Merge pull request #11650 from objectified/feature-docker-connection

allow ansible to connect to docker containers (without using ssh)

lib/ansible/plugins/connections/docker.py

+# Based on the chroot connection plugin by Maykel Moya
+#
+# Connection plugin for configuring docker containers
+# (c) 2014, Lorin Hochstein
+# (c) 2015, Leendert Brouwer
+#
+# Maintainer: Leendert Brouwer (https://github.com/objectified)
+#
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import subprocess
+import time
+import re
+
+from distutils.version import LooseVersion
+
+import ansible.constants as C
+
+from ansible import errors
+from ansible.plugins.connections import ConnectionBase
+
+BUFSIZE = 65536
+
+class Connection(ConnectionBase):
+
+    def __init__(self, play_context, new_stdin, *args, **kwargs):
+        super(Connection, self).__init__(play_context, new_stdin, *args, **kwargs)
+
+        if 'docker_command' in kwargs:
+            self.docker_cmd = kwargs['docker_command']
+        else:
+            self.docker_cmd = 'docker'
+
+        self.can_copy_bothways = False
+
+        docker_version = self._get_docker_version()
+        if LooseVersion(docker_version) >= LooseVersion('1.8.0'):
+            self.can_copy_bothways = True
+
+    def _get_docker_version(self):
+
+        def sanitize_version(version):
+            return re.sub('[^0-9a-zA-Z\.]', '', version)
+
+        cmd = [self.docker_cmd, 'version']
+
+        cmd_output = subprocess.check_output(cmd)
+
+        for line in cmd_output.split('\n'):
+            if line.startswith('Server version:'): # old docker versions
+                return sanitize_version(line.split()[2])
+
+        # no result yet, must be newer Docker version
+        new_docker_cmd = [
+            self.docker_cmd,
+            'version', '--format', "'{{.Server.Version}}'"
+        ]
+
+        cmd_output = subprocess.check_output(new_docker_cmd)
+
+        return sanitize_version(cmd_output)
+
+    @property
+    def transport(self):
+        return 'docker'
+
+    def _connect(self, port=None):
+        """ Connect to the container. Nothing to do """
+        if not self._connected:
+            self._display.vvv("ESTABLISH LOCAL CONNECTION FOR USER: {0}".format(
+                self._play_context.remote_user, host=self._play_context.remote_addr)
+            )
+            self._connected = True
+
+        return self
+
+    def exec_command(self, cmd, tmp_path, in_data=None, sudoable=False):
+        """ Run a command on the local host """
+        super(Connection, self).exec_command(cmd, tmp_path, in_data=in_data, sudoable=sudoable)
+
+        # Don't currently support su
+        if in_data:
+            raise errors.AnsibleError("Internal Error: this module does not "
+                                      "support optimized module pipelining")
+
+        executable = C.DEFAULT_EXECUTABLE.split()[0] if C.DEFAULT_EXECUTABLE else None
+        if executable:
+            local_cmd = [self.docker_cmd, "exec", self._play_context.remote_addr, executable,
+                         '-c', cmd]
+        else:
+            local_cmd = '%s exec "%s" %s' % (self.docker_cmd, self._play_context.remote_addr, cmd)
+
+        self._display.vvv("EXEC %s" % (local_cmd), host=self._play_context.remote_addr)
+        p = subprocess.Popen(local_cmd,
+                             shell=isinstance(local_cmd, basestring),
+                             stdin=subprocess.PIPE,
+                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+        stdout, stderr = p.communicate()
+        return (p.returncode, '', stdout, stderr)
+
+    # Docker doesn't have native support for copying files into running
+    # containers, so we use docker exec to implement this
+    def put_file(self, in_path, out_path):
+        """ Transfer a file from local to container """
+        if not os.path.exists(in_path):
+            raise errors.AnsibleFileNotFound(
+                "file or module does not exist: %s" % in_path)
+
+        self._display.vvv("PUT %s TO %s" % (in_path, out_path), host=self._play_context.remote_addr)
+
+        if self.can_copy_bothways: # only docker >= 1.8.1 can do this natively
+            args = [
+                self.docker_cmd,
+                "cp",
+                "%s" % in_path,
+                "%s:%s" % (self._play_context.remote_addr, out_path)
+            ]
+            subprocess.check_call(args)
+        else:
+            args = [self.docker_cmd, "exec", "-i", self._play_context.remote_addr, "bash", "-c",
+                    "dd of=%s bs=%s" % (format(out_path), BUFSIZE)]
+
+            p = subprocess.Popen(args, stdin=open(in_path),
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+            p.communicate()
+
+    def fetch_file(self, in_path, out_path):
+        """ Fetch a file from container to local. """
+        # out_path is the final file path, but docker takes a directory, not a
+        # file path
+        out_dir = os.path.dirname(out_path)
+
+        args = [self.docker_cmd, "cp", "%s:%s" % (self._play_context.remote_addr, in_path), out_dir]
+
+        self._display.vvv("FETCH %s TO %s" % (in_path, out_path), host=self._play_context.remote_addr)
+        p = subprocess.Popen(args, stdin=subprocess.PIPE,
+                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        p.communicate()
+
+        # Rename if needed
+        actual_out_path = os.path.join(out_dir, os.path.basename(in_path))
+        if actual_out_path != out_path:
+            os.rename(actual_out_path, out_path)
+
+    def close(self):
+        """ Terminate the connection. Nothing to do for Docker"""
+        self._connected = False