add virt module for libvirt interaction/support

library/virt

+#!/usr/bin/python 
+"""
+Virt management features
+
+Copyright 2007, 2012 Red Hat, Inc
+Michael DeHaan <mdehaan@redhat.com>
+Seth Vidal <skvidal@fedoraproject.org>
+
+This software may be freely redistributed under the terms of the GNU
+general public license.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+"""
+
+VIRT_FAILED = 1
+VIRT_SUCCESS = 0
+VIRT_UNAVAILABLE=2
+
+try:
+    import json
+except ImportError:
+    import simplejson as json
+
+
+# other modules
+import os
+import sys
+import subprocess
+try:
+    import libvirt
+except ImportError:
+    print json.dumps({
+        "failed" : True,
+        "msg" : "libvirt python module unavailable",
+        "rc": VIRT_UNAVAILABLE,
+        })   
+    sys.exit(1)
+
+
+import shlex
+
+VIRT_STATE_NAME_MAP = {
+   0 : "running",
+   1 : "running",
+   2 : "running",
+   3 : "paused",
+   4 : "shutdown",
+   5 : "shutdown",
+   6 : "crashed"
+}
+
+class LibvirtConnection(object):
+
+    def __init__(self):
+
+        cmd = subprocess.Popen("uname -r", shell=True, stdout=subprocess.PIPE,
+                                close_fds=True)
+        output = cmd.communicate()[0]
+
+        if output.find("xen") != -1:
+            conn = libvirt.open(None)
+        else:
+            conn = libvirt.open("qemu:///system")
+
+        if not conn:
+            raise Exception("hypervisor connection failure")
+
+        self.conn = conn
+
+    def find_vm(self, vmid):
+        """
+        Extra bonus feature: vmid = -1 returns a list of everything
+        """
+        conn = self.conn
+
+        vms = []
+
+        # this block of code borrowed from virt-manager:
+        # get working domain's name
+        ids = conn.listDomainsID()
+        for id in ids:
+            vm = conn.lookupByID(id)
+            vms.append(vm)
+        # get defined domain
+        names = conn.listDefinedDomains()
+        for name in names:
+            vm = conn.lookupByName(name)
+            vms.append(vm)
+
+        if vmid == -1:
+            return vms
+
+        for vm in vms:
+            if vm.name() == vmid:
+                return vm
+
+        raise Exception("virtual machine %s not found" % vmid)
+
+    def shutdown(self, vmid):
+        return self.find_vm(vmid).shutdown()
+
+    def pause(self, vmid):
+        return self.suspend(self.conn,vmid)
+
+    def unpause(self, vmid):
+        return self.resume(self.conn,vmid)
+
+    def suspend(self, vmid):
+        return self.find_vm(vmid).suspend()
+
+    def resume(self, vmid):
+        return self.find_vm(vmid).resume()
+
+    def create(self, vmid):
+        return self.find_vm(vmid).create()
+
+    def destroy(self, vmid):
+        return self.find_vm(vmid).destroy()
+
+    def undefine(self, vmid):
+        return self.find_vm(vmid).undefine()
+
+    def get_status2(self, vm):
+        state = vm.info()[0]
+        # print "DEBUG: state: %s" % state
+        return VIRT_STATE_NAME_MAP.get(state,"unknown")
+
+    def get_status(self, vmid):
+        state = self.find_vm(vmid).info()[0]
+        return VIRT_STATE_NAME_MAP.get(state,"unknown")
+
+    def nodeinfo(self):
+        return self.conn.getInfo()
+
+    def get_type(self):
+        return self.conn.getType()
+
+    def get_maxVcpus(self, vmid):
+        vm = self.conn.lookupByName(vmid)
+        return vm.maxVcpus()
+
+    def get_maxMemory(self, vmid):
+        vm = self.conn.lookupByName(vmid)
+        return vm.maxMemory()
+
+    def getFreeMemory(self):
+        return self.conn.getFreeMemory()
+
+    def get_autostart(self, vmid):
+        vm = self.conn.lookupByName(vmid)
+        return vm.autostart()
+    
+    def set_autostart(self, vmid, val):
+        vm = self.conn.lookupByName(vmid)
+        return vm.setAutostart(val)
+    
+
+
+class Virt(object):
+
+    def __get_conn(self):
+        self.conn = LibvirtConnection()
+        return self.conn
+
+    def get_vm(self, vmid):
+        self.__get_conn()
+        return self.conn.find_vm(vmid)
+        
+    def state(self):
+        vms = self.list_vms()
+        state = []
+        for vm in vms:
+            state_blurb = self.conn.get_status(vm)
+            state.append("%s %s" % (vm,state_blurb))
+        return state
+
+
+    def info(self):
+        vms = self.list_vms()
+        info = dict()
+        for vm in vms:
+            data = self.conn.find_vm(vm).info()
+            # libvirt returns maxMem, memory, and cpuTime as long()'s, which
+            # xmlrpclib tries to convert to regular int's during serialization.
