plugin engine: remove registration api and add env var

examples/plugins/engine/CMakeLists.txt

@@ -3,14 +3,22 @@
 # accompanying file Copyright.txt for details.
 #------------------------------------------------------------------------------#
 
+add_library(PluginEngineWriteExample
+  ExampleWritePlugin.cpp
+)
+target_link_libraries(PluginEngineWriteExample adios2::cxx11 adios2_core)
+
+add_library(PluginEngineReadExample
+  ExampleReadPlugin.cpp
+)
+target_link_libraries(PluginEngineReadExample adios2::cxx11 adios2_core)
+
 add_executable(examplePluginEngine_write
   examplePluginEngine_write.cpp
-  ExampleWritePlugin.h ExampleWritePlugin.cpp
 )
-target_link_libraries(examplePluginEngine_write adios2::cxx11 adios2_core)
+target_link_libraries(examplePluginEngine_write adios2::cxx11)
 
 add_executable(examplePluginEngine_read
   examplePluginEngine_read.cpp
-  ExampleReadPlugin.h ExampleReadPlugin.cpp
 )
-target_link_libraries(examplePluginEngine_read adios2::cxx11 adios2_core)
+target_link_libraries(examplePluginEngine_read adios2::cxx11)

examples/plugins/engine/ExampleReadPlugin.cpp

@@ -133,3 +133,17 @@ void ExampleReadPlugin::DoClose(const int transportIndex) {}
 } // end namespace engine
 } // end namespace core
 } // end namespace adios2
+
+extern "C" {
+
+adios2::core::engine::ExampleReadPlugin *EngineCreate(adios2::core::IO &io,
+                                                      const std::string &name,
+                                                      const adios2::Mode mode,
+                                                      adios2::helper::Comm comm)
+{
+    return new adios2::core::engine::ExampleReadPlugin(io, name, mode,
+                                                       comm.Duplicate());
+}
+
+void EngineDestroy(adios2::core::engine::ExampleReadPlugin *obj) { delete obj; }
+}

examples/plugins/engine/ExampleReadPlugin.h

@@ -80,4 +80,13 @@ class ExampleReadPlugin : public PluginEngineInterface
 } // end namespace engine
 } // end namespace core
 } // end namespace adios2
+
+extern "C" {
+
+adios2::core::engine::ExampleReadPlugin *
+EngineCreate(adios2::core::IO &io, const std::string &name,
+             const adios2::Mode mode, adios2::helper::Comm comm);
+void EngineDestroy(adios2::core::engine::ExampleReadPlugin *obj);
+}
+
 #endif /* EXAMPLEREADPLUGIN_H_ */

examples/plugins/engine/ExampleWritePlugin.cpp

@@ -113,3 +113,19 @@ void ExampleWritePlugin::WriteVarsFromIO()
 } // end namespace engine
 } // end namespace core
 } // end namespace adios2
+
+extern "C" {
+
+adios2::core::engine::ExampleWritePlugin *
+EngineCreate(adios2::core::IO &io, const std::string &name,
+             const adios2::Mode mode, adios2::helper::Comm comm)
+{
+    return new adios2::core::engine::ExampleWritePlugin(io, name, mode,
+                                                        comm.Duplicate());
+}
+
+void EngineDestroy(adios2::core::engine::ExampleWritePlugin *obj)
+{
+    delete obj;
+}
+}

examples/plugins/engine/ExampleWritePlugin.h

@@ -81,4 +81,13 @@ class ExampleWritePlugin : public PluginEngineInterface
 } // end namespace engine
 } // end namespace core
 } // end namespace adios2
+
+extern "C" {
+
+adios2::core::engine::ExampleWritePlugin *
+EngineCreate(adios2::core::IO &io, const std::string &name,
+             const adios2::Mode mode, adios2::helper::Comm comm);
+void EngineDestroy(adios2::core::engine::ExampleWritePlugin *obj);
+}
+
 #endif /* EXAMPLEWRITEPLUGIN_H_ */

examples/plugins/engine/examplePluginEngine_read.cpp

@@ -15,9 +15,6 @@
 #include <vector>
 
 #include "adios2.h"
-#include "adios2/engine/plugin/PluginEngine.h"
-
-#include "ExampleReadPlugin.h"
 
 void testStreaming(adios2::Engine &reader, std::vector<float> &myFloats,
                    adios2::Variable<float> &var)
@@ -58,10 +55,6 @@ int main(int argc, char *argv[])
 
     std::vector<float> myFloats = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
 
