SERVER-29008 Set TestData.numTestClients property in resmoke.py.

Forwards the value for resmoke.py's --numClientsPerFixture command line
option to the mongo shell running the test. This enables the fuzzer to
know if there are concurrent clients running the test.

(cherry picked from commit 835a13294a78486e0d5458e8814895ea76bf5f7a)

2 files changed, 19 insertions, 10 deletions

diff --git a/buildscripts/resmokelib/core/programs.py b/buildscripts/resmokelib/core/programs.py
index d94cd438ee0..63e2b12de87 100644
--- a/buildscripts/resmokelib/core/programs.py
+++ b/buildscripts/resmokelib/core/programs.py
@@ -116,7 +116,7 @@ def mongos_program(logger, executable=None, process_kwargs=None, **kwargs):
 
 
 def mongo_shell_program(logger, executable=None, connection_string=None, filename=None,
-                        process_kwargs=None, isMainTest=True, **kwargs):
+                        process_kwargs=None, **kwargs):
     """
     Returns a Process instance that starts a mongo shell with arguments
     constructed from 'kwargs'.
@@ -148,7 +148,6 @@ def mongo_shell_program(logger, executable=None, connection_string=None, filenam
             # Only use 'opt_default' if the property wasn't set in the YAML configuration.
             test_data[opt_name] = opt_default
 
-    test_data["isMainTest"] = isMainTest
     global_vars["TestData"] = test_data
 
     # Pass setParameters for mongos and mongod through TestData. The setParameter parsing in
diff --git a/buildscripts/resmokelib/testing/testcases.py b/buildscripts/resmokelib/testing/testcases.py
index 78110ff680d..44bb0d767ea 100644
--- a/buildscripts/resmokelib/testing/testcases.py
+++ b/buildscripts/resmokelib/testing/testcases.py
@@ -344,9 +344,6 @@ class JSTestCase(TestCase):
         test_data = global_vars.get("TestData", {}).copy()
         test_data["minPort"] = core.network.PortAllocator.min_test_port(fixture.job_num)
         test_data["maxPort"] = core.network.PortAllocator.max_test_port(fixture.job_num)
-        # Marks the main test when multiple test clients are run concurrently, to notify the test
-        # of any code that should only be run once. If there is only one client, it is the main one.
-        test_data["isMainTest"] = True
 
         global_vars["TestData"] = test_data
         self.shell_options["global_vars"] = global_vars
@@ -419,19 +416,32 @@ class JSTestCase(TestCase):
                     raise t._get_exception()
 
     def _make_process(self, logger=None, thread_id=0):
+        # Since _make_process() is called by each thread, we make a shallow copy of the mongo shell
+        # options to avoid modifying the shared options for the JSTestCase.
+        shell_options = self.shell_options.copy()
+        global_vars = shell_options["global_vars"].copy()
+        test_data = global_vars["TestData"].copy()
+
+        # We set a property on TestData to mark the main test when multiple clients are going to run
+        # concurrently in case there is logic within the test that must execute only once. We also
+        # set a property on TestData to indicate how many clients are going to run the test so they
+        # can avoid executing certain logic when there may be other operations running concurrently.
+        is_main_test = thread_id == 0
+        test_data["isMainTest"] = is_main_test
+        test_data["numTestClients"] = self.num_clients
+
+        global_vars["TestData"] = test_data
+        shell_options["global_vars"] = global_vars
+
         # If logger is none, it means that it's not running in a thread and thus logger should be
         # set to self.logger.
         logger = utils.default_if_none(logger, self.logger)
-        is_main_test = True
-        if thread_id > 0:
-            is_main_test = False
         return core.programs.mongo_shell_program(
             logger,
             executable=self.shell_executable,
             filename=self.js_filename,
             connection_string=self.fixture.get_driver_connection_url(),
-            isMainTest=is_main_test,
-            **self.shell_options)
+            **shell_options)
 
     def _run_test_in_thread(self, thread_id):
         # Make a logger for each thread.