kafkatest_verifiable_client.cpp

/*
 * Copyright (c) 2015, Confluent Inc
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * librdkafka version of the Java VerifiableProducer and VerifiableConsumer
 * for use with the official Kafka client tests.
 */


#include <iostream>
#include <fstream>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <cstdlib>
#include <cstdio>
#include <csignal>
#include <cstring>
#include <unistd.h>
#include <sys/time.h>
#include <assert.h>
#include <ctype.h>
#include <strings.h>

#ifdef _WIN32
#include "../win32/wingetopt.h"
#elif _AIX
#include <unistd.h>
#else
#include <getopt.h>
#endif

/*
 * Typically include path in a real application would be
 * #include <librdkafka/rdkafkacpp.h>
 */
#include "rdkafkacpp.h"

static volatile sig_atomic_t run = 1;
static bool exit_eof             = false;
static int verbosity             = 1;
static std::string value_prefix;

class Assignment {
 public:
  static std::string name(const std::string &t, int partition) {
    std::stringstream stm;
    stm << t << "." << partition;
    return stm.str();
  }

  Assignment() :
      topic(""),
      partition(-1),
      consumedMessages(0),
      minOffset(-1),
      maxOffset(0) {
    printf("Created assignment\n");
  }
  Assignment(const Assignment &a) {
    topic            = a.topic;
    partition        = a.partition;
    consumedMessages = a.consumedMessages;
    minOffset        = a.minOffset;
    maxOffset        = a.maxOffset;
  }

  Assignment &operator=(const Assignment &a) {
    this->topic            = a.topic;
    this->partition        = a.partition;
    this->consumedMessages = a.consumedMessages;
    this->minOffset        = a.minOffset;
    this->maxOffset        = a.maxOffset;
    return *this;
  }

  int operator==(const Assignment &a) const {
    return !(this->topic == a.topic && this->partition == a.partition);
  }

  int operator<(const Assignment &a) const {
    if (this->topic < a.topic)
      return 1;
    if (this->topic >= a.topic)
      return 0;
    return (this->partition < a.partition);
  }

  void setup(std::string t, int32_t p) {
    assert(!t.empty());
    assert(topic.empty() || topic == t);
    assert(partition == -1 || partition == p);
    topic     = t;
    partition = p;
  }

  std::string topic;
  int partition;
  int consumedMessages;
  int64_t minOffset;
  int64_t maxOffset;
};



static struct {
  int maxMessages;

  struct {
    int numAcked;
    int numSent;
    int numErr;
  } producer;

  struct {
    int consumedMessages;
    int consumedMessagesLastReported;
    int consumedMessagesAtLastCommit;
    bool useAutoCommit;
    std::map<std::string, Assignment> assignments;
  } consumer;
} state = {
    /* .maxMessages = */ -1};


static RdKafka::KafkaConsumer *consumer;


static std::string now() {
  struct timeval tv;
  gettimeofday(&tv, NULL);
  time_t t = tv.tv_sec;
  struct tm tm;
  char buf[64];

  localtime_r(&t, &tm);
  strftime(buf, sizeof(buf), "%H:%M:%S", &tm);
  snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), ".%03d",
           (int)(tv.tv_usec / 1000));

  return buf;
}


static time_t watchdog_last_kick;
static const int watchdog_timeout = 20; /* Must be > socket.timeout.ms */
static void sigwatchdog(int sig) {
  time_t t = time(NULL);
  if (watchdog_last_kick + watchdog_timeout <= t) {
    std::cerr << now() << ": WATCHDOG TIMEOUT ("
              << (int)(t - watchdog_last_kick) << "s): TERMINATING"
              << std::endl;
    int *i = NULL;
    *i     = 100;
    abort();
  }
}

static void watchdog_kick() {
  watchdog_last_kick = time(NULL);

