Issue #54: Getting started with cfn-init
Implemented features:
* sysv and systemd service handling
* yum package management
Running the script:
e.g., sudo python cfn-init -f resource-metadata.json
Example resource metadata file contents:
{
"AWS::CloudFormation::Init": {
"config": {
"packages": {
"yum": {
"rubygem-fattr" : []
}
},
"services": {
"sysvinit": {
"httpd": {
"enabled" : "true",
"ensureRunning" : "true"
}
}
}
}
}
}
This commit is contained in:
Greg Blomquist
parent
56e8d80630
commit
c51273efaa
580
cftools/cfn-init
580
cftools/cfn-init
@ -1,3 +1,4 @@
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#!/usr/bin/python
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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@ -13,4 +14,583 @@
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"""
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Implements cfn-init CloudFormations functionality
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Resource metadata currently implemented:
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* config/packages
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* config/services
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Not implemented yet:
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* config sets
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* config/sources
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* config/commands
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* config/files
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* config/users
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* config/groups
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* command line args
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- placeholders are ignored
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"""
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import argparse
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import json
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import logging
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import os
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import rpmUtils.updates as rpmupdates
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import rpmUtils.miscutils as rpmutils
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import subprocess
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import sys
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logging.basicConfig(level=logging.INFO)
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class CommandRunner(object):
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"""
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Helper class to run a command and store the output.
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"""
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def __init__(self, command):
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self._command = command
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self._stdout = None
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self._stderr = None
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self._status = None
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def __str__(self):
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s = "CommandRunner:"
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s += "\n\tcommand: %s" % self._command
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if self._status:
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s += "\n\tstatus: %s" % self._status
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if self._stdout:
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s += "\n\tstdout: %s" % self._stdout
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if self._stderr:
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s += "\n\tstderr: %s" % self._stderr
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return s
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def run(self):
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"""
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Run the Command and return the output.
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Returns:
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self
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"""
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logging.debug("Running command: %s" % self._command)
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cmd = self._command.split()
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subproc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
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output = subproc.communicate()
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self._status = subproc.returncode
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self._stdout = output[0]
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self._stderr = output[1]
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return self
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@property
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def stdout(self):
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return self._stdout
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@property
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def stderr(self):
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return self._stderr
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@property
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def status(self):
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return self._status
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class RpmHelper(object):
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_rpm_util = rpmupdates.Updates([], [])
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@classmethod
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def prepcache(cls):
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"""
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Prepare the yum cache
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"""
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CommandRunner("yum -y makecache").run()
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@classmethod
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def compare_rpm_versions(cls, v1, v2):
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"""
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Compare two RPM version strings.
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Arguments:
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v1 -- a version string
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v2 -- a version string
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Returns:
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0 -- the versions are equal
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1 -- v1 is greater
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-1 -- v2 is greater
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"""
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if v1 and v2:
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return rpmutils.compareVerOnly(v1, v2)
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elif v1:
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return 1
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elif v2:
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return -1
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else:
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return 0
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@classmethod
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def newest_rpm_version(cls, versions):
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"""
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Returns the highest (newest) version from a list of versions.
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Arguments:
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versions -- A list of version strings
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e.g., ['2.0', '2.2', '2.2-1.fc16', '2.2.22-1.fc16']
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"""
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if versions:
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if isinstance(versions, basestring):
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return versions
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versions = sorted(versions, rpmutils.compareVerOnly,
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reverse=True)
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return versions[0]
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else:
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return None
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@classmethod
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def rpm_package_version(cls, pkg):
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"""
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Returns the version of an installed RPM.
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Arguments:
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pkg -- A package name
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"""
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cmd = "rpm -q --queryformat '%{VERSION}-%{RELEASE}' %s" % pkg
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command = CommandRunner(cmd).run()
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return command.stdout
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@classmethod
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def rpm_package_installed(cls, pkg):
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"""
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Indicates whether pkg is in rpm database.
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Arguments:
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pkg -- A package name (with optional version and release spec).
