Baseline commit

README.rst

@@ -4,9 +4,9 @@ snap.openstack
 
 Helpers for writing Snaps for OpenStack
 
-Please fill here a long description which must be at least 3 lines wrapped on
-80 cols, so that distribution package maintainers can use it in their packages.
-Note that this is a hard requirement.
+This project provides a wrapper for automatically wrapping openstack
+commands in snaps, building out appropriate Oslo configuration and
+logging options on the command line.
 
 * Free software: Apache license
 * Documentation: http://docs.openstack.org/developer/snap.openstack
@@ -16,4 +16,4 @@ Note that this is a hard requirement.
 Features
 --------
 
-* TODO
+* Support for classic mode snap use

doc/source/snap-openstack.yaml

@@ -0,0 +1,45 @@
+# Sample snap-openstack configuration file
+#
+# snap-openstack will automatically substitute the following 
+# in both paths for files and directories and in templates:
+#
+#  SNAP_COMMON -> snap_common
+#  SNAP -> snap
+#  SNAP -> snap_shared
+#
+# Setup is executed for all entry points prior to execution
+# snap-openstack will assure that templated files are in place
+# and that any directory structure in $SNAP_COMMON is created
+setup:
+  dirs:
+    - "{snap_common}/etc/nova.conf.d"
+    - "{snap_common}/etc/nova"
+    - "{snap_common}/logs"
+  templates:
+    "nova-snap.conf.j2": "[snap_common}/etc/nova.conf.d/nova-snap.conf"
+# Entry points are used to execute commands from with the snap
+# with a sane set of defaults in terms of configuration files
+# and directories
+entry_points:
+  # Executes the following:
+  #
+  # nova-manage --config-file=$SNAP/etc/nova/nova,conf \
+  #             --config-file=$SNAP_COMMON/etc/nova/nova.conf \
+  #             --config-dir=$SNAP_COMMON/etc/nova.conf.d \
+  #             --log-file=$SNAP_COMMON/logs/nova-manage.log
+  #
+  # this is designed to be executed from the snapcraft.yaml apps section
+  # using:
+  #
+  #  command: snap-openstack nova-manage
+  # 
+  # any additional arguments will be passed to the underlying binary
+  nova-manage:
+    binary: nova-manage
+    config-files:
+      - "{snap}/etc/nova/nova.conf"
+      - "[snap_common}/etc/nova/nova.conf"
+    config-dirs:
+      - "{snap_common}/etc/nova.conf.d"
+    log-file:
+      - "{snap_common}/logs/nova-manage.log"

requirements.txt

@@ -3,3 +3,6 @@
 # process, which may cause wedges in the gate later.
 
 pbr>=1.6 # Apache-2.0
+
+# Left unversioned as designed to align with OpenStack component being snapped
+jinja2

setup.cfg

@@ -49,3 +49,7 @@ output_file = snap_openstack/locale/snap_openstack.pot
 all_files = 1
 build-dir = releasenotes/build
 source-dir = releasenotes/source
+
+[entry_points]
+console_scripts =
+  snap-openstack = snap_openstack.cmd.run:main

