FIX: Log required cli_cmd not "cli_inband"

[csit.git] / resources / libraries / python / PapiExecutor.py

diff --git a/resources/libraries/python/PapiExecutor.py b/resources/libraries/python/PapiExecutor.py
index 74ff7a0..46fe5d5 100644 (file)
--- a/resources/libraries/python/PapiExecutor.py
+++ b/resources/libraries/python/PapiExecutor.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2019 Cisco and/or its affiliates.
+# Copyright (c) 2020 Cisco and/or its affiliates.

 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at:
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at:


@@ -14,11 +14,11 @@
 """Python API executor library.
 """
 
 """Python API executor library.
 """
 

-import binascii

 import copy
 import glob
 import json
 import shutil
 import copy
 import glob
 import json
 import shutil

+import struct  # vpp-papi can raise struct.error

 import subprocess
 import sys
 import tempfile
 import subprocess
 import sys
 import tempfile


@@ -30,14 +30,14 @@ from robot.api import logger
 from resources.libraries.python.Constants import Constants
 from resources.libraries.python.LocalExecution import run
 from resources.libraries.python.FilteredLogger import FilteredLogger
 from resources.libraries.python.Constants import Constants
 from resources.libraries.python.LocalExecution import run
 from resources.libraries.python.FilteredLogger import FilteredLogger

-from resources.libraries.python.PythonThree import raise_from

 from resources.libraries.python.PapiHistory import PapiHistory
 from resources.libraries.python.ssh import (
     SSH, SSHTimeout, exec_cmd_no_error, scp_node)
 from resources.libraries.python.PapiHistory import PapiHistory
 from resources.libraries.python.ssh import (
     SSH, SSHTimeout, exec_cmd_no_error, scp_node)

+from resources.libraries.python.topology import Topology, SocketType

 from resources.libraries.python.VppApiCrc import VppApiCrcChecker
 
 
 from resources.libraries.python.VppApiCrc import VppApiCrcChecker
 
 

-__all__ = ["PapiExecutor", "PapiSocketExecutor"]
+__all__ = [u"PapiExecutor", u"PapiSocketExecutor"]

 
 
 def dictize(obj):
 
 
 def dictize(obj):


@@ -54,14 +54,14 @@ def dictize(obj):
     from tuple, including its read-only __getitem__ attribute,
     so we cannot monkey-patch it.
 
     from tuple, including its read-only __getitem__ attribute,
     so we cannot monkey-patch it.
 

-    TODO: Create a proxy for namedtuple to allow that.
+    TODO: Create a proxy for named tuple to allow that.

 
     :param obj: Arbitrary object to dictize.
     :type obj: object
     :returns: Dictized object.
     :rtype: same as obj type or collections.OrderedDict
     """
 
     :param obj: Arbitrary object to dictize.
     :type obj: object
     :returns: Dictized object.
     :rtype: same as obj type or collections.OrderedDict
     """

-    if not hasattr(obj, "_asdict"):
+    if not hasattr(obj, u"_asdict"):

         return obj
     ret = obj._asdict()
     old_get = ret.__getitem__
         return obj
     ret = obj._asdict()
     old_get = ret.__getitem__


@@ -70,7 +70,7 @@ def dictize(obj):
     return ret
 
 
     return ret
 
 

-class PapiSocketExecutor(object):
+class PapiSocketExecutor:

     """Methods for executing VPP Python API commands on forwarded socket.
 
     The current implementation connects for the duration of resource manager.
     """Methods for executing VPP Python API commands on forwarded socket.
 
     The current implementation connects for the duration of resource manager.


@@ -89,13 +89,13 @@ class PapiSocketExecutor(object):
     The reconnection is logged at WARN level, so it is prominently shown
     in log.html, so we can see how frequently it happens.
 
     The reconnection is logged at WARN level, so it is prominently shown
     in log.html, so we can see how frequently it happens.
 

-    TODO: Support sockets in NFs somehow.

     TODO: Support handling of retval!=0 without try/except in caller.
 
     Note: Use only with "with" statement, e.g.:
 
     TODO: Support handling of retval!=0 without try/except in caller.
 
     Note: Use only with "with" statement, e.g.:
 

+        cmd = 'show_version'

         with PapiSocketExecutor(node) as papi_exec:
         with PapiSocketExecutor(node) as papi_exec:

-            reply = papi_exec.add('show_version').get_reply(err_msg)
+            reply = papi_exec.add(cmd).get_reply(err_msg)

 
     This class processes two classes of VPP PAPI methods:
     1. Simple request / reply: method='request'.
 
     This class processes two classes of VPP PAPI methods:
     1. Simple request / reply: method='request'.


