Fastify will not allow route registration after ready

[areese159]

🐛 Bug Report

Calling fastify.ready() causes errors to be thrown if you attempt to add routes after it finishes. Specifically, it will throw Cannot add route when fastify instance is already started! which seems like undesired behavior. This seems to be caused by Avvio emitting the start event when calling ready, since ready comes from Avvio. When start is emitted fastify appears to no longer allow route registration which seems to not be the correct behavior. From looking at the documentation on ready it appears this should not be a side effect and only the plugins should be loaded.

To Reproduce

const fastify = require("fastify");
const fp = require("fastify-plugin");

const plugin = fp(function(fastify, opts, next) {
    next();
});
const start = async function () {
    const app = fastify();
    app.register(plugin);
    await app.ready();
    // this will throw an error, specifically "Cannot add route when fastify instance is already started!"
    app.post('/test', function () {});
};
start();

Expected behavior

I would expect that fastify loads the plugins as expected but will continue to allow route registration until listen is called.

const fastify = require("fastify");
const fp = require("fastify-plugin");

const plugin = fp(function(fastify, opts, next) {
    next();
});
const start = async function () {
    const app = fastify();
    app.register(plugin);
    await app.ready();
    // this will not throw an error and fastify will allow you to register the route"
    app.post('/test', function () {});
};
start();

Your Environment

• node version: 10.15.3
• fastify version: >=2.6.0
• os: Linux (Ubuntu)

[delvedor]

Specifically, it will throw Cannot add route when fastify instance is already started! which seems like undesired behavior.

It is the wanted behavior :)
Before start listening for requests, Fastify will "compile" all of your plugins and routes (which are a special kind of plugin) to a fast data structure, so it can be accessed later very quickly.
To allow this, we can't accept new plugins after the invocation of .ready.

The question is, why you need to register more routes after calling ready or listen?

[areese159]

I was trying to have a plugin that would dynamically load the routes. I was trying to call ready so the plugin could do its work and then listen after all the routes were there but there are other ways to handle this. As for the ready issue, would it be possible to update the documentation so its more clear once ready is called nothing else can be added?

[delvedor]

As for the ready issue, would it be possible to update the documentation so its more clear once ready is called nothing else can be added?

Sure! Would you like to send a pr?

I was trying to have a plugin that would dynamically load the routes.

Not sure I'm following you, the plugin system should already take care of loading in order and assuring you that everything will be loaded before start listening.

[areese159]

Yeah, I would be more than happy to submit a PR, ill try and get to that this weekend. As to the other point, I'm trying to make a decorator library. I know one already exists but I don't like that it has to know your folder structure or the fact that it using fs to load all your files. So I was trying to pre-load the plugin before you create your "controllers" so it can decorator them appropriately.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[neuronetio]

I have the same problem, I need to load additional routes dynamically from import(...) without restarting the app.

[neuronetio]

for example when you want to build CMS you need to add routes to articles dynamically without restarting whole app

[mcollina]

Can you please articulate more your use case? I’ve literally never had to load routes dynamically. Why do you to load code dynamically?

[neuronetio]

@mcollina like I sad earlier - good example could be when you create new article in CMS your route is just created dynamically by the user - you don't want to restart an app after that because there may be logged other users as well.
Other example can be if you need to install modules dynamically into your system (downloaded zip) like in prestashop or wordpress) - if you have more than one user - you should not turn off whole app to load routes again.
You should strongly emphasize in documentation that fastify cannot add routes after it starts to listen because people may invest a lot of time (and money) in their projects and then they may hit a wall.

[neuronetio]

CMS, CRM, ERP and similar software very often have dynamic categories/subcategories with dynamic content created by the user. routes are created and removed dynamically.

[Eomm]

why not register parametric URL?

/product/:productId
/plugin/:pluginName

[neuronetio]

@Eomm but when you don't know how many parameters will be?