(Backport 50418, 53996) chroot: add new chroot module

salt/modules/chroot.py

@@ -0,0 +1,169 @@
+# -*- coding: utf-8 -*-
+#
+# Author: Alberto Planas <aplanas@suse.com>
+#
+# Copyright 2018 SUSE LINUX GmbH, Nuernberg, Germany.
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+
+'''
+:maintainer:    Alberto Planas <aplanas@suse.com>
+:maturity:      new
+:depends:       None
+:platform:      Linux
+'''
+from __future__ import absolute_import, print_function, unicode_literals
+import logging
+import os
+import sys
+import tempfile
+
+from salt.defaults.exitcodes import EX_OK
+from salt.exceptions import CommandExecutionError
+from salt.utils.args import clean_kwargs
+
+log = logging.getLogger(__name__)
+
+
+def __virtual__():
+    '''
+    Chroot command is required.
+    '''
+    if __utils__['path.which']('chroot') is not None:
+        return True
+    else:
+        return (False, 'Module chroot requires the command chroot')
+
+
+def exist(root):
+    '''
+    Return True if the chroot environment is present.
+    '''
+    dev = os.path.join(root, 'dev')
+    proc = os.path.join(root, 'proc')
+    sys = os.path.join(root, 'sys')
+    return all(os.path.isdir(i) for i in (root, dev, proc, sys))
+
+
+def create(root):
+    '''
+    Create a basic chroot environment.
+
+    Note that this environment is not functional. The caller needs to
+    install the minimal required binaries, including Python if
+    chroot.call is called.
+
+    root
+        Path to the chroot environment
+
+    CLI Example:
+
+    .. code-block:: bash
+
+        salt myminion chroot.create /chroot
+
+    '''
+    if not exist(root):
+        dev = os.path.join(root, 'dev')
+        proc = os.path.join(root, 'proc')
+        sys = os.path.join(root, 'sys')
+        try:
+            os.makedirs(dev, mode=0o755)
+            os.makedirs(proc, mode=0o555)
+            os.makedirs(sys, mode=0o555)
+        except OSError as e:
+            log.error('Error when trying to create chroot directories: %s', e)
+            return False
+    return True
+
+
+def call(root, function, *args, **kwargs):
+    '''
+    Executes a Salt function inside a chroot environment.
+
+    The chroot does not need to have Salt installed, but Python is
+    required.
+
+    root
+        Path to the chroot environment
+
+    function
+        Salt execution module function
+
+    CLI Example:
+
+    .. code-block:: bash
+
+        salt myminion chroot.call /chroot test.ping
+        salt myminion chroot.call /chroot ssh.set_auth_key user key=mykey
+
+    '''
+
+    if not function:
+        raise CommandExecutionError('Missing function parameter')
+
+    if not exist(root):
+        raise CommandExecutionError('Chroot environment not found')
+
+    # Create a temporary directory inside the chroot where we can
+    # untar salt-thin
+    thin_dest_path = tempfile.mkdtemp(dir=root)
+    thin_path = __utils__['thin.gen_thin'](
+        __opts__['cachedir'],
+        extra_mods=__salt__['config.option']('thin_extra_mods', ''),
+        so_mods=__salt__['config.option']('thin_so_mods', '')
+    )
+    stdout = __salt__['archive.tar']('xzf', thin_path, dest=thin_dest_path)
+    if stdout:
+        __utils__['files.rm_rf'](thin_dest_path)
+        return {'result': False, 'comment': stdout}
+
+    chroot_path = os.path.join(os.path.sep,
+                               os.path.relpath(thin_dest_path, root))
+    try:
+        safe_kwargs = clean_kwargs(**kwargs)
+        salt_argv = [
+            'python{}'.format(sys.version_info[0]),
+            os.path.join(chroot_path, 'salt-call'),
+            '--metadata',
+            '--local',
+            '--log-file', os.path.join(chroot_path, 'log'),
+            '--cachedir', os.path.join(chroot_path, 'cache'),
+            '--out', 'json',
+            '-l', 'quiet',
+            '--',
+            function
+        ] + list(args) + ['{}={}'.format(k, v) for (k, v) in safe_kwargs.items()]
+        ret = __salt__['cmd.run_chroot'](root, [str(x) for x in salt_argv])
+        if ret['retcode'] != EX_OK:
+            raise CommandExecutionError(ret['stderr'])
+
+        # Process "real" result in stdout
+        try:
+            data = __utils__['json.find_json'](ret['stdout'])
+            local = data.get('local', data)
+            if isinstance(local, dict) and 'retcode' in local:
+                __context__['retcode'] = local['retcode']
+            return local.get('return', data)
+        except ValueError:
+            return {
+                'result': False,
+                'comment': "Can't parse container command output"
+            }
+    finally:
+        __utils__['files.rm_rf'](thin_dest_path)