@@ -109,8 +109,9 @@ class PapiSocketExecutor(object):
 
     a. One request with no arguments:
 
 
     a. One request with no arguments:
 

+        cmd = 'show_version'

         with PapiSocketExecutor(node) as papi_exec:
         with PapiSocketExecutor(node) as papi_exec:

-            reply = papi_exec.add('show_version').get_reply(err_msg)
+            reply = papi_exec.add(cmd).get_reply(err_msg)

 
     b. Three requests with arguments, the second and the third ones are the same
        but with different arguments.
 
     b. Three requests with arguments, the second and the third ones are the same
        but with different arguments.


@@ -167,39 +168,42 @@ class PapiSocketExecutor(object):
             return
         cls = self.__class__  # Shorthand for setting class fields.
         package_path = None
             return
         cls = self.__class__  # Shorthand for setting class fields.
         package_path = None

-        tmp_dir = tempfile.mkdtemp(dir="/tmp")
+        tmp_dir = tempfile.mkdtemp(dir=u"/tmp")

         try:
             # Pack, copy and unpack Python part of VPP installation from _node.
             # TODO: Use rsync or recursive version of ssh.scp_node instead?
             node = self._node
         try:
             # Pack, copy and unpack Python part of VPP installation from _node.
             # TODO: Use rsync or recursive version of ssh.scp_node instead?
             node = self._node

-            exec_cmd_no_error(node, ["rm", "-rf", "/tmp/papi.txz"])
+            exec_cmd_no_error(node, [u"rm", u"-rf", u"/tmp/papi.txz"])

             # Papi python version depends on OS (and time).
             # Python 2.7 or 3.4, site-packages or dist-packages.
             # Papi python version depends on OS (and time).
             # Python 2.7 or 3.4, site-packages or dist-packages.

-            installed_papi_glob = "/usr/lib/python*/*-packages/vpp_papi"
+            installed_papi_glob = u"/usr/lib/python3*/*-packages/vpp_papi"

             # We need to wrap this command in bash, in order to expand globs,
             # and as ssh does join, the inner command has to be quoted.
             # We need to wrap this command in bash, in order to expand globs,
             # and as ssh does join, the inner command has to be quoted.

-            inner_cmd = " ".join([
-                "tar", "cJf", "/tmp/papi.txz", "--exclude=*.pyc",
-                installed_papi_glob, "/usr/share/vpp/api"])
-            exec_cmd_no_error(node, ["bash", "-c", "'" + inner_cmd + "'"])
-            scp_node(node, tmp_dir + "/papi.txz", "/tmp/papi.txz", get=True)
-            run(["tar", "xf", tmp_dir + "/papi.txz", "-C", tmp_dir])
-            api_json_directory = tmp_dir + "/usr/share/vpp/api"
+            inner_cmd = u" ".join([
+                u"tar", u"cJf", u"/tmp/papi.txz", u"--exclude=*.pyc",
+                installed_papi_glob, u"/usr/share/vpp/api"
+            ])
+            exec_cmd_no_error(node, [u"bash", u"-c", u"'" + inner_cmd + u"'"])
+            scp_node(node, tmp_dir + u"/papi.txz", u"/tmp/papi.txz", get=True)
+            run([u"tar", u"xf", tmp_dir + u"/papi.txz", u"-C", tmp_dir])
+            api_json_directory = tmp_dir + u"/usr/share/vpp/api"

             # Perform initial checks before .api.json files are gone,
             # by creating the checker instance.
             cls.crc_checker = VppApiCrcChecker(api_json_directory)
             # When present locally, we finally can find the installation path.
             package_path = glob.glob(tmp_dir + installed_papi_glob)[0]
             # Package path has to be one level above the vpp_papi directory.
             # Perform initial checks before .api.json files are gone,
             # by creating the checker instance.
             cls.crc_checker = VppApiCrcChecker(api_json_directory)
             # When present locally, we finally can find the installation path.
             package_path = glob.glob(tmp_dir + installed_papi_glob)[0]
             # Package path has to be one level above the vpp_papi directory.

