enable cloud_to_cloud tests with servers in a separate container
diff --git a/tools/run_tests/run_interop_tests.py b/tools/run_tests/run_interop_tests.py
index e9c4ce0..a2fb124 100755
--- a/tools/run_tests/run_interop_tests.py
+++ b/tools/run_tests/run_interop_tests.py
@@ -34,6 +34,10 @@
 import itertools
 import xml.etree.cElementTree as ET
 import jobset
+import os
+import subprocess
+import sys
+import time
 
 
 _CLOUD_TO_PROD_BASE_ARGS = [
@@ -41,6 +45,9 @@
     '--server_host=grpc-test.sandbox.google.com',
     '--server_port=443']
 
+_CLOUD_TO_CLOUD_BASE_ARGS = [
+    '--server_host_override=foo.test.google.fr']
+
 # TOOD(jtattermusch) wrapped languages use this variable for location 
 # of roots.pem. We might want to use GRPC_DEFAULT_SSL_ROOTS_FILE_PATH
 # supported by C core SslCredentials instead.
@@ -48,6 +55,7 @@
 
 # TODO(jtatttermusch) unify usage of --enable_ssl, --use_tls and --use_tls=true
 
+
 class CXXLanguage:
 
   def __init__(self):
@@ -58,6 +66,10 @@
     return (self.client_cmdline_base + _CLOUD_TO_PROD_BASE_ARGS +
             ['--enable_ssl','--use_prod_roots'])
 
+  def cloud_to_cloud_args(self):
+    return (self.client_cmdline_base + _CLOUD_TO_CLOUD_BASE_ARGS +
+            ['--enable_ssl'])
+
   def cloud_to_prod_env(self):
     return None
 
@@ -75,6 +87,10 @@
     return (self.client_cmdline_base + _CLOUD_TO_PROD_BASE_ARGS +
             ['--use_tls'])
 
+  def cloud_to_cloud_args(self):
+    return (self.client_cmdline_base + _CLOUD_TO_CLOUD_BASE_ARGS +
+            ['--use_tls', '--use_test_ca'])
+
   def cloud_to_prod_env(self):
     return _SSL_CERT_ENV
 
@@ -92,6 +108,10 @@
     return (self.client_cmdline_base + _CLOUD_TO_PROD_BASE_ARGS +
             ['--use_tls=true'])
 
+  def cloud_to_cloud_args(self):
+    return (self.client_cmdline_base + _CLOUD_TO_CLOUD_BASE_ARGS +
+            ['--use_tls=true', '--use_test_ca=true'])
+
   def cloud_to_prod_env(self):
     return _SSL_CERT_ENV
 
@@ -109,6 +129,10 @@
     return (self.client_cmdline_base + _CLOUD_TO_PROD_BASE_ARGS +
             ['--use_tls'])
 
+  def cloud_to_cloud_args(self):
+    return (self.client_cmdline_base + _CLOUD_TO_CLOUD_BASE_ARGS +
+            ['--use_tls', '--use_test_ca'])
+
   def cloud_to_prod_env(self):
     return _SSL_CERT_ENV
 
@@ -126,6 +150,10 @@
     return (self.client_cmdline_base + _CLOUD_TO_PROD_BASE_ARGS +
             ['--use_tls'])
 
+  def cloud_to_cloud_args(self):
+    return (self.client_cmdline_base + _CLOUD_TO_CLOUD_BASE_ARGS +
+            ['--use_tls', '--use_test_ca'])
+
   def cloud_to_prod_env(self):
     return _SSL_CERT_ENV
 
@@ -142,6 +170,10 @@
     'ruby' : RubyLanguage(),
 }
 
+# languages supported as cloud_to_cloud servers 
+# TODO(jtattermusch): enable other languages as servers as well
+_SERVERS = { 'c++' : 8010, 'node' : 8040, 'csharp': 8070 }
+
 # TODO(jtattermusch): add empty_stream once C++ start supporting it.
 # TODO(jtattermusch): add support for auth tests.
 _TEST_CASES = ['large_unary', 'empty_unary', 'ping_pong',
@@ -149,6 +181,7 @@
                'cancel_after_begin', 'cancel_after_first_response',
                'timeout_on_sleeping_server']
 
+
 def cloud_to_prod_jobspec(language, test_case):
   """Creates jobspec for cloud-to-prod interop test"""
   cmdline = language.cloud_to_prod_args() + ['--test_case=%s' % test_case]
@@ -160,34 +193,138 @@
           timeout_seconds=60)
   return test_job
 