  /* Safe guard against hangs-on-exit */
  alarm(watchdog_timeout);
}



static void errorString(const std::string &name,
                        const std::string &errmsg,
                        const std::string &topic,
                        const std::string *key,
                        const std::string &value) {
  std::cout << "{ "
            << "\"name\": \"" << name << "\", "
            << "\"_time\": \"" << now() << "\", "
            << "\"message\": \"" << errmsg << "\", "
            << "\"topic\": \"" << topic << "\", "
            << "\"key\": \"" << (key ? *key : "NULL") << "\", "
            << "\"value\": \"" << value << "\" "
            << "}" << std::endl;
}


static void successString(const std::string &name,
                          const std::string &topic,
                          int partition,
                          int64_t offset,
                          const std::string *key,
                          const std::string &value) {
  std::cout << "{ "
            << "\"name\": \"" << name << "\", "
            << "\"_time\": \"" << now() << "\", "
            << "\"topic\": \"" << topic << "\", "
            << "\"partition\": " << partition << ", "
            << "\"offset\": " << offset << ", "
            << "\"key\": \"" << (key ? *key : "NULL") << "\", "
            << "\"value\": \"" << value << "\" "
            << "}" << std::endl;
}


#if FIXME
static void offsetStatus(bool success,
                         const std::string &topic,
                         int partition,
                         int64_t offset,
                         const std::string &errstr) {
  std::cout << "{ "
               "\"name\": \"offsets_committed\", "
            << "\"success\": " << success << ", "
            << "\"offsets\": [ "
            << " { "
            << " \"topic\": \"" << topic << "\", "
            << " \"partition\": " << partition << ", "
            << " \"offset\": " << (int)offset << ", "
            << " \"error\": \"" << errstr << "\" "
            << " } "
            << "] }" << std::endl;
}
#endif


static void sigterm(int sig) {
  std::cerr << now() << ": Terminating because of signal " << sig << std::endl;

  if (!run) {
    std::cerr << now() << ": Forced termination" << std::endl;
    exit(1);
  }
  run = 0;
}


class ExampleDeliveryReportCb : public RdKafka::DeliveryReportCb {
 public:
  void dr_cb(RdKafka::Message &message) {
    if (message.err()) {
      state.producer.numErr++;
      errorString("producer_send_error", message.errstr(), message.topic_name(),
                  message.key(),
                  std::string(static_cast<const char *>(message.payload()),
                              message.len()));
    } else {
      successString("producer_send_success", message.topic_name(),
                    (int)message.partition(), message.offset(), message.key(),
                    std::string(static_cast<const char *>(message.payload()),
                                message.len()));
      state.producer.numAcked++;
    }
  }
};


class ExampleEventCb : public RdKafka::EventCb {
 public:
  void event_cb(RdKafka::Event &event) {
    switch (event.type()) {
    case RdKafka::Event::EVENT_ERROR:
      std::cerr << now() << ": ERROR (" << RdKafka::err2str(event.err())
                << "): " << event.str() << std::endl;
      break;

    case RdKafka::Event::EVENT_STATS:
      std::cerr << now() << ": \"STATS\": " << event.str() << std::endl;
      break;

    case RdKafka::Event::EVENT_LOG:
      std::cerr << now() << ": LOG-" << event.severity() << "-" << event.fac()
                << ": " << event.str() << std::endl;
      break;

    default:
      std::cerr << now() << ": EVENT " << event.type() << " ("
                << RdKafka::err2str(event.err()) << "): " << event.str()
                << std::endl;
      break;
    }
  }
};


/* Use of this partitioner is pretty pointless since no key is provided
 * in the produce() call. */
class MyHashPartitionerCb : public RdKafka::PartitionerCb {
 public:
  int32_t partitioner_cb(const RdKafka::Topic *topic,
                         const std::string *key,
                         int32_t partition_cnt,
                         void *msg_opaque) {
    return djb_hash(key->c_str(), key->size()) % partition_cnt;
  }

 private:
  static inline unsigned int djb_hash(const char *str, size_t len) {
    unsigned int hash = 5381;
    for (size_t i = 0; i < len; i++)
      hash = ((hash << 5) + hash) + str[i];
    return hash;
  }
};