+            # This throws exceptions, so convert them to strings here and
+            # assume the other end of the xmlrpc connection can figure things
+            # out or doesn't care.
+            info[vm] = {
+                "state"     : VIRT_STATE_NAME_MAP.get(data[0],"unknown"),
+                "maxMem"    : str(data[1]),
+                "memory"    : str(data[2]),
+                "nrVirtCpu" : data[3],
+                "cpuTime"   : str(data[4]),
+            }
+            thisvm = self.conn.find_vm(vm)
+            if hasattr(thisvm, 'autostart'):
+                info[vm]["autostart"] = thisvm.autostart()
+
+        return info
+
+    def nodeinfo(self):
+        self.__get_conn()
+        info = dict()
+        data = self.conn.nodeinfo()
+        info = {
+            "cpumodel"     : str(data[0]),
+            "phymemory"    : str(data[1]),
+            "cpus"         : str(data[2]),
+            "cpumhz"       : str(data[3]),
+            "numanodes"    : str(data[4]),
+            "sockets"      : str(data[5]),
+            "cpucores"     : str(data[6]),
+            "cputhreads"   : str(data[7])
+        }
+        return info
+
+    def list_vms(self):
+        self.conn = self.__get_conn()
+        vms = self.conn.find_vm(-1)
+        results = []
+        for x in vms:
+            try:
+                results.append(x.name())
+            except:
+                pass
+        return results
+
+    def virttype(self):
+        return self.__get_conn().get_type()
+        
+
+    def autostart(self, vmid):
+        self.conn = self.__get_conn()
+        return self.conn.set_autostart(vmid, True)
+
+    def freemem(self):
+        self.conn = self.__get_conn()
+        return self.conn.getFreeMemory()
+
+    def shutdown(self, vmid):
+        """
+        Make the machine with the given vmid stop running.
+        Whatever that takes.
+        """
+        self.__get_conn()
+        self.conn.shutdown(vmid)
+        return 0
+
+
+    def pause(self, vmid):
+
+        """
+        Pause the machine with the given vmid.
+        """
+        self.__get_conn()
+        return self.conn.suspend(vmid)
+
+
+    def unpause(self, vmid):
+
+        """
+        Unpause the machine with the given vmid.
+        """
+
+        self.__get_conn()
+        return self.conn.resume(vmid)
+
+
+    def create(self, vmid):
+
+        """
+        Start the machine via the given mac address.
+        """
+        self.__get_conn()
+        return self.conn.create(vmid)
+
+    def start(self, vmid):
+
+        """
+        Start the machine via the given id/name
+        """
+        self.__get_conn()
+        return self.conn.create(vmid)
+
+
+    def destroy(self, vmid):
+
+        """
+        Pull the virtual power from the virtual domain, giving it virtually no
+        time to virtually shut down.
+        """
+        self.__get_conn()
+        return self.conn.destroy(vmid)
+
+
+    def undefine(self, vmid):
+
+        """
+        Stop a domain, and then wipe it from the face of the earth.