-            package_path = package_path.rsplit('/', 1)[0]
+            package_path = package_path.rsplit(u"/", 1)[0]

             sys.path.append(package_path)
             sys.path.append(package_path)

-            # pylint: disable=import-error
+            # TODO: Pylint says import-outside-toplevel and import-error.
+            # It is right, we should refactor the code and move initialization
+            # of package outside.

             from vpp_papi.vpp_papi import VPPApiClient as vpp_class
             vpp_class.apidir = api_json_directory
             # We need to create instance before removing from sys.path.
             cls.vpp_instance = vpp_class(
             from vpp_papi.vpp_papi import VPPApiClient as vpp_class
             vpp_class.apidir = api_json_directory
             # We need to create instance before removing from sys.path.
             cls.vpp_instance = vpp_class(

-                use_socket=True, server_address="TBD", async_thread=False,
-                read_timeout=14, logger=FilteredLogger(logger, "INFO"))
+                use_socket=True, server_address=u"TBD", async_thread=False,
+                read_timeout=14, logger=FilteredLogger(logger, u"INFO"))

             # Cannot use loglevel parameter, robot.api.logger lacks support.
             # TODO: Stop overriding read_timeout when VPP-1722 is fixed.
         finally:
             # Cannot use loglevel parameter, robot.api.logger lacks support.
             # TODO: Stop overriding read_timeout when VPP-1722 is fixed.
         finally:


@@ -217,56 +221,57 @@ class PapiSocketExecutor(object):
         :returns: self
         :rtype: PapiSocketExecutor
         """
         :returns: self
         :rtype: PapiSocketExecutor
         """

+        time_enter = time.time()

         # Parsing takes longer than connecting, prepare instance before tunnel.
         vpp_instance = self.vpp_instance
         node = self._node
         # Parsing takes longer than connecting, prepare instance before tunnel.
         vpp_instance = self.vpp_instance
         node = self._node

-        self._temp_dir = tempfile.mkdtemp(dir="/tmp")
-        self._local_vpp_socket = self._temp_dir + "/vpp-api.sock"
-        self._ssh_control_socket = self._temp_dir + "/ssh.sock"
+        self._temp_dir = tempfile.mkdtemp(dir=u"/tmp")
+        self._local_vpp_socket = self._temp_dir + u"/vpp-api.sock"
+        self._ssh_control_socket = self._temp_dir + u"/ssh.sock"

         ssh_socket = self._ssh_control_socket
         # Cleanup possibilities.
         ssh_socket = self._ssh_control_socket
         # Cleanup possibilities.

-        ret_code, _ = run(["ls", ssh_socket], check=False)
+        ret_code, _ = run([u"ls", ssh_socket], check=False)

         if ret_code != 2:
             # This branch never seems to be hit in CI,
             # but may be useful when testing manually.
         if ret_code != 2:
             # This branch never seems to be hit in CI,
             # but may be useful when testing manually.

-            run(["ssh", "-S", ssh_socket, "-O", "exit", "0.0.0.0"],
-                check=False, log=True)
+            run(
+                [u"ssh", u"-S", ssh_socket, u"-O", u"exit", u"0.0.0.0"],
+                check=False, log=True
+            )

             # TODO: Is any sleep necessary? How to prove if not?
             # TODO: Is any sleep necessary? How to prove if not?

-            run(["sleep", "0.1"])
-            run(["rm", "-vrf", ssh_socket])
+            run([u"sleep", u"0.1"])
+            run([u"rm", u"-vrf", ssh_socket])

         # Even if ssh can perhaps reuse this file,
         # we need to remove it for readiness detection to work correctly.
         # Even if ssh can perhaps reuse this file,
         # we need to remove it for readiness detection to work correctly.

-        run(["rm", "-rvf", self._local_vpp_socket])
-        # On VIRL, the ssh user is not added to "vpp" group,
-        # so we need to change remote socket file access rights.
-        exec_cmd_no_error(
-            node, "chmod o+rwx " + self._remote_vpp_socket, sudo=True)
-        # We use sleep command. The ssh command will exit in 10 second,
+        run([u"rm", u"-rvf", self._local_vpp_socket])
+        # We use sleep command. The ssh command will exit in 30 second,

         # unless a local socket connection is established,
         # in which case the ssh command will exit only when
         # the ssh connection is closed again (via control socket).
         # unless a local socket connection is established,
         # in which case the ssh command will exit only when
         # the ssh connection is closed again (via control socket).

-        # The log level is to supress "Warning: Permanently added" messages.
+        # The log level is to suppress "Warning: Permanently added" messages.

         ssh_cmd = [
         ssh_cmd = [

-            "ssh", "-S", ssh_socket, "-M",
-            "-o", "LogLevel=ERROR", "-o", "UserKnownHostsFile=/dev/null",
-            "-o", "StrictHostKeyChecking=no", "-o", "ExitOnForwardFailure=yes",
-            "-L", self._local_vpp_socket + ':' + self._remote_vpp_socket,
-            "-p", str(node['port']), node['username'] + "@" + node['host'],
-            "sleep", "10"]
-        priv_key = node.get("priv_key")
+            u"ssh", u"-S", ssh_socket, u"-M",
+            u"-o", u"LogLevel=ERROR", u"-o", u"UserKnownHostsFile=/dev/null",
+            u"-o", u"StrictHostKeyChecking=no",
+            u"-o", u"ExitOnForwardFailure=yes",
+            u"-L", self._local_vpp_socket + u":" + self._remote_vpp_socket,
+            u"-p", str(node[u"port"]), node[u"username"] + u"@" + node[u"host"],
+            u"sleep", u"30"
+        ]
+        priv_key = node.get(u"priv_key")

         if priv_key:
             # This is tricky. We need a file to pass the value to ssh command.
         if priv_key:
             # This is tricky. We need a file to pass the value to ssh command.