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e.g., httpd
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e.g., httpd-2.2.22
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e.g., httpd-2.2.22-1.fc16
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"""
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command = CommandRunner("rpm -q %s" % pkg).run()
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return command.status == 0
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@classmethod
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def yum_package_available(cls, pkg):
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"""
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Indicates whether pkg is available via yum
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Arguments:
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pkg -- A package name (with optional version and release spec).
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e.g., httpd
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e.g., httpd-2.2.22
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e.g., httpd-2.2.22-1.fc16
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"""
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command = CommandRunner("yum -C -y --showduplicates list available %s" % pkg).run()
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return command.status == 0
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@classmethod
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def install(cls, packages, rpms=True):
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"""
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Installs (or upgrades) a set of packages via RPM or via Yum.
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Arguments:
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packages -- a list of packages to install
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rpms -- if True:
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* use RPM to install the packages
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* packages must be a list of URLs to retrieve RPMs
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if False:
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* use Yum to install packages
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* packages is a list of:
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- pkg name (httpd), or
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- pkg name with version spec (httpd-2.2.22), or
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- pkg name with version-release spec (httpd-2.2.22-1.fc16)
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"""
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if rpms:
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cmd = "rpm -U --force --nosignature "
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cmd += " ".join(packages)
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logging.info("Installing packages: %s" % cmd)
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else:
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cmd = "yum -y install "
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cmd += " ".join(packages)
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logging.info("Installing packages: %s" % cmd)
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command = CommandRunner(cmd).run()
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if command.status:
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logging.warn("Failed to install packages: %s" % cmd)
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@classmethod
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def downgrade(cls, packages, rpms=True):
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"""
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Downgrades a set of packages via RPM or via Yum.
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Arguments:
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packages -- a list of packages to downgrade
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rpms -- if True:
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* use RPM to downgrade (replace) the packages
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* packages must be a list of URLs to retrieve the RPMs
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if False:
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* use Yum to downgrade packages
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* packages is a list of:
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- pkg name with version spec (httpd-2.2.22), or
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- pkg name with version-release spec (httpd-2.2.22-1.fc16)
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"""
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if rpms:
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cls.install(packages)
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else:
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cmd = "yum -y downgrade "
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cmd += " ".join(packages)
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logging.info("Downgrading packages: %s" % cmd)
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command = Command(cmd).run()
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if command.status:
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logging.warn("Failed to downgrade packages: %s" % cmd)
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class PackagesHandler(object):
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_packages = {}
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_package_order = ["dpkg", "rpm", "apt", "yum"]
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@staticmethod
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def _pkgsort(pkg1, pkg2):
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order = PackagesHandler._package_order
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p1_name = pkg1[0]
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p2_name = pkg2[0]
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if p1_name in order and p2_name in order:
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return cmp(order.index(p1_name), order.index(p2_name))
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elif p1_name in order:
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return -1
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elif p2_name in order:
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return 1
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else:
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return cmp(p1_name.lower(), p2_name.lower())
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def __init__(self, packages):
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self._packages = packages
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def _handle_gem_packages(self, packages):
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#FIXME: handle rubygems
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pass
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def _handle_python_packages(self, packages):
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#FIXME: handle python easyinstall
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pass
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def _handle_yum_packages(self, packages):
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"""
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Handle installation, upgrade, or downgrade of a set of packages via yum.