/**
 * Print number of records consumed, every 100 messages or on timeout.
 */
static void report_records_consumed(int immediate) {
  std::map<std::string, Assignment> *assignments = &state.consumer.assignments;

  if (state.consumer.consumedMessages <=
      state.consumer.consumedMessagesLastReported + (immediate ? 0 : 999))
    return;

  std::cout << "{ "
               "\"name\": \"records_consumed\", "
            << "\"_totcount\": " << state.consumer.consumedMessages << ", "
            << "\"count\": "
            << (state.consumer.consumedMessages -
                state.consumer.consumedMessagesLastReported)
            << ", "
            << "\"partitions\": [ ";

  for (std::map<std::string, Assignment>::iterator ii = assignments->begin();
       ii != assignments->end(); ii++) {
    Assignment *a = &(*ii).second;
    assert(!a->topic.empty());
    std::cout << (ii == assignments->begin() ? "" : ", ") << " { "
              << " \"topic\": \"" << a->topic << "\", "
              << " \"partition\": " << a->partition << ", "
              << " \"minOffset\": " << a->minOffset << ", "
              << " \"maxOffset\": " << a->maxOffset << " "
              << " } ";
    a->minOffset = -1;
  }

  std::cout << "] }" << std::endl;

  state.consumer.consumedMessagesLastReported = state.consumer.consumedMessages;
}


class ExampleOffsetCommitCb : public RdKafka::OffsetCommitCb {
 public:
  void offset_commit_cb(RdKafka::ErrorCode err,
                        std::vector<RdKafka::TopicPartition *> &offsets) {
    std::cerr << now() << ": Propagate offset for " << offsets.size()
              << " partitions, error: " << RdKafka::err2str(err) << std::endl;

    /* No offsets to commit, dont report anything. */
    if (err == RdKafka::ERR__NO_OFFSET)
      return;

    /* Send up-to-date records_consumed report to make sure consumed > committed
     */
    report_records_consumed(1);

    std::cout << "{ "
              << "\"name\": \"offsets_committed\", "
              << "\"success\": " << (err ? "false" : "true") << ", "
              << "\"error\": \"" << (err ? RdKafka::err2str(err) : "") << "\", "
              << "\"_autocommit\": "
              << (state.consumer.useAutoCommit ? "true" : "false") << ", "
              << "\"offsets\": [ ";
    assert(offsets.size() > 0);
    for (unsigned int i = 0; i < offsets.size(); i++) {
      std::cout << (i == 0 ? "" : ", ") << "{ "
                << " \"topic\": \"" << offsets[i]->topic() << "\", "
                << " \"partition\": " << offsets[i]->partition() << ", "
                << " \"offset\": " << (int)offsets[i]->offset() << ", "
                << " \"error\": \""
                << (offsets[i]->err() ? RdKafka::err2str(offsets[i]->err())
                                      : "")
                << "\" "
                << " }";
    }
    std::cout << " ] }" << std::endl;
  }
};

static ExampleOffsetCommitCb ex_offset_commit_cb;


/**
 * Commit every 1000 messages or whenever there is a consume timeout.
 */
static void do_commit(RdKafka::KafkaConsumer *consumer, int immediate) {
  if (!immediate && (state.consumer.useAutoCommit ||
                     state.consumer.consumedMessagesAtLastCommit + 1000 >
                         state.consumer.consumedMessages))
    return;

  /* Make sure we report consumption before commit,
   * otherwise tests may fail because of commit > consumed. */
  if (state.consumer.consumedMessagesLastReported <
      state.consumer.consumedMessages)
    report_records_consumed(1);

  std::cerr << now() << ": committing "
            << (state.consumer.consumedMessages -
                state.consumer.consumedMessagesAtLastCommit)
            << " messages" << std::endl;

