Host SvelteKit apps with SSR-support via ploi.io (on Hetzner Cloud)

SvelteKit 1.0 was officially released a few hours ago 🥳. Time to dive into NodeJS and SvelteKit hosting. One key advantage of SvelteKit is that you can generate static sites as well as take advantage of Server Side Rendering (SSR). The best thing: You can mix these approaches.

Mix and match prerendered pages for maximum performance with dynamic server-side rendering for maximum flexibility.

In order to use the SSR features, you need to host your app as NodeJS application.

One option for this is to use the awesome server management service ploi.

ploi.io

Ploi.io is like a nice graphical user interface for managing and configuring virtual private servers (VPS). Ploi does not host your site, it's just a middleware service connecting to your servers.

It basically offers three key features:

1. Create and configure (virtual) servers
2. Connect git repositories to these servers
3. Deploy applications via deploy scripts

🇪🇺 An additional advantage is that ploi enables you to deploy NodeJS apps to various server providers like Hetzner Cloud. Hetzner offers servers which are located completely in the European Union (which is good for GDPR-compliance if you or your customers are located in the EU). I blogged about this here briefly.

Prerequisites

Steps I won't cover in this tutorial:

• Sign up for customer account on ploi.io
• Sign up for a customer account on Hetzner Cloud
• Install a new server on Hetzner Cloud via ploi.io (Guide: Server installation). I selected the CX11 type.
• Add an external domain to your server (Guide: How do I connect my domain). You can also use test domains.

Tutorial: Deploy and host SvelteKit

Create a new site on our server

First we need to create a new site on our server:

Expand the advanced settings and use the following:

(Set the project directory to /, otherwise you won't be able to request an SSL cert in the next steps)

Install project from a git repository

Afterwards we can install our project from a git repository:

I added my GitHub account and used my demo repo sveltekit-company-demo:

After adding a repository you can edit the deploy script of your new site:

Replace it with the following, we will need to add npm run build:

cd /home/ploi/sveltekit-company-demo.mandrasch.dev
git pull origin main
# install
npm install
npm run build

# Server restarting is handled by plois NodeJS settings
echo "🚀 Application deployed!"

SSL certificate

We will also need a SSL certificate. Thanks to the Lets's Encrypt initiative this is easily done nowadays:

NodeJS settings (pm2)

Now we need to make adjustments to the NodeJS settings. ploi will use pm2 by default to host our SvelteKit app, Supervisor is also possible.

Change the NodeJS settings to the following:

Important: If you create your first site, it will run on port 3000. SvelteKits adapter-node assumes port 3000 by default. But if you add another site on a server, ploi will use a different port like 3001, 3002, etc. for each new project.

Therefore we need to make sure to set the env variable for the specific port correctly:

PORT=3001 node build/index.js

Thanks very much to aarondiel!

Switch to adapter-node

In order to run our SvelteKit Web App with NodeJS, we also need to apply the following changes to our projects source code.

We need to install adapter-node:

npm i -D @sveltejs/adapter-node

And we need to replace

import adapter from '@sveltejs/adapter-auto';

with

import adapter from '@sveltejs/adapter-node';

in svelte.config.js:

import adapter from '@sveltejs/adapter-node';
import { vitePreprocess } from '@sveltejs/kit/vite';

/** @type {import('@sveltejs/kit').Config} */
const config = {
    kit: {
        adapter: adapter()
    },
    preprocess: vitePreprocess()
};

export default config;

See SvelteKits official docs for all information:

Adapters > Supported Environments > NodeJS

Commit and push these changes.

Deploy (to the build/-directory)

It is time to deploy our app. Let's hit the "Deploy now" button!

You can check the status in the deployments section below:

Spawn the app with pm2

Our app is now successfully prepared in the build/ directory on the server, but we still need to start our app via the pm2 service.

Hit "Spawn" in the NodeJS settings dashboard:

You should see a brief success message and the buttons beneath should change as following:

Congrats, your SvelteKit app is now live! 🥳🥳🥳

If you experience issues, see troubleshooting below.

Have I missed something or can this be optimized? How do you host SvelteKit apps? Let me know in the comments, much appreciated!

Further resources

Troubleshooting

You can check the NodeJS error log for information if something failed. In my case I wasn't aware I need to set the PORT=3001 if I use another port than 300.

Investigating errors is also possible via SSH and pm2 list or pm2 logs command:

See pm2 quickstart docs for more information.

What is pm2?

"PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks." (pm2)

Other similiar tools are nodemon and supervisor.

Reboot configuration

If this is your first time using pm2 on your Hetzner server, you need to add pm2 to the $PATH for server reboots. Follow the ploi.io-guide How to make pm2 start on boot.

In my case I logged in to the Hetzner server ssh ploi@x.x.x.x via terminal / SSH. I previously added my laptops SSH key to ploi, see https://ploi.io/documentation/ssh for more information.

I ran the command pm2 startup and pasted the suggested command (sudo env PATH=$PATH ...):

The root server password was retrieved via mail after the initial server completion (https://ploi.io/documentation/ssh/how-do-i-login-as-root-user):

What is SSR?

