Tracking progress of a file upload using v2 of the aws-sdk gem

progress.rb

require 'aws-sdk'
require 'pathname'

class ProgressIO

  def initialize(io)
    @io = io
    @bytes_read = 0
    @listeners = []
  end

  def read(bytes, output_buffer = nil)
    signal(bytes)
    @io.read(bytes, output_buffer)
  end

  def rewind(*args)
    @bytes_read = 0
    signal(0)
    @io.rewind(*args)
  end

  def size
    @io.size
  end

  def listen(&block)
    @listeners << block
  end

  private

  def signal(bytes)
    @bytes_read += bytes
    @listeners.each do |callback|
      callback.call(@bytes_read, size)
    end
  end

end

s3 = Aws::S3::Client.new
s3.handle(step: :sign, priority: 0) do |context|
  progress = ProgressIO.new(context.http_request.body)
  progress.listen do |bytes_read, total|
    puts "READ #{bytes_read} / #{total}"
  end
  context.http_request.body = progress
  @handler.call(context)
end

File.open('./large-file.txt', 'rb') do |file|
  s3.put_object({
    bucket: 'aws-sdk',
    key: File.basename(file),
    body: file,
  })
end