-            # And we need ssh command, because paramiko does not suport sockets
+            # And we need ssh command, because paramiko does not support sockets

             # (neither ssh_socket, nor _remote_vpp_socket).
             key_file = tempfile.NamedTemporaryFile()
             key_file.write(priv_key)
             # Make sure the content is written, but do not close yet.
             key_file.flush()
             # (neither ssh_socket, nor _remote_vpp_socket).
             key_file = tempfile.NamedTemporaryFile()
             key_file.write(priv_key)
             # Make sure the content is written, but do not close yet.
             key_file.flush()

-            ssh_cmd[1:1] = ["-i", key_file.name]
-        password = node.get("password")
+            ssh_cmd[1:1] = [u"-i", key_file.name]
+        password = node.get(u"password")

         if password:
             # Prepend sshpass command to set password.
         if password:
             # Prepend sshpass command to set password.

-            ssh_cmd[:0] = ["sshpass", "-p", password]
+            ssh_cmd[:0] = [u"sshpass", u"-p", password]

         time_stop = time.time() + 10.0
         # subprocess.Popen seems to be the best way to run commands
         # on background. Other ways (shell=True with "&" and ssh with -f)
         time_stop = time.time() + 10.0
         # subprocess.Popen seems to be the best way to run commands
         # on background. Other ways (shell=True with "&" and ssh with -f)


@@ -276,12 +281,14 @@ class PapiSocketExecutor(object):
         # Check socket presence on local side.
         while time.time() < time_stop:
             # It can take a moment for ssh to create the socket file.
         # Check socket presence on local side.
         while time.time() < time_stop:
             # It can take a moment for ssh to create the socket file.

-            ret_code, _ = run(["ls", "-l", self._local_vpp_socket], check=False)
+            ret_code, _ = run(
+                [u"ls", u"-l", self._local_vpp_socket], check=False
+            )

             if not ret_code:
                 break
             time.sleep(0.1)
         else:
             if not ret_code:
                 break
             time.sleep(0.1)
         else:

-            raise RuntimeError("Local side socket has not appeared.")
+            raise RuntimeError(u"Local side socket has not appeared.")

         if priv_key:
             # Socket up means the key has been read. Delete file by closing it.
             key_file.close()
         if priv_key:
             # Socket up means the key has been read. Delete file by closing it.
             key_file.close()


@@ -289,16 +296,19 @@ class PapiSocketExecutor(object):
         vpp_instance.transport.server_address = self._local_vpp_socket
         # It seems we can get read error even if every preceding check passed.
         # Single retry seems to help.
         vpp_instance.transport.server_address = self._local_vpp_socket
         # It seems we can get read error even if every preceding check passed.
         # Single retry seems to help.

-        for _ in xrange(2):
+        for _ in range(2):

             try:
             try:

-                vpp_instance.connect_sync("csit_socket")
-            except IOError as err:
-                logger.warn("Got initial connect error {err!r}".format(err=err))
+                vpp_instance.connect_sync(u"csit_socket")
+            except (IOError, struct.error) as err:
+                logger.warn(f"Got initial connect error {err!r}")

                 vpp_instance.disconnect()
             else:
                 break
         else:
                 vpp_instance.disconnect()
             else:
                 break
         else:

-            raise RuntimeError("Failed to connect to VPP over a socket.")
+            raise RuntimeError(u"Failed to connect to VPP over a socket.")
+        logger.trace(
+            f"Establishing socket connection took {time.time()-time_enter}s"
+        )

         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):


@@ -308,8 +318,9 @@ class PapiSocketExecutor(object):
         Arguments related to possible exception are entirely ignored.
         """
         self.vpp_instance.disconnect()
         Arguments related to possible exception are entirely ignored.
         """
         self.vpp_instance.disconnect()

-        run(["ssh", "-S", self._ssh_control_socket, "-O", "exit", "0.0.0.0"],
-            check=False)
+        run([
+            u"ssh", u"-S", self._ssh_control_socket, u"-O", u"exit", u"0.0.0.0"
+        ], check=False)

         shutil.rmtree(self._temp_dir)
 
     def add(self, csit_papi_command, history=True, **kwargs):
         shutil.rmtree(self._temp_dir)
 
     def add(self, csit_papi_command, history=True, **kwargs):


