
 
+import ipaddress
+import urllib.parse
+
 import ops
 from pydantic import BaseModel
 
@@ -30,6 +33,13 @@
 SCALESET_RUNNER_GROUP_CONFIG_NAME = "runner-group"
 SCALESET_PRE_INSTALL_SCRIPTS_CONFIG_NAME = "pre-install-scripts"
 
+DOCKERHUB_MIRROR_CONFIG_NAME = "dockerhub-mirror"
+RUNNER_HTTP_PROXY_CONFIG_NAME = "runner-http-proxy"
+APROXY_EXCLUDE_ADDRESSES_CONFIG_NAME = "aproxy-exclude-addresses"
+APROXY_REDIRECT_PORTS_CONFIG_NAME = "aproxy-redirect-ports"
+OTEL_COLLECTOR_ENDPOINT_CONFIG_NAME = "otel-collector-endpoint"
+PRE_JOB_SCRIPT_CONFIG_NAME = "pre-job-script"
+
 IMAGE_RELATION_NAME = "image"
 
 
@@ -292,13 +302,167 @@ def from_charm(cls, charm: ops.CharmBase) -> "ScalesetConfig":
         )
 
 
+def _validate_http_url(config_name: str, value: str) -> None:
+    """Raise CharmConfigInvalidError if value is not a valid http(s) URL.
+
+    Args:
+        config_name: Config option name used in the error message.
+        value: URL string to validate.
+
+    Raises:
+        CharmConfigInvalidError: When the URL has whitespace, a non-http(s) scheme,
+            or an empty netloc.
+    """
+    # Reject embedded whitespace/control characters: the value is later rendered
+    # into scripts and env files, where a newline could inject extra lines.
+    if any(char.isspace() for char in value):
+        raise CharmConfigInvalidError(f"{config_name} must be a valid http(s) URL")
+    parsed = urllib.parse.urlparse(value)
+    if parsed.scheme not in ("http", "https") or not parsed.netloc:
+        raise CharmConfigInvalidError(f"{config_name} must be a valid http(s) URL")
+
+
+class RunnerConfig(BaseModel):
+    """Optional runner-level configuration forwarded to the GARM scaleset.
+
+    Attributes:
+        dockerhub_mirror: Optional Docker registry mirror URL.
+        runner_http_proxy: HTTP proxy address for aproxy to forward to.
+        aproxy_exclude_addresses: Comma-separated IPs/CIDRs excluded from aproxy forwarding.
+        aproxy_redirect_ports: Comma-separated ports or N-M ranges forwarded to aproxy.
+        otel_collector_endpoint: OTEL exporter address for the otel-collector.
+        pre_job_script: Bash snippet appended to the runner pre-job script.
+    """
+
+    dockerhub_mirror: str | None = None
+    runner_http_proxy: str | None = None
+    aproxy_exclude_addresses: str | None = None
+    aproxy_redirect_ports: str | None = None
+    otel_collector_endpoint: str | None = None
+    pre_job_script: str | None = None
+
+    @classmethod
+    def from_charm(cls, charm: ops.CharmBase) -> "RunnerConfig":
+        """Initialize the runner config from charm, applying best-effort validation.
+
+        All options are optional; unset or empty values result in None fields.
+
+        Args:
+            charm: The charm instance.
+
+        Raises:
+            CharmConfigInvalidError: If a set option fails validation.
+
+        Returns:
+            The parsed runner configuration.
+        """
+        url_options = (
+            DOCKERHUB_MIRROR_CONFIG_NAME,
+            RUNNER_HTTP_PROXY_CONFIG_NAME,
+            OTEL_COLLECTOR_ENDPOINT_CONFIG_NAME,
+        )
+        url_values: dict[str, str | None] = {}
+        for config_name in url_options:
+            raw = charm.config.get(config_name)
+            value = str(raw).strip() if raw else None
+            if value:
+                _validate_http_url(config_name, value)
+            url_values[config_name] = value or None
+
+        raw_exclude = charm.config.get(APROXY_EXCLUDE_ADDRESSES_CONFIG_NAME)
+        aproxy_exclude_addresses: str | None = None
+        if raw_exclude:
+            tokens = [t.strip() for t in str(raw_exclude).split(",")]
+            # Reject empty tokens (e.g. trailing comma) as they signal a misconfiguration.
+            for token in tokens:
+                # Each token must be a valid IPv4 address or CIDR: the values are
+                # rendered into an nft IPv4 (`table ip`) ruleset, so a hostname or
+                # IPv6 address would pass validation but fail at runtime (and the
+                # failure would be swallowed by ``|| true``).
+                try:
+                    network = ipaddress.ip_network(token, strict=False)
+                except ValueError as exc:
+                    raise CharmConfigInvalidError(
+                        f"{APROXY_EXCLUDE_ADDRESSES_CONFIG_NAME} must be a comma-separated list "
+                        f"of IPv4 addresses or CIDRs; got invalid token: {token!r}"
+                    ) from exc
+                if network.version != 4:
+                    raise CharmConfigInvalidError(
+                        f"{APROXY_EXCLUDE_ADDRESSES_CONFIG_NAME} only supports IPv4 addresses or "
+                        f"CIDRs (the aproxy nft ruleset is IPv4-only); got: {token!r}"
+                    )
+            aproxy_exclude_addresses = ",".join(tokens)
+
+        raw_ports = charm.config.get(APROXY_REDIRECT_PORTS_CONFIG_NAME)
+        aproxy_redirect_ports: str | None = None
+        if raw_ports:
+            tokens_ports = [t.strip() for t in str(raw_ports).split(",")]
+            for token in tokens_ports:
+                _validate_port_token(token)
+            aproxy_redirect_ports = ",".join(tokens_ports)
+
+        # The aproxy options only take effect alongside a proxy: the runner
+        # template renders the aproxy block solely when runner-http-proxy is set,
+        # so reject these options on their own rather than letting them no-op.
+        if (aproxy_exclude_addresses or aproxy_redirect_ports) and not url_values[
+            RUNNER_HTTP_PROXY_CONFIG_NAME
+        ]:
+            raise CharmConfigInvalidError(
+                f"{APROXY_EXCLUDE_ADDRESSES_CONFIG_NAME} and {APROXY_REDIRECT_PORTS_CONFIG_NAME} "
+                f"require {RUNNER_HTTP_PROXY_CONFIG_NAME} to be set"
+            )
+
+        raw_script = charm.config.get(PRE_JOB_SCRIPT_CONFIG_NAME)
+        pre_job_script = str(raw_script).strip() if raw_script else None
+
+        return cls(
+            dockerhub_mirror=url_values[DOCKERHUB_MIRROR_CONFIG_NAME],
+            runner_http_proxy=url_values[RUNNER_HTTP_PROXY_CONFIG_NAME],
+            aproxy_exclude_addresses=aproxy_exclude_addresses,
+            aproxy_redirect_ports=aproxy_redirect_ports,
+            otel_collector_endpoint=url_values[OTEL_COLLECTOR_ENDPOINT_CONFIG_NAME],
+            pre_job_script=pre_job_script or None,
+        )
+
+
+def _validate_port_token(token: str) -> None:
+    """Raise CharmConfigInvalidError if token is not a valid port or N-M range.
+
+    Args:
+        token: A single comma-split token from the aproxy-redirect-ports config.
+
+    Raises:
+        CharmConfigInvalidError: When the token is not a valid port or N<=M range in 1..65535.
+    """
+    error_msg = (
+        f"{APROXY_REDIRECT_PORTS_CONFIG_NAME} must be a comma-separated list of "
+        "ports or N-M ranges in 1..65535"
+    )
+    if "-" in token:
+        parts = token.split("-", 1)
+        try:
+            low, high = int(parts[0]), int(parts[1])
+        except (ValueError, IndexError):
+            raise CharmConfigInvalidError(error_msg)
+        if not (1 <= low <= 65535 and 1 <= high <= 65535 and low <= high):
+            raise CharmConfigInvalidError(error_msg)
+    else:
+        try:
+            port = int(token)
+        except ValueError:
+            raise CharmConfigInvalidError(error_msg)
+        if not 1 <= port <= 65535:
+            raise CharmConfigInvalidError(error_msg)
+
+
 class CharmState:
     """The charm state.
 
