Simplify the SSH clients

Realistically we just want to execute a command, potentially inside a
container. No need for all the context managers cleverness.

Change-Id: I1a85dcd310f9ec0b24435dcd2d8446de7f48d65b

whitebox_tempest_plugin/services/clients.py

@@ -12,83 +12,48 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-from contextlib import contextmanager
-try:
-    from shlex import quote
-except ImportError:
-    from pipes import quote
 
+from oslo_log import log as logging
 from tempest import config
 from tempest.lib.common import ssh
 
 CONF = config.CONF
+LOG = logging.getLogger(__name__)
+
+
+def sudo(command):
+    return 'sudo %s' % command
+
+
+def in_container(container_name, command):
+    if CONF.whitebox.containers:
+        return 'docker exec -u root %s %s' % (container_name, command)
+    return command
 
 
 class SSHClient(object):
     """A client to execute remote commands, based on tempest.lib.common.ssh."""
 
-    _prefix_command = '/bin/bash -c'
+    def __init__(self, hostname):
-
-    def __init__(self):
         self.ssh_key = CONF.whitebox.ctlplane_ssh_private_key_path
         self.ssh_user = CONF.whitebox.ctlplane_ssh_username
+        self.host = hostname
 
-    def execute(self, hostname=None, cmd=None):
+    def execute(self, command):
-        ssh_client = ssh.Client(hostname, self.ssh_user,
+        ssh_client = ssh.Client(self.host, self.ssh_user,
                                 key_filename=self.ssh_key)
-        cmd = self._prefix_command + ' ' + quote(cmd)
+        LOG.debug("Executing %s", command)
-        return ssh_client.exec_command(cmd)
+        return ssh_client.exec_command(command)
-
-    @contextmanager
-    def prefix_command(self, prefix_command=None):
-        saved_prefix = self._prefix_command
-        self._prefix_command = prefix_command
-        yield self
-        self._prefix_command = saved_prefix
-
-    @contextmanager
-    def sudo_command(self, user=None):
-        if user is not None:
-            user_arg = '-u {}'.format(user)
-        else:
-            user_arg = ''
-        cmd = 'sudo {} /bin/bash -c'.format(user_arg)
-        with self.prefix_command(cmd) as p:
-            yield p
-
-    @contextmanager
-    def container_command(self, container_name, user=None):
-        if user is not None:
-            user_arg = '-u {}'.format(user)
-        else:
-            user_arg = ''
-        cmd = 'sudo docker exec {} -i {} /bin/bash -c'.format(
-              user_arg, container_name)
-        with self.prefix_command(cmd) as p:
-            yield p
 
 
 class VirshXMLClient(SSHClient):
     """A client to obtain libvirt XML from a remote host."""
 
-    def __init__(self, hostname=None):
-        super(VirshXMLClient, self).__init__()
-        self.host = hostname
-
     def dumpxml(self, domain):
-        if CONF.whitebox.containers:
+        command = sudo(in_container('nova_libvirt',
-            ctx = self.container_command('nova_compute', user='root')
+                                    'virsh dumpxml %s' % domain))
-        else:
+        return self.execute(command)
-            ctx = self.sudo_command()
-        with ctx:
-            command = "virsh dumpxml {}".format(domain)
-            return self.execute(self.host, command)
 
     def capabilities(self):
-        if CONF.whitebox.containers:
+        command = sudo(in_container('nova_libvirt', 'virsh capabilities'))
-            ctx = self.container_command('nova_compute', user='root')
+        return self.execute(command)
-        else:
-            ctx = self.sudo_command()
-        with ctx:
-            command = "virsh capabilities"
-            return self.execute(self.host, command)