tools/run_tests/run_tests.py

#!/usr/bin/env python2.7
# Copyright 2015-2016, Google Inc.
# All rights reserved.
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# modification, are permitted provided that the following conditions are
# met:
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"""Run tests in parallel."""

import argparse
import glob
import hashlib
import itertools
import json
import multiprocessing
import os
import platform
import random
import re
import socket
import subprocess
import sys
import tempfile
import traceback
import time
import urllib2
import uuid

import jobset
import report_utils
import watch_dirs


ROOT = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '../..'))
os.chdir(ROOT)


_FORCE_ENVIRON_FOR_WRAPPERS = {}


def platform_string():
  return jobset.platform_string()


# SimpleConfig: just compile with CONFIG=config, and run the binary to test
class SimpleConfig(object):

  def __init__(self, config, environ=None, timeout_multiplier=1):
    if environ is None:
      environ = {}
    self.build_config = config
    self.allow_hashing = (config != 'gcov')
    self.environ = environ
    self.environ['CONFIG'] = config
    self.timeout_multiplier = timeout_multiplier

  def job_spec(self, cmdline, hash_targets, timeout_seconds=5*60,
               shortname=None, environ={}):
    """Construct a jobset.JobSpec for a test under this config

       Args:
         cmdline:      a list of strings specifying the command line the test
                       would like to run
         hash_targets: either None (don't do caching of test results), or
                       a list of strings specifying files to include in a
                       binary hash to check if a test has changed
                       -- if used, all artifacts needed to run the test must
                          be listed
    """
    actual_environ = self.environ.copy()
    for k, v in environ.iteritems():
      actual_environ[k] = v
    return jobset.JobSpec(cmdline=cmdline,
                          shortname=shortname,
                          environ=actual_environ,
                          timeout_seconds=self.timeout_multiplier * timeout_seconds,
                          hash_targets=hash_targets
                              if self.allow_hashing else None,
                          flake_retries=5 if args.allow_flakes else 0,
                          timeout_retries=3 if args.allow_flakes else 0)


# ValgrindConfig: compile with some CONFIG=config, but use valgrind to run
class ValgrindConfig(object):

  def __init__(self, config, tool, args=None):
    if args is None:
      args = []
    self.build_config = config
    self.tool = tool
    self.args = args
    self.allow_hashing = False

  def job_spec(self, cmdline, hash_targets):
    return jobset.JobSpec(cmdline=['valgrind', '--tool=%s' % self.tool] +
                          self.args + cmdline,
                          shortname='valgrind %s' % cmdline[0],
                          hash_targets=None,
                          flake_retries=5 if args.allow_flakes else 0,
                          timeout_retries=3 if args.allow_flakes else 0)


def get_c_tests(travis, test_lang) :
  out = []
  platforms_str = 'ci_platforms' if travis else 'platforms'
  with open('tools/run_tests/tests.json') as f:
    js = json.load(f)
    return [tgt
            for tgt in js
            if tgt['language'] == test_lang and
                platform_string() in tgt[platforms_str] and
                not (travis and tgt['flaky'])]


class CLanguage(object):

  def __init__(self, make_target, test_lang):
    self.make_target = make_target
    self.platform = platform_string()
    self.test_lang = test_lang

  def test_specs(self, config, args):
    out = []
    binaries = get_c_tests(args.travis, self.test_lang)
    for target in binaries:
      if config.build_config in target['exclude_configs']:
        continue
      if self.platform == 'windows':
        binary = 'vsprojects/%s/%s.exe' % (
            _WINDOWS_CONFIG[config.build_config], target['name'])
      else:
        binary = 'bins/%s/%s' % (config.build_config, target['name'])
      if os.path.isfile(binary):
        cmdline = [binary] + target['args']
        out.append(config.job_spec(cmdline, [binary],
                                   shortname=' '.join(cmdline),
                                   environ={'GRPC_DEFAULT_SSL_ROOTS_FILE_PATH':
                                            os.path.abspath(os.path.dirname(
                                                sys.argv[0]) + '/../../src/core/tsi/test_creds/ca.pem')}))
      elif args.regex == '.*' or platform_string() == 'windows':
        print '\nWARNING: binary not found, skipping', binary
    return sorted(out)

