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# Copyright 2009 Canonical Ltd. This software is licensed under the
# GNU Affero General Public License version 3 (see the file LICENSE).
"""Code to represent a single machine instance in EC2."""
__metaclass__ = type
__all__ = [
'EC2Instance',
]
import select
import socket
import subprocess
import sys
import time
import paramiko
class AcceptAllPolicy:
"""We accept all unknown host key."""
# Normally the console output is supposed to contain the Host key
# but it doesn't seem to be the case here, so we trust that the host
# we are connecting to is the correct one.
def missing_host_key(self, client, hostname, key):
pass
class EC2Instance:
"""A single EC2 instance."""
# XXX: JonathanLange 2009-05-31: Make it so that we pass one of these to
# EC2 test runner, rather than the test runner knowing how to make one.
# Right now, the test runner makes one of these directly. Instead, we want
# to make an EC2Account and ask it for one of these instances and then
# pass it to the test runner on construction.
# XXX: JonathanLange 2009-05-31: Separate out demo server maybe?
# XXX: JonathanLange 2009-05-31: Possibly separate out "get an instance"
# and "set up instance for Launchpad testing" logic.
def __init__(self, name, image, instance_type, demo_networks, controller,
vals):
self._name = name
self._image = image
self._controller = controller
self._instance_type = instance_type
self._demo_networks = demo_networks
self._boto_instance = None
self._vals = vals
def error_and_quit(self, msg):
"""Print error message and exit."""
sys.stderr.write(msg)
sys.exit(1)
def log(self, msg):
"""Log a message on stdout, flushing afterwards."""
# XXX: JonathanLange 2009-05-31 bug=383076: Should delete this and use
# Python logging module instead.
sys.stdout.write(msg)
sys.stdout.flush()
def start(self):
"""Start the instance."""
if self._boto_instance is not None:
self.log('Instance %s already started' % self._boto_instance.id)
return
start = time.time()
self.private_key = self._controller.acquire_private_key()
self._controller.acquire_security_group(
demo_networks=self._demo_networks)
reservation = self._image.run(
key_name=self._name, security_groups=[self._name],
instance_type=self._instance_type)
self._boto_instance = reservation.instances[0]
self.log('Instance %s starting..' % self._boto_instance.id)
while self._boto_instance.state == 'pending':
self.log('.')
time.sleep(5)
self._boto_instance.update()
if self._boto_instance.state == 'running':
self.log(' started on %s\n' % self.hostname)
elapsed = time.time() - start
self.log('Started in %d minutes %d seconds\n' %
(elapsed // 60, elapsed % 60))
self._output = self._boto_instance.get_console_output()
self.log(self._output.output)
else:
self.error_and_quit(
'failed to start: %s\n' % self._boto_instance.state)
def shutdown(self):
"""Shut down the instance."""
if self._boto_instance is None:
self.log('no instance created\n')
return
self._boto_instance.update()
if self._boto_instance.state not in ('shutting-down', 'terminated'):
# terminate instance
self._boto_instance.stop()
self._boto_instance.update()
self.log('instance %s\n' % (self._boto_instance.state,))
@property
def hostname(self):
if self._boto_instance is None:
return None
return self._boto_instance.public_dns_name
def connect_as_root(self):
"""Connect to the instance as root.
All subsequent 'perform' and 'subprocess' operations will be done with
root privileges.
"""
# XXX: JonathanLange 2009-06-02: This state-changing method could
# perhaps be written as a function such as run_as_root, or as a method
# that returns a root connection.
for count in range(10):
self.ssh = paramiko.SSHClient()
self.ssh.set_missing_host_key_policy(AcceptAllPolicy())
self.username = 'root'
try:
self.ssh.connect(
self.hostname, username='root',
pkey=self.private_key,
allow_agent=False, look_for_keys=False)
except (socket.error, paramiko.AuthenticationException), e:
self.log('connect_as_root: %r' % (e,))
if count < 9:
time.sleep(5)
self.log('retrying...')
else:
raise
else:
break
def connect_as_user(self):
"""Connect as user.
All subsequent 'perform' and 'subprocess' operations will be done with
user-level privileges.
"""
# XXX: JonathanLange 2009-06-02: This state-changing method could
# perhaps be written as a function such as run_as_user, or as a method
# that returns a user connection.
#
# This does not have the retry logic of connect_as_root because the
# circumstances that make the retries necessary appear to only happen
# on start-up, and connect_as_root is called first.
self.ssh = paramiko.SSHClient()
self.ssh.set_missing_host_key_policy(AcceptAllPolicy())
self.username = self._vals['USER']
self.ssh.connect(self.hostname)
def perform(self, cmd, ignore_failure=False, out=None):
"""Perform 'cmd' on server.
:param ignore_failure: If False, raise an error on non-zero exit
statuses.
:param out: A stream to write the output of the remote command to.
"""
cmd = cmd % self._vals
self.log('%s@%s$ %s\n' % (self.username, self._boto_instance.id, cmd))
session = self.ssh.get_transport().open_session()
session.exec_command(cmd)
session.shutdown_write()
while 1:
select.select([session], [], [], 0.5)
if session.recv_ready():
data = session.recv(4096)
if data:
sys.stdout.write(data)
sys.stdout.flush()
if out is not None:
out.write(data)
if session.recv_stderr_ready():
data = session.recv_stderr(4096)
if data:
sys.stderr.write(data)
sys.stderr.flush()
if session.exit_status_ready():
break
session.close()
# XXX: JonathanLange 2009-05-31: If the command is killed by a signal
# on the remote server, the SSH protocol does not send an exit_status,
# it instead sends a different message with the number of the signal
# that killed the process. AIUI, this code will fail confusingly if
# that happens.
res = session.recv_exit_status()
if res and not ignore_failure:
raise RuntimeError('Command failed: %s' % (cmd,))
return res
def run_with_ssh_agent(self, cmd, ignore_failure=False):
"""Run 'cmd' in a subprocess.
Use this to run commands that require local SSH credentials. For
example, getting private branches from Launchpad.
"""
cmd = cmd % self._vals
self.log('%s@%s$ %s\n' % (self.username, self._boto_instance.id, cmd))
call = ['ssh', '-A', self.hostname,
'-o', 'CheckHostIP no',
'-o', 'StrictHostKeyChecking no',
'-o', 'UserKnownHostsFile ~/.ec2/known_hosts',
cmd]
res = subprocess.call(call)
if res and not ignore_failure:
raise RuntimeError('Command failed: %s' % (cmd,))
return res
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