Struct InMemorySnapshotStore 

pub struct InMemorySnapshotStore<Id, Pos> { /* private fields */ }

In-memory snapshot store with configurable policy.

This is a reference implementation suitable for testing and development. Production systems should implement SnapshotStore with durable storage.

Generic over Id and Pos to match the EventStore types.

Example

use sourcery::{Repository, InMemoryEventStore, InMemorySnapshotStore, JsonCodec};

let repo = Repository::new(InMemoryEventStore::new(JsonCodec))
    .with_snapshots(InMemorySnapshotStore::every(100));

Implementations

impl<Id, Pos> InMemorySnapshotStore<Id, Pos>

pub fn always() -> Self

Create a snapshot store that saves after every command.

Best for aggregates with expensive replay or many events. See the policy guidelines above for choosing an appropriate cadence.

pub fn every(n: u64) -> Self

Create a snapshot store that saves every N events.

Recommended for most use cases. Start with n = 50-100 and tune based on your aggregate’s replay cost. See the policy guidelines above for choosing a policy.

pub fn never() -> Self

Create a snapshot store that never saves (load-only).

Use for read replicas, short-lived aggregates, or when managing snapshots externally. See the policy guidelines above for when this fits.

Trait Implementations

impl<Id: Clone, Pos: Clone> Clone for InMemorySnapshotStore<Id, Pos>

fn clone(&self) -> InMemorySnapshotStore<Id, Pos>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<Id: Debug, Pos: Debug> Debug for InMemorySnapshotStore<Id, Pos>

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

Formats the value using the given formatter.

impl<Id, Pos> Default for InMemorySnapshotStore<Id, Pos>

fn default() -> Self

Returns the “default value” for a type.

impl<Id, Pos> SnapshotStore for InMemorySnapshotStore<Id, Pos>

where Id: Clone + Eq + Hash + Send + Sync + 'static, Pos: Clone + Send + Sync + 'static,

type Error = Infallible

Error type for snapshot operations.

type Id = Id

Aggregate identifier type.

type Position = Pos

Position type for tracking snapshot positions.

fn load<'a>( &'a self, aggregate_kind: &'a str, aggregate_id: &'a Self::Id, ) -> impl Future<Output = Result<Option<Snapshot<Pos>>, Self::Error>> + Send + 'a

Load the most recent snapshot for an aggregate.

fn offer_snapshot<'a, CE, Create>( &'a mut self, aggregate_kind: &'a str, aggregate_id: &'a Self::Id, events_since_last_snapshot: u64, create_snapshot: Create, ) -> impl Future<Output = Result<SnapshotOffer, OfferSnapshotError<Self::Error, CE>>> + Send + 'a

where CE: Error + Send + Sync + 'static, Create: FnOnce() -> Result<Snapshot<Pos>, CE> + 'a,

Whether to store a snapshot, with lazy snapshot creation.