Add LICENSE and headers; move some functions out of pvcf.py and into VMInstance

VMInstance.py

@@ -1,5 +1,25 @@
 #!/usr/bin/env python3
 
+# VMInstance.py - Class implementing a PVC virtual machine and run by pvcd
+# Part of the Parallel Virtual Cluster (PVC) system
+#
+#    Copyright (C) 2018  Joshua M. Boniface <joshua@boniface.me>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+###############################################################################
+
 import os, sys, socket, time, threading, libvirt, kazoo.client, pvcf
 
 class VMInstance:
@@ -210,3 +230,38 @@ class VMInstance:
             domxml, domxmlstat = self.zk.get(self.zkey + '/xml')
             domxml = str(domxml.decode('ascii'))
             self.start_vm(domxml)
+
+# This function is a wrapper for libvirt.lookupByUUID which fixes some problems
+# 1. Takes a text UUID and handles converting it to bytes
+# 2. Try's it and returns a sensible value if not
+def lookupByUUID(tuuid):
+    conn = None
+    dom = None
+    libvirt_name = "qemu:///system"
+
+    # Convert the text UUID to bytes
+    buuid = uuid.UUID(tuuid).bytes
+
+    # Try
+    try:
+        # Open a libvirt connection
+        conn = libvirt.open(libvirt_name)
+        if conn == None:
+            print('>>> %s - Failed to open local libvirt connection.' % self.domuuid)
+            return dom
+    
+        # Lookup the UUID
+        dom = conn.lookupByUUID(buuid)
+
+    # Fail
+    except:
+        pass
+
+    # After everything
+    finally:
+        # Close the libvirt connection
+        if conn != None:
+            conn.close()
+
+    # Return the dom object (or None)
+    return dom