Merge pull request #7265 from thunderboltsid/issue-7094-retry

Retrying: Make the testing scripts executable on Python 3.x

12 files changed, 99 insertions, 81 deletions

diff --git a/tools/run_tests/artifact_targets.py b/tools/run_tests/artifact_targets.py
index bd1269ceb7..e9267be58b 100644
--- a/tools/run_tests/artifact_targets.py
+++ b/tools/run_tests/artifact_targets.py
@@ -40,7 +40,7 @@ def create_docker_jobspec(name, dockerfile_dir, shell_command, environ={},
   environ['RUN_COMMAND'] = shell_command
 
   docker_args=[]
-  for k,v in environ.iteritems():
+  for k,v in environ.items():
     docker_args += ['-e', '%s=%s' % (k, v)]
   docker_env = {'DOCKERFILE_DIR': dockerfile_dir,
                 'DOCKER_RUN_SCRIPT': 'tools/run_tests/dockerize/docker_run.sh',
diff --git a/tools/run_tests/distribtest_targets.py b/tools/run_tests/distribtest_targets.py
index 1a7aa0bfc8..7930f2a0a4 100644
--- a/tools/run_tests/distribtest_targets.py
+++ b/tools/run_tests/distribtest_targets.py
@@ -41,7 +41,7 @@ def create_docker_jobspec(name, dockerfile_dir, shell_command, environ={},
   environ['RELATIVE_COPY_PATH'] = 'test/distrib'
 
   docker_args=[]
-  for k,v in environ.iteritems():
+  for k,v in environ.items():
     docker_args += ['-e', '%s=%s' % (k, v)]
   docker_env = {'DOCKERFILE_DIR': dockerfile_dir,
                 'DOCKER_RUN_SCRIPT': 'tools/run_tests/dockerize/docker_run.sh'}
diff --git a/tools/run_tests/dockerjob.py b/tools/run_tests/dockerjob.py
index e4ca3b7faa..4a7e61b3c4 100755
--- a/tools/run_tests/dockerjob.py
+++ b/tools/run_tests/dockerjob.py
@@ -29,6 +29,8 @@
 
 """Helpers to run docker instances as jobs."""
 
+from __future__ import print_function
+
 import jobset
 import tempfile
 import time
@@ -95,7 +97,7 @@ def remove_image(image, skip_nonexistent=False, max_retries=10):
                        stderr=subprocess.STDOUT) == 0:
       return True
     time.sleep(2)
-  print 'Failed to remove docker image %s' % image
+  print('Failed to remove docker image %s' % image)
   return False
 
 
diff --git a/tools/run_tests/jobset.py b/tools/run_tests/jobset.py
index 3999537c40..b6fb6318e0 100755
--- a/tools/run_tests/jobset.py
+++ b/tools/run_tests/jobset.py
@@ -29,6 +29,8 @@
 
 """Run a group of subprocesses and then finish."""
 
+from __future__ import print_function
+
 import multiprocessing
 import os
 import platform
@@ -123,8 +125,8 @@ def message(tag, msg, explanatory_text=None, do_newline=False):
   try:
     if platform_string() == 'windows' or not sys.stdout.isatty():
       if explanatory_text:
-        print explanatory_text
-      print '%s: %s' % (tag, msg)
+        print(explanatory_text)
+      print('%s: %s' % (tag, msg))
       return
     sys.stdout.write('%s%s%s\x1b[%d;%dm%s\x1b[0m: %s%s' % (
         _BEGINNING_OF_LINE,
@@ -368,7 +370,7 @@ class Jobset(object):
               self._travis,
               self._add_env)
     self._running.add(job)
-    if not self.resultset.has_key(job.GetSpec().shortname):
+    if job.GetSpec().shortname not in self.resultset:
       self.resultset[job.GetSpec().shortname] = []
     return True
 
