Overview

Queue provides at-least-once message delivery between producers and consumers. Send JSON or text messages, receive them in batches, and acknowledge when processing is complete. Unacknowledged messages are automatically re-delivered.

Platform Mapping

| Local | sled (embedded database) | Alien |

When to Use

Use Queue for decoupling producers from consumers — task queues, event pipelines, background job processing, webhook relay.

Don't use Queue for request-response patterns (use Function invocation) or for ordered event streams (Queue does not guarantee ordering).

Stack Definition

Declare a Queue resource in your alien.ts:

const tasks = new alien.Queue("tasks").build()

Queue has no additional configuration options. The backing service (SQS, Pub/Sub, Service Bus) is determined by the deployment platform.

Quick Start

import { queue } from "@alienplatform/sdk"
const tasks = await queue("tasks")

await tasks.send("tasks", { type: "process-image", imageId: "123" })

const messages = await tasks.receive("tasks", 10)
for (const msg of messages) {
  await processTask(msg.payload)
  await tasks.ack("tasks", msg.receiptHandle)
}

let q = ctx.bindings().load_queue("tasks").await?;

q.send("tasks", MessagePayload::Json(json!({"type": "process-image"}))).await?;
let messages = q.receive("tasks", 10).await?;
for msg in messages {
    // process...
    q.ack("tasks", &msg.receipt_handle).await?;
}

Triggers

Queues can automatically trigger functions — one message per invocation:

// alien.ts
const worker = new alien.Function("worker")
  .trigger(tasks)
  .build()

// worker code
import { onQueueMessage } from "@alienplatform/sdk"

onQueueMessage("tasks", async (message) => {
  await processTask(message.payload)
  // auto-acknowledged on success
})

See Behavior & Limits for trigger support per platform.