Express router for better code organisation

A Node/Express app I’m working on has been sprouting routes so much that the server.js file has swollen to 800 lines - way past my 200-250 comfort zone, so it’s time to organise the routes into their own files. That seems like a good topic for a beginner blog post, so let’s dive in.

Imagine we’ve written this little Node/Express app.

import express from "express";
import {
  dbCustomersGet,
  dbCustomersGetById,
  dbCustomersDelete,
  dbOrdersGet,
  dbOrdersGetById,
  dbOrdersGetByCustomerId,
  dbOrdersDelete,
} from "./db.js";

const app = express();
app.set("view engine", "ejs");
const port = 3002;

app.use(express.urlencoded({ extended: true }));

app.get("/", (req, res) => {
  res.redirect("/customers");
});

app.get("/customers", (req, res) => {
  const customers = dbCustomersGet();
  res.render("customers", { customers });
});

app.get("/customers/:id", (req, res) => {
  const customer = dbCustomersGetById(req.params.id);
  const orders = dbOrdersGetByCustomerId(req.params.id);
  res.render("customer", { customer, orders });
});

app.get("/customers/:id/delete", (req, res) => {
  dbCustomersDelete(req.params.id);
  res.redirect("/customers");
});

app.get("/orders", (req, res) => {
  const orders = dbOrdersGet();
  res.render("orders", { orders });
});

app.get("/orders/:id", (req, res) => {
  const order = dbOrdersGetById(req.params.id);
  const customer = dbCustomersGetById(order.customerId);
  res.render("order", { order, customer });
});

app.get("/orders/:id/delete", (req, res) => {
  dbOrdersDelete(req.params.id);
  res.redirect("/orders");
});

app.listen(port, () => {
  console.log(`Listening on http://127.0.0.1:${port}`);
});

Although concocted, this would seem familiar to anyone who’s built a CRUD business app.

A bit of web-scraping with Cheerio

I had an idea for a little holiday project that required a list of episodes from The Rest Is History podcast. On their ‘Episodes’ page, they have a player, and a list of post entries for the most recent eighteen podcasts. There is a ‘show all’ button, but it doesn’t work.

The player does contain the full list of episodes (about 600) including a number of duplicates, so I expected if I inspected the network calls that I’d see a JSON package arriving with what I wanted. This is what I almost always find these days so I’ve had very little call to do any real web scraping - it’s normally just a matter of locating the endpoint and perhaps extracting an API key from a header.

Command chaining with NTFY for long running commands

NTFY is a great open-source push notification service that’s self-hostable or free to use (although I suggest you pay for it as I do). I’ve written before how I use it with UptimeKuma for my uptime monitoring, but another common use is just when I’m initiating long-running commands and backgrounding them.

This magic is possible since we can just curl to send a NTFY notification. For example:

curl -d "😀 demo push message via NTFY" ntfy.sh/blog_demo

Since I’m subscribed to the “blog_demo” topic in NTFY, this message will be pushed to my phone and watch:

Share files securely with Enclosed

My accountant works for one of those giant firms, and it bugs me that I’m emailing him password protected zip files of my accounts rather than to a secure upload facility at his firm. I can fix this with the power of self hosting, by running my own secure file dropping app on a VPS.

There’s a number of applications that do this sort of thing - allow you to upload a file, get a link in return which you can then share to people to download the file. For this to be more secure than emailing, the file needs to be encrypted on the server, and we want to be able to set a password, impose limits on downloads, and limit how long the link lives for. I’ve previously looked at Sharry which adds the ability for unauthenticated users to upload files to you securely, but for this slightly simpler job, I chose Enclosed by Corentin Thomasset .

Moving a Docker image as a file

I’m having a super annoying problem at the moment, I can’t pull down containers from DockerHub. If I hotspot my laptop off my phone it works fine, so it’s some drama with the home internet connection that rebooting the router does not fix.

I’ve had a couple of different errors including Error response from daemon: Get "https://registry-1.docker.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers) and Error response from daemon: Get "https://registry-1.docker.io/v2/": dial tcp: lookup registry-1.docker.io. I can’t actually ping registry-1.docker.io or hub.docker.com, although I can open hub.docker.com in a browser, so it works for ports 80 and 443, but not some other udp ports.

Perils of Benchmarking

I’ve been containerising my websites, with their servers to make deployment simple and robust, and to move to a CI/CD workflow. Since an install of a production web server is large, I would be running about ten of these containers, and there’s already a good server facing the net and doing the reverse-proxying (NGINX Proxy Manager), I chose to bundle the Busy-Box httpd server with my sites inside the Docker containers.

Moving a domain from Wordpress

I love the convenience of a hosted blog on wordpress.com, but one of the justifications for my ‘investment’ in homelab hardware and learning time was that I’d reduce my spend on hosted platforms by self-hosting them. I’ve already quit Evernote and dropped back to the free plan on Dropbox by building systems to replace them for less money and more data sovereignty. And now, the recent Wordpress drama has made me uneasy about Matt having control of domains I’ve got registered with wordpress.

Updating a deployment on fly.io

I’ve had my external UptimeKuma chugging away on fly.io , for free, for months now, and the container image it was based on was a bit out of date, so I wanted to update it. I hadn’t looked at fly.io for months, and couldn’t really recall what I’d done to create it.