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Arguments:
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packages -- a package entries map of the form:
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"pkg_name" : "version",
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"pkg_name" : ["v1", "v2"],
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"pkg_name" : []
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For each package entry:
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* if no version is supplied and the package is already installed, do
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nothing
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* if no version is supplied and the package is _not_ already
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installed, install it
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* if a version string is supplied, and the package is already
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installed, determine whether to downgrade or upgrade (or do nothing
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if version matches installed package)
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* if a version array is supplied, choose the highest version from the
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array and follow same logic for version string above
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"""
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# collect pkgs for batch processing at end
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installs = []
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downgrades = []
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# update yum cache
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RpmHelper.prepcache()
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for pkg_name, versions in packages.iteritems():
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ver = RpmHelper.newest_rpm_version(versions)
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pkg = "%s-%s" % (pkg_name, ver) if ver else pkg_name
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if RpmHelper.rpm_package_installed(pkg):
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pass # FIXME:print non-error, but skipping pkg
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elif not RpmHelper.yum_package_available(pkg):
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logging.warn("Skipping package '%s'. Not available via yum" % pkg)
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elif not ver:
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installs.append(pkg)
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else:
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current_ver = RpmHelper.rpm_package_version(pkg)
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rc = RpmHelper.compare_rpm_versions(current_ver, ver)
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if rc < 0:
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installs.append(pkg)
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elif rc > 0:
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downgrades.append(pkg)
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if installs:
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RpmHelper.install(installs, rpms=False)
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if downgrades:
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RpmHelper.downgrade(downgrades)
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def _handle_rpm_packages(sef, packages):
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"""
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Handle installation, upgrade, or downgrade of a set of packages via rpm.
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Arguments:
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packages -- a package entries map of the form:
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"pkg_name" : "url"
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For each package entry:
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* if the EXACT package is already installed, skip it
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* if a different version of the package is installed, overwrite it
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* if the package isn't installed, install it
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"""
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#FIXME: handle rpm installs
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pass
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def _handle_apt_packages(self, packages):
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#FIXME: handle apt-get
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pass
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# map of function pionters to handle different package managers
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_package_handlers = {
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"yum" : _handle_yum_packages,
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"rpm" : _handle_rpm_packages,
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"apt" : _handle_apt_packages,
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"rubygems" : _handle_gem_packages,
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"python" : _handle_python_packages
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}
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def _package_handler(self, manager_name):
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handler = None
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if manager_name in self._package_handlers:
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handler = self._package_handlers[manager_name]
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return handler
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def apply_packages(self):
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"""
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Install, upgrade, or downgrade packages listed
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Each package is a dict containing package name and a list of versions
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Install order:
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* dpkg
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* rpm
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* apt
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* yum
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"""
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packages = sorted(self._packages.iteritems(), PackagesHandler._pkgsort)
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for manager, package_entries in packages:
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handler = self._package_handler(manager)
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if not handler:
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logging.warn("Skipping invalid package type: %s" % manager)
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else:
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handler(self, package_entries)
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class ServicesHandler(object):
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_services = {}
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def __init__(self, services):
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self._services = services
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def _handle_sysv_command(self, service, command):
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service_exe = "/sbin/service"
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enable_exe = "/sbin/chkconfig"
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cmd = ""
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if "enable" == command:
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cmd = "%s %s on" % (enable_exe, service)
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elif "disable" == command:
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cmd = "%s %s off" % (enable_exe, service)
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elif "start" == command:
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cmd = "%s %s start" % (service_exe, service)
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elif "stop" == command:
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cmd = "%s %s stop" % (service_exe, service)
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elif "status" == command:
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cmd = "%s %s status" % (service_exe, service)
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command = CommandRunner(cmd)
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command.run()
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return command
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def _handle_systemd_command(self, service, command):
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exe = "/bin/systemctl"
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cmd = ""
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if "enable" == command:
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cmd = "%s enable %s" % (exe, service)