@@ -342,10 +353,15 @@ class PapiSocketExecutor(object):
         self.crc_checker.report_initial_conflicts()
         if history:
             PapiHistory.add_to_papi_history(
         self.crc_checker.report_initial_conflicts()
         if history:
             PapiHistory.add_to_papi_history(

-                self._node, csit_papi_command, **kwargs)
+                self._node, csit_papi_command, **kwargs
+            )

         self.crc_checker.check_api_name(csit_papi_command)
         self._api_command_list.append(
         self.crc_checker.check_api_name(csit_papi_command)
         self._api_command_list.append(

-            dict(api_name=csit_papi_command, api_args=copy.deepcopy(kwargs)))
+            dict(
+                api_name=csit_papi_command,
+                api_args=copy.deepcopy(kwargs)
+            )
+        )

         return self
 
     def get_replies(self, err_msg="Failed to get replies."):
         return self
 
     def get_replies(self, err_msg="Failed to get replies."):


@@ -362,7 +378,7 @@ class PapiSocketExecutor(object):
         """
         return self._execute(err_msg=err_msg)
 
         """
         return self._execute(err_msg=err_msg)
 

-    def get_reply(self, err_msg="Failed to get reply."):
+    def get_reply(self, err_msg=u"Failed to get reply."):

         """Get reply from VPP Python API.
 
         The reply is parsed into dict-like object,
         """Get reply from VPP Python API.
 
         The reply is parsed into dict-like object,


@@ -378,11 +394,10 @@ class PapiSocketExecutor(object):
         """
         replies = self.get_replies(err_msg=err_msg)
         if len(replies) != 1:
         """
         replies = self.get_replies(err_msg=err_msg)
         if len(replies) != 1:

-            raise RuntimeError("Expected single reply, got {replies!r}".format(
-                replies=replies))
+            raise RuntimeError(f"Expected single reply, got {replies!r}")

         return replies[0]
 
         return replies[0]
 

-    def get_sw_if_index(self, err_msg="Failed to get reply."):
+    def get_sw_if_index(self, err_msg=u"Failed to get reply."):

         """Get sw_if_index from reply from VPP Python API.
 
         Frequently, the caller is only interested in sw_if_index field
         """Get sw_if_index from reply from VPP Python API.
 
         Frequently, the caller is only interested in sw_if_index field


@@ -397,8 +412,8 @@ class PapiSocketExecutor(object):
         :raises AssertionError: If retval is nonzero, parsing or ssh error.
         """
         reply = self.get_reply(err_msg=err_msg)
         :raises AssertionError: If retval is nonzero, parsing or ssh error.
         """
         reply = self.get_reply(err_msg=err_msg)

-        logger.info("Getting index from {reply!r}".format(reply=reply))
-        return reply["sw_if_index"]
+        logger.trace(f"Getting index from {reply!r}")
+        return reply[u"sw_if_index"]

 
     def get_details(self, err_msg="Failed to get dump details."):
         """Get dump details from VPP Python API.
 
     def get_details(self, err_msg="Failed to get dump details."):
         """Get dump details from VPP Python API.


@@ -418,30 +433,57 @@ class PapiSocketExecutor(object):
         return self._execute(err_msg)
 
     @staticmethod
         return self._execute(err_msg)
 
     @staticmethod

-    def run_cli_cmd(node, cmd, log=True):
+    def run_cli_cmd(
+            node, cli_cmd, log=True, remote_vpp_socket=Constants.SOCKSVR_PATH):

         """Run a CLI command as cli_inband, return the "reply" field of reply.
 
         Optionally, log the field value.
 
         :param node: Node to run command on.
         """Run a CLI command as cli_inband, return the "reply" field of reply.
 
         Optionally, log the field value.
 
         :param node: Node to run command on.

-        :param cmd: The CLI command to be run on the node.
+        :param cli_cmd: The CLI command to be run on the node.
+        :param remote_vpp_socket: Path to remote socket to tunnel to.