diff --git a/tools/run_tests/package_targets.py b/tools/run_tests/package_targets.py
index 39a11a243d..ce3f08dfbc 100644
--- a/tools/run_tests/package_targets.py
+++ b/tools/run_tests/package_targets.py
@@ -39,7 +39,7 @@ def create_docker_jobspec(name, dockerfile_dir, shell_command, environ={},
   environ['RUN_COMMAND'] = shell_command
 
   docker_args=[]
-  for k,v in environ.iteritems():
+  for k,v in environ.items():
     docker_args += ['-e', '%s=%s' % (k, v)]
   docker_env = {'DOCKERFILE_DIR': dockerfile_dir,
                 'DOCKER_RUN_SCRIPT': 'tools/run_tests/dockerize/docker_run.sh',
diff --git a/tools/run_tests/port_server.py b/tools/run_tests/port_server.py
index 83f8e6cd35..e9b3f7ff79 100755
--- a/tools/run_tests/port_server.py
+++ b/tools/run_tests/port_server.py
@@ -30,8 +30,10 @@
 
 """Manage TCP ports for unit tests; started by run_tests.py"""
 
+from __future__ import print_function
+
 import argparse
-import BaseHTTPServer
+from six.moves import BaseHTTPServer
 import hashlib
 import os
 import socket
@@ -46,7 +48,7 @@ _MY_VERSION = 9
 
 
 if len(sys.argv) == 2 and sys.argv[1] == 'dump_version':
-  print _MY_VERSION
+  print(_MY_VERSION)
   sys.exit(0)
 
 
@@ -62,7 +64,7 @@ if args.logfile is not None:
   sys.stderr = open(args.logfile, 'w')
   sys.stdout = sys.stderr
 
-print 'port server running on port %d' % args.port
+print('port server running on port %d' % args.port)
 
 pool = []
 in_use = {}
@@ -152,7 +154,7 @@ class Handler(BaseHTTPServer.BaseHTTPRequestHandler):
       self.send_header('Content-Type', 'text/plain')
       self.end_headers()
       now = time.time()
-      self.wfile.write(yaml.dump({'pool': pool, 'in_use': dict((k, now - v) for k, v in in_use.iteritems())}))
+      self.wfile.write(yaml.dump({'pool': pool, 'in_use': dict((k, now - v) for k, v in in_use.items())}))
     elif self.path == '/quitquitquit':
       self.send_response(200)
       self.end_headers()
@@ -164,4 +166,4 @@ while keep_running:
   httpd.handle_request()
   sys.stderr.flush()
 
-print 'done'
+print('done')
diff --git a/tools/run_tests/report_utils.py b/tools/run_tests/report_utils.py
index 35dcaca3d3..5648a694cd 100644
--- a/tools/run_tests/report_utils.py
+++ b/tools/run_tests/report_utils.py
@@ -29,6 +29,8 @@
 
 """Generate XML and HTML test reports."""
 
+from __future__ import print_function
+
 try:
   from mako.runtime import Context
   from mako.template import Template
@@ -60,7 +62,7 @@ def render_junit_xml_report(resultset, xml_report):
   root = ET.Element('testsuites')
   testsuite = ET.SubElement(root, 'testsuite', id='1', package='grpc', 
                             name='tests')
-  for shortname, results in resultset.iteritems(): 
+  for shortname, results in resultset.items():
     for result in results:
       xml_test = ET.SubElement(testsuite, 'testcase', name=shortname) 
       if result.elapsed_time:
@@ -83,10 +85,10 @@ def render_interop_html_report(
   try:
     mytemplate = Template(filename=template_file, format_exceptions=True)
   except NameError:
-    print 'Mako template is not installed. Skipping HTML report generation.'
+    print('Mako template is not installed. Skipping HTML report generation.')
     return
   except IOError as e:
-    print 'Failed to find the template %s: %s' % (template_file, e)
+    print('Failed to find the template %s: %s' % (template_file, e))
     return
 
   sorted_test_cases = sorted(test_cases)
diff --git a/tools/run_tests/run_interop_tests.py b/tools/run_tests/run_interop_tests.py
index 13a4a49325..f9065c5bfd 100755
--- a/tools/run_tests/run_interop_tests.py
+++ b/tools/run_tests/run_interop_tests.py
@@ -30,6 +30,8 @@
 
 """Run interop (cross-language) tests in parallel."""
 
