@tremendo-studio/flyio-broadcast/dist/index.js

A utility library for broadcasting messages between Fly.io app instances.

import { promises as dns } from "dns";
const PORT = process.env?.PORT;
const PRIVATE_IP = process.env?.FLY_PRIVATE_IP;
const isRunningOnFly = !!process?.env?.FLY_APP_NAME;
export function createBroadcaster(appName, path) {
    return {
        broadcast: (message) => broadcast(path, appName, message),
        getIPs: () => getAllInstanceIPs(appName),
    };
}
async function broadcast(path, appName, message) {
    if (!isRunningOnFly)
        return Promise.resolve([]);
    const instanceIPs = (await getAllInstanceIPs(appName)).filter((ip) => ip !== PRIVATE_IP);
    const broadcastPromises = instanceIPs.map(async (ip) => {
        const url = `http://[${ip}]:${PORT}${path}`;
        try {
            const response = await fetch(url, {
                method: "POST",
                headers: {
                    "Content-Type": "application/json",
                },
                body: message,
            });
            if (!response.ok) {
                throw new Error(`Failed to broadcast to ${ip}: ${response.statusText}`);
            }
            return {
                ok: true,
                ip,
                data: await response.json(),
            };
        }
        catch (error) {
            if (error?.message) {
                return {
                    ok: false,
                    ip,
                    error: error.message,
                };
            }
        }
        return {
            ok: false,
            ip,
            error: "",
        };
    });
    return (await Promise.all(broadcastPromises));
}
async function getAllInstanceIPs(appName) {
    if (!isRunningOnFly)
        return Promise.resolve([]);
    try {
        return await dns.resolve6(`${appName}.internal`);
    }
    catch (error) {
        return [];
    }
}