-    /** Register Plugin with the PluginEngine **/
-    adios2::core::engine::PluginEngine::RegisterPlugin<
-        adios2::core::engine::ExampleReadPlugin>("MyPlugin");
-
     try
     {
         /** ADIOS class factory of IO class objects */
@@ -73,7 +66,8 @@ int main(int argc, char *argv[])
 
         /** Engine derived class, spawned to start IO operations */
         io.SetEngine("Plugin");
-        io.SetParameters({{"PluginName", "MyPlugin"}});
+        io.SetParameters({{"PluginName", "ReadPlugin"}});
+        io.SetParameters({{"PluginLibrary", "PluginEngineRead"}});
         adios2::Engine reader = io.Open("TestPlugin", adios2::Mode::Read);
 
         auto var = io.InquireVariable<float>("data");

examples/plugins/engine/examplePluginEngine_write.cpp

@@ -15,9 +15,6 @@
 #include <vector>
 
 #include "adios2.h"
-#include "adios2/engine/plugin/PluginEngine.h"
-
-#include "ExampleWritePlugin.h"
 
 void testStreaming(adios2::Engine &writer, std::vector<float> &myFloats,
                    adios2::Variable<float> &var)
@@ -49,10 +46,6 @@ int main(int argc, char *argv[])
     std::vector<float> myFloats = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
     const std::size_t Nx = myFloats.size();
 
-    /** Register Plugin with the PluginEngine **/
-    adios2::core::engine::PluginEngine::RegisterPlugin<
-        adios2::core::engine::ExampleWritePlugin>("MyPlugin");
-
     try
     {
         /** ADIOS class factory of IO class objects */
@@ -69,7 +62,8 @@ int main(int argc, char *argv[])
 
         /** Engine derived class, spawned to start IO operations */
         io.SetEngine("Plugin");
-        io.SetParameters({{"PluginName", "MyPlugin"}});
+        io.SetParameters({{"PluginName", "WritePlugin"}});
+        io.SetParameters({{"PluginLibrary", "PluginEngineWrite"}});
         adios2::Engine writer = io.Open("TestPlugin", adios2::Mode::Write);
 
         if (streaming)

source/adios2/engine/plugin/PluginEngine.cpp

@@ -13,13 +13,14 @@
 #include "PluginEngineInterface.h"
 
 #include <functional>
-#include <map>
 #include <memory>
 #include <stdexcept>
 #include <utility>
 
 #include "adios2/helper/adiosDynamicBinder.h"
 
+#include <adios2sys/SystemTools.hxx>
+
 namespace adios2
 {
 namespace core
@@ -31,27 +32,12 @@ namespace engine
 
 struct PluginEngine::Impl
 {
-    using Registry =
-        std::map<std::string, std::pair<EngineCreateFun, EngineDestroyFun>>;
-    static Registry m_Registry;
-
-    std::string m_PluginName;
+    std::string m_PluginName = "UserPlugin";
     std::unique_ptr<helper::DynamicBinder> m_Binder;
     EngineCreateFun m_HandleCreate;
     EngineDestroyFun m_HandleDestroy;
     PluginEngineInterface *m_Plugin = nullptr;
 };
-PluginEngine::Impl::Registry PluginEngine::Impl::m_Registry;
-
-/******************************************************************************/
-
-void PluginEngine::RegisterPlugin(const std::string pluginName,
-                                  EngineCreateFun create,
-                                  EngineDestroyFun destroy)
-{
-    PluginEngine::Impl::m_Registry.emplace(pluginName,
-                                           std::make_pair(create, destroy));
-}
 
 /******************************************************************************/
 
@@ -80,56 +66,43 @@ void PluginEngine::EndStep() { m_Impl->m_Plugin->EndStep(); }
 void PluginEngine::Init()
 {
     auto paramPluginNameIt = m_IO.m_Parameters.find("PluginName");
-    if (paramPluginNameIt == m_IO.m_Parameters.end())
+    if (paramPluginNameIt != m_IO.m_Parameters.end())
+    {
+        m_Impl->m_PluginName = paramPluginNameIt->second;
+    }
+
+    std::string pluginPath;
+    adios2sys::SystemTools::GetEnv("ADIOS2_PLUGIN_PATH", pluginPath);
+
+    auto paramPluginLibraryIt = m_IO.m_Parameters.find("PluginLibrary");
+    if (paramPluginLibraryIt == m_IO.m_Parameters.end())
     {
-        throw std::invalid_argument("PluginEngine: PluginName must be "
-                                    "specified in engine parameters");
+        throw std::invalid_argument(
+            "PluginEngine: PluginLibrary must be specified in "
+            "engine parameters if no PluginName "
+            "is specified");
     }
-    m_Impl->m_PluginName = paramPluginNameIt->second;
+    std::string &pluginLibrary = paramPluginLibraryIt->second;
 
