#1550 document and test order of parsing arguments passed from cli, f…

…ile and appConfig

docs/md/tutorial.md

@@ -65,6 +65,8 @@ int main(int argc, char** argv) {
 
 It is worth noting that if you run your application with any of vt's command-line arguments and at the same time you define and pass `AppConfig` to `vt::initialize`, CLI arguments have a higher priority. In other words, if you predefine in source code and give from the command line the same vt's argument, but with a different value, the program will use the CLI one.
 
+There is also an option to use configuration file. Refer to CLI11 documentation for details https://cliutils.github.io/CLI11/book/chapters/config.html. Important thing to remember - CLI11 processes configuration file before command line arguments, so in the end command line arguments might overwrite values defined in configuration file.
+
 \section tutorial-walkthrough Tutorial Code Snippets
 
 This page walks through the tutorial that exists in the source code. See

src/vt/configs/arguments/args.cc

@@ -716,7 +716,7 @@ std::tuple<int, std::string> ArgConfig::parse(
     return parseToConfig(argc, argv, config_);
   }
 
-  // if user defines appConfig, parse into temporary config for later comparison.
+  // If user defines appConfig, parse into temporary config for later comparison.
   AppConfig config{*appConfig};
   auto const parse_result = parseToConfig(argc, argv, config);
 

tests/unit/runtime/test_initialization.cc

@@ -47,6 +47,8 @@
 
 #include <vt/collective/startup.h>
 
+#include <fstream>
+
 namespace vt { namespace tests { namespace unit {
 
 struct TestInitialization : TestParallelHarness { };
@@ -161,4 +163,93 @@ TEST_F(TestInitialization, test_initialize_with_args_and_appconfig) {
   EXPECT_EQ(custom_argv[2], nullptr);
 }
 
+TEST_F(TestInitialization, test_initialize_with_file_and_args) {
+  MPI_Comm comm = MPISingletonMultiTest::Get()->getComm();
+
+  static char prog_name[]{"vt_program"};
+  static char cli_argument[]{"--cli_argument=100"};
+  static char vt_no_terminate[]{"--vt_no_terminate"};
+  static char vt_lb_name[]{"--vt_lb_name=RotateLB"};
+  static char vt_input_config[]{"--vt_input_config=test_cfg.toml"};
+
+  std::vector<char *> custom_args;
+  custom_args.emplace_back(prog_name);
+  custom_args.emplace_back(cli_argument);
+  custom_args.emplace_back(vt_no_terminate);
+  custom_args.emplace_back(vt_input_config);
+  custom_args.emplace_back(vt_lb_name);
+  custom_args.emplace_back(nullptr);
+
+  int custom_argc = custom_args.size() - 1;
+  char **custom_argv = custom_args.data();
+
+  EXPECT_EQ(custom_argc, 5);
+
+  int this_rank;
+  MPI_Comm_rank(comm, &this_rank);
+  if (this_rank == 0) {
+    std::ofstream cfg_file_{"test_cfg.toml", std::ofstream::out | std::ofstream::trunc};
+    cfg_file_ << "vt_lb_name = RandomLB\n";
+    cfg_file_.close();
+  }
+  MPI_Barrier(comm);
+
+  vt::initialize(custom_argc, custom_argv, no_workers, true, &comm);
+
+  EXPECT_EQ(theConfig()->prog_name, "vt_program");
+  EXPECT_EQ(theConfig()->vt_no_terminate, true);
+  EXPECT_EQ(theConfig()->vt_lb_name, "RotateLB");
+
+  EXPECT_EQ(custom_argc, 2);
+  EXPECT_STREQ(custom_argv[0], "vt_program");
+  EXPECT_STREQ(custom_argv[1], "--cli_argument=100");
+  EXPECT_EQ(custom_argv[2], nullptr);
+}
+
+TEST_F(TestInitialization, test_initialize_with_file_args_and_appconfig) {
+  MPI_Comm comm = MPISingletonMultiTest::Get()->getComm();
+
+  static char prog_name[]{"vt_program"};
+  static char cli_argument[]{"--cli_argument=100"};
+  static char vt_no_terminate[]{"--vt_no_terminate"};
+  static char vt_lb_name[]{"--vt_lb_name=RotateLB"};
+  static char vt_input_config[]{"--vt_input_config=test_cfg.toml"};
+
+  std::vector<char*> custom_args;
+  custom_args.emplace_back(prog_name);
+  custom_args.emplace_back(cli_argument);
+  custom_args.emplace_back(vt_no_terminate);
+  custom_args.emplace_back(vt_input_config);
+  custom_args.emplace_back(vt_lb_name);
+  custom_args.emplace_back(nullptr);
+
+  int custom_argc = custom_args.size() - 1;
+  char** custom_argv = custom_args.data();
+
+  EXPECT_EQ(custom_argc, 5);
+
+  arguments::AppConfig appConfig{};
+  appConfig.vt_lb_name = "GreedyLB";
+
+  int this_rank;
+  MPI_Comm_rank(comm, &this_rank);
+  if (this_rank == 0) {
+    std::ofstream cfg_file_{"test_cfg.toml", std::ofstream::out | std::ofstream::trunc};
+    cfg_file_ << "vt_lb_name = RandomLB\n";
+    cfg_file_.close();
+  }
+  MPI_Barrier(comm);
+
+  vt::initialize(custom_argc, custom_argv, no_workers, true, &comm, &appConfig);
+
+  EXPECT_EQ(theConfig()->prog_name, "vt_program");
+  EXPECT_EQ(theConfig()->vt_no_terminate, true);
+  EXPECT_EQ(theConfig()->vt_lb_name, "RotateLB");
+
+  EXPECT_EQ(custom_argc, 2);
+  EXPECT_STREQ(custom_argv[0], "vt_program");
+  EXPECT_STREQ(custom_argv[1], "--cli_argument=100");
+  EXPECT_EQ(custom_argv[2], nullptr);
+}
+
 }}} // end namespace vt::tests::unit