Struct HandlersConfig 

pub struct HandlersConfig {
    pub bindings: BindingsConfig,
    pub pooling: bool,
    pub sync_max_timeout_ms: Option<u64>,
    pub async_max_timeout_ms: Option<u64>,
    pub async_max_concurrency: Option<usize>,
    pub async_max_fuel: Option<u64>,
    pub outbound_timeout_ms: Option<u64>,
}

handlers section — server-side handler runtime config (read by serve). Parsed in every build (so config files stay portable), but only consumed when the handlers feature is compiled in.

Fields

bindings: BindingsConfig

handlers.bindings — which backend serves each handler binding.

pooling: bool

Use the wasmtime pooling instance allocator: faster instantiation at the cost of a large up-front virtual-memory reservation. Off by default — opt in and benchmark for your workload.

sync_max_timeout_ms: Option<u64>

Engine-wide safety max on a connection-bearing invocation (a site handler or a synchronous function/webhook invoke), milliseconds. A route or function may declare a lower timeout, never a higher one. Kept tight on purpose: a client, proxy, and the shared request pool are all blocked while a sync handler runs. Absent ⇒ 10s (the historical default). This is a node safety ceiling, not a per-invocation budget, and is distinct from a per-site max_timeout_ms.

async_max_timeout_ms: Option<u64>

Engine-wide safety max on a durable async invocation — the drain that runs ?mode=async calls, workflow steps, cron/queue/blob triggers, and wasi:messaging consumers, milliseconds. No client is connected and the work is retried + dead-lettered, so this can be far larger than the sync ceiling: it is what lets a legitimately long background job (e.g. an LLM generation) declare and actually get minutes of runtime. Absent ⇒ 15 minutes. Runs on its own concurrency budget (async_max_concurrency), so a long job never starves live traffic.

async_max_concurrency: Option<usize>

Max concurrent in-flight async-lane invocations, kept separate from the (larger) request pool so a burst of long background jobs can’t exhaust the slots live site traffic needs. Absent ⇒ 8.

async_max_fuel: Option<u64>

Optional CPU fuel ceiling for an async-lane invocation. A large async timeout bounds only wall-clock; without a fuel bound a CPU-bound guest can spin for the whole window. Absent ⇒ unmetered (same as the sync default).

outbound_timeout_ms: Option<u64>

Optional ceiling on a guest’s outbound wasi:http call — the connect and time-to-first-byte wait — milliseconds, independent of the invocation timeout, so a hung upstream is bounded on its own terms. The streaming (between-bytes) timeout is left at wasmtime’s default so a slow token stream is not cut mid-flight. Absent ⇒ wasmtime’s default.

Trait Implementations

impl Clone for HandlersConfig

fn clone(&self) -> HandlersConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HandlersConfig

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

Formats the value using the given formatter.

impl Default for HandlersConfig

fn default() -> HandlersConfig

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for HandlersConfig

where HandlersConfig: Default,

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.