-    // First we check to see if we can find the plugin currently registerd
-    auto registryEntryIt =
-        PluginEngine::Impl::m_Registry.find(m_Impl->m_PluginName);
+    m_Impl->m_Binder.reset(
+        new helper::DynamicBinder(pluginLibrary, pluginPath));
 
-    if (registryEntryIt != PluginEngine::Impl::m_Registry.end())
+    m_Impl->m_HandleCreate = reinterpret_cast<EngineCreatePtr>(
+        m_Impl->m_Binder->GetSymbol("EngineCreate"));
+    if (!m_Impl->m_HandleCreate)
     {
-        m_Impl->m_HandleCreate = registryEntryIt->second.first;
-        m_Impl->m_HandleDestroy = registryEntryIt->second.second;
+        throw std::runtime_error("PluginEngine: Unable to locate "
+                                 "EngineCreate symbol in specified plugin "
+                                 "library");
     }
-    else
+
+    m_Impl->m_HandleDestroy = reinterpret_cast<EngineDestroyPtr>(
+        m_Impl->m_Binder->GetSymbol("EngineDestroy"));
+    if (!m_Impl->m_HandleDestroy)
     {
-        // It's not currently registered so try to load it from a shared
-        // library
-        //
-        auto paramPluginLibraryIt = m_IO.m_Parameters.find("PluginLibrary");
-        if (paramPluginLibraryIt == m_IO.m_Parameters.end())
-        {
-            throw std::invalid_argument(
-                "PluginEngine: PluginLibrary must be specified in "
-                "engine parameters if no PluginName "
-                "is specified");
-        }
-        std::string &pluginLibrary = paramPluginLibraryIt->second;
-
-        m_Impl->m_Binder.reset(new helper::DynamicBinder(pluginLibrary));
-
-        m_Impl->m_HandleCreate = reinterpret_cast<EngineCreatePtr>(
-            m_Impl->m_Binder->GetSymbol("EngineCreate"));
-        if (!m_Impl->m_HandleCreate)
-        {
-            throw std::runtime_error("PluginEngine: Unable to locate "
-                                     "EngineCreate symbol in specified plugin "
-                                     "library");
-        }
-
-        m_Impl->m_HandleDestroy = reinterpret_cast<EngineDestroyPtr>(
-            m_Impl->m_Binder->GetSymbol("EngineDestroy"));
-        if (!m_Impl->m_HandleDestroy)
-        {
-            throw std::runtime_error("PluginEngine: Unable to locate "
-                                     "EngineDestroy symbol in specified plugin "
-                                     "library");
-        }
+        throw std::runtime_error("PluginEngine: Unable to locate "
+                                 "EngineDestroy symbol in specified plugin "
+                                 "library");
     }
 }
 

source/adios2/engine/plugin/PluginEngine.h

@@ -18,14 +18,12 @@
 #include <memory>      // for unique_ptr
 #include <string>      // for string
 #include <type_traits> // for add_pointer
-#include <vector>      // for vector
 
 #include "adios2/common/ADIOSMacros.h"
 #include "adios2/common/ADIOSTypes.h"
 #include "adios2/core/Engine.h"
 #include "adios2/core/IO.h"
 #include "adios2/core/Variable.h"
-#include "adios2/core/VariableCompound.h"
 #include "adios2/helper/adiosComm.h"
 
 namespace adios2
@@ -49,23 +47,6 @@ class PluginEngine : public Engine
     using EngineDestroyFun =
         std::function<std::remove_pointer<EngineDestroyPtr>::type>;
 
-    static void RegisterPlugin(const std::string pluginName,
-                               EngineCreateFun create,
-                               EngineDestroyFun destroy);
-    static void RegisterPlugin(const std::string pluginName,
-                               EngineCreatePtr create, EngineDestroyPtr destroy)
-    {
-        RegisterPlugin(pluginName, EngineCreateFun(create),
-                       EngineDestroyFun(destroy));
-    }
-
-    // This is just a shortcut method to handle the case where the class type is
-    // directly available to the caller so a simple new and delete call is
-    // sufficient to create and destroy the engine object
-    template <typename T>
-    static void RegisterPlugin(const std::string name);
-
-public:
     PluginEngine(IO &io, const std::string &name, const Mode mode,
                  helper::Comm comm);
     virtual ~PluginEngine();
@@ -99,6 +80,4 @@ class PluginEngine : public Engine
 } // end namespace core
 } // end namespace adios2
 
-#include "PluginEngine.inl"
-
 #endif /* ADIOS2_ENGINE_PLUGIN_PLUGINENGINE_H_ */