Gemfile

source "https://rubygems.org"

gem 'aws-sdk'
gem 'trollop'
gem "listen", "~> 2.0.0.beta.2"

slam.rb

#!/usr/bin/env ruby

require 'Bundler'
Bundler.require(:default)

opts = Trollop::options do
  opt :bucket, "Select the S3 bucket to archive to",       :short => 'b', :type => String
  opt :source, "Source directory to watch for archival",   :short => 's', :type => String, :default => '.'
  opt :target, "Target directory to write S3 archives to", :short => 't', :type => String, :default => 'backups'
end

Trollop::die :bucket, "must be given" if not opts[:bucket_given]

s3 = AWS::S3.new(
  :access_key_id => '<access key id>',
  :secret_access_key => '<secret access key>'
)

# TODO: this check is naive and insufficient
# check for and add a bucket lifecycle policy to transition to glacier "immediately"
bucket = s3.buckets[opts[:bucket]]
if not bucket.lifecycle_configuration.rules
  bucket.lifecycle_configuration.update do
    add_rule(opts[:target], :glacier_transition_time => 0)
  end
end

# setup filesystem listener and implement "new" files -> S3
listener = Listen.to(opts[:source]) do |modified, added, removed|
  if added
    added.each do |path|
      srcpath = Pathname.new(path)
      putkey  = File.join(opts[:target], srcpath.basename)
      obj = bucket.objects[putkey].write(:file => srcpath.realpath)
    end
  end
end
listener.start
sleep

Usage and options

Example usage:

./slam.rb --bucket upload-bucket-name --source /path/to/staging/directory

Help:

./slam.rb --help
Options:
  --bucket, -b <s>:   Select the S3 bucket to archive to
  --source, -s <s>:   Source directory to watch for archival (default: .)
  --target, -t <s>:   Target directory to write S3 archives to (default: backups)
        --help, -h:   Show this message