+from __future__ import print_function
+
 import argparse
 import atexit
 import dockerjob
@@ -372,7 +374,7 @@ def docker_run_cmdline(cmdline, image, docker_args=[], cwd=None, environ=None):
 
   # turn environ into -e docker args
   if environ:
-    for k,v in environ.iteritems():
+    for k,v in environ.items():
       docker_cmdline += ['-e', '%s=%s' % (k,v)]
 
   # set working directory
@@ -674,15 +676,15 @@ servers = set(s for s in itertools.chain.from_iterable(_SERVERS
 
 if args.use_docker:
   if not args.travis:
-    print 'Seen --use_docker flag, will run interop 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.'
+    print('Seen --use_docker flag, will run interop 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)
 
 if not args.use_docker and servers:
-  print 'Running interop servers is only supported with --use_docker option enabled.'
+  print('Running interop servers is only supported with --use_docker option enabled.')
   sys.exit(1)
 
 languages = set(_LANGUAGES[l]
@@ -768,7 +770,7 @@ try:
     (server_host, server_port) = server[1].split(':')
     server_addresses[server_name] = (server_host, server_port)
 
-  for server_name, server_address in server_addresses.iteritems():
+  for server_name, server_address in server_addresses.items():
     (server_host, server_port) = server_address
     server_language = _LANGUAGES.get(server_name, None)
     skip_server = []  # test cases unimplemented by server
@@ -800,7 +802,7 @@ try:
         jobs.append(test_job)
 
   if not jobs:
-    print 'No jobs to run.'
+    print('No jobs to run.')
     for image in docker_images.itervalues():
       dockerjob.remove_image(image, skip_nonexistent=True)
     sys.exit(1)
@@ -814,7 +816,7 @@ try:
 
   report_utils.render_junit_xml_report(resultset, 'report.xml')
 
-  for name, job in resultset.iteritems():
+  for name, job in resultset.items():
     if "http2" in name:
       job[0].http2results = aggregate_http2_results(job[0].message)
 
@@ -826,12 +828,12 @@ try:
 
 finally:
   # Check if servers are still running.
-  for server, job in server_jobs.iteritems():
+  for server, job in server_jobs.items():
     if not job.is_running():
-      print 'Server "%s" has exited prematurely.' % server
+      print('Server "%s" has exited prematurely.' % server)
 
   dockerjob.finish_jobs([j for j in server_jobs.itervalues()])
 
   for image in docker_images.itervalues():
-    print 'Removing docker image %s' % image
+    print('Removing docker image %s' % image)
     dockerjob.remove_image(image)
diff --git a/tools/run_tests/run_performance_tests.py b/tools/run_tests/run_performance_tests.py
index 14901caf07..5fdf7a407d 100755
--- a/tools/run_tests/run_performance_tests.py
+++ b/tools/run_tests/run_performance_tests.py
@@ -30,6 +30,8 @@
 
 """Run performance tests locally or remotely."""
 
