Struct ServiceSubnetRegistry 

pub struct ServiceSubnetRegistry { /* private fields */ }

Tracks per-service-per-node subnet assignments carved from the cluster CIDR. Each (service_name, node_id) pair gets its own slice of size slice_prefix (default /28). Assignments are deterministic — the same (service, node) pair always maps to the same starting slot via FNV hash, with linear probing on collision. Mirrors NodeSliceAllocator’s pattern; see that type for the rationale (in particular the choice of FNV over DefaultHasher for cross-process reproducibility).

Snapshot/restore is wired the same way NodeSliceAllocator does it, so the scheduler’s Raft state can persist + replay assignments. The snapshot’s Vec<((String, String), IpNet)> is the wire-stable shape: avoid HashMap here because non-deterministic map ordering would yield unstable serialized bytes under postcard/serde.

Node IDs are stored as String (matching NodeSliceAllocator); the scheduler converts its own NodeId to/from String at the boundary.

Implementations

impl ServiceSubnetRegistry

pub fn new(cluster_cidr: IpNet, slice_prefix: u8) -> Result<Self>

Create a new service subnet registry that carves /slice_prefix-sized slices out of cluster_cidr.

Errors

Returns OverlayError::InvalidCidr if slice_prefix is not strictly more specific than cluster_cidr.prefix_len(), or if it exceeds the address family’s maximum prefix length.

pub fn assign(&mut self, service: &str, node: &str) -> Result<IpNet>

Assign (or return an existing) subnet for (service, node).

Idempotent: repeated calls with the same key return the same slice without re-assigning.

Errors

Returns OverlayError::NoAvailableIps if every slice in the cluster CIDR is already assigned to some other (service, node) pair.

pub fn release(&mut self, service: &str, node: &str) -> Option<IpNet>

Release the subnet for (service, node). Returns the freed slice if one was assigned, None otherwise.

pub fn get(&self, service: &str, node: &str) -> Option<IpNet>

Look up the current assignment for (service, node), if any.

pub fn assigned_count(&self) -> usize

Number of currently-assigned (service, node) pairs.

pub fn capacity(&self) -> u64

Total number of slices the cluster CIDR can hold at the configured slice prefix.

pub fn cluster_cidr(&self) -> IpNet

Cluster CIDR the registry operates over.

pub fn slice_prefix(&self) -> u8

Slice prefix length (e.g. 28 for /28 slices).

pub fn snapshot(&self) -> ServiceSubnetRegistrySnapshot

Build a persistable snapshot for Raft / durable leader state.

The returned snapshot has assignments sorted by (service, node) so the serialized bytes are deterministic across processes — important when Raft compares snapshots by hash.

pub fn restore(snapshot: ServiceSubnetRegistrySnapshot) -> Result<Self>

Rebuild a registry from a snapshot.

Errors

Returns OverlayError::InvalidCidr if the snapshot’s slice prefix is inconsistent with its assignments, or if any assigned slice is not contained in the cluster CIDR.

Trait Implementations

impl Clone for ServiceSubnetRegistry

fn clone(&self) -> ServiceSubnetRegistry

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ServiceSubnetRegistry

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

Formats the value using the given formatter.