  def make_targets(self, test_regex):
    if platform_string() != 'windows' and test_regex != '.*':
      # use the regex to minimize the number of things to build
      return [target['name']
              for target in get_c_tests(False, self.test_lang)
              if re.search(test_regex, target['name'])]
    if platform_string() == 'windows':
      # don't build tools on windows just yet
      return ['buildtests_%s' % self.make_target]
    return ['buildtests_%s' % self.make_target, 'tools_%s' % self.make_target]

  def pre_build_steps(self):
    if self.platform == 'windows':
      return [['tools\\run_tests\\pre_build_c.bat']]
    else:
      return []

  def build_steps(self):
    return []

  def post_tests_steps(self):
    if self.platform == 'windows':
      return []
    else:
      return [['tools/run_tests/post_tests_c.sh']]

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return True

  def __str__(self):
    return self.make_target


class NodeLanguage(object):

  def test_specs(self, config, args):
    return [config.job_spec(['tools/run_tests/run_node.sh'], None,
                            environ=_FORCE_ENVIRON_FOR_WRAPPERS)]

  def pre_build_steps(self):
    # Default to 1 week cache expiration
    return [['tools/run_tests/pre_build_node.sh']]

  def make_targets(self, test_regex):
    return []

  def build_steps(self):
    return [['tools/run_tests/build_node.sh']]

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'node'


class PhpLanguage(object):

  def test_specs(self, config, args):
    return [config.job_spec(['src/php/bin/run_tests.sh'], None,
                            environ=_FORCE_ENVIRON_FOR_WRAPPERS)]

  def pre_build_steps(self):
    return []

  def make_targets(self, test_regex):
    return ['static_c', 'shared_c']

  def build_steps(self):
    return [['tools/run_tests/build_php.sh']]

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'php'


class PythonLanguage(object):

  def __init__(self):
    self._build_python_versions = ['2.7']
    self._has_python_versions = []

  def test_specs(self, config, args):
    environment = dict(_FORCE_ENVIRON_FOR_WRAPPERS)
    environment['PYVER'] = '2.7'
    return [config.job_spec(
        ['tools/run_tests/run_python.sh'],
        None,
        environ=environment,
        shortname='py.test',
        timeout_seconds=15*60
    )]

  def pre_build_steps(self):
    return []

  def make_targets(self, test_regex):
    return ['static_c', 'grpc_python_plugin', 'shared_c']

  def build_steps(self):
    commands = []
    for python_version in self._build_python_versions:
      try:
        with open(os.devnull, 'w') as output:
          subprocess.check_call(['which', 'python' + python_version],
                                stdout=output, stderr=output)
        commands.append(['tools/run_tests/build_python.sh', python_version])
        self._has_python_versions.append(python_version)
      except:
        jobset.message('WARNING', 'Missing Python ' + python_version,
                       do_newline=True)
    return commands

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'python'


class RubyLanguage(object):

  def test_specs(self, config, args):
    return [config.job_spec(['tools/run_tests/run_ruby.sh'], None,
                            environ=_FORCE_ENVIRON_FOR_WRAPPERS)]

  def pre_build_steps(self):
    return [['tools/run_tests/pre_build_ruby.sh']]

  def make_targets(self, test_regex):
    return ['static_c']

  def build_steps(self):
    return [['tools/run_tests/build_ruby.sh']]

  def post_tests_steps(self):
    return [['tools/run_tests/post_tests_ruby.sh']]