         :param log: If True, the response is logged.
         :type node: dict
         :param log: If True, the response is logged.
         :type node: dict

-        :type cmd: str
+        :type remote_vpp_socket: str
+        :type cli_cmd: str

         :type log: bool
         :returns: CLI output.
         :rtype: str
         """
         :type log: bool
         :returns: CLI output.
         :rtype: str
         """

-        cli = 'cli_inband'
-        args = dict(cmd=cmd)
-        err_msg = "Failed to run 'cli_inband {cmd}' PAPI command on host " \
-                  "{host}".format(host=node['host'], cmd=cmd)
-        with PapiSocketExecutor(node) as papi_exec:
-            reply = papi_exec.add(cli, **args).get_reply(err_msg)["reply"]
+        cmd = u"cli_inband"
+        args = dict(
+            cmd=cli_cmd
+        )
+        err_msg = f"Failed to run 'cli_inband {cli_cmd}' PAPI command " \
+            f"on host {node[u'host']}"
+
+        with PapiSocketExecutor(node, remote_vpp_socket) as papi_exec:
+            reply = papi_exec.add(cmd, **args).get_reply(err_msg)["reply"]

         if log:
         if log:

-            logger.info("{cmd}:\n{reply}".format(cmd=cmd, reply=reply))
+            logger.info(
+                f"{cli_cmd} ({node[u'host']} - {remote_vpp_socket}):\n"
+                f"{reply.strip()}"
+            )

         return reply
 
         return reply
 

+    @staticmethod
+    def run_cli_cmd_on_all_sockets(node, cli_cmd, log=True):
+        """Run a CLI command as cli_inband, on all sockets in topology file.
+
+        :param node: Node to run command on.
+        :param cli_cmd: The CLI command to be run on the node.
+        :param log: If True, the response is logged.
+        :type node: dict
+        :type cli_cmd: str
+        :type log: bool
+        """
+        sockets = Topology.get_node_sockets(node, socket_type=SocketType.PAPI)
+        if sockets:
+            for socket in sockets.values():
+                PapiSocketExecutor.run_cli_cmd(
+                    node, cli_cmd, log=log, remote_vpp_socket=socket
+                )
+

     @staticmethod
     def dump_and_log(node, cmds):
         """Dump and log requested information, return None.
     @staticmethod
     def dump_and_log(node, cmds):
         """Dump and log requested information, return None.


@@ -454,10 +496,9 @@ class PapiSocketExecutor(object):
         with PapiSocketExecutor(node) as papi_exec:
             for cmd in cmds:
                 dump = papi_exec.add(cmd).get_details()
         with PapiSocketExecutor(node) as papi_exec:
             for cmd in cmds:
                 dump = papi_exec.add(cmd).get_details()

-                logger.debug("{cmd}:\n{data}".format(
-                    cmd=cmd, data=pformat(dump)))
+                logger.debug(f"{cmd}:\n{pformat(dump)}")

 
 

-    def _execute(self, err_msg="Undefined error message"):
+    def _execute(self, err_msg=u"Undefined error message", exp_rv=0):

         """Turn internal command list into data and execute; return replies.
 
         This method also clears the internal command list.
         """Turn internal command list into data and execute; return replies.
 
         This method also clears the internal command list.


@@ -482,43 +523,42 @@ class PapiSocketExecutor(object):
         self._api_command_list = list()
         replies = list()
         for command in local_list:
         self._api_command_list = list()
         replies = list()
         for command in local_list:

-            api_name = command["api_name"]
+            api_name = command[u"api_name"]

             papi_fn = getattr(vpp_instance.api, api_name)
             try:
                 try:
             papi_fn = getattr(vpp_instance.api, api_name)
             try:
                 try:

-                    reply = papi_fn(**command["api_args"])
-                except IOError as err:
-                    # Ocassionally an error happens, try reconnect.
-                    logger.warn("Reconnect after error: {err!r}".format(
-                        err=err))
+                    reply = papi_fn(**command[u"api_args"])
+                except (IOError, struct.error) as err:
+                    # Occasionally an error happens, try reconnect.
+                    logger.warn(f"Reconnect after error: {err!r}")

                     self.vpp_instance.disconnect()
                     self.vpp_instance.disconnect()

-                    # Testing showes immediate reconnect fails.
+                    # Testing shows immediate reconnect fails.

                     time.sleep(1)
                     time.sleep(1)

-                    self.vpp_instance.connect_sync("csit_socket")
-                    logger.trace("Reconnected.")
-                    reply = papi_fn(**command["api_args"])
-            except (AttributeError, IOError) as err:
-                raise_from(AssertionError(err_msg), err, level="INFO")
+                    self.vpp_instance.connect_sync(u"csit_socket")
+                    logger.trace(u"Reconnected.")
+                    reply = papi_fn(**command[u"api_args"])
+            except (AttributeError, IOError, struct.error) as err:
+                raise AssertionError(err_msg) from err

             # *_dump commands return list of objects, convert, ordinary reply.
             if not isinstance(reply, list):
                 reply = [reply]
             for item in reply:
                 self.crc_checker.check_api_name(item.__class__.__name__)
                 dict_item = dictize(item)
             # *_dump commands return list of objects, convert, ordinary reply.
             if not isinstance(reply, list):
                 reply = [reply]
             for item in reply:
                 self.crc_checker.check_api_name(item.__class__.__name__)
                 dict_item = dictize(item)