  RdKafka::ErrorCode err;
  err = consumer->commitSync(&ex_offset_commit_cb);

  std::cerr << now() << ": "
            << "sync commit returned " << RdKafka::err2str(err) << std::endl;

  state.consumer.consumedMessagesAtLastCommit = state.consumer.consumedMessages;
}


void msg_consume(RdKafka::KafkaConsumer *consumer,
                 RdKafka::Message *msg,
                 void *opaque) {
  switch (msg->err()) {
  case RdKafka::ERR__TIMED_OUT:
    /* Try reporting consumed messages */
    report_records_consumed(1);
    /* Commit one every consume() timeout instead of on every message.
     * Also commit on every 1000 messages, whichever comes first. */
    do_commit(consumer, 1);
    break;


  case RdKafka::ERR_NO_ERROR: {
    /* Real message */
    if (verbosity > 2)
      std::cerr << now() << ": Read msg from " << msg->topic_name() << " ["
                << (int)msg->partition() << "]  at offset " << msg->offset()
                << std::endl;

    if (state.maxMessages >= 0 &&
        state.consumer.consumedMessages >= state.maxMessages)
      return;


    Assignment *a = &state.consumer.assignments[Assignment::name(
        msg->topic_name(), msg->partition())];
    a->setup(msg->topic_name(), msg->partition());

    a->consumedMessages++;
    if (a->minOffset == -1)
      a->minOffset = msg->offset();
    if (a->maxOffset < msg->offset())
      a->maxOffset = msg->offset();

    if (msg->key()) {
      if (verbosity >= 3)
        std::cerr << now() << ": Key: " << *msg->key() << std::endl;
    }

    if (verbosity >= 3)
      fprintf(stderr, "%.*s\n", static_cast<int>(msg->len()),
              static_cast<const char *>(msg->payload()));

    state.consumer.consumedMessages++;

    report_records_consumed(0);

    do_commit(consumer, 0);
  } break;

  case RdKafka::ERR__PARTITION_EOF:
    /* Last message */
    if (exit_eof) {
      std::cerr << now() << ": Terminate: exit on EOF" << std::endl;
      run = 0;
    }
    break;

  case RdKafka::ERR__UNKNOWN_TOPIC:
  case RdKafka::ERR__UNKNOWN_PARTITION:
    std::cerr << now() << ": Consume failed: " << msg->errstr() << std::endl;
    run = 0;
    break;

  case RdKafka::ERR_GROUP_COORDINATOR_NOT_AVAILABLE:
    std::cerr << now() << ": Warning: " << msg->errstr() << std::endl;
    break;

  default:
    /* Errors */
    std::cerr << now() << ": Consume failed: " << msg->errstr() << std::endl;
    run = 0;
  }
}



class ExampleConsumeCb : public RdKafka::ConsumeCb {
 public:
  void consume_cb(RdKafka::Message &msg, void *opaque) {
    msg_consume(consumer_, &msg, opaque);
  }
  RdKafka::KafkaConsumer *consumer_;
};

class ExampleRebalanceCb : public RdKafka::RebalanceCb {
 private:
  static std::string part_list_json(
      const std::vector<RdKafka::TopicPartition *> &partitions) {
    std::ostringstream out;
    for (unsigned int i = 0; i < partitions.size(); i++)
      out << (i == 0 ? "" : ", ") << "{ "
          << " \"topic\": \"" << partitions[i]->topic() << "\", "
          << " \"partition\": " << partitions[i]->partition() << " }";
    return out.str();
  }

 public:
  void rebalance_cb(RdKafka::KafkaConsumer *consumer,
                    RdKafka::ErrorCode err,
                    std::vector<RdKafka::TopicPartition *> &partitions) {
    std::cerr << now() << ": rebalance_cb " << RdKafka::err2str(err) << " for "
              << partitions.size() << " partitions" << std::endl;
    /* Send message report prior to rebalancing event to make sure they
     * are accounted for on the "right side" of the rebalance. */
    report_records_consumed(1);

    if (err == RdKafka::ERR__ASSIGN_PARTITIONS)
      consumer->assign(partitions);
    else {
      do_commit(consumer, 1);
      consumer->unassign();
    }

    std::cout << "{ "
              << "\"name\": \"partitions_"
              << (err == RdKafka::ERR__ASSIGN_PARTITIONS ? "assigned"
                                                         : "revoked")
              << "\", "
              << "\"partitions\": [ " << part_list_json(partitions) << "] }"
              << std::endl;
  }
};



