mirror of
https://github.com/retspen/webvirtcloud
synced 2026-11-08 11:16:47 +00:00
1d48cc6881
- A paste reaches the VM whole: the non-blocking console stream takes it in parts, or none while the VM is busy, and the rest was dropped. The worker sends the rest until the VM has it, for at most five seconds. - A libvirt error while the console is open (the host gone, the VM undefined or migrated) ends the session with one line in the terminal instead of a Python traceback; libvirt no longer prints its errors on the terminal. Errors are shown as users see them elsewhere: a host that cannot be reached is not named. - The terminal says when the VM is not running and its console will open when it starts. The terminal is raw before the console opens, and the stream is dropped once when both threads see the VM stop.
123 lines
4.3 KiB
Python
Executable file
123 lines
4.3 KiB
Python
Executable file
#!/usr/bin/env python3
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# consolecallback <instance id> - the serial console of one VM on stdin/stdout
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# (socketiod runs it in a pty, one per client). It opens the console through
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# the compute's connection (its stored credentials); the connection's event
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# loop thread runs the stream callbacks. The console survives guest reboots.
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import os
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import sys
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import time
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import tty
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import django
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ROOT_PATH = os.path.abspath(os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", ".."))
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if ROOT_PATH not in sys.path:
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sys.path.append(ROOT_PATH)
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os.environ.setdefault("DJANGO_SETTINGS_MODULE", "webvirtcloud.settings")
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django.setup()
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import libvirt # noqa: E402
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from instances.models import Instance # noqa: E402
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from operations.utils import public_error_text # noqa: E402
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from vrtManager.connection import connection_manager # noqa: E402
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# libvirt prints its errors on stderr, which is the user's terminal: they are
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# raised and told in one line instead
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libvirt.registerErrorHandler(lambda context, error: None, None)
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SEND_WAIT = 5 # seconds a paste may wait for the VM to take it
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def say(text):
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os.write(1, ("\r\n[%s]\r\n" % text).encode())
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class Console:
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def __init__(self, connection, uuid):
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self.domain = connection.lookupByUUIDString(uuid)
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self.connection = connection
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self.stream = None
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self.running = True
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def check(self):
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"""Open the stream while the VM runs, drop it while it does not."""
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active = self.domain.state()[0] in (libvirt.VIR_DOMAIN_RUNNING, libvirt.VIR_DOMAIN_PAUSED)
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if active and self.stream is None:
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stream = self.connection.newStream(libvirt.VIR_STREAM_NONBLOCK)
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self.domain.openConsole(None, stream, 0) # a console in use is refused
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stream.eventAddCallback(libvirt.VIR_STREAM_EVENT_READABLE, from_vm, self)
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self.stream = stream
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elif not active and self.stream is not None:
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self.close_stream()
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say("The VM is not running: its console opens again when it starts")
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def close_stream(self):
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stream, self.stream = self.stream, None
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if stream is None: # the other thread closed it
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return
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try:
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stream.eventRemoveCallback()
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stream.abort()
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except libvirt.libvirtError:
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pass
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def from_client(watch, fd, events, console):
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try:
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data = os.read(fd, 1024)
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except OSError:
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data = b""
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if not data: # the client is gone
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console.running = False
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return
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stream = console.stream # the main thread may drop it meanwhile
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deadline = time.monotonic() + SEND_WAIT
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try:
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# a non-blocking stream takes part of a paste, or none (-2) while the VM is busy
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while data and stream is not None and time.monotonic() < deadline:
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sent = stream.send(data)
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if sent == -2:
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time.sleep(0.01)
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else:
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data = data[sent:]
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except libvirt.libvirtError:
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console.close_stream()
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def from_vm(stream, events, console):
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try:
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data = stream.recv(1024)
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except libvirt.libvirtError: # the VM shut down
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data = None
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if not data or data == -2: # -2: nothing to read now
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if data != -2:
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console.close_stream()
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return
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os.write(1, data)
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def main():
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instance = Instance.objects.select_related("compute").get(pk=int(sys.argv[1]))
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c = instance.compute
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try:
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console = Console(connection_manager.get_connection(c.hostname, c.login, c.password, c.type), instance.uuid)
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tty.setraw(0) # before the console opens: nothing typed is echoed by the terminal
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console.check()
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except libvirt.libvirtError as err:
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say("Cannot open the console of %s: %s" % (instance.name, public_error_text(err)))
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sys.exit(1)
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if console.stream is None:
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say("The VM is not running: its console opens when it starts")
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libvirt.virEventAddHandle(0, libvirt.VIR_EVENT_HANDLE_READABLE, from_client, console)
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try:
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while console.running:
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time.sleep(0.2)
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console.check()
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except libvirt.libvirtError as err: # the host went away, the VM was undefined or migrated
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say("The console of %s closed: %s" % (instance.name, public_error_text(err)))
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sys.exit(1)
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if __name__ == "__main__":
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main()
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