python_plugin_common_interface.h

#ifndef _PYTHON_PLUGIN_BASE_INTERFACE_H
#define _PYTHON_PLUGIN_BASE_INTERFACE_H
/*
 * Fledge common plugin interface
 *
 * Copyright (c) 2019 Dianomic Systems
 *
 * Released under the Apache 2.0 Licence
 *
 * Author: Massimiliano Pinto, Amandeep Singh Arora
 */
 
#include <cctype>
#include <plugin_manager.h>
 
#define SHIM_SCRIPT_REL_PATH  "/python/fledge/plugins/common/shim/"
#define SHIM_SCRIPT_POSTFIX "_shim"
 
using namespace std;
 
class PythonModule
{
    public:
        PythonModule(PyObject* module,
                bool init,
                string name,
                string type,
                PyThreadState* state) :
            m_module(module),
            m_init(init),
            m_name(name),
            m_type(type),
            m_tState(state)
        {
        };
 
        ~PythonModule()
        {
            // Destroy loaded Python module
            Py_CLEAR(m_module);
            m_module = NULL;
        };
 
        void    setCategoryName(string category)
        {
            m_categoryName = category;
        };
 
        string& getCategoryName()
        {
            return m_categoryName;
        };
 
    public:
        PyObject* m_module;
        bool      m_init;
        string    m_name;
        string    m_type;
        PyThreadState*  m_tState;
        string    m_categoryName;
};
 
extern "C" {
// This is the map of Python object initialised in each 
// South, Notification, Filter  plugin interfaces
static map<string, PythonModule*> *pythonModules = new map<string, PythonModule*>();
// Map of PLUGIN_HANDLE objects, updated by plugin_init calls
static map<PLUGIN_HANDLE, PythonModule*> *pythonHandles = new map<PLUGIN_HANDLE, PythonModule*>();
 
// Global variable gPluginName set by PluginInterfaceInit:
// it has a different memory address when set/read by
// PluginInterfaceInit in South, Filter or Notification
// Only used in plugin_info_fn calls
static string gPluginName;
 
// Common methods to all plugin interfaces
static PLUGIN_INFORMATION *plugin_info_fn();
static PLUGIN_HANDLE plugin_init_fn(ConfigCategory *);
static void plugin_reconfigure_fn(PLUGIN_HANDLE*, const std::string&);
static void plugin_shutdown_fn(PLUGIN_HANDLE);
 
static void logErrorMessage();
static bool numpyImportError = false;
 
void PluginInterfaceCleanup(const string& pluginName)
{
    bool removePython = false;
 
    if (!pythonModules)
    {
        Logger::getLogger()->error("pythonModules map is NULL "
                       "in PluginInterfaceCleanup, plugin '%s'",
                       pluginName.c_str());
 
        return;
    }
 
    // Acquire GIL
    PyGILState_STATE state = PyGILState_Ensure();
 
    // Look for Python module, pluginName is the key
    auto it = pythonModules->find(pluginName);
    if (it != pythonModules->end())
    {
        // Remove Python 3.x environment?
        removePython = it->second->m_init;
 
        // Remove this element
        pythonModules->erase(it);
    }
 
    // Look for Python module handle
    for (auto h = pythonHandles->begin();
          h != pythonHandles->end(); )
    {
        // Compare pluginName with m_name
        if (h->second->m_name.compare(pluginName) == 0)
        {
            // Remove PythonModule object
            if (h->second->m_module)
            {
                Py_CLEAR(h->second->m_module);
                h->second->m_module = NULL;
            }
 
            // Remove PythonModule
            delete h->second;
            h->second = NULL;
 
            // Remove this element
            h = pythonHandles->erase(h);
        }
        else
        {
            ++h;
        }
    }
 
    // Remove PythonModule object
    if (it->second &&
        it->second->m_module)
    {
        Py_CLEAR(it->second->m_module);
        it->second->m_module = NULL;
    }
 
    // Remove all maps if empty
    if (pythonModules->size() == 0)
    {
        // Remove map object
        delete pythonModules;
    }
    if (pythonHandles->size() == 0)
    {
        // Remove map object
        delete pythonHandles;
    }
 
    if (removePython)
    {
        Logger::getLogger()->debug("Removing Python interpreter "
                       "started by plugin '%s'",
                       pluginName.c_str());
 
