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authorStuart Mackie <wsmackie@juniper.net>2016-10-07 12:24:58 -0700
committerStuart Mackie <wsmackie@juniper.net>2016-10-07 12:24:58 -0700
commit4faa7f927149a5c4ef7a03523f7bc14523cb9baa (patch)
tree0be55aa0809cc395e45baeae63db660b4e72fe83 /charms/trusty/ceilometer/charmhelpers/contrib/openstack/templating.py
parent82f1a7eb5535b30a95b1e71ff18c315d40d1e6f0 (diff)
Charms for Contrail 3.1 with Mitaka
Change-Id: Id37f3b9743d1974e31fcd7cd9c54be41bb0c47fb Signed-off-by: Stuart Mackie <wsmackie@juniper.net>
Diffstat (limited to 'charms/trusty/ceilometer/charmhelpers/contrib/openstack/templating.py')
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+# Copyright 2014-2015 Canonical Limited.
+#
+# This file is part of charm-helpers.
+#
+# charm-helpers is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# charm-helpers 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with charm-helpers. If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+import six
+
+from charmhelpers.fetch import apt_install, apt_update
+from charmhelpers.core.hookenv import (
+ log,
+ ERROR,
+ INFO
+)
+from charmhelpers.contrib.openstack.utils import OPENSTACK_CODENAMES
+
+try:
+ from jinja2 import FileSystemLoader, ChoiceLoader, Environment, exceptions
+except ImportError:
+ apt_update(fatal=True)
+ apt_install('python-jinja2', fatal=True)
+ from jinja2 import FileSystemLoader, ChoiceLoader, Environment, exceptions
+
+
+class OSConfigException(Exception):
+ pass
+
+
+def get_loader(templates_dir, os_release):
+ """
+ Create a jinja2.ChoiceLoader containing template dirs up to
+ and including os_release. If directory template directory
+ is missing at templates_dir, it will be omitted from the loader.
+ templates_dir is added to the bottom of the search list as a base
+ loading dir.
+
+ A charm may also ship a templates dir with this module
+ and it will be appended to the bottom of the search list, eg::
+
+ hooks/charmhelpers/contrib/openstack/templates
+
+ :param templates_dir (str): Base template directory containing release
+ sub-directories.
+ :param os_release (str): OpenStack release codename to construct template
+ loader.
+ :returns: jinja2.ChoiceLoader constructed with a list of
+ jinja2.FilesystemLoaders, ordered in descending
+ order by OpenStack release.
+ """
+ tmpl_dirs = [(rel, os.path.join(templates_dir, rel))
+ for rel in six.itervalues(OPENSTACK_CODENAMES)]
+
+ if not os.path.isdir(templates_dir):
+ log('Templates directory not found @ %s.' % templates_dir,
+ level=ERROR)
+ raise OSConfigException
+
+ # the bottom contains tempaltes_dir and possibly a common templates dir
+ # shipped with the helper.
+ loaders = [FileSystemLoader(templates_dir)]
+ helper_templates = os.path.join(os.path.dirname(__file__), 'templates')
+ if os.path.isdir(helper_templates):
+ loaders.append(FileSystemLoader(helper_templates))
+
+ for rel, tmpl_dir in tmpl_dirs:
+ if os.path.isdir(tmpl_dir):
+ loaders.insert(0, FileSystemLoader(tmpl_dir))
+ if rel == os_release:
+ break
+ log('Creating choice loader with dirs: %s' %
+ [l.searchpath for l in loaders], level=INFO)
+ return ChoiceLoader(loaders)
+
+
+class OSConfigTemplate(object):
+ """
+ Associates a config file template with a list of context generators.
+ Responsible for constructing a template context based on those generators.
