plugin.cpp

/*
 * Fledge "Python 3.5" filter plugin.
 *
 * Copyright (c) 2018 Dianomic Systems
 *
 * Released under the Apache 2.0 Licence
 *
 * Author: Massimiliano Pinto
 */

#define FILTER_NAME "python35"

#include <utils.h>
#include <plugin_api.h>
#include <config_category.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string>
#include <iostream>
#include <filter_plugin.h>
#include <filter.h>
#include <version.h>
#include <pyruntime.h>

#include "python35.h"

static void* libpython_handle = NULL;

/**
 * The Python 3.5 script module to load is set in
 * 'script' config item and it doesn't need the trailing .py
 *
 * Example:
 * if filename is 'readings_filter.py', just set 'readings_filter'
 * via Fledge configuration managewr
 *
 * Note:
 * Python 3.5 filter code needs two methods.
 *
 * One is the filtering method to call which must have
 * the same as the script name: it can not be changed.
 * The second one is the configuration entry point
 * method 'set_filter_config': it can not be changed
 *
 * Example: readings_filter.py
 *
 * expected two methods:
 * - set_filter_config(configuration) // Input is a string
 *   It sets the configuration internally as dict
 *
 * - readings_filter(readings) // Input is a dict
 *   It returns a dict with filtered input data
 */

// Filter default configuration
static const char *default_config = QUOTE({
	"plugin" : {
		"description" : "Python 3.5 filter plugin", 
		"type" : "string", 
		"readonly": "true",
		"default" : FILTER_NAME
		},
	 "enable": {
	 	"description": "A switch that can be used to enable or disable execution of the Python 3.5 filter.",
		"type": "boolean",
		"displayName": "Enabled",
		"default": "false"
		},
	"config" : {
		"description" : "Python 3.5 filter configuration.",
		"type" : "JSON",
		"order": "2",
		"displayName" : "Configuration",
		"default" : "{}"
		},
	"script" : {
		"description" : "Python 3.5 module to load.",
		"type": "script",
		"order": "1",
		"displayName" : "Python script",
		"default": ""
		},
	"encode_attribute_names" : {
		"description" : "Whether to encode/decode attribute names",
		"type": "boolean",
		"displayName": "Encode attribute names",
		"default": "true"
		}
	});
using namespace std;

/**
 * The Filter plugin interface
 */
extern "C" {
/**
 * The plugin information structure
 */
static PLUGIN_INFORMATION info = {
        FILTER_NAME,              // Name
        VERSION,                  // Version
        0,                        // Flags
        PLUGIN_TYPE_FILTER,       // Type
        "1.0.0",                  // Interface version
	default_config	          // Default plugin configuration
};

/**
 * Return the information about this plugin
 */
PLUGIN_INFORMATION *plugin_info()
{
	return &info;
}

/**
 * Initialise the plugin, called to get the plugin handle and setup the
 * output handle that will be passed to the output stream. The output stream
 * is merely a function pointer that is called with the output handle and
 * the new set of readings generated by the plugin.
 *     (*output)(outHandle, readings);
 * Note that the plugin may not call the output stream if the result of
 * the filtering is that no readings are to be sent onwards in the chain.
 * This allows the plugin to discard data or to buffer it for aggregation
 * with data that follows in subsequent calls
 *
 * @param config	The configuration category for the filter
 * @param outHandle	A handle that will be passed to the output stream
 * @param output	The output stream (function pointer) to which data is passed
 * @return		An opaque handle that is used in all subsequent calls to the plugin
 */
PLUGIN_HANDLE plugin_init(ConfigCategory* config,
			  OUTPUT_HANDLE *outHandle,
			  OUTPUT_STREAM output)
{
	Python35Filter *filter = new Python35Filter(FILTER_NAME,
						*config,
						outHandle,
						output);
	filter->init();

	// return NULL aborts the filter pipeline set up
	return (PLUGIN_HANDLE)filter;
}

/**
 * Ingest a set of readings into the plugin for processing
 *
 * NOTE: in case of any error no data will be passed onwards in the pipeline
 *
 * @param handle	The plugin handle returned from plugin_init
 * @param readingSet	The readings to process
 */
void plugin_ingest(PLUGIN_HANDLE *handle,
		   READINGSET *readingSet)
{
	Python35Filter *filter = (Python35Filter *)handle;
	filter->ingest(readingSet);
}

/**
 * Call the shutdown method in the plugin
 *
 * @param handle	The plugin handle returned from plugin_init
 */
void plugin_shutdown(PLUGIN_HANDLE *handle)
{
	Python35Filter* filter = (Python35Filter *)handle;

	filter->shutdown();

	// Remove filter object
	delete filter;
}

/**
 * Apply filter plugin reconfiguration
 *
 * @param    handle	The plugin handle returned from plugin_init
 * @param    newConfig	The new configuration to apply.
 */
void plugin_reconfigure(PLUGIN_HANDLE *handle, const string& newConfig)
{
	Python35Filter* filter = (Python35Filter *)handle;

	filter->reconfigure(newConfig);
}

// End of extern "C"
};