        // Cleanup Python 3.5
        Py_Finalize();
    }
    else
    {
        PyGILState_Release(state);
    }
 
    Logger::getLogger()->debug("PluginInterfaceCleanup succesfully "
                   "called for plugin '%s'",
                   pluginName.c_str());
}
 
static void* PluginInterfaceGetInfo()
{
    return (void *) plugin_info_fn;
}
 
void set_loglevel_in_python_module(PyObject *python_module, string s)
{
    string& _loglevel = Logger::getLogger()->getMinLevel();
    for (auto & c: _loglevel) c = toupper(c);
    const char *loglevel = _loglevel.c_str();
    
    PyObject* mod = python_module;
    if (mod != NULL)
    {
        PyObject* loggerObj = PyObject_GetAttrString(mod, "_LOGGER");
        if (loggerObj != NULL)
        {
            PyObject* method = PyObject_GetAttrString(loggerObj, "setLevel");
            if (method != NULL)
            {
                PyObject *args = PyTuple_New(1);
                PyObject *pValue = Py_BuildValue("s", loglevel);
                PyTuple_SetItem(args, 0, pValue);
                PyObject* retVal = PyObject_Call(method, args, NULL);
 
                Py_CLEAR(args);
                Py_CLEAR(method);
                Py_CLEAR(loggerObj);
                if (retVal != NULL)
                {
                    Logger::getLogger()->debug("%s: %s: _LOGGER.setLevel(%s) done successfully", __FUNCTION__, s.c_str(), loglevel);
                }
                else
                {
                    Logger::getLogger()->warn("%s: _LOGGER.setLevel(%s) failed", __FUNCTION__, loglevel);
                    if (PyErr_Occurred())
                    {       
                        logErrorMessage();
                        return;
                    }
                }
            }
            else
            {
                Logger::getLogger()->warn("%s: Method 'setLevel' not found", __FUNCTION__);
                Py_CLEAR(loggerObj);
            }
        }
        else
        {
            Logger::getLogger()->warn("%s: Object '_LOGGER' not found in python module", __FUNCTION__);
        }
    }
    else
        Logger::getLogger()->warn("%s: module is NULL", __FUNCTION__);
 
    PyErr_Clear();
}
 
const char *json_dumps(PyObject *json_dict)
{
    PyObject *rval;
    PyObject *mod, *method;
 
    PyGILState_STATE state = PyGILState_Ensure();
    if ((mod = PyImport_ImportModule("json")) != NULL)
    {
        if ((method = PyObject_GetAttrString(mod, "dumps")) != NULL)
        {
            PyObject *args = PyTuple_New(1);
            PyObject *pValue = Py_BuildValue("O", json_dict);
            PyTuple_SetItem(args, 0, pValue);
            
            rval = PyObject_Call(method, args, NULL);
            Py_CLEAR(args);
            Py_CLEAR(method);
            Py_CLEAR(mod);
            
            if (rval == NULL)
            {
                if (PyErr_Occurred())
                {
                    logErrorMessage();
                    return NULL;
                }
            }
            else
                Logger::getLogger()->info("%s:%d, rval type=%s", __FUNCTION__, __LINE__, (Py_TYPE(rval))->tp_name);
            
        }
        else
        {
            Logger::getLogger()->fatal("Method 'dumps' not found");
            Py_CLEAR(mod);
        }
        // Remove references
        
    }
    else
    {
        Logger::getLogger()->fatal("Failed to import module");
    }
 
    // Reset error
    PyErr_Clear();
 
    PyGILState_Release(state);
 
    const char *retVal = PyUnicode_AsUTF8(rval);
    Logger::getLogger()->debug("%s: retVal=%s", __FUNCTION__, retVal);
    
    return retVal;
}
 
 
PyObject *json_loads(const char *json_str)
{
PyObject *rval;
PyObject *mod, *method;
 
    PyGILState_STATE state = PyGILState_Ensure();
    if ((mod = PyImport_ImportModule("json")) != NULL)
    {
        if ((method = PyObject_GetAttrString(mod, "loads")) != NULL)
        {
            PyObject *args = PyTuple_New(1);
            PyObject *pValue = Py_BuildValue("s", json_str);
            PyTuple_SetItem(args, 0, pValue);
 
