Crate boson_backend_nats 

NATS JetStream QueueBackend for fleet-scale deployments (Mode 2 remote / multi-host).

When to use: broker-backed fleets with NATS JetStream (KV and/or workqueue). Not a boson facade feature — depend on this crate directly. Mode 2 workers need unique worker_id and lease_ttl_secs > 0.

Getting started: Mode 2. Full Compose / KV vs WorkQueue / env: crate README.

Fleet URL precedence: BOSON_NATS_POOL_ROUTING over BOSON_NATS_URLS (see connect_fleet_from_env).

Mode 2 — Enqueue binary

Shared NATS with the worker. No claim loop in this process:

use std::sync::Arc;

use boson_backend_nats::NatsQueueBackend;
use boson_core::JsonExecutionContextFactory;
use boson_runtime::{configure, Boson};

let url = std::env::var("BOSON_NATS_URL")
    .unwrap_or_else(|_| "nats://127.0.0.1:4222".into());
let backend = NatsQueueBackend::connect(&url).await?;
let boson = Boson::builder()
    .queue_backend(Arc::new(backend))
    .execution_context_factory(JsonExecutionContextFactory)
    .auto_registry()
    .without_worker()
    .build()?;
configure(boson);
// MyTask::send_with(...).await?;

Also connect_auto / connect_fleet_from_env with the same without_worker + configure pattern.

Mode 2 — Worker binary

Same NATS URL / fleet, unique worker_id, and lease_ttl_secs > 0:

use std::sync::Arc;

use boson_backend_nats::NatsQueueBackend;
use boson_core::JsonExecutionContextFactory;
use boson_runtime::Boson;

let url = std::env::var("BOSON_NATS_URL")
    .unwrap_or_else(|_| "nats://127.0.0.1:4222".into());
let backend = NatsQueueBackend::connect(&url).await?;
let _boson = Boson::builder()
    .queue_backend(Arc::new(backend))
    .execution_context_factory(JsonExecutionContextFactory)
    .worker_id(std::env::var("BOSON_WORKER_ID").unwrap_or_else(|_| "worker-1".into()))
    .lease_ttl_secs(30)
    .auto_registry()
    .build()?;

Other Mode 2 backends: SQLite, Postgres, Redis.

Custom adapters: How to implement on QueueBackend.

Modules

keys

Key paths for JetStream KV (mirrors Redis layout).

Structs

NatsEnqueueConfig

Resolved enqueue pipeline settings.

NatsQueueBackend

NATS JetStream KV queue backend.

NatsWorkQueueBackend

NATS JetStream WorkQueue backend (stream ready queue + KV job bodies).

Enums

EnqueueMode

How enqueue writes job data to JetStream.

Functions

connect_auto

Connect KV or WorkQueue backend based on BOSON_NATS_QUEUE_MODE.

connect_fleet_from_env

Connect one WorkQueue backend per fleet URL.

install_default_nats_backend

Install default NATS backend on global router (tests).