-                if "retval" in dict_item.keys():
+                if u"retval" in dict_item.keys():

                     # *_details messages do not contain retval.
                     # *_details messages do not contain retval.

-                    retval = dict_item["retval"]
-                    if retval != 0:
+                    retval = dict_item[u"retval"]
+                    if retval != exp_rv:

                         # TODO: What exactly to log and raise here?
                         # TODO: What exactly to log and raise here?

-                        err = AssertionError("Retval {rv!r}".format(rv=retval))
-                        # Lowering log level, some retval!=0 calls are expected.
-                        # TODO: Expose level argument so callers can decide?
-                        raise_from(AssertionError(err_msg), err, level="DEBUG")
+                        raise AssertionError(
+                            f"Retval {retval!r} does not match expected "
+                            f"retval {exp_rv!r}"
+                        )

                 replies.append(dict_item)
         return replies
 
 
                 replies.append(dict_item)
         return replies
 
 

-class PapiExecutor(object):
+class PapiExecutor:

     """Contains methods for executing VPP Python API commands on DUTs.
 
     TODO: Remove .add step, make get_stats accept paths directly.
     """Contains methods for executing VPP Python API commands on DUTs.
 
     TODO: Remove .add step, make get_stats accept paths directly.


@@ -562,7 +602,6 @@ class PapiExecutor(object):
         :param node: Node to run command(s) on.
         :type node: dict
         """
         :param node: Node to run command(s) on.
         :type node: dict
         """

-

         # Node to run command(s) on.
         self._node = node
 
         # Node to run command(s) on.
         self._node = node
 


@@ -575,15 +614,16 @@ class PapiExecutor(object):
         try:
             self._ssh.connect(self._node)
         except IOError:
         try:
             self._ssh.connect(self._node)
         except IOError:

-            raise RuntimeError("Cannot open SSH connection to host {host} to "
-                               "execute PAPI command(s)".
-                               format(host=self._node["host"]))
+            raise RuntimeError(
+                f"Cannot open SSH connection to host {self._node[u'host']} "
+                f"to execute PAPI command(s)"
+            )

         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         self._ssh.disconnect(self._node)
 
         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         self._ssh.disconnect(self._node)
 

-    def add(self, csit_papi_command="vpp-stats", history=True, **kwargs):
+    def add(self, csit_papi_command=u"vpp-stats", history=True, **kwargs):

         """Add next command to internal command list; return self.
 
         The argument name 'csit_papi_command' must be unique enough as it cannot
         """Add next command to internal command list; return self.
 
         The argument name 'csit_papi_command' must be unique enough as it cannot


@@ -602,27 +642,36 @@ class PapiExecutor(object):
         """
         if history:
             PapiHistory.add_to_papi_history(
         """
         if history:
             PapiHistory.add_to_papi_history(

-                self._node, csit_papi_command, **kwargs)
-        self._api_command_list.append(dict(
-            api_name=csit_papi_command, api_args=copy.deepcopy(kwargs)))
+                self._node, csit_papi_command, **kwargs
+            )
+        self._api_command_list.append(
+            dict(
+                api_name=csit_papi_command, api_args=copy.deepcopy(kwargs)
+            )
+        )

         return self
 
         return self
 

-    def get_stats(self, err_msg="Failed to get statistics.", timeout=120):
+    def get_stats(
+            self, err_msg=u"Failed to get statistics.", timeout=120,
+            socket=Constants.SOCKSTAT_PATH):

         """Get VPP Stats from VPP Python API.
 
         :param err_msg: The message used if the PAPI command(s) execution fails.
         :param timeout: Timeout in seconds.
         """Get VPP Stats from VPP Python API.
 
         :param err_msg: The message used if the PAPI command(s) execution fails.
         :param timeout: Timeout in seconds.

+        :param socket: Path to Stats socket to tunnel to.

         :type err_msg: str
         :type timeout: int
         :type err_msg: str
         :type timeout: int

+        :type socket: str

         :returns: Requested VPP statistics.
         :rtype: list of dict
         """
         :returns: Requested VPP statistics.
         :rtype: list of dict
         """

-
-        paths = [cmd['api_args']['path'] for cmd in self._api_command_list]
+        paths = [cmd[u"api_args"][u"path"] for cmd in self._api_command_list]

         self._api_command_list = list()
 
         stdout = self._execute_papi(
         self._api_command_list = list()
 
         stdout = self._execute_papi(

-            paths, method='stats', err_msg=err_msg, timeout=timeout)
+            paths, method=u"stats", err_msg=err_msg, timeout=timeout,
+            socket=socket
+        )

 
         return json.loads(stdout)
 
 
         return json.loads(stdout)
 