            Logger::getLogger()->debug("%s:%d: method=%p, args=%p, pValue=%p", __FUNCTION__, __LINE__, method, args, pValue);
            rval = PyObject_Call(method, args, NULL);
            Py_CLEAR(args);
            Py_CLEAR(method);
            Py_CLEAR(mod);
            
            if (rval == NULL)
            {
                if (PyErr_Occurred())
                {
                    logErrorMessage();
                    return NULL;
                }
            }
            else
                Logger::getLogger()->debug("%s:%d, rval type=%s", __FUNCTION__, __LINE__, (Py_TYPE(rval))->tp_name);
 
        }
        else
        {
            Logger::getLogger()->fatal("Method 'loads' not found");
            Py_CLEAR(mod);
        }
    }
    else
    {
        Logger::getLogger()->fatal("Failed to import module");
    }
 
    // Reset error
    PyErr_Clear();
 
    PyGILState_Release(state);
    
    return rval;
}
 
 
static PLUGIN_INFORMATION *Py2C_PluginInfo(PyObject* pyRetVal)
{
    // Create returnable PLUGIN_INFORMATION structure
    PLUGIN_INFORMATION *info = new PLUGIN_INFORMATION;
        info->options = 0;
 
    // these are borrowed references returned by PyDict_Next
    PyObject *dKey, *dValue;
    Py_ssize_t dPos = 0;
    
    PyObject* objectsRepresentation = PyObject_Repr(pyRetVal);
    const char* s = PyUnicode_AsUTF8(objectsRepresentation);
    Logger::getLogger()->debug("Py2C_PluginInfo(): plugin_info returned: %s", s);
    Py_CLEAR(objectsRepresentation);
 
    // dKey and dValue are borrowed references
    while (PyDict_Next(pyRetVal, &dPos, &dKey, &dValue))
    {
        const char* ckey = PyUnicode_AsUTF8(dKey);
        const char* cval = PyUnicode_AsUTF8(dValue);
        Logger::getLogger()->debug("%s:%d, key=%s, value=%s, dValue type=%s", __FUNCTION__, __LINE__, ckey, cval, (Py_TYPE(dValue))->tp_name);
 
        char *valStr = NULL;
        if (!PyDict_Check(dValue))
        {
            valStr = new char [string(cval).length()+1];
            std::strcpy (valStr, cval);
            Logger::getLogger()->debug("%s:%d, key=%s, value=%s, valStr=%s", __FUNCTION__, __LINE__, ckey, cval, valStr);
        }
 
        if(!strcmp(ckey, "name"))
        {
            info->name = valStr;
        }
        else if(!strcmp(ckey, "version"))
        {
            info->version = valStr;
        }
        else if(!strcmp(ckey, "mode"))
        {
            // Need to also handle mode values of the form "poll|control"
            stringstream ss(valStr); 
            string s;
 
            info->options = 0;
            
            // Tokenizing w.r.t. pipe '|'
            while(getline(ss, s, '|'))
            {
                Logger::getLogger()->debug("%s: mode: Found token %s", __FUNCTION__, s.c_str());
                if (s.compare("async")==0)
                {
                    info->options |= SP_ASYNC;
                }
                else if (s.compare("control")==0)
                {
                    info->options |= SP_CONTROL;
                }
                else if (s.compare("poll")==0)
                {
                    // Nothing to set
                }
                else if (s.compare("none")==0)
                {
                    // Ignore
                }
                else
                    Logger::getLogger()->warn("%s: mode: Unknown token/value %s", __FUNCTION__, s.c_str());
            }
 
            delete[] valStr;
        }
        else if(!strcmp(ckey, "type"))
        {
            info->type = valStr;
        }
        else if(!strcmp(ckey, "interface"))
        {
            info->interface = valStr;
        }
        else if(!strcmp(ckey, "config"))
        {            
            // if 'config' value is of dict type, convert it to string
            if (strcmp((Py_TYPE(dValue))->tp_name, "dict")==0)
            {
                PyObject* objectsRepresentation = PyObject_Repr(dValue);
                const char* s = PyUnicode_AsUTF8(objectsRepresentation);
                Logger::getLogger()->debug("Py2C_PluginInfo(): INPUT: config value=%s", s);
                Py_CLEAR(objectsRepresentation);
 
                info->config = json_dumps(dValue);
                Logger::getLogger()->info("Py2C_PluginInfo(): OUTPUT: config value=%s", info->config);
            }
            else
                info->config = valStr;
        }
        else
            Logger::getLogger()->info("%s:%d: Unexpected key %s", __FUNCTION__, __LINE__, ckey);
    }
 
    return info;
}
 
static PLUGIN_INFORMATION *plugin_info_fn()
{
    if (!pythonModules)
    {
        Logger::getLogger()->error("pythonModules map is NULL "
                       "in plugin_info_fn, plugin '%s'",
                       gPluginName.c_str());
        return NULL;
    }
 
