Add spot instance support

rebased on current 0.5.0 with original work at mitchellh#32

lib/vagrant-aws/action/run_instance.rb

@@ -100,7 +100,12 @@ def call(env)
           begin
             env[:ui].warn(I18n.t("vagrant_aws.warn_ssh_access")) unless allows_ssh_port?(env, security_groups, subnet_id)
 
-            server = env[:aws_compute].servers.create(options)
+            server = if region_config.spot_instance
+                       server_from_spot_request(env, region_config)
+                     else
+                       env[:aws_compute].servers.create(options)
+                     end
+            raise Errors::FogError, :message => "server is nil" unless server
           rescue Fog::Compute::AWS::NotFound => e
             # Invalid subnet doesn't have its own error so we catch and
             # check the error message here.
@@ -176,6 +181,72 @@ def call(env)
           @app.call(env)
         end
 
+        # returns a fog server or nil
+        def server_from_spot_request(env, config)
+          # prepare request args
+          options = {
+            'InstanceCount'                                  => 1,
+            'LaunchSpecification.KeyName'                    => config.keypair_name,
+            'LaunchSpecification.Placement.AvailabilityZone' => config.availability_zone,
+            'LaunchSpecification.UserData'                   => config.user_data,
+            'LaunchSpecification.SubnetId'                   => config.subnet_id,
+            'ValidUntil'                                     => config.spot_valid_until
+          }
+          security_group_key = config.subnet_id.nil? ? 'LaunchSpecification.SecurityGroup' : 'LaunchSpecification.SecurityGroupId'
+          options[security_group_key] = config.security_groups
+          options.delete_if { |key, value| value.nil? }
+
+          env[:ui].info(I18n.t("vagrant_aws.launching_spot_instance"))
+          env[:ui].info(" -- Price: #{config.spot_max_price}")
+          env[:ui].info(" -- Valid until: #{config.spot_valid_until}") if config.spot_valid_until
+          env[:ui].info(" -- Monitoring: #{config.monitoring}") if config.monitoring
+
+          # create the spot instance
+          spot_req = env[:aws_compute].request_spot_instances(
+            config.ami,
+            config.instance_type,
+            config.spot_max_price,
+            options).body["spotInstanceRequestSet"].first
+
+          spot_request_id = spot_req["spotInstanceRequestId"]
+          @logger.info("Spot request ID: #{spot_request_id}")
+
+          # initialize state
+          status_code = ""
+          while true
+            sleep 5 # TODO make it a param
+
+            raise Errors::FogError, :message => "Interrupted" if env[:interrupted]
+            spot_req = env[:aws_compute].describe_spot_instance_requests(
+              'spot-instance-request-id' => [spot_request_id]).body["spotInstanceRequestSet"].first
+
+            # waiting for spot request ready
+            next unless spot_req
+
+            # display something whenever the status code changes
+            if status_code != spot_req["state"]
+              env[:ui].info(spot_req["fault"]["message"])
+              status_code = spot_req["state"]
+            end
+            spot_state = spot_req["state"].to_sym
+            case spot_state
+            when :not_created, :open
+              @logger.debug("Spot request #{spot_state} #{status_code}, waiting")
+            when :active
+              break; # :)
+            when :closed, :cancelled, :failed
+              msg = "Spot request #{spot_state} #{status_code}, aborting"
+              @logger.error(msg)
+              raise Errors::FogError, :message => msg
+            else
+              @logger.debug("Unknown spot state #{spot_state} #{status_code}, waiting")
+            end
+          end
+          # cancel the spot request but let the server go thru
+          env[:aws_compute].cancel_spot_instance_requests(spot_request_id)
+          env[:aws_compute].servers.get(spot_req["instanceId"])
+        end
+
         def recover(env)
           return if env["vagrant.error"].is_a?(Vagrant::Errors::VagrantError)
 

lib/vagrant-aws/config.rb

@@ -108,6 +108,21 @@ class Config < Vagrant.plugin("2", :config)
       # @return [Array<Hash>]
       attr_accessor :block_device_mapping
 
+      # Launch as spot instance
+      #
+      # @return [Boolean]
+      attr_accessor :spot_instance
+
+      # Spot request max price
+      #
+      # @return [String]
+      attr_accessor :spot_max_price
+
+      # Spot request validity
+      #
+      # @return [Time]
+      attr_accessor :spot_valid_until
+
       # Indicates whether an instance stops or terminates when you initiate shutdown from the instance
       #
       # @return [bool]
@@ -162,6 +177,10 @@ def initialize(region_specific=false)
         @user_data              = UNSET_VALUE
         @use_iam_profile        = UNSET_VALUE
         @block_device_mapping   = []
+        @use_iam_profile        = UNSET_VALUE
+        @spot_instance          = UNSET_VALUE
+        @spot_max_price         = UNSET_VALUE
+        @spot_valid_until       = UNSET_VALUE
         @elastic_ip             = UNSET_VALUE
         @iam_instance_profile_arn  = UNSET_VALUE
         @iam_instance_profile_name = UNSET_VALUE
@@ -297,6 +316,15 @@ def finalize!
         # User Data is nil by default
         @user_data = nil if @user_data == UNSET_VALUE
 
+        # By default don't use spot requests
+        @spot_instance = false if @spot_instance == UNSET_VALUE
+
+        # Required, no default
+        @spot_max_price = nil if @spot_max_price == UNSET_VALUE
+
+        # Default: Request is effective indefinitely.
+        @spot_valid_until = nil if @spot_valid_until == UNSET_VALUE
+
         # default false
         @terminate_on_shutdown = false if @terminate_on_shutdown == UNSET_VALUE
 
@@ -362,6 +390,7 @@ def validate(machine)
           end
 
           errors << I18n.interpolate("vagrant_aws.config.ami_required", :region => @region)  if config.ami.nil?
+          errors << I18n.interpolate("vagrant_aws.config.spot_price_required") if config.spot_instance && config.spot_max_price.nil?
         end
 
         { "AWS Provider" => errors }

locales/en.yml

@@ -16,6 +16,8 @@ en:
 
     launching_instance: |-
       Launching an instance with the following settings...
+    launching_spot_instance: |-
+      Launching a spot request instance with the following settings...
     launch_no_keypair: |-
       Warning! You didn't specify a keypair to launch your instance with.
       This can sometimes result in not being able to access your instance.
@@ -59,6 +61,8 @@ en:
         An access key ID must be specified via "access_key_id"
       ami_required: |-
         An AMI must be configured via "ami" (region: #{region})
+      spot_price_required: |-
+        Spot request is missing "spot_max_price"
       private_key_missing: |-
         The specified private key for AWS could not be found
       region_required: |-

spec/vagrant-aws/config_spec.rb

@@ -32,6 +32,9 @@
     its("user_data")         { should be_nil }
     its("use_iam_profile")   { should be_false }
     its("block_device_mapping")  {should == [] }
+    its("spot_instance")     { should be_false }
+    its("spot_max_price")    { should be_nil }
+    its("spot_valid_until")  { should be_nil }
     its("elastic_ip")        { should be_nil }
     its("terminate_on_shutdown") { should == false }
     its("ssh_host_attribute") { should be_nil }