aws_test.rb

creds = {
  "AWS_ACCESS_KEY_ID" => 'foo',
  "AWS_SECRET_ACCESS_KEY" => "foo"
}

require 'aws4'
require 'pp'
require 'faraday'
require 'json'
require 'time'

# create a signer
signer = AWS4::Signer.new(
  access_key: creds['AWS_ACCESS_KEY_ID'],
  secret_key: creds['AWS_SECRET_ACCESS_KEY'],
  region: "us-east-1"
)

# build request
headers = {
  "Date" => Time.now.iso8601,
  "Content-Type" => "application/x-amz-json-1.0",
  "host" => "search-heroku-support-lrvw3kyqlzblfmcjcluus2rn74.us-east-1.es.amazonaws.com"
}
body="{}"

# sign headers
uri = URI("https://search-heroku-support-lrvw3kyqlzblfmcjcluus2rn74.us-east-1.es.amazonaws.com/_cat/health")
headers_signed = signer.sign("GET", uri, headers, body, true)
pp headers_signed

conn = Faraday.new(:url => "https://search-heroku-support-lrvw3kyqlzblfmcjcluus2rn74.us-east-1.es.amazonaws.com/")

resp = conn.get do |req|
  req.url '/_cat/health'
  req.headers = headers_signed
end

pp resp.status
pp resp.body