osmo-python-tests/osmopy/osmo_verify_transcript_comm...

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add osmo_verify_transcript_{vty,ctrl}.py for easier vty and ctrl testing While adding VTY and CTRL tests to new programs like OsmoHLR, I wanted to have a simple way to translate a VTY interaction transcript to a VTY python test. It is fairly trivial to simply read in a transcript, extract both the commands to send as well as the expected results, and to verify these without having to write one line of application-specific code. From there it was just a little step to allow the same for CTRL interaction. With osmo_verify_transcript_vty.py and osmo_verify_transcript_ctrl.py, it is possible to have a simple text file of a telnet VTY or CTRL interface interaction and run it against a given application. With the --update option, the scripts run the given command and rewrite the transcript file to whatever the application currently produces as response. Backed by version control, it is super easy to tweak commands, --update the test results and verify that only the desired bits changed. A '...' wildcard can skip any number of lines in the expected result and is usually preserved during --update. This python3 implementation is independent from the previous obscvty implementations. Take the opportunity to clarify/fix a few aspects: for example, it is now possible to verify the hints that the interactive VTY displays when the user enters '?' in various places, and to evaluate the prompt character '>'/'#'. Unitl now, code is duplicated/scattered across various vty_test_runner.py scripts in different git repositories. Now, a VTY or CTRL transcript is enough to put a complete test in place. The simplest invocation is directly from the Makefile, feeding an application commandline, the proper port number to contact it and e.g. a VTY prompt name. This new code is also usable as python modules, to be able to build more complex tests that require specialized intermediate actions, possibly coordinating launch of applications or data manipulation. The first repository to employ this is osmo-hlr.git. See change-ids I42b3b70a0439a8f2e4964d7cc31e593c1f0d7537 for VTY and Iff93abe370b8f3ecf42082d1d0eaa1fbeca5b122 for CTRL. Change-Id: Id47331009910e651372b9c9c76e12f2e8964cc2c
2017-10-15 01:01:09 +00:00
#!/usr/bin/env python3
#
# (C) 2017 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
# All rights reserved.
#
# Author: Neels Hofmeyr <nhofmeyr@sysmocom.de>
#
# This program 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.
#
# This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
'''
Common code for verify_transcript_vty.py and verify_transcript_ctrl.py.
'''
import argparse
import sys
import os
import subprocess
import time
import traceback
import socket
import shlex
class Interact:
class StepBase:
command = None
result = None
leading_blanks = None
def __init__(self):
self.result = []
def verify_interact_state(self, interact_instance):
# for example to verify that the last VTY prompt received shows the
# right node.
pass
def command_str(self, interact_instance=None):
return self.command
def __str__(self):
return '%s\n%s' % (self.command_str(), '\n'.join(self.result))
@staticmethod
def is_next_step(line, interact_instance):
assert not "implemented by InteractVty.VtyStep and InteractCtrl.CtrlStep"
socket = None
def __init__(self, step_class, port, host, verbose=False, update=False):
'''
host is the hostname to connect to.
port is the CTRL port to connect on.
'''
self.Step = step_class
self.port = port
self.host = host
self.verbose = verbose
self.update = update
def connect(self):
assert self.socket is None
retries = 30
took = 0
while True:
took += 1
try:
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.setblocking(1)
self.socket.connect((self.host, int(self.port)))
except IOError:
retries -= 1
if retries <= 0:
raise
time.sleep(.1)
continue
break
def close(self):
if self.socket is None:
return
self.socket.close()
self.socket = None
def command(self, command):
assert not "implemented separately by InteractVty and InteractCtrl"
def verify_transcript_file(self, transcript_file):
with open(transcript_file, 'r') as f:
content = f.read()
try:
result = self.verify_transcript(content)
except:
print('Error while verifying transcript file %r' % transcript_file, file=sys.stderr)
sys.stderr.flush()
raise
if not self.update:
return
content = '\n'.join(result)
with open(transcript_file, 'w') as f:
f.write(content)
def verify_transcript(self, transcript):
''''
transcript is a "screenshot" of a session, a multi-line string
including commands and expected results.
Feed commands to self.command() and verify the expected results.