/**
 * @brief Read (Java client) configuration file
 */
static void read_conf_file(RdKafka::Conf *conf, const std::string &conf_file) {
  std::ifstream inf(conf_file.c_str());

  if (!inf) {
    std::cerr << now() << ": " << conf_file << ": could not open file"
              << std::endl;
    exit(1);
  }

  std::cerr << now() << ": " << conf_file << ": read config file" << std::endl;

  std::string line;
  int linenr = 0;

  while (std::getline(inf, line)) {
    linenr++;

    // Ignore comments and empty lines
    if (line[0] == '#' || line.length() == 0)
      continue;

    // Match on key=value..
    size_t d = line.find("=");
    if (d == 0 || d == std::string::npos) {
      std::cerr << now() << ": " << conf_file << ":" << linenr << ": " << line
                << ": ignoring invalid line (expect key=value): "
                << ::std::endl;
      continue;
    }

    std::string key = line.substr(0, d);
    std::string val = line.substr(d + 1);

    std::string errstr;
    if (conf->set(key, val, errstr)) {
      std::cerr << now() << ": " << conf_file << ":" << linenr << ": " << key
                << "=" << val << ": " << errstr << ": ignoring error"
                << std::endl;
    } else {
      std::cerr << now() << ": " << conf_file << ":" << linenr << ": " << key
                << "=" << val << ": applied to configuration" << std::endl;
    }
  }

  inf.close();
}



int main(int argc, char **argv) {
  std::string brokers = "localhost";
  std::string errstr;
  std::vector<std::string> topics;
  std::string mode  = "P";
  int throughput    = 0;
  int32_t partition = RdKafka::Topic::PARTITION_UA;
  MyHashPartitionerCb hash_partitioner;
  int64_t create_time = -1;

  std::cerr << now() << ": librdkafka version " << RdKafka::version_str()
            << " (" << RdKafka::version() << ")" << std::endl;

  /*
   * Create configuration objects
   */
  RdKafka::Conf *conf = RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL);

  /* Java VerifiableProducer defaults to acks=all */
  if (conf->set("acks", "all", errstr)) {
    std::cerr << now() << ": " << errstr << std::endl;
    exit(1);
  }

  /* Avoid slow shutdown on error */
  if (conf->set("message.timeout.ms", "60000", errstr)) {
    std::cerr << now() << ": " << errstr << std::endl;
    exit(1);
  }

  {
    char hostname[128];
    gethostname(hostname, sizeof(hostname) - 1);
    conf->set("client.id", std::string("rdkafka@") + hostname, errstr);
  }

  conf->set("log.thread.name", "true", errstr);

  /* auto commit is explicitly enabled with --enable-autocommit */
  conf->set("enable.auto.commit", "false", errstr);

  /* keep protocol request timeouts under the watchdog timeout
   * to make sure things like commitSync() dont fall victim to the watchdog. */
  conf->set("socket.timeout.ms", "10000", errstr);

  conf->set("fetch.wait.max.ms", "500", errstr);
  conf->set("fetch.min.bytes", "4096", errstr);

  conf->set("enable.partition.eof", "true", errstr);

  for (int i = 1; i < argc; i++) {
    const char *name = argv[i];
    const char *val  = i + 1 < argc ? argv[i + 1] : NULL;

    if (val && !strncmp(val, "-", 1))
      val = NULL;

    std::cout << now() << ": argument: " << name << " " << (val ? val : "")
              << std::endl;