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'ruby'


class CSharpLanguage(object):
  def __init__(self):
    self.platform = platform_string()

  def test_specs(self, config, args):
    with open('src/csharp/tests.json') as f:
      tests_json = json.load(f)
    assemblies = tests_json['assemblies']
    tests = tests_json['tests']

    msbuild_config = _WINDOWS_CONFIG[config.build_config]
    assembly_files = ['%s/bin/%s/%s.dll' % (a, msbuild_config, a)
                      for a in assemblies]

    extra_args = ['-labels'] + assembly_files

    if self.platform == 'windows':
      script_name = 'tools\\run_tests\\run_csharp.bat'
      extra_args += ['-domain=None']
    else:
      script_name = 'tools/run_tests/run_csharp.sh'

    if config.build_config == 'gcov':
      # On Windows, we only collect C# code coverage.
      # On Linux, we only collect coverage for native extension.
      # For code coverage all tests need to run as one suite.
      return [config.job_spec([script_name] + extra_args, None,
                              shortname='csharp.coverage',
                              environ=_FORCE_ENVIRON_FOR_WRAPPERS)]
    else:
      specs = []
      for test in tests:
        cmdline = [script_name, '-run=%s' % test] + extra_args
        if self.platform == 'windows':
          # use different output directory for each test to prevent
          # TestResult.xml clash between parallel test runs.
          cmdline += ['-work=test-result/%s' % uuid.uuid4()]
        specs.append(config.job_spec(cmdline, None,
                                     shortname='csharp.%s' % test,
                                     environ=_FORCE_ENVIRON_FOR_WRAPPERS))
      return specs

  def pre_build_steps(self):
    if self.platform == 'windows':
      return [['tools\\run_tests\\pre_build_csharp.bat']]
    else:
      return [['tools/run_tests/pre_build_csharp.sh']]

  def make_targets(self, test_regex):
    # For Windows, this target doesn't really build anything,
    # everything is build by buildall script later.
    if self.platform == 'windows':
      return []
    else:
      return ['grpc_csharp_ext']

  def build_steps(self):
    if self.platform == 'windows':
      return [['src\\csharp\\buildall.bat']]
    else:
      return [['tools/run_tests/build_csharp.sh']]

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'csharp'


class ObjCLanguage(object):

  def test_specs(self, config, args):
    return [config.job_spec(['src/objective-c/tests/run_tests.sh'], None,
                            environ=_FORCE_ENVIRON_FOR_WRAPPERS)]

  def pre_build_steps(self):
    return []

  def make_targets(self, test_regex):
    return ['grpc_objective_c_plugin', 'interop_server']

  def build_steps(self):
    return [['src/objective-c/tests/build_tests.sh']]

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'objc'


class Sanity(object):

  def test_specs(self, config, args):
    return [config.job_spec(['tools/run_tests/run_sanity.sh'], None, timeout_seconds=15*60),
            config.job_spec(['tools/run_tests/check_sources_and_headers.py'], None)]

  def pre_build_steps(self):
    return []

  def make_targets(self, test_regex):
    return ['run_dep_checks']

  def build_steps(self):
    return []

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return False

  def __str__(self):
    return 'sanity'


class Build(object):

  def test_specs(self, config, args):
    return []

  def pre_build_steps(self):
    return []

  def make_targets(self, test_regex):
    return ['static']

  def build_steps(self):
    return []

  def post_tests_steps(self):
    return []

  def makefile_name(self):
    return 'Makefile'

  def supports_multi_config(self):
    return True

  def __str__(self):
    return self.make_target


# different configurations we can run under
_CONFIGS = {
    'dbg': SimpleConfig('dbg'),
    'opt': SimpleConfig('opt'),
    'tsan': SimpleConfig('tsan', timeout_multiplier=2, environ={
        'TSAN_OPTIONS': 'suppressions=tools/tsan_suppressions.txt:halt_on_error=1:second_deadlock_stack=1'}),
    'msan': SimpleConfig('msan', timeout_multiplier=1.5),
    'ubsan': SimpleConfig('ubsan'),
    'asan': SimpleConfig('asan', timeout_multiplier=1.5, environ={
        'ASAN_OPTIONS': 'suppressions=tools/asan_suppressions.txt:detect_leaks=1:color=always',
        'LSAN_OPTIONS': 'suppressions=tools/asan_suppressions.txt:report_objects=1'}),
    'asan-noleaks': SimpleConfig('asan', environ={
        'ASAN_OPTIONS': 'detect_leaks=0:color=always'}),
    'gcov': SimpleConfig('gcov'),
    'memcheck': ValgrindConfig('valgrind', 'memcheck', ['--leak-check=full']),
    'helgrind': ValgrindConfig('dbg', 'helgrind')
    }