+from __future__ import print_function
+
 import argparse
 import itertools
 import jobset
@@ -310,7 +312,7 @@ def create_scenarios(languages, workers_by_lang, remote_host=None, regex='.*',
                             'in the same scenario')
           if custom_server_lang:
             if not workers_by_lang.get(custom_server_lang, []):
-              print 'Warning: Skipping scenario %s as' % scenario_json['name']
+              print('Warning: Skipping scenario %s as' % scenario_json['name'])
               print('SERVER_LANGUAGE is set to %s yet the language has '
                     'not been selected with -l' % custom_server_lang)
               continue
@@ -319,7 +321,7 @@ def create_scenarios(languages, workers_by_lang, remote_host=None, regex='.*',
               workers[idx] = workers_by_lang[custom_server_lang][idx]
           if custom_client_lang:
             if not workers_by_lang.get(custom_client_lang, []):
-              print 'Warning: Skipping scenario %s as' % scenario_json['name']
+              print('Warning: Skipping scenario %s as' % scenario_json['name'])
               print('CLIENT_LANGUAGE is set to %s yet the language has '
                     'not been selected with -l' % custom_client_lang)
               continue
@@ -344,14 +346,14 @@ def finish_qps_workers(jobs):
   while any(job.is_running() for job in jobs):
     for job in qpsworker_jobs:
       if job.is_running():
-        print 'QPS worker "%s" is still running.' % job.host_and_port
+        print('QPS worker "%s" is still running.' % job.host_and_port)
     if retries > 10:
-      print 'Killing all QPS workers.'
+      print('Killing all QPS workers.')
       for job in jobs:
         job.kill()
     retries += 1
     time.sleep(3)
-  print 'All QPS workers finished.'
+  print('All QPS workers finished.')
 
 
 argp = argparse.ArgumentParser(description='Run performance tests.')
diff --git a/tools/run_tests/run_stress_tests.py b/tools/run_tests/run_stress_tests.py
index e42ee24ffb..de4a22877c 100755
--- a/tools/run_tests/run_stress_tests.py
+++ b/tools/run_tests/run_stress_tests.py
@@ -29,6 +29,8 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 """Run stress test in C++"""
 
+from __future__ import print_function
+
 import argparse
 import atexit
 import dockerjob
@@ -93,7 +95,7 @@ def docker_run_cmdline(cmdline, image, docker_args=[], cwd=None, environ=None):
 
   # turn environ into -e docker args
   if environ:
-    for k, v in environ.iteritems():
+    for k, v in environ.items():
       docker_cmdline += ['-e', '%s=%s' % (k, v)]
 
   # set working directory
@@ -140,7 +142,7 @@ def cloud_to_cloud_jobspec(language,
       '--num_channels_per_server=%s' % num_channels_per_server,
       '--metrics_port=%s' % metrics_port
   ]))
-  print cmdline
+  print(cmdline)
   cwd = language.client_cwd
   environ = language.global_env()
   if docker_image:
@@ -287,7 +289,7 @@ try:
     (server_host, server_port) = server[1].split(':')
     server_addresses[server_name] = (server_host, server_port)
 
-  for server_name, server_address in server_addresses.iteritems():
+  for server_name, server_address in server_addresses.items():
     (server_host, server_port) = server_address
     for language in languages:
       test_job = cloud_to_cloud_jobspec(
@@ -302,7 +304,7 @@ try:
       jobs.append(test_job)
 
   if not jobs:
-    print 'No jobs to run.'
+    print('No jobs to run.')
     for image in docker_images.itervalues():
       dockerjob.remove_image(image, skip_nonexistent=True)
     sys.exit(1)
@@ -317,12 +319,12 @@ try:
 
 finally:
   # Check if servers are still running.
-  for server, job in server_jobs.iteritems():
+  for server, job in server_jobs.items():
     if not job.is_running():
-      print 'Server "%s" has exited prematurely.' % server
+      print('Server "%s" has exited prematurely.' % server)
 
   dockerjob.finish_jobs([j for j in server_jobs.itervalues()])
 
   for image in docker_images.itervalues():
-    print 'Removing docker image %s' % image
+    print('Removing docker image %s' % image)
     dockerjob.remove_image(image)
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 3fa838c2ed..59d2cad856 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -30,6 +30,8 @@
 
 """Run tests in parallel."""
 