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elif "disable" == command:
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cmd = "%s disable %s" % (exe, service)
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elif "start" == command:
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cmd = "%s start %s" % (exe, service)
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elif "stop" == command:
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cmd = "%s stop %s" % (exe, service)
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elif "status" == command:
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cmd = "%s status %s" % (exe, service)
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command = CommandRunner(cmd)
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command.run()
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return command
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def _handle_service(self, handler, service, properties):
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if "enabled" in properties:
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enable = to_boolean(properties["enabled"])
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if enable:
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logging.info("Enabling service %s" % service)
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handler(self, service, "enable")
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else:
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logging.info("Disabling service %s" % service)
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handler(self, service, "disable")
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if "ensureRunning" in properties:
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ensure_running = to_boolean(properties["ensureRunning"])
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command = handler(self, service, "status")
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running = command.status == 0
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if ensure_running and not running:
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logging.info("Starting service %s" % service)
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handler(self, service, "start")
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elif not ensure_running and running:
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logging.info("Stopping service %s" % service)
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handler(self, service, "stop")
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def _handle_services(self, handler, services):
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for service, properties in services.iteritems():
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self._handle_service(handler, service, properties)
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# map of function pointers to various service handlers
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_service_handlers = {
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"sysvinit" : _handle_sysv_command,
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"systemd" : _handle_systemd_command
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}
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def _service_handler(self, manager_name):
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handler = None
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if manager_name in self._service_handlers:
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handler = self._service_handlers[manager_name]
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return handler
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def apply_services(self):
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"""
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Starts, stops, enables, disables services
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"""
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for manager, service_entries in self._services.iteritems():
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handler = self._service_handler(manager)
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if not handler:
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logging.warn("Skipping invalid service type: %s" % manager)
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else:
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self._handle_services(handler, service_entries)
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class Metadata(object):
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_metadata = None
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_init_key = "AWS::CloudFormation::Init"
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def __init__(self, metadata):
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self._metadata = json.loads(metadata)
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def _is_valid_metadata(self):
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"""
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Should find the AWS::CloudFormation::Init json key
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"""
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is_valid = self._metadata and self._init_key in self._metadata and self._metadata[self._init_key]
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if is_valid:
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self._metadata = self._metadata[self._init_key]
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return is_valid
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def _process_config(self):
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"""
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Parse and process a config section
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* packages
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* sources (not yet)
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* users (not yet)
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* groups (not yet)
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* files (not yet)
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* commands (not yet)
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* services
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"""
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self._config = self._metadata["config"]
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PackagesHandler(self._config.get("packages")).apply_packages()
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#FIXME: handle sources
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#FIXME: handle users
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#FIXME: handle groups
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#FIXME: handle files
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#FIXME: handle commands
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ServicesHandler(self._config.get("services")).apply_services()
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def process(self):
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"""
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Process the resource metadata
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"""
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# FIXME: when config sets are implemented, this should select the correct
|
||||
# config set from the metadata, and send each config in the config set to
|
||||
# process_config
|
||||
if not self._is_valid_metadata():
|
||||
raise Exception("invalid metadata")
|
||||
else:
|
||||
self._process_config()
|
||||
|
||||
|
||||
def to_boolean(b):
|
||||
val = b.lower().strip() if isinstance(b, basestring) else b
|
||||
return b in [True, 'true', 'yes', '1', 1]
|
||||
|
||||
|
||||
def get_metadata(fname):
|
||||
"""
|
||||
Read the metadata from the given filename and return the string
|
||||
"""
|
||||
f = open(fname)
|
||||
meta = f.read()
|
||||
f.close()
|
||||
return meta
|
||||
|
||||
|
||||
## Main
|
||||
description = " "
|
||||
parser = argparse.ArgumentParser(description=description)
|
||||
parser.add_argument("-f", "--metadata-file",
|
||||
dest="metafile",
|
||||
help="File containing the resource metadata to process",
|
||||
required=True)
|
||||
parser.add_argument('-s', '--stack',
|
||||
dest="stack_name",
|
||||
help="A Heat stack name",
|
||||
required=False)
|
||||
parser.add_argument('-r', '--resource',
|
||||
dest="logical_resource_id",
|
||||
help="A Heat logical resource ID",
|
||||
required=False)
|
||||
parser.add_argument('--access-key',
|
||||
dest="access_key",
|
||||
help="A Keystone access key",
|
||||
required=False)
|
||||
parser.add_argument('--secret-key',
|
||||
dest="secret_key",
|
||||
help="A Keystone secret key",
|
||||
required=False)
|
||||
parser.add_argument('--region',
|
||||
dest="region",
|
||||
help="Openstack region",
|
||||
required=False)
|
||||
args = parser.parse_args()
|
||||
# FIXME: implement real arg
|
||||
|
||||
metadata = Metadata(get_metadata(args.metafile))
|
||||
try:
|
||||
metadata.process()
|
||||
except Exception as e:
|
||||
logging.exception("Error processing metadata")
|
||||
exit(1)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user