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#!/usr/bin/python
#
# Fetch and run user-data from EC2
# Copyright 2009 Canonical Ltd.
#
# Author: Soren Hansen <soren@canonical.com>
#
# 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 <http://www.gnu.org/licenses/>.
#
import email
import os
import subprocess
import sys
import tempfile
import ec2init
content_type_handlers = { 'text/x-shellscript' : handle_shell_script,
'text/x-ebs-mount-description' : handle_ebs_mount_description }
def main():
ec2 = ec2init.EC2Init()
semaphore = '/var/lib/ec2/already-ran.%s' % amiId
amiId = ec2.get_ami_id()
if os.path.exists(semaphore):
print "ec2-run-user-data already ran for this instance."
return 0
user_data = ec2.get_user_data()
msg = email.message_from_string(user_data)
if msg.is_multipart():
handle_part(msg)
else:
handle_payload(user_data)
# Touch the semaphore file
file(semaphore, 'a').close()
def handle_part(part):
if part.is_multipart():
for p in part.get_payload():
handle_part(p)
else:
if part.get_content_type() in content_type_handlers:
content_type_handlers[part.get_content_type](part.get_payload())
return
handle_unknown_payload(part.get_payload())
def handle_unknown_payload(payload):
# Try to detect magic
if payload.startswith('#!'):
content_type_handlers['text/x-shellscript'](payload)
def handle_ebs_mount_description(payload):
(volume_description, path) = payload.split(':')
(identifier_type, identifier) = volume_description.split('=')
if identifier_type == 'device':
device = identifier
# Perhaps some day the volume id -> device path mapping
# will be exposed through meta-data.
# elif identifier_type == 'volume':
# device = extract_device_name_from_meta_data
else:
return
def handle_shell_script(payload):
(fd, path) = tempfile.mkstemp()
fp = os.fdopen(fd, 'a')
fp.write(payload)
fp.close()
os.chmod(path, 0700)
# Run the user data script and pipe its output to logger
user_data_process = subprocess.Popen([path], stdout=subprocess.PIPE)
logger_process = subprocess.Popen(['logger', '-t', 'user-data'], stdin=user_data_process.stdout)
logger_process.communicate()
os.unlink(path)
if __name__ == '__main__':
main()
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