_DEFAULT = ['opt']
_LANGUAGES = {
    'c++': CLanguage('cxx', 'c++'),
    'c': CLanguage('c', 'c'),
    'node': NodeLanguage(),
    'php': PhpLanguage(),
    'python': PythonLanguage(),
    'ruby': RubyLanguage(),
    'csharp': CSharpLanguage(),
    'objc' : ObjCLanguage(),
    'sanity': Sanity(),
    'build': Build(),
    }

_WINDOWS_CONFIG = {
    'dbg': 'Debug',
    'opt': 'Release',
    'gcov': 'Debug',
    }


def _windows_arch_option(arch):
  """Returns msbuild cmdline option for selected architecture."""
  if arch == 'default' or arch == 'windows_x86':
    return '/p:Platform=Win32'
  elif arch == 'windows_x64':
    return '/p:Platform=x64'
  else:
    print 'Architecture %s not supported on current platform.' % arch
    sys.exit(1)

    
def _windows_build_bat(compiler):
  """Returns name of build.bat for selected compiler."""
  if compiler == 'default' or compiler == 'vs2013':
    return 'vsprojects\\build_vs2013.bat'
  elif compiler == 'vs2015':
    return 'vsprojects\\build_vs2015.bat'
  elif compiler == 'vs2010':
    return 'vsprojects\\build_vs2010.bat'
  else:
    print 'Compiler %s not supported.' % compiler
    sys.exit(1)
    
    
def _windows_toolset_option(compiler):
  """Returns msbuild PlatformToolset for selected compiler."""
  if compiler == 'default' or compiler == 'vs2013':
    return '/p:PlatformToolset=v120'
  elif compiler == 'vs2015':
    return '/p:PlatformToolset=v140'
  elif compiler == 'vs2010':
    return '/p:PlatformToolset=v100'
  else:
    print 'Compiler %s not supported.' % compiler
    sys.exit(1)
   

def runs_per_test_type(arg_str):
    """Auxilary function to parse the "runs_per_test" flag.

       Returns:
           A positive integer or 0, the latter indicating an infinite number of
           runs.

       Raises:
           argparse.ArgumentTypeError: Upon invalid input.
    """
    if arg_str == 'inf':
        return 0
    try:
        n = int(arg_str)
        if n <= 0: raise ValueError
        return n
    except:
        msg = '\'{}\' is not a positive integer or \'inf\''.format(arg_str)
        raise argparse.ArgumentTypeError(msg)

# parse command line
argp = argparse.ArgumentParser(description='Run grpc tests.')
argp.add_argument('-c', '--config',
                  choices=['all'] + sorted(_CONFIGS.keys()),
                  nargs='+',
                  default=_DEFAULT)
argp.add_argument('-n', '--runs_per_test', default=1, type=runs_per_test_type,
        help='A positive integer or "inf". If "inf", all tests will run in an '
             'infinite loop. Especially useful in combination with "-f"')
argp.add_argument('-r', '--regex', default='.*', type=str)
argp.add_argument('-j', '--jobs', default=2 * multiprocessing.cpu_count(), type=int)
argp.add_argument('-s', '--slowdown', default=1.0, type=float)
argp.add_argument('-f', '--forever',
                  default=False,
                  action='store_const',
                  const=True)
argp.add_argument('-t', '--travis',
                  default=False,
                  action='store_const',
                  const=True)
argp.add_argument('--newline_on_success',
                  default=False,
                  action='store_const',
                  const=True)
argp.add_argument('-l', '--language',
                  choices=['all'] + sorted(_LANGUAGES.keys()),
                  nargs='+',
                  default=['all'])
argp.add_argument('-S', '--stop_on_failure',
                  default=False,
                  action='store_const',
                  const=True)
argp.add_argument('--use_docker',
                  default=False,
                  action='store_const',
                  const=True,
                  help='Run all the tests under docker. That provides ' +
                  'additional isolation and prevents the need to install ' +
                  'language specific prerequisites. Only available on Linux.')
argp.add_argument('--allow_flakes',
                  default=False,
                  action='store_const',
                  const=True,
                  help='Allow flaky tests to show as passing (re-runs failed tests up to five times)')
argp.add_argument('--arch',
                  choices=['default', 'windows_x86', 'windows_x64'],
                  default='default',
                  help='Selects architecture to target. For some platforms "default" is the only supported choice.')
argp.add_argument('--compiler',
                  choices=['default', 'vs2010', 'vs2013', 'vs2015'],
                  default='default',
                  help='Selects compiler to use. For some platforms "default" is the only supported choice.')
argp.add_argument('--build_only',
                  default=False,
                  action='store_const',
                  const=True,
                  help='Perform all the build steps but dont run any tests.')
argp.add_argument('--update_submodules', default=[], nargs='*',
                  help='Update some submodules before building. If any are updated, also run generate_projects. ' +
                       'Submodules are specified as SUBMODULE_NAME:BRANCH; if BRANCH is omitted, master is assumed.')
argp.add_argument('-a', '--antagonists', default=0, type=int)
argp.add_argument('-x', '--xml_report', default=None, type=str,
        help='Generates a JUnit-compatible XML report')
args = argp.parse_args()

