2 minute read

Deploying static websites to Amazon S3

Amazon S3 is a great choice for hosting static content (like blogs), but the process of deploying can leave a little to be desired — unless you leverage a build tool like Rake.

I recently switched hosting for this site — from Heroku to Amazon S3. I’ve always used Jekyll to build it, but had been using Heroku for the convenience of push-to-deploy (I use custom plugins as well as SASS, so I’m unable to use GitHub Pages without mucking up my site’s git history).

My hesitation to use Amazon S3 has always been deploying — I wanted something as simple as Heroku’s push-to-deploy. After a bit of struggling, I ended up writing a Rake task to do it all for me. To see the complete source (including the build task), check out this site on GitHub.

Rake task to deploy the _site/ directory to an S3 bucket:

desc "Deploy site to Amazon S3"
task :deploy => :build do
  require "s3"

  id = ENV["WWWDUNKMANME_ID"]
  key = ENV["WWWDUNKMANME_KEY"]

  if id.nil? || key.nil?
    puts "S3 credentials not found in environment."
    exit 1
  end

  service = S3::Service.new(:access_key_id => id, :secret_access_key => key)
  bucket = service.buckets.find("www.dunkman.me")

  local_files = Dir["_site/**/*"].map { |file| file.sub(/_site\//, "") }
  remote_files = bucket.objects

  puts "Checking for remote files to delete..."
  changes = false
  remote_files.each do |remote_file|
    unless File.exists? "_site/#{remote_file.key}"
      remote_file.destroy
      puts " |  #{remote_file.key} has been removed."
      changes = true
    end
  end

  unless changes
    puts "  (no files to delete)"
  end

  puts
  puts "Checking for local files to upload..."
  changes = false
  local_files.each do |local_file|
    next if File.directory? "_site/#{local_file}"
    files = remote_files.select { |remote_file| remote_file.key == local_file }
    remote_file = files.first

    if remote_file
      local_md5 = Digest::MD5.file("_site/#{local_file}").hexdigest
      remote_md5 = remote_file.etag

      unless local_md5 == remote_md5
        remote_file.content = open("_site/#{local_file}")
        remote_file.content_type = "" # Use default
        remote_file.save
        puts " |  #{local_file} has changed."
        changes = true
      end
    else
      remote_file = bucket.objects.build(local_file)
      remote_file.content = open("_site/#{local_file}")
      remote_file.content_type = "" # Use default
      remote_file.save
      puts " |  #{local_file} is new."
      changes = true
    end

  end

  unless changes
    puts "  (no files to upload)"
  end

  puts
end