+from __future__ import print_function
+
 import argparse
 import ast
 import collections
@@ -48,7 +50,7 @@ import sys
 import tempfile
 import traceback
 import time
-import urllib2
+from six.moves import urllib
 import uuid
 
 import jobset
@@ -93,7 +95,7 @@ class Config(object):
                        would like to run
     """
     actual_environ = self.environ.copy()
-    for k, v in environ.iteritems():
+    for k, v in environ.items():
       actual_environ[k] = v
     return jobset.JobSpec(cmdline=self.tool_prefix + cmdline,
                           shortname=shortname,
@@ -202,7 +204,7 @@ class CLanguage(object):
                                             flaky=target.get('flaky', False),
                                             environ=env))
         elif self.args.regex == '.*' or self.platform == 'windows':
-          print '\nWARNING: binary not found, skipping', binary
+          print('\nWARNING: binary not found, skipping', binary)
     return sorted(out)
 
   def make_targets(self):
@@ -393,7 +395,7 @@ class PythonLanguage(object):
     return [self.config.job_spec(
         config.run,
         timeout_seconds=5*60,
-        environ=dict(environment.items() +
+        environ=dict(list(environment.items()) +
                      [('GRPC_PYTHON_TESTRUNNER_FILTER', suite_name)]),
         shortname='%s.test.%s' % (config.name, suite_name),)
         for suite_name in tests_json
@@ -764,7 +766,7 @@ def _windows_arch_option(arch):
   elif arch == 'x64':
     return '/p:Platform=x64'
   else:
-    print 'Architecture %s not supported.' % arch
+    print('Architecture %s not supported.' % arch)
     sys.exit(1)
 
 
@@ -782,11 +784,11 @@ def _check_arch_option(arch):
     elif runtime_arch == '32bit' and arch == 'x86':
       return
     else:
-      print 'Architecture %s does not match current runtime architecture.' % arch
+      print('Architecture %s does not match current runtime architecture.' % arch)
       sys.exit(1)
   else:
     if args.arch != 'default':
-      print 'Architecture %s not supported on current platform.' % args.arch
+      print('Architecture %s not supported on current platform.' % args.arch)
       sys.exit(1)
 
 
@@ -800,7 +802,7 @@ def _windows_build_bat(compiler):
   elif compiler == 'vs2010':
     return 'vsprojects\\build_vs2010.bat'
   else:
-    print 'Compiler %s not supported.' % compiler
+    print('Compiler %s not supported.' % compiler)
     sys.exit(1)
 
 
@@ -814,7 +816,7 @@ def _windows_toolset_option(compiler):
   elif compiler == 'vs2010':
     return '/p:PlatformToolset=v100'
   else:
-    print 'Compiler %s not supported.' % compiler
+    print('Compiler %s not supported.' % compiler)
     sys.exit(1)
 
 
@@ -825,7 +827,7 @@ def _docker_arch_suffix(arch):
   elif arch == 'x86':
     return 'x86'
   else:
-    print 'Architecture %s not supported with current settings.' % arch
+    print('Architecture %s not supported with current settings.' % arch)
     sys.exit(1)
 
 
@@ -941,7 +943,7 @@ for spec in args.update_submodules:
     branch = spec[1]
   cwd = 'third_party/%s' % submodule
   def git(cmd, cwd=cwd):
-    print 'in %s: git %s' % (cwd, cmd)
+    print('in %s: git %s' % (cwd, cmd))
     subprocess.check_call('git %s' % cmd, cwd=cwd, shell=True)
   git('fetch')
   git('checkout %s' % branch)
@@ -952,8 +954,8 @@ 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.'
+    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
@@ -980,18 +982,18 @@ for l in languages:
 language_make_options=[]
 if any(language.make_options() for language in languages):
   if not 'gcov' in args.config and len(languages) != 1:
-    print 'languages with custom make options cannot be built simultaneously with other languages'
+    print('languages with custom make options cannot be built simultaneously with other languages')
     sys.exit(1)
   else:
     language_make_options = next(iter(languages)).make_options()
 
