Improve SSH multi line splitter parser

This patch improves the SSH multi line splitter parser to take into
account some cases that were not covered as well as fix some of the tests.

Code fixes:

- On slow SSH connections we may not get the initial dump of stdin in
  the response, so looking for the "exit" command we sent will never
  find it and the parsing will fail.  We now look for the prompt and
  ignore whether we have the stdin data or not, since it's not really
  relevant.

- Sometimes we get empty prompts in the SSH response, which either break
  the current parsing or makes us return bad data.  We now remove all
  empty prompts.

Code improvements:

- We were always removing the last 2 lines from the response without
  actually checking if these 2 lines are the exit command and an empty
  line.  Now we search for the final exit command that we execute to
  determine the end of the valid output data.

- If the output data has any "\r" at the end of a line the parser
  returns them, which we shouldn't. They should be removed just like we
  remove the "\r\n" when splitting the lines.

Test fixes in HPE3ParClientMockSSHTestCase::test_strip_input_from_output:

- In a couple of places tests are passing [cmd, X, Y] to the parser
  expecting a failure, which we get, and we think everything is working
  as expected, but the failure is not for the reasons we want, so we are
  not testing anything.  By passing that data we are effectively passing
  [['foo', '-v'], X, Y] which will break the parser because that's
  "garbage".

- The data passed and expected in the success case can be misleading, as
  it doesn't include the exit prompt and doesn't expect the footer to be
  returned, but the footer should be returned and parsing a command that
  doesn't have the last exit command is not valid.

Closes #78

Author: Akrog

hpe3parclient/ssh.py

@@ -208,52 +208,54 @@ def strip_input_from_output(cmd, output):
         in the output so that it knows what it is stripping (or else it
         raises an exception).
         """
-
-        # Keep output lines after the 'exit'.
-        # 'exit' is the last of the stdin.
+        # Search for the prompt.  It may or may not be the first line, because
+        # on fast connections we get a "dump" of stdin with all the commands
+        # we've sent, but we don't on slow connections.
         for i, line in enumerate(output):
-            if line == 'exit':
+            prompt_pct = line.find('% setclienv csvtable 1')
+            if prompt_pct >= 0:
+                prompt = line[:prompt_pct + 1] + ' '
                 output = output[i + 1:]
                 break
         else:
-            reason = "Did not find 'exit' in output."
-            HPE3PARSSHClient.raise_stripper_error(reason, output)
-
-        if not output:
-            reason = "Did not find any output after 'exit'."
-            HPE3PARSSHClient.raise_stripper_error(reason, output)
-
-        # The next line is prompt plus setclienv command.
-        # Use this to get the prompt string.
-        prompt_pct = output[0].find('% setclienv csvtable 1')
-        if prompt_pct < 0:
             reason = "Did not find '% setclienv csvtable 1' in output."
             HPE3PARSSHClient.raise_stripper_error(reason, output)
-        prompt = output[0][0:prompt_pct + 1]
-        del output[0]
 
-        # Next find the prompt plus the command.
+        # Some systems return additional empty prompts, others return an
+        # extra \r after commands.  In both cases this prevents us from finding
+        # the output delimiters, and makes us return useless data to caller, so
+        # fix them.
+        output = [line.rstrip('\r\n') for line in output if line != prompt]
+
+        # Output starts right after the command we sent.
         # It might be broken into multiple lines, so loop and
         # append until we find the whole prompt plus command.
         command_string = ' '.join(cmd)
         if re.match('|'.join(tpd_commands), command_string):
             escp_command_string = command_string.replace('"', '\\"')
             command_string = "Tpd::rtpd " + '"' + escp_command_string + '"'
-        seek = ' '.join((prompt, command_string))
+        seek = prompt + command_string
         found = ''
         for i, line in enumerate(output):
-            found = ''.join((found, line.rstrip('\r\n')))
+            found = found + line
             if found == seek:
-                # Found the whole thing.  Use the rest as output now.
-                output = output[i + 1:]
+                # Output is right after this line, drop everything before it
+                del output[:i + 1]
                 break
         else:
             HPE3PARSSHClient._logger.debug("Command: %s" % command_string)
             reason = "Did not find match for command in output"
             HPE3PARSSHClient.raise_stripper_error(reason, output)
 
-        # Always strip the last 2
-        return output[:len(output) - 2]
+        # Output stops right before exit command is executed
+        try:
+            exit_index = output.index(prompt + 'exit')
+            del output[exit_index:]
+        except ValueError:
+            reason = "Did not find 'exit' in output."
+            HPE3PARSSHClient.raise_stripper_error(reason, output)
+
+        return output
 
     def run(self, cmd, multi_line_stripper=False):
         """Runs a CLI command over SSH, without doing any result parsing."""

test/test_HPE3ParClient_FilePersona_Mock.py

@@ -258,17 +258,17 @@ def test_strip_input_from_output(self):
             'CSIM-EOS08_1611165 cli% createvfs -fpg marktestfpg -wait '
             '127.0.0.2 255.255.255.\r',
             '0 UT5_VFS_150651\r',
-            'VFS UT5_VFS_150651 already exists within FPG marktestfpg\r',
+            'VFS UT5_VFS_150651 already exists within FPG marktestfpg',
             'CSIM-EOS08_1611165 cli% exit\r',
             ''
         ]
         expected = [
-            'VFS UT5_VFS_150651 already exists within FPG marktestfpg\r']
+            'VFS UT5_VFS_150651 already exists within FPG marktestfpg']
 
         actual = ssh.HPE3PARSSHClient.strip_input_from_output(cmd, out)
         self.assertEqual(expected, actual)
 