@@ -647,27 +696,33 @@ class PapiExecutor(object):
             :rtype: dict or str or int
             """
             if isinstance(val, dict):
             :rtype: dict or str or int
             """
             if isinstance(val, dict):

-                for val_k, val_v in val.iteritems():
+                for val_k, val_v in val.items():

                     val[str(val_k)] = process_value(val_v)
                     val[str(val_k)] = process_value(val_v)

-                return val
+                retval = val

             elif isinstance(val, list):
                 for idx, val_l in enumerate(val):
                     val[idx] = process_value(val_l)
             elif isinstance(val, list):
                 for idx, val_l in enumerate(val):
                     val[idx] = process_value(val_l)

-                return val
+                retval = val

             else:
             else:

-                return binascii.hexlify(val) if isinstance(val, str) else val
+                retval = val.encode().hex() if isinstance(val, str) else val
+            return retval

 
         api_data_processed = list()
         for api in api_d:
             api_args_processed = dict()
 
         api_data_processed = list()
         for api in api_d:
             api_args_processed = dict()

-            for a_k, a_v in api["api_args"].iteritems():
+            for a_k, a_v in api[u"api_args"].items():

                 api_args_processed[str(a_k)] = process_value(a_v)
                 api_args_processed[str(a_k)] = process_value(a_v)

-            api_data_processed.append(dict(api_name=api["api_name"],
-                                           api_args=api_args_processed))
+            api_data_processed.append(
+                dict(
+                    api_name=api[u"api_name"],
+                    api_args=api_args_processed
+                )
+            )

         return api_data_processed
 
         return api_data_processed
 

-    def _execute_papi(self, api_data, method='request', err_msg="",
-                      timeout=120):
+    def _execute_papi(
+            self, api_data, method=u"request", err_msg=u"", timeout=120,
+            socket=None):

         """Execute PAPI command(s) on remote node and store the result.
 
         :param api_data: List of APIs with their arguments.
         """Execute PAPI command(s) on remote node and store the result.
 
         :param api_data: List of APIs with their arguments.


@@ -685,32 +740,32 @@ class PapiExecutor(object):
         :raises RuntimeError: If PAPI executor failed due to another reason.
         :raises AssertionError: If PAPI command(s) execution has failed.
         """
         :raises RuntimeError: If PAPI executor failed due to another reason.
         :raises AssertionError: If PAPI command(s) execution has failed.
         """

-

         if not api_data:
         if not api_data:

-            raise RuntimeError("No API data provided.")
+            raise RuntimeError(u"No API data provided.")

 
         json_data = json.dumps(api_data) \
 
         json_data = json.dumps(api_data) \

-            if method in ("stats", "stats_request") \
+            if method in (u"stats", u"stats_request") \

             else json.dumps(self._process_api_data(api_data))
 
             else json.dumps(self._process_api_data(api_data))
 

-        cmd = "{fw_dir}/{papi_provider} --method {method} --data '{json}'".\
-            format(
-                fw_dir=Constants.REMOTE_FW_DIR, method=method, json=json_data,
-                papi_provider=Constants.RESOURCES_PAPI_PROVIDER)
+        sock = f" --socket {socket}" if socket else u""
+        cmd = f"{Constants.REMOTE_FW_DIR}/{Constants.RESOURCES_PAPI_PROVIDER}" \
+            f" --method {method} --data '{json_data}'{sock}"

         try:
             ret_code, stdout, _ = self._ssh.exec_command_sudo(
         try:
             ret_code, stdout, _ = self._ssh.exec_command_sudo(

-                cmd=cmd, timeout=timeout, log_stdout_err=False)
+                cmd=cmd, timeout=timeout, log_stdout_err=False
+            )

         # TODO: Fail on non-empty stderr?
         except SSHTimeout:
         # TODO: Fail on non-empty stderr?
         except SSHTimeout:

-            logger.error("PAPI command(s) execution timeout on host {host}:"
-                         "\n{apis}".format(host=self._node["host"],
-                                           apis=api_data))
+            logger.error(
+                f"PAPI command(s) execution timeout on host "
+                f"{self._node[u'host']}:\n{api_data}"
+            )

             raise
         except Exception as exc:
             raise
         except Exception as exc:

-            raise_from(RuntimeError(
-                "PAPI command(s) execution on host {host} "
-                "failed: {apis}".format(
-                    host=self._node["host"], apis=api_data)), exc)
+            raise RuntimeError(
+                f"PAPI command(s) execution on host {self._node[u'host']} "
+                f"failed: {api_data}"
+            ) from exc

         if ret_code != 0:
             raise AssertionError(err_msg)
 
         if ret_code != 0:
             raise AssertionError(err_msg)