 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.'
+    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)
 
   dockerfile_dirs = set([l.dockerfile_dir() for l in languages])
@@ -1075,7 +1077,7 @@ build_steps = list(set(
                    for l in languages
                    for cmdline in l.pre_build_steps()))
 if make_targets:
-  make_commands = itertools.chain.from_iterable(make_jobspec(build_config, list(targets), makefile) for (makefile, targets) in make_targets.iteritems())
+  make_commands = itertools.chain.from_iterable(make_jobspec(build_config, list(targets), makefile) for (makefile, targets) in make_targets.items())
   build_steps.extend(set(make_commands))
 build_steps.extend(set(
                    jobset.JobSpec(cmdline, environ=build_step_environ(build_config), timeout_seconds=None)
@@ -1092,13 +1094,13 @@ forever = args.forever
 
 def _shut_down_legacy_server(legacy_server_port):
   try:
-    version = int(urllib2.urlopen(
+    version = int(urllib.request.urlopen(
         'http://localhost:%d/version_number' % legacy_server_port,
         timeout=10).read())
   except:
     pass
   else:
-    urllib2.urlopen(
+    urllib.request.urlopen(
         'http://localhost:%d/quitquitquit' % legacy_server_port).read()
 
 
@@ -1120,29 +1122,29 @@ def _start_port_server(port_server_port):
   # if not running ==> start a new one
   # otherwise, leave it up
   try:
-    version = int(urllib2.urlopen(
+    version = int(urllib.request.urlopen(
         'http://localhost:%d/version_number' % port_server_port,
         timeout=10).read())
-    print 'detected port server running version %d' % version
+    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
+    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
+    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()
+      print('port_server version mismatch: killing the old one')
+      urllib.request.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
+    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)
@@ -1168,34 +1170,34 @@ def _start_port_server(port_server_port):
     waits = 0
     while True:
       if waits > 10:
-        print 'killing port server due to excessive start up waits'
+        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'
+        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,
+          urllib.request.urlopen('http://localhost:%d/get' % port_server_port,
                           timeout=1).read()
-          print 'last ditch attempt to contact port server succeeded'
+          print('last ditch attempt to contact port server succeeded')
           break
         except:
           traceback.print_exc()
           port_log = open(logfile, 'r').read()
-          print port_log
+          print(port_log)
           sys.exit(1)
       try:
-        urllib2.urlopen('http://localhost:%d/get' % port_server_port,
+        urllib.request.urlopen('http://localhost:%d/get' % port_server_port,
                         timeout=1).read()
-        print 'port server is up and ready'
+        print('port server is up and ready')
         break
       except socket.timeout:
-        print 'waiting for port_server: timeout'
+        print('waiting for port_server: timeout')
         traceback.print_exc();
         time.sleep(1)
         waits += 1
-      except urllib2.URLError:
-        print 'waiting for port_server: urlerror'
+      except urllib.error.URLError:
+        print('waiting for port_server: urlerror')
         traceback.print_exc();
         time.sleep(1)
         waits += 1
diff --git a/tools/run_tests/task_runner.py b/tools/run_tests/task_runner.py
index b42aa17cbb..2e3fa443b9 100755
--- a/tools/run_tests/task_runner.py
+++ b/tools/run_tests/task_runner.py
@@ -30,6 +30,8 @@
 
 """Runs selected gRPC test/build tasks."""
 
+from __future__ import print_function
+
 import argparse
 import atexit
 import jobset
@@ -111,7 +113,7 @@ build_jobs = []
 for target in targets:
   build_jobs.append(target.build_jobspec())
 if not build_jobs:
-  print 'Nothing to build.'
+  print('Nothing to build.')
   sys.exit(1)
 
 jobset.message('START', 'Building targets.', do_newline=True)