    // Look for Python module for gPluginName key
    auto it = pythonModules->find(gPluginName);
    if (it == pythonModules->end() ||
        !it->second ||
        !it->second->m_module)
    {
        Logger::getLogger()->fatal("plugin_handle: plugin_info(): "
                       "pModule is NULL for plugin '%s'",
                       gPluginName.c_str());
        return NULL;
    }
    PyObject* pFunc; 
    PyGILState_STATE state = PyGILState_Ensure();
 
    // Fetch required method in loaded object
    pFunc = PyObject_GetAttrString(it->second->m_module, "plugin_info");
    if (!pFunc)
    {
        Logger::getLogger()->fatal("Cannot find method 'plugin_info' "
                       "in loaded python module '%s', m_module=%p",
                       gPluginName.c_str(), it->second->m_module);
    }
 
    if (!pFunc || !PyCallable_Check(pFunc))
    {
        // Failure
        if (PyErr_Occurred())
        {       
            logErrorMessage();
        }
 
        Logger::getLogger()->fatal("Cannot call method 'plugin_info' "
                       "in loaded python module '%s'",
                       gPluginName.c_str());
        Py_CLEAR(pFunc);
 
        PyGILState_Release(state);
        return NULL;
    }
 
    // Call Python method passing an object
    PyObject* pReturn = PyObject_CallFunction(pFunc, NULL);
 
    Py_CLEAR(pFunc);
 
    PLUGIN_INFORMATION *info = NULL;
 
    // Handle returned data
    if (!pReturn)
    {
        Logger::getLogger()->error("Called python script method 'plugin_info' "
                        ": error while getting result object, plugin '%s'",
                       gPluginName.c_str());
        logErrorMessage();
        info = NULL;
    }
    else
    {
        // Parse plugin information
        info = Py2C_PluginInfo(pReturn);
 
        // Remove pReturn object
        Py_CLEAR(pReturn);
    }
 
    if (info)
    {
        // bump interface version to atleast 2.x so that we are able to handle
        // list of readings from python plugins in plugin_poll
        if (info->interface[0] =='1' &&
            info->interface[1] == '.')
        {
            Logger::getLogger()->info("plugin_handle: plugin_info(): "
                           "Updating interface version "
                           "from '%s' to '2.0.0', plugin '%s'",
                           info->interface,
                           gPluginName.c_str());
            delete[] info->interface;
            char *valStr = new char[6];
            std::strcpy(valStr, "2.0.0");
            info->interface = valStr;
        }
 
        Logger::getLogger()->info("plugin_handle: plugin_info(): info={name=%s, "
                       "version=%s, options=%d, type=%s, interface=%s, config=%s}",
                       info->name,
                       info->version,
                       info->options,
                       info->type,
                       info->interface,
                       info->config);
    }
 
    PyGILState_Release(state);
 
    return info;
}
 
static PLUGIN_HANDLE plugin_init_fn(ConfigCategory *config)
{
    // Get plugin name
    string pName = config->getValue("plugin");
 
    if (!pythonModules)
    {
        Logger::getLogger()->error("pythonModules map is NULL "
                       "in plugin_init_fn, plugin '%s'",
                       pName.c_str());
        return NULL;
    }
 
    Logger::getLogger()->debug("plugin_handle: plugin_init(): "
                   "config->itemsToJSON()='%s'",
                   config->itemsToJSON().c_str());
 
    bool loadModule = false;
    bool reloadModule = false;
    bool pythonInitState = false;
    string loadPluginType;
 
    PythonModule* module = NULL;
    PyThreadState* newInterp = NULL;
 
