Manage runtime environments (#452)

* Add `Env` class that manages all runtime environments.
* Changed `NPKIT_DUMP_DIR` to `MSCCLPP_NPKIT_DUMP_DIR`.

test/executor_test.cc

@@ -5,6 +5,7 @@
 #include <unistd.h>
 
 #include <iostream>
+#include <mscclpp/env.hpp>
 #include <mscclpp/executor.hpp>
 #include <mscclpp/npkit/npkit.hpp>
 #include <mscclpp/utils.hpp>
@@ -109,7 +110,7 @@ int main(int argc, char* argv[]) {
   const std::string executionPlanPath = argv[2];
   const int niters = std::stoi(argv[3]);
   const int ngraphIters = std::stoi(argv[4]);
-  const char* npkitDumpDir = getenv("NPKIT_DUMP_DIR");
+  const char* npkitDumpDir = mscclpp::env()->npkitDumpDir.c_str();
   mscclpp::PacketType packetType = mscclpp::PacketType::LL16;
   if (argc == 6) {
     packetType = parsePacketType(argv[5]);

test/mp_unit/executor_tests.cc

@@ -4,6 +4,7 @@
 #include <mpi.h>
 
 #include <filesystem>
+#include <mscclpp/env.hpp>
 #include <mscclpp/npkit/npkit.hpp>
 
 #include "mp_unit_tests.hpp"
@@ -31,14 +32,14 @@ void ExecutorTest::SetUp() {
   bootstrap->initialize(id);
   std::shared_ptr<mscclpp::Communicator> communicator = std::make_shared<mscclpp::Communicator>(bootstrap);
   executor = std::make_shared<mscclpp::Executor>(communicator);
-  npkitDumpDir = getenv("NPKIT_DUMP_DIR");
-  if (npkitDumpDir != nullptr) {
+  npkitDumpDir = mscclpp::env()->npkitDumpDir;
+  if (npkitDumpDir != "") {
     NpKit::Init(gEnv->rank);
   }
 }
 
 void ExecutorTest::TearDown() {
-  if (npkitDumpDir != nullptr) {
+  if (npkitDumpDir != "") {
     NpKit::Dump(npkitDumpDir);
     NpKit::Shutdown();
   }

test/mp_unit/mp_unit_tests.hpp

@@ -170,6 +170,6 @@ class ExecutorTest : public MultiProcessTest {
   void TearDown() override;
 
   std::shared_ptr<mscclpp::Executor> executor;
-  const char* npkitDumpDir;
+  std::string npkitDumpDir;
 };
 #endif  // MSCCLPP_MP_UNIT_TESTS_HPP_