Deno Queues

Deno Queues, built on Deno KV, allow you to offload parts of your application or schedule work for the future to run asynchronously. It's an easy way to add scalable background processing to your project.

Describe the shape of your message object (optional)

interface Notification {
  forUser: string;
  body: string;
}

Get a reference to a KV instance

const kv = await Deno.openKv();

Create a notification object

const message: Notification = {
  forUser: "alovelace",
  body: "You've got mail!",
};

Enqueue the message for immediate delivery

await kv.enqueue(message);

Enqueue the message for delivery in 3 days

const delay = 1000 * 60 * 60 * 24 * 3;
await kv.enqueue(message, { delay });

Retrieve an unsent message by configuring a key

const backupKey = ["failed_notifications", "alovelace", Date.now()];
await kv.enqueue(message, { keysIfUndelivered: [backupKey] });

... disaster strikes ... Get the unsent message

const r = await kv.get<Notification>(backupKey);
console.log("Found failed notification for:", r.value?.forUser);

Listen for and handle messages.

kv.listenQueue((msg: Notification) => {
  console.log(`Dear ${msg.forUser}: ${msg.body}`);
});

Run this example locally using the Deno CLI:

deno run --unstable https://examples.deno.land/queues.ts

Additional resources:

Deno Cron Hashing