    // Check wether plugin pName has been already loaded
    for (auto h = pythonHandles->begin();
          h != pythonHandles->end();
          ++h)
    {
        if (h->second->m_name.compare(pName) == 0)
        {
            Logger::getLogger()->debug("%s_plugin_init_fn: already loaded "
                           "a plugin with name '%s'. Loading a new ",
                           h->second->m_type.c_str(),
                           pName.c_str());
 
            // Set Python library loaded state
            pythonInitState = h->second->m_init;
 
            // Set plugin type
            loadPluginType = h->second->m_type;
 
            // Set load indicator
            loadModule = true;
        }
    }
 
    if (!loadModule)
    {
 
        // Plugin name not previously loaded: check current Python module
        // pName is the key
        auto it = pythonModules->find(pName);
        if (it == pythonModules->end())
        {
            Logger::getLogger()->debug("plugin_handle: plugin_init(): "
                           "pModule not found for plugin '%s': ",
                           pName.c_str());
 
            // Set plugin type
            PluginManager* pMgr = PluginManager::getInstance(); 
            PLUGIN_HANDLE tmp = pMgr->findPluginByName(pName);
            if (tmp)
            {
                PLUGIN_INFORMATION* pInfo = pMgr->getInfo(tmp);
                if (pInfo)
                {
                    loadPluginType = string(pInfo->type);
                }
            }
 
            // Set reload indicator
            reloadModule = true;
        }
        else
        {
            if (it->second && it->second->m_module)
            {
                // Just use current loaded module: no load or re-load action
                module = it->second;
 
                // Set Python library loaded state
                pythonInitState = it->second->m_init;
            }
            else
            {
                Logger::getLogger()->fatal("plugin_handle: plugin_init(): "
                               "found pModule is NULL for plugin '%s': ",
                               pName.c_str());
                return NULL;
            }
        }
    }
 
    Logger::getLogger()->info("%s:%d: loadModule=%s, reloadModule=%s", 
                                __FUNCTION__, __LINE__, loadModule?"TRUE":"FALSE", reloadModule?"TRUE":"FALSE");
 
    // Acquire GIL
    PyGILState_STATE state = PyGILState_Ensure();
 
    // Import Python module using a new interpreter
    if (loadModule || reloadModule)
    {
        string fledgePythonDir;
    
        string fledgeRootDir(getenv("FLEDGE_ROOT"));
        fledgePythonDir = fledgeRootDir + "/python";
 
        int argc = 2;
 
        // Set Python path for embedded Python 3.x
        // Get current sys.path - borrowed reference
        PyObject* sysPath = PySys_GetObject((char *)"path");
        PyList_Append(sysPath, PyUnicode_FromString((char *) fledgePythonDir.c_str()));
        
        // Set sys.argv for embedded Python 3.x
        wchar_t* argv[argc];
        argv[0] = Py_DecodeLocale("", NULL);
        argv[1] = Py_DecodeLocale(pName.c_str(), NULL);
        if (argc > 2)
        {
            argv[2] = Py_DecodeLocale(loadPluginType.c_str(), NULL);
        }
 
        // Set script parameters
        PySys_SetArgv(argc, argv);
 
        Logger::getLogger()->debug("%s_plugin_init_fn, %sloading plugin '%s', ",
                       loadPluginType.c_str(),
                       reloadModule ? "re-" : "", 
                       pName.c_str());
 
        // Import Python script
        PyObject *newObj = PyImport_ImportModule(pName.c_str());
 
        // Check result
        if (newObj)
        {
            // Create a new PythonModule
            PythonModule* newModule;
            if ((newModule = new PythonModule(newObj,
                              pythonInitState,
                              pName,
                              loadPluginType,
                              NULL)) == NULL)
            {
                // Release lock
                PyGILState_Release(state);
 
                Logger::getLogger()->fatal("plugin_handle: plugin_init(): "
                               "failed to create Python module "
                               "object, plugin '%s'",
                               pName.c_str());
                return NULL;
            }
 
            // Set module
            module = newModule;
        }
        else
        {
            logErrorMessage();
 
            // Release lock
            PyGILState_Release(state);
 
            Logger::getLogger()->fatal("plugin_handle: plugin_init(): "
                           "failed to import plugin '%s'",
                           pName.c_str());
            return NULL;
        }
    }
 
    Logger::getLogger()->debug("%s_plugin_init_fn for '%s', pModule '%p', ",
                   loadPluginType.c_str(),
                   module->m_name.c_str(),
                   module->m_module);
 
