Add missing libvirt_lxc connection plugin (#111)

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

plugins/connection/libvirt_lxc.py

@@ -0,0 +1,181 @@
+# Based on local.py (c) 2012, Michael DeHaan <michael.dehaan@gmail.com>
+# Based on chroot.py (c) 2013, Maykel Moya <mmoya@speedyrails.com>
+# (c) 2013, Michael Scherer <misc@zarb.org>
+# (c) 2015, Toshio Kuratomi <tkuratomi@ansible.com>
+# (c) 2017 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+DOCUMENTATION = """
+    author: Michael Scherer <misc@zarb.org>
+    connection: libvirt_lxc
+    short_description: Run tasks in lxc containers via libvirt
+    description:
+        - Run commands or put/fetch files to an existing lxc container using libvirt
+    options:
+      remote_addr:
+        description:
+            - Container identifier
+        default: The set user as Libvirt LXC configuration
+        vars:
+            - name: ansible_host
+            - name: ansible_libvirt_lxc_host
+"""
+
+import distutils.spawn
+import os
+import os.path
+import subprocess
+import traceback
+
+from ansible import constants as C
+from ansible.errors import AnsibleError
+from ansible.module_utils.six.moves import shlex_quote
+from ansible.module_utils._text import to_bytes
+from ansible.plugins.connection import ConnectionBase, BUFSIZE
+from ansible.utils.display import Display
+
+display = Display()
+
+
+class Connection(ConnectionBase):
+    ''' Local lxc based connections '''
+
+    transport = 'libvirt_lxc'
+    has_pipelining = True
+    # su currently has an undiagnosed issue with calculating the file
+    # checksums (so copy, for instance, doesn't work right)
+    # Have to look into that before re-enabling this
+    default_user = 'root'
+    has_tty = False
+
+    def __init__(self, play_context, new_stdin, *args, **kwargs):
+        super(Connection, self).__init__(play_context, new_stdin, *args, **kwargs)
+        self.lxc = self._play_context.remote_addr
+
+        self.virsh = self._search_executable('virsh')
+
+        self._check_domain(self.lxc)
+
+    def _search_executable(self, executable):
+        cmd = distutils.spawn.find_executable(executable)
+        if not cmd:
+            raise AnsibleError("%s command not found in PATH") % executable
+        return cmd
+
+    def _check_domain(self, domain):
+        p = subprocess.Popen([self.virsh, '-q', '-c', 'lxc:///', 'dominfo', to_bytes(domain)],
+                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        p.communicate()
+        if p.returncode:
+            raise AnsibleError("%s is not a lxc defined in libvirt" % domain)
+
+    def _connect(self):
+        ''' connect to the lxc; nothing to do here '''
+        super(Connection, self)._connect()
+        if not self._connected:
+            display.vvv("THIS IS A LOCAL LXC DIR", host=self.lxc)
+            self._connected = True
+
+    def _buffered_exec_command(self, cmd, stdin=subprocess.PIPE):
+        ''' run a command on the chroot.  This is only needed for implementing
+        put_file() get_file() so that we don't have to read the whole file
+        into memory.
+
+        compared to exec_command() it looses some niceties like being able to
+        return the process's exit code immediately.
+        '''
+        executable = C.DEFAULT_EXECUTABLE.split()[0] if C.DEFAULT_EXECUTABLE else '/bin/sh'
+        local_cmd = [self.virsh, '-q', '-c', 'lxc:///', 'lxc-enter-namespace']
+
+        if C.DEFAULT_LIBVIRT_LXC_NOSECLABEL:
+            local_cmd += ['--noseclabel']
+
+        local_cmd += [self.lxc, '--', executable, '-c', cmd]
+
+        display.vvv("EXEC %s" % (local_cmd,), host=self.lxc)
+        local_cmd = [to_bytes(i, errors='surrogate_or_strict') for i in local_cmd]
+        p = subprocess.Popen(local_cmd, shell=False, stdin=stdin,
+                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+        return p
+
+    def exec_command(self, cmd, in_data=None, sudoable=False):
+        ''' run a command on the chroot '''
+        super(Connection, self).exec_command(cmd, in_data=in_data, sudoable=sudoable)
+
+        p = self._buffered_exec_command(cmd)
+
+        stdout, stderr = p.communicate(in_data)
+        return (p.returncode, stdout, stderr)
+
+    def _prefix_login_path(self, remote_path):
+        ''' Make sure that we put files into a standard path
+
+            If a path is relative, then we need to choose where to put it.
+            ssh chooses $HOME but we aren't guaranteed that a home dir will
+            exist in any given chroot.  So for now we're choosing "/" instead.
+            This also happens to be the former default.
+
+            Can revisit using $HOME instead if it's a problem
+        '''
+        if not remote_path.startswith(os.path.sep):
+            remote_path = os.path.join(os.path.sep, remote_path)
+        return os.path.normpath(remote_path)
+
+    def put_file(self, in_path, out_path):
+        ''' transfer a file from local to lxc '''
+        super(Connection, self).put_file(in_path, out_path)
+        display.vvv("PUT %s TO %s" % (in_path, out_path), host=self.lxc)
+
+        out_path = shlex_quote(self._prefix_login_path(out_path))
+        try:
+            with open(to_bytes(in_path, errors='surrogate_or_strict'), 'rb') as in_file:
+                if not os.fstat(in_file.fileno()).st_size:
+                    count = ' count=0'
+                else:
+                    count = ''
+                try:
+                    p = self._buffered_exec_command('dd of=%s bs=%s%s' % (out_path, BUFSIZE, count), stdin=in_file)
+                except OSError:
+                    raise AnsibleError("chroot connection requires dd command in the chroot")
+                try:
+                    stdout, stderr = p.communicate()
+                except Exception:
+                    traceback.print_exc()
+                    raise AnsibleError("failed to transfer file %s to %s" % (in_path, out_path))
+                if p.returncode != 0:
+                    raise AnsibleError("failed to transfer file %s to %s:\n%s\n%s" % (in_path, out_path, stdout, stderr))
+        except IOError:
+            raise AnsibleError("file or module does not exist at: %s" % in_path)
+
+    def fetch_file(self, in_path, out_path):
+        ''' fetch a file from lxc to local '''
+        super(Connection, self).fetch_file(in_path, out_path)
+        display.vvv("FETCH %s TO %s" % (in_path, out_path), host=self.lxc)
+
+        in_path = shlex_quote(self._prefix_login_path(in_path))
+        try:
+            p = self._buffered_exec_command('dd if=%s bs=%s' % (in_path, BUFSIZE))
+        except OSError:
+            raise AnsibleError("chroot connection requires dd command in the chroot")
+
+        with open(to_bytes(out_path, errors='surrogate_or_strict'), 'wb+') as out_file:
+            try:
+                chunk = p.stdout.read(BUFSIZE)
+                while chunk:
+                    out_file.write(chunk)
+                    chunk = p.stdout.read(BUFSIZE)
+            except Exception:
+                traceback.print_exc()
+                raise AnsibleError("failed to transfer file %s to %s" % (in_path, out_path))
+            stdout, stderr = p.communicate()
+            if p.returncode != 0:
+                raise AnsibleError("failed to transfer file %s to %s:\n%s\n%s" % (in_path, out_path, stdout, stderr))
+
+    def close(self):
+        ''' terminate the connection; nothing to do here '''
+        super(Connection, self).close()
+        self._connected = False