if args.use_docker:
  if not args.travis:
    print 'Seen --use_docker flag, will run tests under docker.'
    print
    print 'IMPORTANT: The changes you are testing need to be locally committed'
    print 'because only the committed changes in the current branch will be'
    print 'copied to the docker environment.'
    time.sleep(5)

  child_argv = [ arg for arg in sys.argv if not arg == '--use_docker' ]
  run_tests_cmd = 'tools/run_tests/run_tests.py %s' % ' '.join(child_argv[1:])

  # TODO(jtattermusch): revisit if we need special handling for arch here
  # set arch command prefix in case we are working with different arch.
  arch_env = os.getenv('arch')
  if arch_env:
    run_test_cmd = 'arch %s %s' % (arch_env, run_test_cmd)

  env = os.environ.copy()
  env['RUN_TESTS_COMMAND'] = run_tests_cmd
  if args.xml_report:
    env['XML_REPORT'] = args.xml_report
  if not args.travis:
    env['TTY_FLAG'] = '-t'  # enables Ctrl-C when not on Jenkins.

  subprocess.check_call(['tools/jenkins/build_docker_and_run_tests.sh'],
                        shell=True,
                        env=env)
  sys.exit(0)

# update submodules if necessary
need_to_regenerate_projects = False
for spec in args.update_submodules:
  spec = spec.split(':', 1)
  if len(spec) == 1:
    submodule = spec[0]
    branch = 'master'
  elif len(spec) == 2:
    submodule = spec[0]
    branch = spec[1]
  cwd = 'third_party/%s' % submodule
  def git(cmd, cwd=cwd):
    print 'in %s: git %s' % (cwd, cmd)
    subprocess.check_call('git %s' % cmd, cwd=cwd, shell=True)
  git('fetch')
  git('checkout %s' % branch)
  git('pull origin %s' % branch)
  if os.path.exists('src/%s/gen_build_yaml.py' % submodule):
    need_to_regenerate_projects = True
if need_to_regenerate_projects:
  if jobset.platform_string() == 'linux':
    subprocess.check_call('tools/buildgen/generate_projects.sh', shell=True)
  else:
    print 'WARNING: may need to regenerate projects, but since we are not on'
    print '         Linux this step is being skipped. Compilation MAY fail.'