The way this works is that that you create a fly.toml file that sets out the details of your app. From memory I think I used the one from the docs and gave it a unique name, the name of the Docker image, the port, the datacentre location, and the directory for the persisted data. The you run fly deploy from the directory with the toml file (having already installed the CLI tool and logged in) and you’re in business.

Controlling Docker container startup order

A very common scenario when running services in Docker containers is that one service is going to depend on another. The most common example is going to be if you have a service that needs a database - you’re going to want the container running the database to be ready for business before the service that needs it starts. And conversely, when you shut things down, you want to stop the service before you kill the database or you may lose some data.

Fixing TLS for wget in BusyBox

I’ve been containerising my static websites with BusyBox (because it’s small), and in an earlier post showed how to even get the container to update parts of the site by reaching out with wget to download resources from elsewhere and saving them inside the container where we are serving the ‘static’ site from. I’d done this by including a bash script in the container with the wget in a loop with a sleep. Then started the script and the httpd server in the CMD line of the dockerfile.

Fancier Website in a Docker Container

The previous post went over how to bundle a static website into a Docker container. That’s a neat little trick - keeping the entire website and making it trivial to install on a VPS behind Nginx Proxy Manager. It worked great for most of my little websites.

But…

A couple of my websites had very minor ‘dynamic’ content. One was pulling down the local temperature from OpenWeather, then exposing a cut-down version of that as a REST endpoint so all my servers could grab it without me being rate-limited by OpenWeather for abusing my free API key. Another one re-hosted an image that changes a couple of times a day from an unreliable service.

Website in a Docker Container

Having figured out how to use the GitHub package registry, I was a bit inspired by this blog post from Florin Lipan to deliver all my little static websites as Docker containers. I’m not as focused as he is about making them tiny, but I did steal the idea of using BusyBox httpd for serving them, resulting in about 4MB containers. That’s small enough for me, and since they are all very similar, there’s a fair bit of layer reuse going on.

rsync between Synology NAS

A while ago, I devised a complicated system where I could drop files in a web interface running on an LXD container and the files would then magically appear in a directory on a remote NAS in the morning. It turned out to not be very robust, and I gave up on it after a while.

Also, really there should be no need for it - underneath, it was just using rsync to move the files, so why not just do that direct from one NAS to another? Well, mainly because my NASs are all Synology - which I love, and they’ve been great, but in an effort to make them usable by muggles, Synology tend to somewhat complicate things for Linux command line wizards.

Containerised NGINX Proxy Manager & the 502 error

If you’re used to running NGINX Proxy Manager in front of your web apps, and switch to running it in a container, you’re going to need to learn a little about Docker networks to get everything connected. If you just do your regular setup, and direct the proxy for an address to 127.0.0.1:<some port>, it won’t exist, and you’ll visit your page to find the “502 Bad Gateway openresty” message.

dockerfile - CMD vs ENTRYPOINT

There are two entries we often have at the end of a dockerfile (which is the file that tells Docker how an image is to be built).

They are similar in that when the container is launched from an image, these commands will be executed. For example, both of the dockerfiles below will print “Hello World” when run.

doc-entry:

FROM debian:stable-slim
ENTRYPOINT ["echo", "Hello World from ENTRYPOINT"]

doc-cmd:

FROM debian:stable-slim
CMD ["echo", "Hello World"]

User environment variables are not available in cron

I’m used to using the docker-compose.yaml or dockerfile to set environment variables for containers running my apps, but ran into an issue recently where the variable seemed to be set some of the time, but at others it didn’t appear to exist.

I had a script set to run by cron inside the container, and it turns out that the environment variables set for the container are available in the user space, but not in cron, even if running with that user’s permissions. This is probably old news to established Linux users but it threw me for a while. I’d exec into the container and the script would work perfectly, then wait another minute for cron to run it and it would fail 🤦‍♀️ It was exasperated by my discovery that I didn’t know how to console.log debug from inside a container cron job as well - the subject of an earlier post.

Outputting to the console, in Docker, from a cron job

If you’re googling this exact title, you’re probably bumping your head against the same things I was today. I was debugging a completely different project, and needed to print to the console, from a cron job, in a Docker container. Turns out this isn’t as straightforward as I thought.

Foreground cron

Before you even get to the problem space, here’s a tip. If you want to have a cron job running in a container, start cron in the foreground. If you do not, Docker realises nothing is going on, and exits. If you want to keep the container active so your cron jobs get a chance to execute, then start it in the foreground.

Peek inside a Docker image

A ‘dockerfile’ contains all the instructions to build a Docker image. Here’s my first draft for a project I’m working on:

FROM node:20
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
CMD ["node", "server.js"]

COPY . . is copying all of the files in my project into the working directory of the image so they can be run. Of course we don’t need them all for the app - for example the node_modules directory will be created when we npm install so no need to copy that, and I don’t need all my dot files in the container.

Hosting Your Own Docker Registry

The Docker Personal (ie free tier) plan currently allows one private repository, but even if you want to pay for the next level where you can have unlimited repositories, you may still want to host your own private registry - it’s going to be quicker inside your network, and you won’t run up against Docker’s pull/push limits if you are hammering it with your CI/CD system.

Certbot - removing a domain

I had a number of domains all running on one host when I first set them up with certbot. One started to be serious, so I moved it to another host and ran certbot there. That all worked perfectly, but of course, the old domain is still part of the original certificate, so when I went to renew it, it came up with some errors.

Here’s a few commands that are going to help navigate this situation if you’ve found yourself in the same spot: