extensions/mqtt/processors/PublishMQTT.h

/**
 * @file PublishMQTT.h
 * PublishMQTT class declaration
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef __PUBLISH_MQTT_H__
#define __PUBLISH_MQTT_H__

#include "FlowFileRecord.h"
#include "core/Processor.h"
#include "core/ProcessSession.h"
#include "core/Core.h"
#include "core/Resource.h"
#include "core/Property.h"
#include "core/logging/LoggerConfiguration.h"
#include "MQTTClient.h"
#include "AbstractMQTTProcessor.h"

namespace org {
namespace apache {
namespace nifi {
namespace minifi {
namespace processors {

// PublishMQTT Class
class PublishMQTT : public processors::AbstractMQTTProcessor {
 public:
  // Constructor
  /*!
   * Create a new processor
   */
  explicit PublishMQTT(std::string name, utils::Identifier uuid = utils::Identifier())
      : processors::AbstractMQTTProcessor(name, uuid),
        logger_(logging::LoggerFactory<PublishMQTT>::getLogger()) {
    retain_ = false;
    max_seg_size_ = ULLONG_MAX;
  }
  // Destructor
  virtual ~PublishMQTT() = default;
  // Processor Name
  static constexpr char const* ProcessorName = "PublishMQTT";
  // Supported Properties
  static core::Property Retain;
  static core::Property MaxFlowSegSize;

  static core::Relationship Failure;
  static core::Relationship Success;

  // Nest Callback Class for read stream
  class ReadCallback : public InputStreamCallback {
   public:
    ReadCallback(uint64_t flow_size, uint64_t max_seg_size, const std::string &key, MQTTClient client, int qos, bool retain, MQTTClient_deliveryToken &token)
        : flow_size_(flow_size),
          max_seg_size_(max_seg_size),
          key_(key),
          client_(client),
          qos_(qos),
          retain_(retain),
          token_(token) {
      status_ = 0;
      read_size_ = 0;
    }
    ~ReadCallback() = default;
    int64_t process(const std::shared_ptr<io::BaseStream>& stream) {
      if (flow_size_ < max_seg_size_)
        max_seg_size_ = flow_size_;
      std::vector<unsigned char> buffer;
      buffer.reserve(max_seg_size_);
      read_size_ = 0;
      status_ = 0;
      while (read_size_ < flow_size_) {
        int readRet = stream->read(&buffer[0], max_seg_size_);
        if (readRet < 0) {
          status_ = -1;
          return read_size_;
        }
        if (readRet > 0) {
          MQTTClient_message pubmsg = MQTTClient_message_initializer;
          pubmsg.payload = &buffer[0];
          pubmsg.payloadlen = readRet;
          pubmsg.qos = qos_;
          pubmsg.retained = retain_;
          if (MQTTClient_publishMessage(client_, key_.c_str(), &pubmsg, &token_) != MQTTCLIENT_SUCCESS) {
            status_ = -1;
            return -1;
          }
          read_size_ += readRet;
        } else {
          break;
        }
      }
      return read_size_;
    }
    uint64_t flow_size_;
    uint64_t max_seg_size_;
    std::string key_;
    MQTTClient client_;
    ;
    int status_;
    size_t read_size_;
    int qos_;
    int retain_;
    MQTTClient_deliveryToken &token_;
  };

 public:
  /**
   * Function that's executed when the processor is scheduled.
   * @param context process context.
   * @param sessionFactory process session factory that is used when creating
   * ProcessSession objects.
   */
  void onSchedule(const std::shared_ptr<core::ProcessContext> &context, const std::shared_ptr<core::ProcessSessionFactory> &factory) override;
  // OnTrigger method, implemented by NiFi PublishMQTT
  void onTrigger(const std::shared_ptr<core::ProcessContext> &context, const std::shared_ptr<core::ProcessSession> &session) override;
  // Initialize, over write by NiFi PublishMQTT
  void initialize(void) override;

 protected:

 private:
  uint64_t max_seg_size_;
  bool retain_;
  std::shared_ptr<logging::Logger> logger_;
};

REGISTER_RESOURCE(PublishMQTT, "PublishMQTT serializes FlowFile content as an MQTT payload, sending the message to the configured topic and broker.");

} /* namespace processors */
} /* namespace minifi */
} /* namespace nifi */
} /* namespace apache */
} /* namespace org */

#endif