    if (val) {
      if (!strcmp(name, "--topic"))
        topics.push_back(val);
      else if (!strcmp(name, "--broker-list"))
        brokers = val;
      else if (!strcmp(name, "--max-messages"))
        state.maxMessages = atoi(val);
      else if (!strcmp(name, "--throughput"))
        throughput = atoi(val);
      else if (!strcmp(name, "--producer.config") ||
               !strcmp(name, "--consumer.config"))
        read_conf_file(conf, val);
      else if (!strcmp(name, "--group-id"))
        conf->set("group.id", val, errstr);
      else if (!strcmp(name, "--session-timeout"))
        conf->set("session.timeout.ms", val, errstr);
      else if (!strcmp(name, "--reset-policy")) {
        if (conf->set("auto.offset.reset", val, errstr)) {
          std::cerr << now() << ": " << errstr << std::endl;
          exit(1);
        }
      } else if (!strcmp(name, "--assignment-strategy")) {
        /* The system tests pass the Java class name(s) rather than
         * the configuration value. Fix it.
         * "org.apache.kafka.clients.consumer.RangeAssignor,.." -> "range,.."
         */
        std::string s = val;
        size_t pos;

        while ((pos = s.find("org.apache.kafka.clients.consumer.")) !=
               std::string::npos)
          s.erase(pos, strlen("org.apache.kafka.clients.consumer."));

        while ((pos = s.find("Assignor")) != std::string::npos)
          s.erase(pos, strlen("Assignor"));

        std::transform(s.begin(), s.end(), s.begin(), tolower);

        std::cerr << now() << ": converted " << name << " " << val << " to "
                  << s << std::endl;

        if (conf->set("partition.assignment.strategy", s.c_str(), errstr)) {
          std::cerr << now() << ": " << errstr << std::endl;
          exit(1);
        }
      } else if (!strcmp(name, "--value-prefix")) {
        value_prefix = std::string(val) + ".";
      } else if (!strcmp(name, "--acks")) {
        if (conf->set("acks", val, errstr)) {
          std::cerr << now() << ": " << errstr << std::endl;
          exit(1);
        }
      } else if (!strcmp(name, "--message-create-time")) {
        create_time = (int64_t)atoi(val);
      } else if (!strcmp(name, "--debug")) {
        conf->set("debug", val, errstr);
      } else if (!strcmp(name, "-X")) {
        char *s = strdup(val);
        char *t = strchr(s, '=');
        if (!t)
          t = (char *)"";
        else {
          *t = '\0';
          t++;
        }
        if (conf->set(s, t, errstr)) {
          std::cerr << now() << ": " << errstr << std::endl;
          exit(1);
        }
        free(s);
      } else {
        std::cerr << now() << ": Unknown option " << name << std::endl;
        exit(1);
      }

      i++;

    } else {
      if (!strcmp(name, "--consumer"))
        mode = "C";
      else if (!strcmp(name, "--producer"))
        mode = "P";
      else if (!strcmp(name, "--enable-autocommit")) {
        state.consumer.useAutoCommit = true;
        conf->set("enable.auto.commit", "true", errstr);
      } else if (!strcmp(name, "-v"))
        verbosity++;
      else if (!strcmp(name, "-q"))
        verbosity--;
      else {
        std::cerr << now() << ": Unknown option or missing argument to " << name
                  << std::endl;
        exit(1);
      }
    }
  }

  if (topics.empty() || brokers.empty()) {
    std::cerr << now() << ": Missing --topic and --broker-list" << std::endl;
    exit(1);
  }


  /*
   * Set configuration properties
   */
  conf->set("metadata.broker.list", brokers, errstr);

  ExampleEventCb ex_event_cb;
  conf->set("event_cb", &ex_event_cb, errstr);

  signal(SIGINT, sigterm);
  signal(SIGTERM, sigterm);
  signal(SIGALRM, sigwatchdog);


  if (mode == "P") {
    /*
     * Producer mode
     */

    ExampleDeliveryReportCb ex_dr_cb;

    /* Set delivery report callback */
    conf->set("dr_cb", &ex_dr_cb, errstr);

    /*
     * Create producer using accumulated global configuration.
     */
    RdKafka::Producer *producer = RdKafka::Producer::create(conf, errstr);
    if (!producer) {
      std::cerr << now() << ": Failed to create producer: " << errstr
                << std::endl;
      exit(1);
    }

    std::cerr << now() << ": % Created producer " << producer->name()
              << std::endl;