# grab config
run_configs = set(_CONFIGS[cfg]
                  for cfg in itertools.chain.from_iterable(
                      _CONFIGS.iterkeys() if x == 'all' else [x]
                      for x in args.config))
build_configs = set(cfg.build_config for cfg in run_configs)

if args.travis:
  _FORCE_ENVIRON_FOR_WRAPPERS = {'GRPC_TRACE': 'api'}

if 'all' in args.language:
  lang_list = _LANGUAGES.keys()
else:
  lang_list = args.language
# We don't support code coverage on some languages
if 'gcov' in args.config:
  for bad in ['objc', 'sanity', 'build']:
    if bad in lang_list:
      lang_list.remove(bad)

languages = set(_LANGUAGES[l] for l in lang_list)

if len(build_configs) > 1:
  for language in languages:
    if not language.supports_multi_config():
      print language, 'does not support multiple build configurations'
      sys.exit(1)

if platform_string() != 'windows':
  if args.arch != 'default':
    print 'Architecture %s not supported on current platform.' % args.arch
    sys.exit(1)
  if args.compiler != 'default':
    print 'Compiler %s not supported on current platform.' % args.compiler
    sys.exit(1)

if platform_string() == 'windows':
  def make_jobspec(cfg, targets, makefile='Makefile'):
    extra_args = []
    # better do parallel compilation
    # empirically /m:2 gives the best performance/price and should prevent
    # overloading the windows workers.
    extra_args.extend(['/m:2'])
    # disable PDB generation: it's broken, and we don't need it during CI
    extra_args.extend(['/p:Jenkins=true'])
    return [
      jobset.JobSpec([_windows_build_bat(args.compiler),
                      'vsprojects\\%s.sln' % target,
                      '/p:Configuration=%s' % _WINDOWS_CONFIG[cfg],
                      _windows_toolset_option(args.compiler),
                      _windows_arch_option(args.arch)] +
                      extra_args,
                      shell=True, timeout_seconds=90*60)
      for target in targets]
else:
  def make_jobspec(cfg, targets, makefile='Makefile'):
    if targets:
      return [jobset.JobSpec([os.getenv('MAKE', 'make'),
                              '-f', makefile,
                              '-j', '%d' % (multiprocessing.cpu_count() + 1),
                              'EXTRA_DEFINES=GRPC_TEST_SLOWDOWN_MACHINE_FACTOR=%f' %
                              args.slowdown,
                              'CONFIG=%s' % cfg] + targets,
                             timeout_seconds=30*60)]
    else:
      return []
make_targets = {}
for l in languages:
  makefile = l.makefile_name()
  make_targets[makefile] = make_targets.get(makefile, set()).union(
      set(l.make_targets(args.regex)))

def build_step_environ(cfg):
  environ = {'CONFIG': cfg}
  msbuild_cfg = _WINDOWS_CONFIG.get(cfg)
  if msbuild_cfg:
    environ['MSBUILD_CONFIG'] = msbuild_cfg
  return environ

build_steps = list(set(
                   jobset.JobSpec(cmdline, environ=build_step_environ(cfg), flake_retries=5)
                   for cfg in build_configs
                   for l in languages
                   for cmdline in l.pre_build_steps()))
if make_targets:
  make_commands = itertools.chain.from_iterable(make_jobspec(cfg, list(targets), makefile) for cfg in build_configs for (makefile, targets) in make_targets.iteritems())
  build_steps.extend(set(make_commands))
build_steps.extend(set(
                   jobset.JobSpec(cmdline, environ=build_step_environ(cfg), timeout_seconds=10*60)
                   for cfg in build_configs
                   for l in languages
                   for cmdline in l.build_steps()))

post_tests_steps = list(set(
                        jobset.JobSpec(cmdline, environ=build_step_environ(cfg))
                        for cfg in build_configs
                        for l in languages
                        for cmdline in l.post_tests_steps()))
runs_per_test = args.runs_per_test
forever = args.forever


class TestCache(object):
  """Cache for running tests."""