    Logger::getLogger()->debug("%s:%d: calling set_loglevel_in_python_module(), loglevel=%s", __FUNCTION__, __LINE__, Logger::getLogger()->getMinLevel().c_str());
    set_loglevel_in_python_module(module->m_module, module->m_name + " plugin_init");
    
    PyObject *config_dict = json_loads(config->itemsToJSON().c_str());
    
    // Call Python method passing an object
    PyObject* pReturn = PyObject_CallMethod(module->m_module,
                        "plugin_init",
                        "O",
                        config_dict);
 
    Py_CLEAR(config_dict);
 
    // Handle returned data
    if (!pReturn)
    {
        Logger::getLogger()->error("Called python script method plugin_init : "
                       "error while getting result object, plugin '%s'",
                       pName.c_str());
        logErrorMessage();
    }
    else
    {
        Logger::getLogger()->debug("plugin_handle: plugin_init(): "
                       "got handle from python plugin='%p', *handle %p, plugin '%s'",
                       pReturn,
                       &pReturn,
                       pName.c_str());
    }
 
    // Add the handle to handles map as key, PythonModule object as value
    std::pair<std::map<PLUGIN_HANDLE, PythonModule*>::iterator, bool> ret;
    if (pythonHandles)
    {
        // Add to handles map the PythonModule object
        ret = pythonHandles->insert(pair<PLUGIN_HANDLE, PythonModule*>
            ((PLUGIN_HANDLE)pReturn, module));
 
        if (ret.second)
        {
            Logger::getLogger()->debug("plugin_handle: plugin_init(): "
                           "handle %p of python plugin '%s' "
                           "added to pythonHandles map",
                           pReturn,
                           pName.c_str());
        }
        else
        {
            Logger::getLogger()->error("plugin_handle: plugin_init(): "
                           "failed to insert handle %p of "
                           "python plugin '%s' to pythonHandles map",
                           pReturn,
                           pName.c_str());
 
            Py_CLEAR(module->m_module);
            module->m_module = NULL;
            delete module;
            module = NULL;
 
            Py_CLEAR(pReturn);
            pReturn = NULL;
        }
    }
 
    // Release locks
    if (newInterp)
    {
        PyEval_ReleaseThread(newInterp);
    }
    else
    {
        PyGILState_Release(state);
    }
 
    return pReturn ? (PLUGIN_HANDLE) pReturn : NULL;
}
 
static void plugin_reconfigure_fn(PLUGIN_HANDLE* handle,
                  const std::string& config)
{
    Logger::getLogger()->debug("%s:%d: config=%s", __FUNCTION__, __LINE__, config.c_str());
    
    if (!handle)
    {
        Logger::getLogger()->fatal("plugin_handle: plugin_reconfigure(): "
                       "handle is NULL");
        return;
    }
 
    if (!pythonHandles)
    {
        Logger::getLogger()->error("pythonHandles map is NULL "
                       "in plugin_reconfigure, plugin handle '%p'",
                       handle);
        return;
    }
 
    // Look for Python module for handle key
    auto it = pythonHandles->find(*handle);
    if (it == pythonHandles->end() ||
        !it->second ||
        !it->second->m_module)
    {
        Logger::getLogger()->fatal("plugin_handle: plugin_reconfigure(): "
                       "pModule is NULL, plugin handle '%p'",
                       handle);
        return;
    }
 
    std::mutex mtx;
    PyObject* pFunc;
    lock_guard<mutex> guard(mtx);
    PyGILState_STATE state = PyGILState_Ensure();
 
    Logger::getLogger()->debug("plugin_handle: plugin_reconfigure(): "
                   "pModule=%p, *handle=%p, plugin '%s'",
                   it->second->m_module,
                   *handle,
                   it->second->m_name.c_str());
    
    if(config.compare("logLevel") == 0)
    {
        Logger::getLogger()->debug("calling set_loglevel_in_python_module() for updating loglevel");
        set_loglevel_in_python_module(it->second->m_module, it->second->m_name+" plugin_reconf");
        PyGILState_Release(state);
        return;
    }
    