    /*
     * Create topic handle.
     */
    RdKafka::Topic *topic =
        RdKafka::Topic::create(producer, topics[0], NULL, errstr);
    if (!topic) {
      std::cerr << now() << ": Failed to create topic: " << errstr << std::endl;
      exit(1);
    }

    static const int delay_us = throughput ? 1000000 / throughput : 10;

    if (state.maxMessages == -1)
      state.maxMessages = 1000000; /* Avoid infinite produce */

    for (int i = 0; run && i < state.maxMessages; i++) {
      /*
       * Produce message
       */
      std::ostringstream msg;
      msg << value_prefix << i;
      while (true) {
        RdKafka::ErrorCode resp;
        if (create_time == -1) {
          resp = producer->produce(
              topic, partition,
              RdKafka::Producer::RK_MSG_COPY /* Copy payload */,
              const_cast<char *>(msg.str().c_str()), msg.str().size(), NULL,
              NULL);
        } else {
          resp = producer->produce(
              topics[0], partition,
              RdKafka::Producer::RK_MSG_COPY /* Copy payload */,
              const_cast<char *>(msg.str().c_str()), msg.str().size(), NULL, 0,
              create_time, NULL);
        }

        if (resp == RdKafka::ERR__QUEUE_FULL) {
          producer->poll(100);
          continue;
        } else if (resp != RdKafka::ERR_NO_ERROR) {
          errorString("producer_send_error", RdKafka::err2str(resp),
                      topic->name(), NULL, msg.str());
          state.producer.numErr++;
        } else {
          state.producer.numSent++;
        }
        break;
      }

      producer->poll(delay_us / 1000);
      usleep(1000);
      watchdog_kick();
    }
    run = 1;

    while (run && producer->outq_len() > 0) {
      std::cerr << now() << ": Waiting for " << producer->outq_len()
                << std::endl;
      producer->poll(1000);
      watchdog_kick();
    }

    std::cerr << now() << ": " << state.producer.numAcked << "/"
              << state.producer.numSent << "/" << state.maxMessages
              << " msgs acked/sent/max, " << state.producer.numErr << " errored"
              << std::endl;

    delete topic;
    delete producer;


  } else if (mode == "C") {
    /*
     * Consumer mode
     */

    conf->set("auto.offset.reset", "smallest", errstr);

    ExampleRebalanceCb ex_rebalance_cb;
    conf->set("rebalance_cb", &ex_rebalance_cb, errstr);

    conf->set("offset_commit_cb", &ex_offset_commit_cb, errstr);


    /*
     * Create consumer using accumulated global configuration.
     */
    consumer = RdKafka::KafkaConsumer::create(conf, errstr);
    if (!consumer) {
      std::cerr << now() << ": Failed to create consumer: " << errstr
                << std::endl;
      exit(1);
    }

    std::cerr << now() << ": % Created consumer " << consumer->name()
              << std::endl;

    /*
     * Subscribe to topic(s)
     */
    RdKafka::ErrorCode resp = consumer->subscribe(topics);
    if (resp != RdKafka::ERR_NO_ERROR) {
      std::cerr << now() << ": Failed to subscribe to " << topics.size()
                << " topics: " << RdKafka::err2str(resp) << std::endl;
      exit(1);
    }

    watchdog_kick();

    /*
     * Consume messages
     */
    while (run) {
      RdKafka::Message *msg = consumer->consume(500);
      msg_consume(consumer, msg, NULL);
      delete msg;
      watchdog_kick();
    }

    std::cerr << now() << ": Final commit on termination" << std::endl;

    /* Final commit */
    do_commit(consumer, 1);

    /*
     * Stop consumer
     */
    consumer->close();

    delete consumer;
  }

  std::cout << "{ \"name\": \"shutdown_complete\" }" << std::endl;

  /*
   * Wait for RdKafka to decommission.
   * This is not strictly needed (when check outq_len() above), but
   * allows RdKafka to clean up all its resources before the application
   * exits so that memory profilers such as valgrind wont complain about
   * memory leaks.
   */
  RdKafka::wait_destroyed(5000);

  std::cerr << now() << ": EXITING WITH RETURN VALUE 0" << std::endl;
  return 0;
}