[openstack|compute] Basic examples for Compute

This contains some basics examples on how to set up a VM, do power
operations, and find floating IP pools. It should be enough for a
beginner to get started and familiar with Fog so that more complex
things can be searched by the user.

Get list of image names

lib/fog/openstack/examples/compute/basics.rb

@@ -0,0 +1,74 @@
+# OpenStack Compute (Nova) Example
+
+require 'fog'
+
+auth_url = "https://example.net/v2.0/tokens"
+username = 'admin@example.net'
+password = 'secret'
+tenant   = 'My Compute Tenant' # String
+
+compute_client ||= ::Fog::Compute.new(:provider           => :openstack,
+                                      :openstack_api_key  => password  ,
+                                      :openstack_username => username  ,
+                                      :openstack_auth_url => auth_url  ,
+                                      :openstack_tenant   => tenant)
+
+# Create VM
+# Options include metadata, availability zone, etc...
+
+begin
+  vm = compute_client.servers.create(name, image, flavor, options = {})
+rescue => e
+  puts JSON.parse(e.response.body)['badRequest']['message']
+end
+
+# Destroy VM
+
+vm = compute_client.servers.get(vm.id) # Retrieve previously created vm by UUID
+floating_ips = vm.all_addresses # fetch and release its floating IPs
+floating_ips.each do |address|
+  compute_client.disassociate_address(uuid, address['ip'])
+  compute_client.release_address(address['id'])
+end
+vm.destroy
+
+# Power operations helper
+
+# vm.start / vm.stop / vm.pause should work after this
+class Server < Fog::Compute::Server
+  def start
+    if state.downcase == 'paused'
+      service.unpause_server(id) # resumes from frozen VM state
+    else
+      service.resume_server(id)  # resumes from hibernation
+    end
+  end
+
+  def stop
+    service.suspend_server(id) # hibernates the VM at hypervisor-level
+  end
+
+  def pause
+    service.pause_server(id)   # stores VM state in RAM
+  end
+end
+
+# Images available at tenant
+image_names = compute_client.images.map { |image| image['name'] }
+
+
+# Floating IP address pools available at tenant
+compute_client.addresses.get_address_pools
+# response.body #=> { 'name' => 'pool1' }, { 'name' => 'pool2' }
+
+# VNC console
+vm.console.body # returns VNC url
+
+# "console" => {
+#                "url"  => "http://vmvncserver:6080/vnc_auto.html?token=231",
+#                "type" => "novnc"
+#              }
+
+
+
+