Add st2tests.config.coord_opts_as_env_vars for itests

Integration tests need to start subprocesses that use the
same redis as the test. This matters when running under
pantsbuild, because pants runs several instances of pytest
in parallel. This PR prepares to add support, to disambiguate
test runs--similar to the database logic--using the env var:
ST2TESTS_PARALLEL_SLOT.
In any case, when an integration test runs production
code in a subprocess, the production code does not use--
and should not use--any ST2TESTS_* vars, meaning the
subprocess ends up using what is configured in the conf
file instead of the (planned) parallel-safe coordinator.

Thanks to a new-ish oslo_config feature, we can now
update config via env variables. So, make use of that
in integration tests to override the conf-file provided
values with test-provided values.

st2api/tests/integration/test_gunicorn_configs.py

@@ -43,6 +43,7 @@ def test_st2api_wsgi_entry_point(self):
         env = os.environ.copy()
         env["ST2_CONFIG_PATH"] = ST2_CONFIG_PATH
         env.update(st2tests.config.db_opts_as_env_vars())
+        env.update(st2tests.config.coord_opts_as_env_vars())
         process = subprocess.Popen(cmd, env=env, shell=True, preexec_fn=os.setsid)
         try:
             self.add_process(process=process)
@@ -63,6 +64,7 @@ def test_st2auth(self):
         env = os.environ.copy()
         env["ST2_CONFIG_PATH"] = ST2_CONFIG_PATH
         env.update(st2tests.config.db_opts_as_env_vars())
+        env.update(st2tests.config.coord_opts_as_env_vars())
         process = subprocess.Popen(cmd, env=env, shell=True, preexec_fn=os.setsid)
         try:
             self.add_process(process=process)

st2common/tests/integration/test_register_content_script.py

@@ -212,4 +212,5 @@ def test_register_recreate_virtualenvs(self):
     def _run_command(cmd):
         env = os.environ.copy()
         env.update(st2tests.config.db_opts_as_env_vars())
+        env.update(st2tests.config.coord_opts_as_env_vars())
         return run_command(cmd=cmd, env=env)

st2common/tests/integration/test_service_setup_log_level_filtering.py

@@ -231,6 +231,7 @@ def _start_process(config_path, env=None):
         cwd = os.path.abspath(cwd)
         env = env or os.environ.copy()
         env.update(st2tests.config.db_opts_as_env_vars())
+        env.update(st2tests.config.coord_opts_as_env_vars())
         process = subprocess.Popen(
             cmd,
             env=env,

st2reactor/tests/integration/test_garbage_collector.py

@@ -277,6 +277,7 @@ def _start_garbage_collector(self):
         subprocess = concurrency.get_subprocess_module()
         env = os.environ.copy()
         env.update(st2tests.config.db_opts_as_env_vars())
+        env.update(st2tests.config.coord_opts_as_env_vars())
         process = subprocess.Popen(
             CMD_INQUIRY,
             stdout=subprocess.PIPE,

st2reactor/tests/integration/test_sensor_container.py

@@ -246,6 +246,7 @@ def _start_sensor_container(self, cmd=DEFAULT_CMD):
         subprocess = concurrency.get_subprocess_module()
         env = os.environ.copy()
         env.update(st2tests.config.db_opts_as_env_vars())
+        env.update(st2tests.config.coord_opts_as_env_vars())
         print("Using command: %s" % (" ".join(cmd)))
         process = subprocess.Popen(
             cmd,

st2tests/st2tests/config.py

@@ -165,6 +165,13 @@ def _override_coordinator_opts(noop=False):
     CONF.set_override(name="lock_timeout", override=1, group="coordination")
 
 
+def coord_opts_as_env_vars() -> Dict[str, str]:
+    env = {}
+    if CONF.coordination.url is not None:
+        env["ST2_COORDINATION__URL"] = CONF.coordination.url
+    return env
+
+
 def _override_workflow_engine_opts():
     cfg.CONF.set_override("retry_stop_max_msec", 200, group="workflow_engine")
     cfg.CONF.set_override("retry_wait_fixed_msec", 100, group="workflow_engine")