-    def test_strip_input_from_output_no_exit(self):
+    def test_strip_input_from_output_no_stdin(self):
         cmd = [
             'createvfs',
             '-fpg',
@@ -279,10 +279,6 @@ def test_strip_input_from_output_no_exit(self):
             'UT5_VFS_150651'
         ]
         out = [
-            'setclienv csvtable 1',
-            'createvfs -fpg marktestfpg -wait 127.0.0.2 255.255.255.0 '
-            'UT5_VFS_150651',
-            'XXXt',  # Don't match
             'CSIM-EOS08_1611165 cli% setclienv csvtable 1\r',
             'CSIM-EOS08_1611165 cli% createvfs -fpg marktestfpg -wait '
             '127.0.0.2 255.255.255.\r',
@@ -291,9 +287,11 @@ def test_strip_input_from_output_no_exit(self):
             'CSIM-EOS08_1611165 cli% exit\r',
             ''
         ]
-        self.assertRaises(exceptions.SSHException,
-                          ssh.HPE3PARSSHClient.strip_input_from_output,
-                          cmd, out)
+        expected = [
+            'VFS UT5_VFS_150651 already exists within FPG marktestfpg']
+
+        actual = ssh.HPE3PARSSHClient.strip_input_from_output(cmd, out)
+        self.assertEqual(expected, actual)
 
     def test_strip_input_from_output_no_setclienv(self):
         cmd = [

test/test_HPE3ParClient_MockSSH.py

@@ -210,6 +210,14 @@ def test_sanitize_cert(self):
         self.assertEqual(expected, out)
 
     def test_strip_input_from_output(self):
+        def gen_output(*args):
+            result = []
+            for arg in args:
+                if isinstance(arg, list):
+                    result.extend(arg)
+                else:
+                    result.append(arg)
+            return result
         cmd = ['foo', '-v']
         # nothing after exit
         output = ['exit']
@@ -224,30 +232,68 @@ def test_strip_input_from_output(self):
                           cmd,
                           output)
         # no setclienv csv
-        output = [cmd, 'exit', 'out']
+        output = cmd + ['exit', 'out']
         self.assertRaises(exceptions.SSHException,
                           ssh.HPE3PARSSHClient.strip_input_from_output,
                           cmd,
                           output)
         # command not in output after exit
-        output = [cmd, 'exit', 'PROMPT% setclienv csvtable 1']
+        output = gen_output('setclienv csvtable 1',
+                            cmd,
+                            'exit',
+                            'PROMPT% setclienv csvtable 1')
+        self.assertRaises(exceptions.SSHException,
+                          ssh.HPE3PARSSHClient.strip_input_from_output,
+                          cmd,
+                          output)
+        # Missing exit prompt because output was cut
+        output = gen_output('setclienv csvtable 1',
+                            cmd,
+                            'exit',
+                            'PROMPT% setclienv csvtable 1',
+                            'PROMPT% foo -v',
+                            'out1',
+                            'out2')
         self.assertRaises(exceptions.SSHException,
                           ssh.HPE3PARSSHClient.strip_input_from_output,
                           cmd,
                           output)
         # success
-        output = [cmd,
-                  'setclienv csvtable 1',
-                  'exit',
-                  'PROMPT% setclienv csvtable 1',
-                  'PROMPT% foo -v',
-                  'out1',
-                  'out2',
-                  'out3',
-                  '------',
-                  'totals']
+        expected = ['out1', 'out2', 'out3', '------', 'totals']
+        output = gen_output('setclienv csvtable 1',
+                            cmd,
+                            'exit',
+                            'PROMPT% setclienv csvtable 1',
+                            'PROMPT% foo -v',
+                            'out1',
+                            'out2',
+                            'out3',
+                            '------',
+                            'totals',
+                            'PROMPT% exit')
+        result = ssh.HPE3PARSSHClient.strip_input_from_output(cmd, output)
+        self.assertEqual(expected, result)
+
+        # succeed even on slow connection that's missing the stdin dump
+        output = output[4:]
+        result = ssh.HPE3PARSSHClient.strip_input_from_output(cmd, output)
+        self.assertEqual(expected, result)
+
+        # succeed with empty prompts and extra \r on commands
+        output = gen_output('setclienv csvtable 1',
+                            cmd,
+                            'exit',
+                            'PROMPT% setclienv csvtable 1\r',
+                            'PROMPT% ',
+                            'PROMPT% foo -v\r',
+                            'out1',
+                            'out2',
+                            'out3',
+                            '------',
+                            'totals',
+                            'PROMPT% exit\r')
         result = ssh.HPE3PARSSHClient.strip_input_from_output(cmd, output)
-        self.assertEqual(['out1', 'out2', 'out3'], result)
+        self.assertEqual(expected, result)
 
     @mock.patch('hpe3parclient.client.ssh.HPE3PARSSHClient', spec=True)
     def test_verify_get_port(self, mock_ssh_client):