'''
# parse steps
steps = []
step = None
blank_lines = 0
for line in transcript.splitlines():
if not line:
blank_lines += 1
continue
next_step_started = self.Step.is_next_step(line, self)
if next_step_started:
if step:
steps.append(step)
step = next_step_started
step.leading_blanks = blank_lines
blank_lines = 0
elif step:
# we only count blank lines directly preceding the start of a
# next step. Insert blank lines in the middle of a response
# back into the response:
if blank_lines:
step.result.extend([''] * blank_lines)
blank_lines = 0
step.result.append(line)
if step:
steps.append(step)
step = None
actual_result = []
# run steps
step_nr = 0
for step in steps:
step_nr += 1
try:
if self.verbose:
if step.leading_blanks:
print('\n' * step.leading_blanks, end='')
print(step.command_str())
sys.stdout.flush()
step.verify_interact_state(self)
res = self.command(step.command)
if self.verbose:
sys.stderr.flush()
sys.stdout.flush()
print('\n'.join(res))
sys.stdout.flush()
if step.leading_blanks:
actual_result.extend([''] * step.leading_blanks)
actual_result.append(step.command_str(self))
match_result = self.match_lines(step.result, res)
if self.update:
if match_result is True:
# preserve any wildcards
actual_result.extend(step.result)
else:
# mismatch, take exactly what came in
actual_result.extend(res)
continue
if match_result is not True:
raise Exception('Result mismatch:\n%s\n\nExpected:\n[\n%s\n]\n\nGot:\n[\n%s\n%s\n]'
% (match_result, step, step.command_str(), '\n'.join(res)))
except:
print('Error during transcript step %d:\n[\n%s\n]' % (step_nr, step),
file=sys.stderr)
sys.stderr.flush()
raise
# final line ending
actual_result.append('')
return actual_result
@staticmethod
def match_lines(expect, got):
'''
Match two lists of strings, allowing certain wildcards:
- In 'expect', if a line is exactly '...', it matches any number of
arbitrary lines in 'got'; the implementation is trivial and skips
lines to the first occurence in 'got' that continues after '...'.
Return 'True' on match, or a string describing the mismatch.
'''
def match_line(expect_line, got_line):
return expect_line == got_line
e = 0
g = 0
while e < len(expect):
if expect[e] == '...':
e += 1
if e >= len(expect):
# anything left in 'got' is accepted.
return True
# look for the next occurence of the expected line in 'got'
while g < len(got) and not match_line(expect[e], got[g]):
g += 1
continue
if g >= len(got):
return 'Cannot find line %r' % expect[e]
if not match_line(expect[e], got[g]):
return 'Mismatch:\nExpect:\n%r\nGot:\n%r' % (expect[e], got[g])
e += 1
g += 1
if g < len(got):
return 'Did not expect line %r' % got[g]
return True
def end_process(proc):
if not proc:
return
rc = proc.poll()
if rc is not None:
print('Process has already terminated with', rc)
proc.wait()
return
proc.terminate()
time_to_wait_for_term = 5
wait_step = 0.001
waited_time = 0
while True:
# poll returns None if proc is still running
if proc.poll() is not None:
break
waited_time += wait_step
# make wait_step approach 1.0
wait_step = (1. + 5. * wait_step) / 6.
if waited_time >= time_to_wait_for_term:
break
time.sleep(wait_step)
if proc.poll() is None:
# termination seems to be slower than that, let's just kill
proc.kill()
print("Killed child process")
elif waited_time > .002:
print("Terminating took %.3fs" % waited_time)
proc.wait()
class Application:
proc = None
_devnull = None
@staticmethod
def devnull():
if Application._devnull is None:
Application._devnull = open(os.devnull, 'w')
return Application._devnull
def __init__(self, command_tuple, purge_output=True):
self.command_tuple = command_tuple
self.purge_output = purge_output
def run(self):
out_err = None
if self.purge_output:
out_err = Application.devnull()
print('Launching: cd %r; %s' % (os.getcwd(), ' '.join(self.command_tuple)))
self.proc = subprocess.Popen(self.command_tuple, stdout=out_err, stderr=out_err)
def stop(self):
end_process(self.proc)
def verify_application(command_tuple, interact, transcript_file, verbose):
passed = None
application = None
sys.stdout.flush()
sys.stderr.flush()
if command_tuple:
application = Application(command_tuple, purge_output=not verbose)
application.run()
try:
interact.connect()
interact.verify_transcript_file(transcript_file)
passed = True
except:
traceback.print_exc()
passed = False
interact.close()
if application:
application.stop()
sys.stdout.flush()
sys.stderr.flush()
return passed
def common_parser():
parser = argparse.ArgumentParser()
parser.add_argument('-r', '--run', dest='command_str',
help='command to run to launch application to test,'
' including command line arguments. If omitted, no'
' application is launched.')
parser.add_argument('-p', '--port', dest='port',
help="Port that the application opens.")
parser.add_argument('-H', '--host', dest='host', default='localhost',
help="Host that the application opens the port on.")
parser.add_argument('-u', '--update', dest='update', action='store_true',
help='Do not verify, but OVERWRITE transcripts based on'
' the applications current behavior. OVERWRITES TRANSCRIPT'
' FILES.')
parser.add_argument('-v', '--verbose', action='store_true',
help='Print commands and application output')
parser.add_argument('transcript_files', nargs='*', help='transcript files to verify')
return parser
def main(command_str, transcript_files, interact, verbose):
if command_str:
command_tuple = shlex.split(command_str)
else:
command_tuple = None
results = []
for t in transcript_files:
passed = verify_application(command_tuple=command_tuple,
interact=interact,
transcript_file=t,
verbose=verbose)
results.append((passed, t))
print('\nRESULTS:')
all_passed = True
for passed, t in results:
print('%s: %s' % ('pass' if passed else 'FAIL', t))
all_passed = all_passed and passed
print()
if not all_passed:
sys.exit(1)
# vim: tabstop=4 shiftwidth=4 expandtab nocin ai