+
+def cloud_to_cloud_jobspec(language, test_case, server_name, server_host,
+                           server_port):
+  """Creates jobspec for cloud-to-cloud interop test"""
+  cmdline = language.cloud_to_cloud_args() + ['--test_case=%s' % test_case,
+     '--server_host=%s' % server_host,
+     '--server_port=%s' % server_port ]
+  test_job = jobset.JobSpec(
+          cmdline=cmdline,
+          cwd=language.client_cwd,
+          shortname="cloud_to_cloud:%s:%s_server:%s" % (language, server_name,
+                                                 test_case),
+          timeout_seconds=60)
+  return test_job
+
 argp = argparse.ArgumentParser(description='Run interop tests.')
 argp.add_argument('-l', '--language',
                   choices=['all'] + sorted(_LANGUAGES),
                   nargs='+',
-                  default=['all'])
+                  default=['all'],
+                  help='Clients to run.')
+argp.add_argument('-j', '--jobs', default=24, type=int)
+argp.add_argument('--cloud_to_prod',
+                  default=False,
+                  action='store_const',
+                  const=True,
+                  help='Run cloud_to_prod tests.')
+argp.add_argument('-s', '--server',
+                  choices=['all'] + sorted(_SERVERS),
+                  action='append',
+                  help='Run cloud_to_cloud servers in a separate docker ' +
+                       'image. Servers can only be started automatically if ' +
+                       '--use_docker option is enabled.',
+                  default=[])
+argp.add_argument('--override_server',
+                  action='append',
+                  type=lambda kv: kv.split("="),
+                  help='Use servername=HOST:PORT to explicitly specify a server. E.g. csharp=localhost:50000',
+                  default=[])
+argp.add_argument('-t', '--travis',
+                  default=False,
+                  action='store_const',
+                  const=True)
+argp.add_argument('--use_docker',
+                  default=False,
+                  action='store_const',
+                  const=True,
+                  help='Run all the interop tests under docker. That provides ' +
+                  'additional isolation and prevents the need to install ' +
+                  'language specific prerequisites. Only available on Linux.')
 args = argp.parse_args()
 
+servers = set(s for s in itertools.chain.from_iterable(_SERVERS.iterkeys()
+                                                       if x == 'all' else [x]
+                                                       for x in args.server))
+
+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.'
+    time.sleep(5)
+
+  child_argv = [ arg for arg in sys.argv if not arg == '--use_docker' ]
+  run_tests_cmd = ('tools/run_tests/run_interop_tests.py %s' %
+                   " ".join(child_argv[1:]))
+
+  # cmdline args to pass to the container running servers.
+  servers_extra_docker_args = ''
+  server_port_tuples = ''
+  for server in servers:
+    port = _SERVERS[server]
+    servers_extra_docker_args += ' -p %s' % port
+    servers_extra_docker_args += ' -e SERVER_PORT_%s=%s' % (server.replace("+", "x"), port)
+    server_port_tuples += ' %s:%s' % (server, port)
+
+  env = os.environ.copy()
+  env['RUN_TESTS_COMMAND'] = run_tests_cmd
+  env['SERVERS_DOCKER_EXTRA_ARGS'] = servers_extra_docker_args
+  env['SERVER_PORT_TUPLES'] = server_port_tuples
+  if not args.travis:
+    env['TTY_FLAG'] = '-t'  # enables Ctrl-C when not on Jenkins.
+
+  subprocess.check_call(['tools/jenkins/build_docker_and_run_interop_tests.sh'],
+                        shell=True,
+                        env=env)
+  sys.exit(0)
+
 languages = set(_LANGUAGES[l]
                 for l in itertools.chain.from_iterable(
                       _LANGUAGES.iterkeys() if x == 'all' else [x]
                       for x in args.language))
 
-# TODO(jtattermusch): make python script generate cmdline params for interop
-# tests. It's easier to manage than in a shell script.
 jobs = []
-jobNumber = 0
-for language in languages:
-  for test_case in _TEST_CASES:
-    test_job = cloud_to_prod_jobspec(language, test_case)
-    jobs.append(test_job)
-    jobNumber+=1
+if args.cloud_to_prod:
+  for language in languages:
+    for test_case in _TEST_CASES:
+      test_job = cloud_to_prod_jobspec(language, test_case)
+      jobs.append(test_job)
+
+# default servers to "localhost" and the default port
+server_addresses = dict((s, ("localhost", _SERVERS[s])) for s in servers)
+
+for server in args.override_server:
+  server_name = server[0]
+  (server_host, server_port) = server[1].split(":")
+  server_addresses[server_name] = (server_host, server_port)
+
+for server_name, server_address in server_addresses.iteritems():
+  (server_host, server_port) = server_address
+  for language in languages:
+    for test_case in _TEST_CASES:
+      test_job = cloud_to_cloud_jobspec(language,
+                                        test_case,
+                                        server_name,
+                                        server_host,
+                                        server_port)
+      jobs.append(test_job)
+
+if not jobs:
+  print "No jobs to run."
+  sys.exit(1)
 
 root = ET.Element('testsuites')
 testsuite = ET.SubElement(root, 'testsuite', id='1', package='grpc', name='tests')
 
-jobset.run(jobs, maxjobs=jobNumber, xml_report=testsuite)
+if jobset.run(jobs, newline_on_success=True, maxjobs=args.jobs, xml_report=testsuite):
+  jobset.message('SUCCESS', 'All tests passed', do_newline=True)
+else:
+  jobset.message('FAILED', 'Some tests failed', do_newline=True)
 
 tree = ET.ElementTree(root)
-tree.write('report.xml', encoding='UTF-8')
-
-
+tree.write('report.xml', encoding='UTF-8')
\ No newline at end of file