  def __init__(self, use_cache_results):
    self._last_successful_run = {}
    self._use_cache_results = use_cache_results
    self._last_save = time.time()

  def should_run(self, cmdline, bin_hash):
    if cmdline not in self._last_successful_run:
      return True
    if self._last_successful_run[cmdline] != bin_hash:
      return True
    if not self._use_cache_results:
      return True
    return False

  def finished(self, cmdline, bin_hash):
    self._last_successful_run[cmdline] = bin_hash
    if time.time() - self._last_save > 1:
      self.save()

  def dump(self):
    return [{'cmdline': k, 'hash': v}
            for k, v in self._last_successful_run.iteritems()]

  def parse(self, exdump):
    self._last_successful_run = dict((o['cmdline'], o['hash']) for o in exdump)

  def save(self):
    with open('.run_tests_cache', 'w') as f:
      f.write(json.dumps(self.dump()))
    self._last_save = time.time()

  def maybe_load(self):
    if os.path.exists('.run_tests_cache'):
      with open('.run_tests_cache') as f:
        self.parse(json.loads(f.read()))


def _start_port_server(port_server_port):
  # check if a compatible port server is running
  # if incompatible (version mismatch) ==> start a new one
  # if not running ==> start a new one
  # otherwise, leave it up
  try:
    version = int(urllib2.urlopen(
        'http://localhost:%d/version_number' % port_server_port,
        timeout=1).read())
    print 'detected port server running version %d' % version
    running = True
  except Exception as e:
    print 'failed to detect port server: %s' % sys.exc_info()[0]
    print e.strerror
    running = False
  if running:
    current_version = int(subprocess.check_output(
        [sys.executable, os.path.abspath('tools/run_tests/port_server.py'),
         'dump_version']))
    print 'my port server is version %d' % current_version
    running = (version >= current_version)
    if not running:
      print 'port_server version mismatch: killing the old one'
      urllib2.urlopen('http://localhost:%d/quitquitquit' % port_server_port).read()
      time.sleep(1)
  if not running:
    fd, logfile = tempfile.mkstemp()
    os.close(fd)
    print 'starting port_server, with log file %s' % logfile
    args = [sys.executable, os.path.abspath('tools/run_tests/port_server.py'),
            '-p', '%d' % port_server_port, '-l', logfile]
    env = dict(os.environ)
    env['BUILD_ID'] = 'pleaseDontKillMeJenkins'
    if platform_string() == 'windows':
      # Working directory of port server needs to be outside of Jenkins
      # workspace to prevent file lock issues.
      tempdir = tempfile.mkdtemp()
      port_server = subprocess.Popen(
          args,
          env=env,
          cwd=tempdir,
          creationflags = 0x00000008, # detached process
          close_fds=True)
    else:
      port_server = subprocess.Popen(
          args,
          env=env,
          preexec_fn=os.setsid,
          close_fds=True)
    time.sleep(1)
    # ensure port server is up
    waits = 0
    while True:
      if waits > 10:
        print 'killing port server due to excessive start up waits'
        port_server.kill()
      if port_server.poll() is not None:
        print 'port_server failed to start'
        # try one final time: maybe another build managed to start one
        time.sleep(1)
        try:
          urllib2.urlopen('http://localhost:%d/get' % port_server_port,
                          timeout=1).read()
          print 'last ditch attempt to contact port server succeeded'
          break
        except:
          traceback.print_exc();
          port_log = open(logfile, 'r').read()
          print port_log
          sys.exit(1)
      try:
        urllib2.urlopen('http://localhost:%d/get' % port_server_port,
                        timeout=1).read()
        print 'port server is up and ready'
        break
      except socket.timeout:
        print 'waiting for port_server: timeout'
        traceback.print_exc();
        time.sleep(1)
        waits += 1
      except urllib2.URLError:
        print 'waiting for port_server: urlerror'
        traceback.print_exc();
        time.sleep(1)
        waits += 1
      except:
        traceback.print_exc();
        port_server.kill()
        raise


def _calculate_num_runs_failures(list_of_results):
  """Caculate number of runs and failures for a particular test.

