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Diffstat (limited to 'charms/trusty/ceilometer/charmhelpers/contrib/hardening/templating.py')
-rw-r--r-- | charms/trusty/ceilometer/charmhelpers/contrib/hardening/templating.py | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/charms/trusty/ceilometer/charmhelpers/contrib/hardening/templating.py b/charms/trusty/ceilometer/charmhelpers/contrib/hardening/templating.py new file mode 100644 index 0000000..d2ab7dc --- /dev/null +++ b/charms/trusty/ceilometer/charmhelpers/contrib/hardening/templating.py @@ -0,0 +1,71 @@ +# Copyright 2016 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 + +from charmhelpers.core.hookenv import ( + log, + DEBUG, + WARNING, +) + +try: + from jinja2 import FileSystemLoader, Environment +except ImportError: + from charmhelpers.fetch import apt_install + from charmhelpers.fetch import apt_update + apt_update(fatal=True) + apt_install('python-jinja2', fatal=True) + from jinja2 import FileSystemLoader, Environment + + +# NOTE: function separated from main rendering code to facilitate easier +# mocking in unit tests. +def write(path, data): + with open(path, 'wb') as out: + out.write(data) + + +def get_template_path(template_dir, path): + """Returns the template file which would be used to render the path. + + The path to the template file is returned. + :param template_dir: the directory the templates are located in + :param path: the file path to be written to. + :returns: path to the template file + """ + return os.path.join(template_dir, os.path.basename(path)) + + +def render_and_write(template_dir, path, context): + """Renders the specified template into the file. + + :param template_dir: the directory to load the template from + :param path: the path to write the templated contents to + :param context: the parameters to pass to the rendering engine + """ + env = Environment(loader=FileSystemLoader(template_dir)) + template_file = os.path.basename(path) + template = env.get_template(template_file) + log('Rendering from template: %s' % template.name, level=DEBUG) + rendered_content = template.render(context) + if not rendered_content: + log("Render returned None - skipping '%s'" % path, + level=WARNING) + return + + write(path, rendered_content.encode('utf-8').strip()) + log('Wrote template %s' % path, level=DEBUG) |