my personal checklist deploying to Heroku

This post serves as my single source of truth deploying local changes to a Heroku app.

Local(production) to Github(production)

1. Pull the latest changes from master git pull origin master
2. Switch to production branch. Update that shit git checkout production
3. Look over diffs for both master/production branches. It's more or less a sanity check git diff production..master. Take notes of features you're merging
4. Looks good? Merge changes from master to production on your production branch git merge master
5. Push the latest version production to Github git push origin production

---

Github(production) to Heroku Staging

1. Check Heroku for green status: heroku status
2. Push to production:master branch on staging, update the schema (if needed) and reboot the app git push staging production:master && heroku run rake db:migrate -r staging && heroku restart -r staging
3. Wait for the dyno slug to change watch -n 5 bin/deploy_slug_information (details below on this script)
4. Login to staging. Poke around features you just merged
5. Check JS console for any interesting front end errors
6. Check Honeybadger for server errors

---

Github(production) to Heroku Production

1. Push to production:master branch on staging, update the schema (if needed) and reboot the app git push production production:master && heroku run rake db:migrate -r production && heroku restart -r production
2. Ensure latest SHA release is the same as production branch heroku releases -r production | grep <production_SHA>
3. Check HoneyBadger for errors from release

---

How to run watch -n 5 bin/deploy_slug_information:

Setup an executable in your bin directory to watch ./bin/deploy_slug_information

#!/bin/bash

URL="https://my-app-name.com"

if [ "$1" == "staging" ]; then
  URL="https://my-app-name-staging.com"
fi

URL+="/deploy_slug_information.json"

echo $URL
curl -s $URL
echo

---

Add middleware to your Rails app app/middleware/deploy_slug_information.rb

class DeploySlugInformationMiddleware
  HEADER        = "X-Slug-Commit".freeze
  JSON_ENDPOINT = "/deploy_slug_information.json".freeze

  def initialize(app)
    @app         = app
    @partial_sha = (ENV["HEROKU_SLUG_COMMIT"].to_s[0, 4].presence || "unknown").freeze
  end

  def call(env)
    if env["PATH_INFO"] == JSON_ENDPOINT
      json_endpoint_reply(env)
    else
      header_injection_reply(env)
    end
  end

  private

  def header_injection_reply(env)
    status, headers, response = @app.call(env)
    headers[HEADER] = @partial_sha
    [status, headers, response]
  end

  def json_endpoint_reply(env)
    body = { slug_commit: @partial_sha }.to_json

    headers = {
      "Content-Length" => body.length.to_s,
      "Content-Type"   => "application/json",
    }

    [200, headers, [body]]
  end
end

Tips

• Unix trick - use fc to edit and execute your most recently used shell command.