Improve the performance of grabbing remote data from a host

hwinfo/tools/inspector.py

@@ -13,18 +13,20 @@
 from hwinfo.host import dmidecode
 from hwinfo.host import cpuinfo
 
-def remote_command(host, username, password, cmd):
+def get_ssh_client(host, username, password, timeout=10):
     client = paramiko.SSHClient()
     client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
-    client.connect(host, username=username, password=password, timeout=10)
+    client.connect(host, username=username, password=password, timeout=timeout)
+    return client
+
+def remote_command(client, cmd):
     cmdstr = ' '.join(cmd)
     #print "Executing '%s' on host '%s'" % (cmdstr, host)
     _, stdout, stderr = client.exec_command(cmdstr)
     output = stdout.readlines()
     error = stderr.readlines()
     if error:
         raise Exception("stderr: %s" % error)
-    client.close()
     return ''.join(output)
 
 def local_command(cmd):
@@ -44,12 +46,22 @@ def __init__(self, host='localhost', username=None, password=None):
         self.host = host
         self.username = username
         self.password = password
+        self.client = None
+        if self.is_remote():
+            self.client = get_ssh_client(self.host, self.username, self.password)
+
+    def __del__(self):
+        if self.client:
+            self.client.close()
+
+    def is_remote(self):
+        return self.host != 'localhost'
 
     def exec_command(self, cmd):
-        if self.host == 'localhost':
-            return local_command(cmd)
+        if self.is_remote():
+            return remote_command(self.client, cmd)
         else:
-            return remote_command(self.host, self.username, self.password, cmd)
+            return local_command(cmd)
 
     def get_lspci_data(self):
         return self.exec_command(['lspci', '-nnmm'])

hwinfo/tools/tests/test_inspector.py

@@ -13,11 +13,13 @@ def test_local_exec_command(self, local_command):
         host.exec_command('ls')
         inspector.local_command.assert_called_once_with('ls')
 
+    @patch('hwinfo.tools.inspector.get_ssh_client')
     @patch('hwinfo.tools.inspector.remote_command')
-    def test_remote_exec_command(self, remote_command):
+    def test_remote_exec_command(self, remote_command, get_ssh_client):
+        mclient = get_ssh_client.return_value = mock.MagicMock()
         host = inspector.Host('mymachine', 'root', 'pass')
         host.exec_command('ls')
-        inspector.remote_command.assert_called_once_with('mymachine', 'root', 'pass', 'ls')
+        inspector.remote_command.assert_called_once_with(mclient, 'ls')
 
     @patch('hwinfo.tools.inspector.Host.exec_command')
     def test_get_pci_devices(self, exec_command):
@@ -35,6 +37,15 @@ def test_get_info(self, mock_exec_command, mock_dmidecode_parser_cls):
         rec = host.get_info()
         self.assertEqual(rec, {'key':'value'})
 
+    def test_is_not_remote(self):
+        host = inspector.Host()
+        self.assertEqual(host.is_remote(), False)
+
+    @patch('hwinfo.tools.inspector.get_ssh_client')
+    def test_is_remote(self, get_ssh_client):
+        get_ssh_client.return_value = mock.MagicMock()
+        host = inspector.Host('test', 'user', 'pass')
+        self.assertEqual(host.is_remote(), True)
 
 class RemoteCommandTests(unittest.TestCase):
 
@@ -47,15 +58,15 @@ def setUp(self):
     def test_ssh_connect(self, ssh_client_cls):
         client = ssh_client_cls.return_value = mock.Mock()
         client.exec_command.return_value = self.stdout, self.stdin, self.stderr
-        inspector.remote_command('test', 'user', 'pass', 'ls')
+        inspector.get_ssh_client('test', 'user', 'pass')
         client.connect.assert_called_with('test', password='pass', username='user', timeout=10)
 
     @patch('paramiko.SSHClient')
     def test_ssh_connect_error(self, ssh_client_cls):
         client = ssh_client_cls.return_value = mock.Mock()
         client.exec_command.return_value = self.stdout, self.stdin, StringIO("Error")
         with self.assertRaises(Exception) as context:
-            inspector.remote_command('test', 'user', 'pass', 'ls')
+            inspector.remote_command(client, 'ls')
         self.assertEqual(context.exception.message, "stderr: ['Error']")
 
 class LocalCommandTests(unittest.TestCase):