kaylareopelle

How to instrument your Rails application with OpenTelemetry

This gist accompanies a workshop titled "How to instrument your Rails app with OpenTelemetry" that was held at RailsConf 2025 in Philadelphia on July 9, 2025.

• Repository
• Slides
• Recording

xiaohui-zhangxh

class Api::ApplicationController < ActionController::API
  include Pagy::Backend
  include PagyCollectionSerializer::ControllerMixin
end

lingceng

class Chatgpt::PlainChatgptClient
  def self.chat(parameters)
    @client ||= generate_client

    res = @client.post("/v1/chat/completions") do |req|
      if parameters[:stream].is_a?(Proc)
        req.options.on_data = to_json_stream(user_proc: parameters[:stream])
        parameters[:stream] = true
      end

Reiss-Cashmore

#!/bin/zsh

#Credit: Original idea and script disable.sh by pwnsdx https://gist.github.com/pwnsdx/d87b034c4c0210b988040ad2f85a68d3
#*****Work in progress*****
#Disabling unwanted services on macOS 11 Big Sur
#Modifications written in /private/var/db/com.apple.xpc.launchd/ disabled.plist, disabled.501.plist & disabled.205.plist
#Disabling SIP might not be required, still testing.

sudo mkdir  mnt
sudo mount -o nobrowse -t apfs /dev/disk1s5 mnt/

equivalent

• Rails 7.0.2
• stimulus js
• importmaps
• dropzone.js
• direct upload ActiveStorage

This is simple implementation of technologies in hobby project of mine built in Rails7 where I need direct upload to S3.

memoryleak

#!/usr/bin/env bash
sudo hdiutil create -o /tmp/Monterey -size 16g -volname Monterey -layout SPUD -fs HFS+J
sudo hdiutil attach /tmp/Monterey.dmg -noverify -mountpoint /Volumes/Monterey
sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/Monterey --nointeraction
hdiutil eject -force  /Volumes/Install\ macOS\ Monterey
hdiutil convert /tmp/Monterey.dmg -format UDTO -o ~/Downloads/Monterey
mv -v ~/Downloads/Monterey.cdr ~/Downloads/Monterey.iso
sudo rm -fv /tmp/Monterey.dmg

hopsoft

FROM ruby:3.0-alpine

RUN apk add --no-cache --update \
ack \
bash \
build-base \
curl \
git \
htop \
less \

iccir

# iPhone with home button
xcrun simctl status_bar booted clear    
xcrun simctl status_bar booted override \
  --time "9:41 AM" \
  --wifiBars 3 --cellularBars 4 --operatorName ""
xcrun simctl spawn booted defaults write com.apple.springboard SBShowBatteryPercentage 1

# iPhone X
xcrun simctl status_bar booted clear    
xcrun simctl status_bar booted override --time "9:41" --wifiBars 3 --cellularBars 4

ole

A dump of the SwiftUI.framework binary for the iOS simulator (as of Xcode 12.0 beta 2) using the swift-reflection-dump tool.

Note: I used a Swift 5.3 compiler build from a few weeks ago that I had laying around. Because of ABI stability, I don't think the swift-reflection-dump version has to match the compiler version that was used to build the binary, but I'm not 100% sure.

mfts

brew install certbot

# change <my.domain> to preferred domain
certbot certonly --manual --preferred-challenges dns --server https://acme-v02.api.letsencrypt.org/directory --manual-public-ip-logging-ok -d '*.<my.domain>' -d <my.domain>

# add certificates to heroku
heroku certs:add -a eduqai-prod /etc/letsencrypt/live/<my.domain>/fullchain.pem /etc/letsencrypt/live/<my.domain>/privkey.pem

# may need to run with sudo