Enum PolicyMode 

pub enum PolicyMode {
    MonitorOnly,
    Autoscale(AutoscaleConfig),
}

D19, as an enforced invariant rather than a convention.

04-subsystem-contracts.md:

• “MonitorOnly requires routing_labels and max_capacity to be None.”
• “Autoscale requires both to be Some.”

The contract writes those as three flat, independently-Optional fields on ScalePolicy, which admits four combinations of which two are illegal. This enum admits exactly the two legal ones, so the illegal pair has no representation — b1 asks for that explicitly: “Prefer a representation where the illegal combination cannot be built at all over one that is merely validated on the way in.”

The flat shape is still reachable: PolicyMode::routing_labels, PolicyMode::min_capacity, and PolicyMode::max_capacity return exactly the Options the contract names, and PolicyMode::from_persisted rebuilds the mode from them. That is b2’s load path, and it is where a hand-edited database row is rejected.

Variants

MonitorOnly

Contributes runners and workflow counts to the dashboard; owns no routing label; skipped entirely by reconciliation.

Autoscale(AutoscaleConfig)

Starts runners, up to max_capacity and the host ceiling.

Implementations

impl PolicyMode

pub const fn monitor_only() -> Self

pub fn autoscale( routing_labels: RoutingLabels, min_capacity: u16, max_capacity: NonZeroU16, ) -> Result<Self, PolicyError>

Errors

PolicyError::InvertedCapacityRange.

pub fn from_persisted( routing_labels: Option<RoutingLabels>, min_capacity: u16, max_capacity: Option<NonZeroU16>, ) -> Result<Self, PolicyError>

Rebuild the mode from the flat persisted shape.

This is the gate b2 puts every load through. All four combinations of routing_labels/max_capacity arrive here, and two of them are refused with a named error rather than being coerced into something plausible.

Errors

Each illegal shape gets its own variant, so b2 can say which column of which row is wrong rather than “invalid policy”.

pub const fn routing_labels(&self) -> Option<&RoutingLabels>

The contract’s routing_labels: Option<NonEmpty<Label>>, in Option form.

pub const fn min_capacity(&self) -> u16

pub const fn max_capacity(&self) -> Option<NonZeroU16>

pub const fn autoscale_config(&self) -> Option<&AutoscaleConfig>

pub const fn is_autoscale(&self) -> bool

pub const fn is_monitor_only(&self) -> bool

Trait Implementations

impl Clone for PolicyMode

fn clone(&self) -> PolicyMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PolicyMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for PolicyMode

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for PolicyMode

impl PartialEq for PolicyMode

fn eq(&self, other: &PolicyMode) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for PolicyMode

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for PolicyMode