    // Fetch required method in loaded object
    pFunc = PyObject_GetAttrString(it->second->m_module, "plugin_reconfigure");
    if (!pFunc)
    {
        Logger::getLogger()->fatal("Cannot find method 'plugin_reconfigure' "
                       "in loaded python module '%s'",
                       it->second->m_name.c_str());
    }
 
    if (!pFunc || !PyCallable_Check(pFunc))
    {
        // Failure
        if (PyErr_Occurred())
        {
            logErrorMessage();
        }
 
        Logger::getLogger()->fatal("Cannot call method plugin_reconfigure "
                       "in loaded python module '%s'",
                       it->second->m_name.c_str());
        Py_CLEAR(pFunc);
 
        PyGILState_Release(state);
        return;
    }
 
    Logger::getLogger()->debug("plugin_reconfigure with %s", config.c_str());
 
    PyObject *new_config_dict = json_loads(config.c_str());
 
    // Call Python method passing an object and a C string
    PyObject* pReturn = PyObject_CallFunction(pFunc,
                          "OO",
                          *handle,
                          new_config_dict);
 
    Py_CLEAR(pFunc);
    Py_CLEAR(new_config_dict);
 
    // Handle returned data
    if (!pReturn)
    {
        Logger::getLogger()->error("Called python script method plugin_reconfigure "
                       ": error while getting result object, plugin '%s'",
                       it->second->m_name.c_str());
        logErrorMessage();
        //*handle = NULL; // not sure if this should be treated as unrecoverable failure on python plugin side
    }
    else
    {
        // Save PythonModule
        PythonModule* currentModule = it->second;
 
        Py_CLEAR(*handle);
        *handle = pReturn;
 
        if (pythonHandles)
        {
            // Remove current handle from the pythonHandles map
            pythonHandles->erase(it);
 
            // Add the handle to handles map as key, PythonModule object as value
            std::pair<std::map<PLUGIN_HANDLE, PythonModule*>::iterator, bool> ret;
            ret = pythonHandles->insert(pair<PLUGIN_HANDLE, PythonModule*>
                ((PLUGIN_HANDLE)*handle, currentModule));
 
            Logger::getLogger()->debug("plugin_handle: plugin_reconfigure(): "
                           "updated handle %p of python plugin '%s'"
                           " in pythonHandles map",
                           *handle,
                           currentModule->m_name.c_str());
        }
        else
        {
            Logger::getLogger()->error("plugin_handle: plugin_reconfigure(): "
                           "failed to update handle %p of python plugin '%s'"
                           " in pythonHandles map",
                           *handle,
                           currentModule->m_name.c_str());
        }
    }
 
    PyGILState_Release(state);
}
 
static void logErrorMessage()
{
    PyObject* type;
    PyObject* value;
    PyObject* traceback;
 
    numpyImportError = false;
 
    PyErr_Fetch(&type, &value, &traceback);
    PyErr_NormalizeException(&type, &value, &traceback);
 
    PyObject* str_exc_value = PyObject_Repr(value);
    PyObject* pyExcValueStr = PyUnicode_AsEncodedString(str_exc_value, "utf-8", "Error ~");
    const char* pErrorMessage = value ?
                    PyBytes_AsString(pyExcValueStr) :
                    "no error description.";
    Logger::getLogger()->warn("logErrorMessage: Error '%s', plugin '%s'",
                   pErrorMessage,
                   gPluginName.c_str());
    
    // Check for numpy/pandas import errors
    const char *err1 = "implement_array_function method already has a docstring";
    const char *err2 = "cannot import name 'check_array_indexer' from 'pandas.core.indexers'";
 
    numpyImportError = strstr(pErrorMessage, err1) || strstr(pErrorMessage, err2);
    
    std::string fcn = "";
    fcn += "def get_pretty_traceback(exc_type, exc_value, exc_tb):\n";
    fcn += "    import sys, traceback\n";
    fcn += "    lines = []\n"; 
    fcn += "    lines = traceback.format_exception(exc_type, exc_value, exc_tb)\n";
    fcn += "    output = '\\n'.join(lines)\n";
    fcn += "    return output\n";
 