  Args:
    list_of_results: (List) of JobResult object.
  Returns:
    A tuple of total number of runs and failures.
  """
  num_runs = len(list_of_results)  # By default, there is 1 run per JobResult.
  num_failures = 0
  for jobresult in list_of_results:
    if jobresult.retries > 0:
      num_runs += jobresult.retries
    if jobresult.num_failures > 0:
      num_failures += jobresult.num_failures
  return num_runs, num_failures


def _build_and_run(
    check_cancelled, newline_on_success, cache, xml_report=None, build_only=False):
  """Do one pass of building & running tests."""
  # build latest sequentially
  num_failures, _ = jobset.run(
      build_steps, maxjobs=1, stop_on_failure=True,
      newline_on_success=newline_on_success, travis=args.travis)
  if num_failures:
    return 1

  if build_only:
    return 0

  # start antagonists
  antagonists = [subprocess.Popen(['tools/run_tests/antagonist.py'])
                 for _ in range(0, args.antagonists)]
  port_server_port = 32767
  _start_port_server(port_server_port)
  resultset = None
  num_test_failures = 0
  try:
    infinite_runs = runs_per_test == 0
    one_run = set(
      spec
      for config in run_configs
      for language in languages
      for spec in language.test_specs(config, args)
      if re.search(args.regex, spec.shortname))
    # When running on travis, we want out test runs to be as similar as possible
    # for reproducibility purposes.
    if args.travis:
      massaged_one_run = sorted(one_run, key=lambda x: x.shortname)
    else:
      # whereas otherwise, we want to shuffle things up to give all tests a
      # chance to run.
      massaged_one_run = list(one_run)  # random.shuffle needs an indexable seq.
      random.shuffle(massaged_one_run)  # which it modifies in-place.
    if infinite_runs:
      assert len(massaged_one_run) > 0, 'Must have at least one test for a -n inf run'
    runs_sequence = (itertools.repeat(massaged_one_run) if infinite_runs
                     else itertools.repeat(massaged_one_run, runs_per_test))
    all_runs = itertools.chain.from_iterable(runs_sequence)

    num_test_failures, resultset = jobset.run(
        all_runs, check_cancelled, newline_on_success=newline_on_success,
        travis=args.travis, infinite_runs=infinite_runs, maxjobs=args.jobs,
        stop_on_failure=args.stop_on_failure,
        cache=cache if not xml_report else None,
        add_env={'GRPC_TEST_PORT_SERVER': 'localhost:%d' % port_server_port})
    if resultset:
      for k, v in resultset.iteritems():
        num_runs, num_failures = _calculate_num_runs_failures(v)
        if num_failures == num_runs:  # what about infinite_runs???
          jobset.message('FAILED', k, do_newline=True)
        elif num_failures > 0:
          jobset.message(
              'FLAKE', '%s [%d/%d runs flaked]' % (k, num_failures, num_runs),
              do_newline=True)
        else:
          jobset.message('PASSED', k, do_newline=True)
  finally:
    for antagonist in antagonists:
      antagonist.kill()
    if xml_report and resultset:
      report_utils.render_junit_xml_report(resultset, xml_report)

  number_failures, _ = jobset.run(
      post_tests_steps, maxjobs=1, stop_on_failure=True,
      newline_on_success=newline_on_success, travis=args.travis)
  if num_test_failures or number_failures:
    return 2

  if cache: cache.save()

  return 0


test_cache = TestCache(runs_per_test == 1)
test_cache.maybe_load()

if forever:
  success = True
  while True:
    dw = watch_dirs.DirWatcher(['src', 'include', 'test', 'examples'])
    initial_time = dw.most_recent_change()
    have_files_changed = lambda: dw.most_recent_change() != initial_time
    previous_success = success
    success = _build_and_run(check_cancelled=have_files_changed,
                             newline_on_success=False,
                             cache=test_cache,
                             build_only=args.build_only) == 0
    if not previous_success and success:
      jobset.message('SUCCESS',
                     'All tests are now passing properly',
                     do_newline=True)
    jobset.message('IDLE', 'No change detected')
    while not have_files_changed():
      time.sleep(1)
else:
  result = _build_and_run(check_cancelled=lambda: False,
                          newline_on_success=args.newline_on_success,
                          cache=test_cache,
                          xml_report=args.xml_report,
                          build_only=args.build_only)
  if result == 0:
    jobset.message('SUCCESS', 'All tests passed', do_newline=True)
  else:
    jobset.message('FAILED', 'Some tests failed', do_newline=True)
  sys.exit(result)