snap_openstack/base.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python
+
+# Copyright 2016 Canonical UK Limited
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+import subprocess
+import yaml
+import logging
+
+from snap_openstack.renderer import SnapFileRenderer
+
+LOG = logging.getLogger(__name__)
+
+
+SNAP_ENV = ['SNAP_NAME',
+            'SNAP_VERSION',
+            'SNAP_REVISION',
+            'SNAP_ARCH',
+            'SNAP_LIBRARY_PATH',
+            'SNAP',
+            'SNAP_DATA',
+            'SNAP_COMMON',
+            'SNAP_USER_DATA',
+            'SNAP_USER_COMMON',
+            'TMPDIR']
+
+
+def snap_env():
+    '''Grab SNAP* environment variables
+
+    @return dict of all SNAP* environment variables indexed in lower case
+    '''
+    _env = {}
+    for key in SNAP_ENV:
+        _env[key.lower()] = os.environ.get(key)
+    return _env
+
+
+def ensure_dir(filepath):
+    '''Ensure that the directory structure to support a give file path exists'''
+    dir_name = os.path.dirname(filepath)
+    if not os.path.exists(dir_name):
+        LOG.info('Creating directory {}'.format(dir_name))
+        os.makedirs(dir_name, 0o750)
+
+
+class OpenStackSnap():
+    '''Main executor class for snap-openstack'''
+
+    def __init__(self, config_file):
+        with open(config_file, 'r') as config:
+            self.configuration = yaml.load(config)
+        self.snap_env = snap_env()
+
+    def setup(self):
+        '''Perform any pre-execution snap setup
+
+        Run this method prior to use of the execute metho
+        '''
+        setup = self.configuration['setup']
+        renderer = SnapFileRenderer()
+
+        for dirs in setup['dirs']:
+            dir_name = dirs.format(self.snap_env)
+            ensure_dir(dir_name)
+
+        for template in setup['templates']:
+            target = setup['templates'][template]
+            target_file = target.format(self.snap_env)
+            ensure_dir(target_file)
+            LOG.info('Rendering {} to {}'.format(template,
+                                                 target_file))
+            with open(target_file, 'w') as tf:
+                os.fchmod(tf.fileno(), 0o550)
+                tf.write(renderer.render(template,
+                                         self.snap_env))
+
+    def execute(self, argv):
+        '''Execute snap command building out configuration and log options'''
+        entry_point = self.configuration['entry_points'].get(argv[1])
+        if not entry_point:
+            _msg = 'Enable to find entry point for {}'.format(argv[1])
+            LOG.error(_msg)
+            raise ValueError(_msg)
+
+        other_args = argv[:2]
+        # Build out command to run
+        cmd = [entry_point['binary']]
+
+        for cfile in entry_point.get('config-files', []):
+            cfile = cfile.format(self.snap_env)
+            if os.path.exists(cfile):
+                cmd.append('--config-file={}'.format(cfile))
+            else:
+                LOG.warning('Configuration file {} not found'
+                            ', skipping'.format(cfile))
+
+        for cdir in entry_point.get('config-dirs', []):
+            cdir = cdir.format(self.snap_env)
+            if os.path.exists(cdir):
+                cmd.append('--config-dir={}'.format(cdir))
+            else:
+                LOG.warning('Configuration directory {} not found'
+                            ', skipping'.format(cdir))
+
+        log_file = entry_point.get('log-file')
+        if log_file:
+            log_file = log_file.format(self.snap_env)
+            cmd.append('--log-file={}'.format(log_file))
+
+        # Ensure any arguments passed to wrapper are propagated
+        cmd.extend(other_args)
+        subprocess.check_call(cmd)

snap_openstack/cmd/run.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python
+
+# Copyright 2016 Canonical UK Limited
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+import sys
+import logging
+
+from snap_openstack.base import OpenStackSnap
+
+LOG = logging.getLogger(__name__)
+
+CONFIG_FILE = 'snap-openstack.yaml'
+
+def main():
+    logging.basicConfig(level=logging.INFO)
+    snap = os.environ.get('SNAP')
+    if not snap:
+        LOG.error('Not executing in snap environment, exiting')
+        sys.exit(1)
+    config_path = os.path.join(snap,
+                               CONFIG_FILE)
+    if os.path.exists(config_path):
+        LOG.info('Using snap wrapper: {}'.format(config_path))
+        s_openstack = OpenStackSnap(config_path)
+        s_openstack.setup()
+        s_openstack.execute(sys.argv)
+    else:
+        LOG.error('Unable to find snap-openstack.yaml configuration file')
+        sys.exit(1)
+

snap_openstack/renderer.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+
+# Copyright 2016 Canonical UK Limited
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+import logging
+
+from jinja2 import FileSystemLoader, Environment, exceptions
+
+LOG = logging.getLogger(__name__)
+
+
+class SnapFileRenderer():
+    '''Helper class for rendering snap templates for runtime use'''
+
+    def __init__(self):
+        self._loaders = [
+            FileSystemLoader(os.path.join(os.environ.get('SNAP'),
+                                          'templates'))
+        ]
+        self._tmpl_env = Environment(loader=self._loaders)
+
+    def render(self, template_name, env):
+        '''Render j2 template using SNAP environment context
+
+        @param template_name: name of the template to use for rendering
+        @return: string of rendered context, ready to write back to a file
+        '''
+        try:
+            template = self._tmpl_env.get_template(template_name)
+        except exceptions.TemplateNotFound as te:
+            LOG.error('Unable to locate template: {}'.format(template_name))
+            raise te
+        return template.render(env)