+        by deleting the disk image and it's configuration file.
+        """
+
+        self.__get_conn()
+        return self.conn.undefine(vmid)
+
+
+    def status(self, vmid):
+
+        """
+        Return a state suitable for server consumption.  Aka, codes.py values, not XM output.
+        """
+
+        self.__get_conn()
+        return self.conn.get_status(vmid)
+
+
+    def get_xml(self, vmid):
+        """
+        Recieve a Vm id as input
+        Return an xml describing vm config returned by a libvirt call
+        """
+        conn = libvirt.openReadOnly(None)
+        if conn == None:
+            return (-1,'Failed to open connection to the hypervisor')
+        try:
+            domV = conn.lookupByName(vmid)
+        except:
+            return (-1,'Failed to find the main domain')
+        return domV.XMLDesc(0)
+
+
+    def get_maxVcpus(self, vmid):
+        """
+        Gets the max number of VCPUs on a guest
+        """
+
+        self.__get_conn()
+        return self.conn.get_maxVcpus(vmid)
+
+    def get_max_memory(self, vmid):
+        """
+        Gets the max memory on a guest
+        """
+
+        self.__get_conn()
+        return self.conn.get_MaxMemory(vmid)
+
+def main():
+    rc = VIRT_SUCCESS
+    vm_commands = ['create','status', 'start', 'stop', 'pause', 'unpause', 
+                'shutdown', 'undefine', 'destroy', 'get_xml', 'autostart']
+    host_commands = ['freemem', 'list_vms', 'info', 'nodeinfo', 'virttype']
+    
+    
+    msg = """
+    virtmodule arguments:
+    - queryvm guest <queryable item from libvirt domain api> <more of those>
+    - guest commands: (all require a single guest name an argument)
+       %s
+    - host commands:
+       %s
+    
+    """ % (', '.join(sorted(vm_commands)), ', '.join(sorted(host_commands)))
+    
+    if len(sys.argv) == 1:
+        return VIRT_FAILED, msg
+
+    argfile = sys.argv[1]
+    if not os.path.exists(argfile):
+        msg = "Argument file not found"
+        return VIRT_FAILED, msg
+
+    args = open(argfile, 'r').read()
+    items = shlex.split(args)
+
+    if not len(items):
+        return VIRT_FAILED, msg
+
+    basecmd = items[0]
+    v = Virt()
+
+    if basecmd in ('queryvm'):
+        if len(items) < 3:
+            msg = "queryvm requires at least 2 arguments: guest itemname [itemname]"
+            return VIRT_FAILED, msg
+        
+        guest = items[1]
+        reqs = items[2:]
+        res = {}
+        for req in reqs:
+            vm = v.get_vm(guest)
+            if hasattr(vm, req):
+                data = getattr(vm,req)()
+                res[req] = data
+        return rc, res
+        
+    # any methods that require the guest/vmid as the argument must be listed here
+    elif basecmd in vm_commands:
+        if len(items) < 2:
+            msg = "%s requires 1 argument: guest" % basecmd
+        return VIRT_FAILED, msg
+                         
+        guest = items[1]
+        res = getattr(v, basecmd)(guest)
+        if type(res) != dict:
+            res = { basecmd: res }
+        return rc, res
+    
+    elif hasattr(v, basecmd):
+        res = getattr(v, basecmd)()
+        return rc, res
+        
+    else:
+        msg = "Command %s not recognized" % basecmd
+        rc = VIRT_FAILED
+        
+    return rc, msg
+    
+if __name__ == "__main__":
+    try:
+        rc, result = main()
+    except Exception, e:
+        rc = 1
+        result = str(e)
+
+    if rc != 0: # something went wrong emit the msg
+        print json.dumps({
+            "failed" : rc,
+            "msg" : result,
+            "rc": rc,
+        })   
+        sys.exit(rc)
+    else:
+        print json.dumps(result)
+