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A while back I wrote the attached code to demonstrate how to use events and serial console to create a serial console that stays up even when the VM is down. It might need some work, as I am not terribly strong with Python. * examples/python/consolecallback.py: New file. * examples/python/Makefile.am (EXTRA_DIST): Ship it.
89 lines
2.8 KiB
Python
89 lines
2.8 KiB
Python
#!/usr/bin/env python
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# consolecallback - provide a persistent console that survives guest reboots
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import sys, os, logging, libvirt, tty, termios, atexit
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def reset_term():
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termios.tcsetattr(0, termios.TCSADRAIN, attrs)
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def error_handler(unused, error):
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# The console stream errors on VM shutdown; we don't care
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if (error[0] == libvirt.VIR_ERR_RPC and
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error[1] == libvirt.VIR_FROM_STREAMS):
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return
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logging.warn(error)
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class Console(object):
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def __init__(self, uri, uuid):
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self.uri = uri
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self.uuid = uuid
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self.connection = libvirt.open(uri)
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self.domain = self.connection.lookupByUUIDString(uuid)
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self.state = self.domain.state(0)
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self.connection.domainEventRegister(lifecycle_callback, self)
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self.stream = None
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self.run_console = True
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logging.info("%s initial state %d, reason %d",
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self.uuid, self.state[0], self.state[1])
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def check_console(console):
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if (console.state[0] == libvirt.VIR_DOMAIN_RUNNING or
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console.state[0] == libvirt.VIR_DOMAIN_PAUSED):
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if console.stream == None:
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console.stream = console.connection.newStream(libvirt.VIR_STREAM_NONBLOCK)
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console.domain.openConsole(None, console.stream, 0)
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console.stream.eventAddCallback(libvirt.VIR_STREAM_EVENT_READABLE, stream_callback, console)
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else:
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if console.stream:
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console.stream.eventRemoveCallback()
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console.stream = None
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return console.run_console
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def stdin_callback(watch, fd, events, console):
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readbuf = os.read(fd, 1024)
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if readbuf.startswith(" "):
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console.run_console = False
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return
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if console.stream:
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console.stream.send(readbuf)
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def stream_callback(stream, events, console):
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try:
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received_data = console.stream.recv(1024)
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except:
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return
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os.write(0, received_data)
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def lifecycle_callback (connection, domain, event, detail, console):
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console.state = console.domain.state(0)
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logging.info("%s transitioned to state %d, reason %d",
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console.uuid, console.state[0], console.state[1])
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# main
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if len(sys.argv) != 3:
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print "Usage:", sys.argv[0], "URI UUID"
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print "for example:", sys.argv[0], "'qemu:///system' '32ad945f-7e78-c33a-e96d-39f25e025d81'"
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sys.exit(1)
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uri = sys.argv[1]
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uuid = sys.argv[2]
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print "Escape character is ^]"
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logging.basicConfig(filename='msg.log', level=logging.DEBUG)
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logging.info("URI: %s", uri)
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logging.info("UUID: %s", uuid)
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libvirt.virEventRegisterDefaultImpl()
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libvirt.registerErrorHandler(error_handler, None)
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atexit.register(reset_term)
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attrs = termios.tcgetattr(0)
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tty.setraw(0)
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console = Console(uri, uuid)
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console.stdin_watch = libvirt.virEventAddHandle(0, libvirt.VIR_EVENT_HANDLE_READABLE, stdin_callback, console)
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while check_console(console):
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libvirt.virEventRunDefaultImpl()
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