+ """
+ def __init__(self, config_file, contexts):
+ self.config_file = config_file
+
+ if hasattr(contexts, '__call__'):
+ self.contexts = [contexts]
+ else:
+ self.contexts = contexts
+
+ self._complete_contexts = []
+
+ def context(self):
+ ctxt = {}
+ for context in self.contexts:
+ _ctxt = context()
+ if _ctxt:
+ ctxt.update(_ctxt)
+ # track interfaces for every complete context.
+ [self._complete_contexts.append(interface)
+ for interface in context.interfaces
+ if interface not in self._complete_contexts]
+ return ctxt
+
+ def complete_contexts(self):
+ '''
+ Return a list of interfaces that have satisfied contexts.
+ '''
+ if self._complete_contexts:
+ return self._complete_contexts
+ self.context()
+ return self._complete_contexts
+
+
+class OSConfigRenderer(object):
+ """
+ This class provides a common templating system to be used by OpenStack
+ charms. It is intended to help charms share common code and templates,
+ and ease the burden of managing config templates across multiple OpenStack
+ releases.
+
+ Basic usage::
+
+ # import some common context generates from charmhelpers
+ from charmhelpers.contrib.openstack import context
+
+ # Create a renderer object for a specific OS release.
+ configs = OSConfigRenderer(templates_dir='/tmp/templates',
+ openstack_release='folsom')
+ # register some config files with context generators.
+ configs.register(config_file='/etc/nova/nova.conf',
+ contexts=[context.SharedDBContext(),
+ context.AMQPContext()])
+ configs.register(config_file='/etc/nova/api-paste.ini',
+ contexts=[context.IdentityServiceContext()])
+ configs.register(config_file='/etc/haproxy/haproxy.conf',
+ contexts=[context.HAProxyContext()])
+ # write out a single config
+ configs.write('/etc/nova/nova.conf')
+ # write out all registered configs
+ configs.write_all()
+
+ **OpenStack Releases and template loading**
+
+ When the object is instantiated, it is associated with a specific OS
+ release. This dictates how the template loader will be constructed.
+
+ The constructed loader attempts to load the template from several places
+ in the following order:
+ - from the most recent OS release-specific template dir (if one exists)
+ - the base templates_dir
+ - a template directory shipped in the charm with this helper file.
+
+ For the example above, '/tmp/templates' contains the following structure::
+
+ /tmp/templates/nova.conf
+ /tmp/templates/api-paste.ini
+ /tmp/templates/grizzly/api-paste.ini
+ /tmp/templates/havana/api-paste.ini
+
+ Since it was registered with the grizzly release, it first seraches
+ the grizzly directory for nova.conf, then the templates dir.
+
+ When writing api-paste.ini, it will find the template in the grizzly
+ directory.
+
+ If the object were created with folsom, it would fall back to the
+ base templates dir for its api-paste.ini template.
+
+ This system should help manage changes in config files through
+ openstack releases, allowing charms to fall back to the most recently
+ updated config template for a given release
+
+ The haproxy.conf, since it is not shipped in the templates dir, will
+ be loaded from the module directory's template directory, eg
+ $CHARM/hooks/charmhelpers/contrib/openstack/templates. This allows
+ us to ship common templates (haproxy, apache) with the helpers.
+
+ **Context generators**
+
+ Context generators are used to generate template contexts during hook
+ execution. Doing so may require inspecting service relations, charm
+ config, etc. When registered, a config file is associated with a list
+ of generators. When a template is rendered and written, all context
+ generates are called in a chain to generate the context dictionary
+ passed to the jinja2 template. See context.py for more info.
+ """
+ def __init__(self, templates_dir, openstack_release):
+ if not os.path.isdir(templates_dir):
+ log('Could not locate templates dir %s' % templates_dir,
+ level=ERROR)
+ raise OSConfigException
+
+ self.templates_dir = templates_dir
+ self.openstack_release = openstack_release
+ self.templates = {}
+ self._tmpl_env = None
+
+ if None in [Environment, ChoiceLoader, FileSystemLoader]:
+ # if this code is running, the object is created pre-install hook.
