Module memory_tracking 

Memory tracking and enforcement for the WASM sandbox.

MemoryTracker implements Wasmtime’s ResourceLimiter trait so the host can deny linear-memory growth that would exceed the configured cap, and observe the per-store peak. Wire it into a Store<T> by holding the tracker inside the store’s data type and installing the limiter:

struct StoreData {
    wasi: WasiCtx,
    tracker: MemoryTracker,
}

let mut store = Store::new(&engine, StoreData {
    wasi: wasi_ctx,
    tracker: MemoryTracker::with_byte_limit(10 * 1024 * 1024),
});
store.limiter(|d| &mut d.tracker as &mut dyn wasmtime::ResourceLimiter);

Modern Wasmtime (≥27) removed the standalone Store::set_limits API in favor of the closure-based Store::limiter, which is why the limiter must live inside the store’s data type.

Structs

MemoryStats

Snapshot of a tracker’s state. Cheap to clone for emitting on the invocation metrics bus or returning from a status endpoint.

MemoryTracker

Memory tracker for a single Wasmtime Store.