    PyRun_SimpleString(fcn.c_str());
    PyObject* mod = PyImport_ImportModule("__main__");
    if (mod != NULL) {
        PyObject* method = PyObject_GetAttrString(mod, "get_pretty_traceback");
        if (method != NULL) {
            PyObject* outStr = PyObject_CallObject(method, Py_BuildValue("OOO", type, value, traceback));
            if (outStr != NULL) {
                PyObject* tmp = PyUnicode_AsASCIIString(outStr);
                if (tmp != NULL) {
                    std::string pretty = PyBytes_AsString(tmp);
                    Logger::getLogger()->warn("%s", pretty.c_str());
                    Logger::getLogger()->printLongString(pretty.c_str());
                }
                Py_CLEAR(tmp);
            }
            Py_CLEAR(outStr);
        }
        Py_CLEAR(method);
    }
 
    // Reset error
    PyErr_Clear();
 
    // Remove references
    Py_CLEAR(type);
    Py_CLEAR(value);
    Py_CLEAR(traceback);
    Py_CLEAR(str_exc_value);
    Py_CLEAR(pyExcValueStr);
    Py_CLEAR(mod);
}
 
static void plugin_shutdown_fn(PLUGIN_HANDLE handle)
{
    if (!handle)
    {
        Logger::getLogger()->fatal("plugin_handle: plugin_shutdown_fn: "
                       "handle is NULL");
        return;
    }
 
    if (!pythonHandles)
    {
        Logger::getLogger()->error("pythonHandles map is NULL "
                       "in plugin_shutdown_fn, plugin handle '%p'",
                       handle);
        return;
    }
 
    // Look for Python module for handle key
    auto it = pythonHandles->find(handle);
    if (it == pythonHandles->end() ||
        !it->second ||
        !it->second->m_module)
    {
        Logger::getLogger()->fatal("plugin_handle: plugin_shutdown_fn: "
                       "pModule is NULL, plugin handle '%p'",
                       handle);
        return;
    }
 
    if (! Py_IsInitialized()) {
 
        Logger::getLogger()->debug("%s - Python environment not initialized, exiting from the function ", __FUNCTION__);
        return;
    }
 
    PyObject* pFunc; 
    PyGILState_STATE state = PyGILState_Ensure();
 
    // Fetch required method in loaded object
    pFunc = PyObject_GetAttrString(it->second->m_module, "plugin_shutdown");
    if (!pFunc)
    {
        Logger::getLogger()->fatal("Cannot find method 'plugin_shutdown' "
                       "in loaded python module '%s'",
                       it->second->m_name.c_str());
    }
 
    if (!pFunc || !PyCallable_Check(pFunc))
    {
        // Failure
        if (PyErr_Occurred())
        {
            logErrorMessage();
        }
 
        Logger::getLogger()->fatal("Cannot call method 'plugin_shutdown' "
                       "in loaded python module '%s'",
                       it->second->m_name.c_str());
        Py_CLEAR(pFunc);
 
        PyGILState_Release(state);
        return;
    }
 
    // Call Python method passing an object
    PyObject* pReturn = PyObject_CallFunction(pFunc,
                          "O",
                          handle);
 
    Py_CLEAR(pFunc);
 
 
    if (false) // no seperate python interpreter is used anymore for python plugins
    {
        // Switch to Interpreter thread
        PyThreadState* swapState = PyThreadState_Swap(it->second->m_tState);
 
        // Remove Python module
        Py_CLEAR(it->second->m_module);
        it->second->m_module = NULL;
 
        // Stop Interpreter thread
        Py_EndInterpreter(it->second->m_tState);
 
        Logger::getLogger()->debug("plugin_shutdown_fn: Py_EndInterpreter of '%p' "
                       "for plugin '%s'",
                       it->second->m_tState,
                       it->second->m_name.c_str());
        // Return to main thread
        PyThreadState_Swap(swapState);
 
        // Set pointer to null
        it->second->m_tState = NULL;
    }
    else
    {
        // Remove Python module
        Py_CLEAR(it->second->m_module);
        it->second->m_module = NULL;
    }
 
    PythonModule* module = it->second;
    string pName = it->second->m_name;
 
    // Remove item
    pythonHandles->erase(it);
 
    // Look for Python module, pName is the key
    auto m = pythonModules->find(pName);
    if (m != pythonModules->end())
    {
        // Remove this element
        pythonModules->erase(m);
    }
 
    // Release module object
    delete module;
    module = NULL;
 
    // Release GIL
    PyGILState_Release(state);
 
    Logger::getLogger()->debug("plugin_shutdown_fn succesfully "
                   "called for plugin '%s'",
                   pName.c_str());
}
 
};
#endif