+ # jinja2 shouldn't get touched until the module is reloaded on next
+ # hook execution, with proper jinja2 bits successfully imported.
+ apt_install('python-jinja2')
+
+ def register(self, config_file, contexts):
+ """
+ Register a config file with a list of context generators to be called
+ during rendering.
+ """
+ self.templates[config_file] = OSConfigTemplate(config_file=config_file,
+ contexts=contexts)
+ log('Registered config file: %s' % config_file, level=INFO)
+
+ def _get_tmpl_env(self):
+ if not self._tmpl_env:
+ loader = get_loader(self.templates_dir, self.openstack_release)
+ self._tmpl_env = Environment(loader=loader)
+
+ def _get_template(self, template):
+ self._get_tmpl_env()
+ template = self._tmpl_env.get_template(template)
+ log('Loaded template from %s' % template.filename, level=INFO)
+ return template
+
+ def render(self, config_file):
+ if config_file not in self.templates:
+ log('Config not registered: %s' % config_file, level=ERROR)
+ raise OSConfigException
+ ctxt = self.templates[config_file].context()
+
+ _tmpl = os.path.basename(config_file)
+ try:
+ template = self._get_template(_tmpl)
+ except exceptions.TemplateNotFound:
+ # if no template is found with basename, try looking for it
+ # using a munged full path, eg:
+ # /etc/apache2/apache2.conf -> etc_apache2_apache2.conf
+ _tmpl = '_'.join(config_file.split('/')[1:])
+ try:
+ template = self._get_template(_tmpl)
+ except exceptions.TemplateNotFound as e:
+ log('Could not load template from %s by %s or %s.' %
+ (self.templates_dir, os.path.basename(config_file), _tmpl),
+ level=ERROR)
+ raise e
+
+ log('Rendering from template: %s' % _tmpl, level=INFO)
+ return template.render(ctxt)
+
+ def write(self, config_file):
+ """
+ Write a single config file, raises if config file is not registered.
+ """
+ if config_file not in self.templates:
+ log('Config not registered: %s' % config_file, level=ERROR)
+ raise OSConfigException
+
+ _out = self.render(config_file)
+
+ with open(config_file, 'wb') as out:
+ out.write(_out)
+
+ log('Wrote template %s.' % config_file, level=INFO)
+
+ def write_all(self):
+ """
+ Write out all registered config files.
+ """
+ [self.write(k) for k in six.iterkeys(self.templates)]
+
+ def set_release(self, openstack_release):
+ """
+ Resets the template environment and generates a new template loader
+ based on a the new openstack release.
+ """
+ self._tmpl_env = None
+ self.openstack_release = openstack_release
+ self._get_tmpl_env()
+
+ def complete_contexts(self):
+ '''
+ Returns a list of context interfaces that yield a complete context.
+ '''
+ interfaces = []
+ [interfaces.extend(i.complete_contexts())
+ for i in six.itervalues(self.templates)]
+ return interfaces
+
+ def get_incomplete_context_data(self, interfaces):
+ '''
+ Return dictionary of relation status of interfaces and any missing
+ required context data. Example:
+ {'amqp': {'missing_data': ['rabbitmq_password'], 'related': True},
+ 'zeromq-configuration': {'related': False}}
+ '''
+ incomplete_context_data = {}
+
+ for i in six.itervalues(self.templates):
+ for context in i.contexts:
+ for interface in interfaces:
+ related = False
+ if interface in context.interfaces:
+ related = context.get_related()
+ missing_data = context.missing_data
+ if missing_data:
+ incomplete_context_data[interface] = {'missing_data': missing_data}
+ if related:
+ if incomplete_context_data.get(interface):
+ incomplete_context_data[interface].update({'related': True})
+ else:
+ incomplete_context_data[interface] = {'related': True}
+ else:
+ incomplete_context_data[interface] = {'related': False}
+ return incomplete_context_data