     Attributes:
         provider_config: OpenStack provider configuration.
         github_app_config: GitHub App configuration.
         scaleset_config: Scaleset configuration.
+        runner_config: Optional runner-level configuration.
         image_id: OpenStack image UUID received from the image builder relation, or None.
     """
 
@@ -308,6 +472,7 @@ def __init__(
         provider_config: ProviderConfig,
         github_app_config: GithubAppConfig,
         scaleset_config: ScalesetConfig,
+        runner_config: RunnerConfig,
         image_id: str | None,
     ) -> None:
         """Initialize the charm state.
@@ -316,11 +481,13 @@ def __init__(
             provider_config: The OpenStack provider configuration.
             github_app_config: The GitHub App configuration.
             scaleset_config: The scaleset configuration.
+            runner_config: The optional runner configuration.
             image_id: The OpenStack image UUID from the image builder relation.
         """
         self.provider_config = provider_config
         self.github_app_config = github_app_config
         self.scaleset_config = scaleset_config
+        self.runner_config = runner_config
         self.image_id = image_id
 
     @classmethod
@@ -339,14 +506,26 @@ 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)
+        runner_config = RunnerConfig.from_charm(charm)
         image_id = _get_image_id_from_relation(charm)
         return cls(
             provider_config=provider_config,
             github_app_config=github_app_config,
             scaleset_config=scaleset_config,
+            runner_config=runner_config,
             image_id=image_id,
         )
 
+    @property
+    def provider_name(self) -> str:
+        """Derived GARM provider name for scalesets."""
+        return f"openstack-{self.provider_config.project_name}"
+
+    @property
+    def credentials_name(self) -> str:
+        """Derived GARM credentials name for scalesets."""
+        return f"github-app-{self.github_app_config.client_id}"
+
 
 def _get_image_id_from_relation(charm: ops.CharmBase) -> str | None:
     """Return the OpenStack image UUID from the image builder relation, if available.