Use open socket method for opening socket

This commit updates pool manager to use a method for opening a socket
instead of opening it directly from check_pending_vm. Support is added
for specifying the domain of the VM to connect to, which lays the
groundwork for doing away with the assumption of having DNS search
domains set for vmpooler to move VMs to the ready state.

Additionally, this commit adds a block to ensure open_socket closes open connections. Without this change sockets are opened to each VM before moving to the ready state, and never explicitly closed.

Also, use open socket for check_ready_vm

lib/vmpooler/pool_manager.rb

@@ -26,29 +26,30 @@ def check_pending_vm(vm, pool, timeout, vsphere)
       end
     end
 
-    def open_socket(host, domain=nil, timeout=5, port=22)
+    def open_socket(host, domain=nil, timeout=5, port=22, &block)
       Timeout.timeout(timeout) do
-        target_host = vm
-        target_host = "#{vm}.#{domain}" if domain
-        TCPSocket.new target_host, port
+        target_host = host
+        target_host = "#{host}.#{domain}" if domain
+        sock = TCPSocket.new target_host, port
+        begin
+          yield sock if block_given?
+        ensure
+          sock.close
+        end
       end
     end
 
     def _check_pending_vm(vm, pool, timeout, vsphere)
       host = vsphere.find_vm(vm)
 
-      if host
-        begin
-          Timeout.timeout(5) do
-            TCPSocket.new vm, 22
-          end
-          move_pending_vm_to_ready(vm, pool, host)
-        rescue
-          fail_pending_vm(vm, pool, timeout)
-        end
-      else
-        fail_pending_vm(vm, pool, timeout)
+      if ! host
+        fail_pending_vm(vm, pool, timeout, false)
+        return
       end
+      open_socket vm
+      move_pending_vm_to_ready(vm, pool, host)
+    rescue
+      fail_pending_vm(vm, pool, timeout)
     end
 
     def fail_pending_vm(vm, pool, timeout, exists=true)
@@ -137,12 +138,12 @@ def check_ready_vm(vm, pool, ttl, vsphere)
           end
 
           begin
-            Timeout.timeout(5) do
-              TCPSocket.new vm, 22
-            end
+            open_socket vm
           rescue
             if $redis.smove('vmpooler__ready__' + pool, 'vmpooler__completed__' + pool, vm)
               $logger.log('d', "[!] [#{pool}] '#{vm}' is unreachable, removed from 'ready' queue")
+            else
+              $logger.log('d', "[!] [#{pool}] '#{vm}' is unreachable, and failed to remove from 'ready' queue")
             end
           end
         end