[openstack|glance] Added image service example

Download CirrOS 0.3.0 image from launchpad (~6.5MB) to /tmp
and upload it to Glance (the OpenStack Image Service).

lib/fog/openstack/examples/image/upload-test-image.rb

@@ -0,0 +1,77 @@
+require 'securerandom'
+require 'rubygems/package'
+require 'zlib'
+require 'fog'
+
+#
+# Download CirrOS 0.3.0 image from launchpad (~6.5MB) to /tmp
+# and upload it to Glance (the OpenStack Image Service).
+#
+# You will need to source OpenStack credentials since the script
+# reads the following envionment variables:
+#
+#  OS_PASSWORD
+#  OS_USERNAME
+#  OS_AUTH_URL
+#  OS_TENANT_NAME
+#
+# Should work with Fog >= 1.9, ruby 1.8.7 and 2.0
+#
+image_url = "https://launchpadlibrarian.net/83305869/cirros-0.3.0-x86_64-uec.tar.gz"
+image_out = File.open("/tmp/cirros-image-#{SecureRandom.hex}", 'wb')
+extract_path = "/tmp/cirros-#{SecureRandom.hex}-dir"
+ami = "#{extract_path}/cirros-0.3.0-x86_64-blank.img"
+aki = "#{extract_path}/cirros-0.3.0-x86_64-vmlinuz"
+ari = "#{extract_path}/cirros-0.3.0-x86_64-initrd"
+
+FileUtils.mkdir_p extract_path
+
+# Efficient image write
+puts "Downloading Cirros image..."
+streamer = lambda do |chunk, remaining_bytes, total_bytes|
+  image_out.write chunk
+end
+Excon.get image_url, :response_block => streamer
+image_out.close
+puts "Image downloaded to #{image_out.path}"
+
+puts "Extracting image contents to #{extract_path}..."
+Gem::Package::TarReader.new(Zlib::GzipReader.open(image_out.path)).each do |entry|
+  FileUtils.mkdir_p "#{extract_path}/#{File.dirname(entry.full_name)}"
+  File.open "#{extract_path}/#{entry.full_name}", 'w' do |f|
+    f.write entry.read
+  end
+end
+
+image_service = Fog::Image.new({
+  :provider => 'OpenStack',
+  :openstack_api_key => ENV['OS_PASSWORD'],
+  :openstack_username => ENV["OS_USERNAME"],
+  :openstack_auth_url => ENV["OS_AUTH_URL"] + "/tokens",
+  :openstack_tenant => ENV["OS_TENANT_NAME"]
+})
+
+puts "Uploading AKI..."
+aki = image_service.images.create :name => 'cirros-0.3.0-amd64-aki',
+                                  :size => File.size(aki),
+                                  :disk_format => 'aki',
+                                  :container_format => 'aki',
+                                  :location => aki
+
+puts "Uploading ARI..."
+ari = image_service.images.create :name => 'cirros-0.3.0-amd64-ari',
+                                  :size => File.size(ari),
+                                  :disk_format => 'ari',
+                                  :container_format => 'ari',
+                                  :location => ari
+
+puts "Uploading AMI..."
+image_service.images.create :name => 'cirros-0.3.0-amd64',
+                            :size => File.size(ami),
+                            :disk_format => 'ami',
+                            :container_format => 'ami',
+                            :location => ami,
+                            :properties => {
+                              'kernel_id'  => aki.id,
+                              'ramdisk_id' => ari.id
+                            }