• Rich Harris explains why SvelteKit pushes for Server Side Rendering (and against SPA / CSR)
• https://kit.svelte.dev/docs/glossary
• https://learn.svelte.dev/tutorial/ssr
• ... and more resources on YouTube, Twitter, Mastodon, etc.

SvelteKit hosting and GDPR

I blogged about this topic briefly:

How to host SvelteKit SSR apps (GDPR-compliant)?

In general: Big big kudos to Vercel for sponsoring the open source development of Svelte and SvelteKit in a massive way (https://vercel.com/blog/vercel-welcomes-rich-harris-creator-of-svelte)! 🙏👏

Comments

[Kolja]

Great and thanks a lot.
Today I had my first try with Vercelli to deploy a SvelteKit app. Easy, but I concern about GDPR. So Hetzner might be a better way for German websites.
And now I have a nice step by step tutorial 🥰

[Matthias Andrasch]

Nice! Have fun with the tutorial (and if you want let me know if it works for you as well). Cheers! :)

[Johannes Mutter]

A couple of issues I had with setting up Ploi NodeJs server with SvelteKit and how to resolve them:

1. Adding SSL Certificate will fail if NodeJs is running (since the SvelteKit router won’t let you access ".well-known" directory where the temporary SSL keys are stored for Let’s Encrypt). So make sure you remove NodeJs while adding SSL certificates and hit "Spawn" afterwards again.

2. I had to adjust the NGINX config for the site (not server) to make the node process of SvelteKit accessible, which in my case only worked if it was on Port 3000. The NGINX config can be found in Ploi at servers>sites>your site>manage>
   

# Ploi Webserver Configuration, do not remove!
include /etc/nginx/ploi/YOUR_WEBSITE_DOMAIN/before/*;

upstream app {
  server 127.0.0.1:3000;
}

server {
  include /etc/nginx/ssl/YOUR_WEBSITE_DOMAIN;

  root /home/ploi/YOUR_WEBSITE_DOMAIN/;
  server_name YOUR_WEBSITE_DOMAIN www.YOUR_WEBSITE_DOMAIN;

  ssl_protocols TLSv1.2 TLSv1.3;
  ssl_ciphers 'XXXXXXXXXXX';
  ssl_prefer_server_ciphers on;
  ssl_dhparam /etc/nginx/dhparams.pem;

  add_header X-Frame-Options "SAMEORIGIN";
  add_header X-XSS-Protection "1; mode=block";
  add_header X-Content-Type-Options "nosniff";

  charset utf-8;

  # logs can get big, check this folder from time to time
  access_log off;
  error_log  /var/log/nginx/YOUR_WEBSITE_DOMAIN-error.log error;

  # deny for security
  location ~ /\.(?!well-known).* {
    deny all;
  }

  # required for let’s encrypt
  location ~ /.well-known/acme-challenge {  
    allow all;  
    root /var/www/html; 
  }

  # Ploi Configuration, do not remove!
  include /etc/nginx/ploi/YOUR_WEBSITE_DOMAIN/server/*;

  # sveltekit node app
  location / {
    proxy_pass http://app;  # upstream
    proxy_http_version 1.1;

    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $host;

    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-NginX-Proxy true;
    proxy_set_header X-Forwarded-Proto $scheme;
  }

  # Serve static files
  location ~ ^/(robots.txt|humans.txt) {
    proxy_pass http://app;
    root /home/ploi/YOUR_WEBSITE_DOMAIN;
    access_log off;
    log_not_found off;
    expires 30d; # cache expiration
  }
  location ~* \.(p?jpe?g|pjp|jfif|svg|tif|eps|bmp|a?png|gif|mp4|mov|heic|webp|avif|ico)$ {
    proxy_pass http://app;
    root /home/ploi/YOUR_WEBSITE_DOMAIN;
    access_log off;
    log_not_found off;
    expires 30d;
  }

  # error pages are handled by SvelteKit, no need to add them here
}

# Ploi Webserver Configuration, do not remove!
include /etc/nginx/ploi/YOUR_WEBSITE_DOMAIN/after/*;

Make sure to replace all the uppercase written text with your variables (e.g. YOUR_WEBSITE_NAME). Also don’t remove the config that Ploi generates for you.

[Matthias Andrasch]

Hey, thanks for reply!

Regarding 2.), did you use PORT=3001 node build/index.js as start command when using another port? I got a working app on port 3001 with that and I haven't edited the nginx conf manually.

(But I'm not an expert on nginx confs yet, so don't know when these are updated by ploi after changes / what restarts are needed)

And I'm using latest SvelteKit github.com/mandrasch/sveltekit-com....

[Johannes Mutter]

So I just tried port 3001 with the start command PORT=3001 node build/index.js. It only works after manually setting proxy_pass http://localhost:3001; in NGINX config server > location. I guess the default behaviour for the feature "replace NGINX virtual host template" sets the proxy to 3000. Also the script doesn’t for example set the server names correctly if you have multiple domains & aliases, like in my case. That’s why I had to adjust the NGINX config manually.

[Matthias Andrasch]

Ah, interesting! Thanks for reply and insights!