I need to take input as structure instead of string in producer and print that in consumer using librdkafka library.I made changes in the producer code and even able to get the structure, but in the consumer it is not showing plz help if there need some more changes
Here is the code producer code:
struct date
{
int d, m, y;
};
int main(int argc, char** argv) {
rd_kafka_t* rk; /* Producer instance handle */
rd_kafka_conf_t* conf; /* Temporary configuration object */
char errstr[512]; /* librdkafka API error reporting buffer */
//char buf[512]; /* Message value temporary buffer */
const char* brokers; /* Argument: broker list */
const char* topic; /* Argument: topic to produce to */
struct date d1;
struct date* ptr ;
ptr = &d1;
int i;
brokers ="localhost:9092";
topic = "test";
/*
* Create Kafka client configuration place-holder
*/
conf = rd_kafka_conf_new();
/* Set bootstrap broker(s) as a comma-separated list of
* host or host:port (default port 9092).
* librdkafka will use the bootstrap brokers to acquire the full
* set of brokers from the cluster. */
if (rd_kafka_conf_set(conf, "bootstrap.servers", brokers,
errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK) {
fprintf(stderr, "%s\n", errstr);
return 1;
}
/* Set the delivery report callback.
* This callback will be called once per message to inform
* the application if delivery succeeded or failed.
* See dr_msg_cb() above.
* The callback is only triggered from rd_kafka_poll() and
* rd_kafka_flush(). */
rd_kafka_conf_set_dr_msg_cb(conf, dr_msg_cb);
/*
* Create producer instance.
*
* NOTE: rd_kafka_new() takes ownership of the conf object
* and the application must not reference it again after
* this call.
*/
rk = rd_kafka_new(RD_KAFKA_PRODUCER, conf, errstr, sizeof(errstr));
if (!rk) {
fprintf(stderr,
"%% Failed to create new producer: %s\n", errstr);
return 1;
}
/* Signal handler for clean shutdown */
signal(SIGINT, stop);
fprintf(stderr, "%% enter \n");
/*fprintf(stderr,
"%% Type some text and hit enter to produce message\n"
"%% Or just hit enter to only serve delivery reports\n"
"%% Press Ctrl-C or Ctrl-D to exit\n");*/
while (run && fscanf_s(stdin, "%d/%d/%d", &d1.d, &d1.m,&d1.y))
{
size_t len = sizeof(d1);
rd_kafka_resp_err_t err;
fprintf(stdout, "%d/%d/%d \n", d1.d, d1.m, d1.y);
//if ([len - 1] == '\n') /* Remove newline */
// d1[--len] = '\0';
if (len == 0) {
/* Empty line: only serve delivery reports */
rd_kafka_poll(rk, 0/*non-blocking */);
continue;
}
retry:
err = rd_kafka_producev(
/* Producer handle */
rk,
/* Topic name */
RD_KAFKA_V_TOPIC(topic),
/* Make a copy of the payload. */
RD_KAFKA_V_MSGFLAGS(RD_KAFKA_MSG_F_COPY),
/* Message value and length */
RD_KAFKA_V_VALUE(ptr, len),
/* Per-Message opaque, provided in
* delivery report callback as
* msg_opaque. */
RD_KAFKA_V_OPAQUE(NULL),
/* End sentinel */
RD_KAFKA_V_END);
if (err) {
/*
* Failed to *enqueue* message for producing.
*/
fprintf(stderr,
"%% Failed to produce to topic %s: %s\n",
topic, rd_kafka_err2str(err));
if (err == RD_KAFKA_RESP_ERR__QUEUE_FULL) {
/* If the internal queue is full, wait for
* messages to be delivered and then retry.
* The internal queue represents both
* messages to be sent and messages that have
* been sent or failed, awaiting their
* delivery report callback to be called.
*
* The internal queue is limited by the
* configuration property
* queue.buffering.max.messages */
rd_kafka_poll(rk, 1000/*block for max 1000ms*/);
goto retry;
}
}
else {
fprintf(stderr, "%% Enqueued message (%zd bytes) "
"for topic %s\n",
len, topic);
}
/* A producer application should continually serve
* the delivery report queue by calling rd_kafka_poll()
* at frequent intervals.
* Either put the poll call in your main loop, or in a
* dedicated thread, or call it after every
* rd_kafka_produce() call.
* Just make sure that rd_kafka_poll() is still called
* during periods where you are not producing any messages
* to make sure previously produced messages have their
* delivery report callback served (and any other callbacks
* you register). */
rd_kafka_poll(rk, 0/*non-blocking*/);
}
/* Wait for final messages to be delivered or fail.
* rd_kafka_flush() is an abstraction over rd_kafka_poll() which
* waits for all messages to be delivered. */
fprintf(stderr, "%% Flushing final messages..\n");
rd_kafka_flush(rk, 10 * 1000 /* wait for max 10 seconds */);
/* If the output queue is still not empty there is an issue
* with producing messages to the clusters. */
if (rd_kafka_outq_len(rk) > 0)
fprintf(stderr, "%% %d message(s) were not delivered\n",
rd_kafka_outq_len(rk));
/* Destroy the producer instance */
rd_kafka_destroy(rk);
return 0;
}
consumer code:
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <ctype.h>
/* Typical include path would be <librdkafka/rdkafka.h>, but this program
* is builtin from within the librdkafka source tree and thus differs. */
//#include <librdkafka/rdkafka.h>
#include "rdkafka.h"
static volatile sig_atomic_t run = 1;
/**
* @brief Signal termination of program
*/
static void stop(int sig) {
run = 0;
}
struct date
{
int d, m, y;
};
/**
* @returns 1 if all bytes are printable, else 0.
*/
static int is_printable(struct date* ptr, size_t len)
{
size_t i;
for (i = 0; i < len; i++)
if (!isdigit(d1.d && d1.m && d1.y))
return 0;
return 1;
}
int main(int argc, char **argv) {
rd_kafka_t* rk; /* Consumer instance handle */
rd_kafka_conf_t* conf; /* Temporary configuration object */
rd_kafka_resp_err_t err; /* librdkafka API error code */
char errstr[512]; /* librdkafka API error reporting buffer */
const char* brokers; /* Argument: broker list */
const char* groupid; /* Argument: Consumer group id */
char** topics; /* Argument: list of topics to subscribe to */
int topic_cnt; /* Number of topics to subscribe to */
rd_kafka_topic_partition_list_t* subscription; /* Subscribed topics */
int i;
struct date d1;
struct date* ptr;
ptr = &d1;
/*
* Argument validation
*/
/*if (argc < 4) {
fprintf(stderr,
"%% Usage: "
"%s <broker> <group.id> <topic1> <topic2>..\n",
argv[0]);
return 1;
}*/
brokers = "localhost:9092";
groupid = "test-consumer-group";
char* topic[] = {"test"};
topics = &topic;
topic_cnt = 1;
/*
* Create Kafka client configuration place-holder
*/
conf = rd_kafka_conf_new();
/* Set bootstrap broker(s) as a comma-separated list of
* host or host:port (default port 9092).
* librdkafka will use the bootstrap brokers to acquire the full
* set of brokers from the cluster. */
if (rd_kafka_conf_set(conf, "bootstrap.servers", brokers,
errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK) {
fprintf(stderr, "%s\n", errstr);
rd_kafka_conf_destroy(conf);
return 1;
}
/* Set the consumer group id.
* All consumers sharing the same group id will join the same
* group, and the subscribed topic' partitions will be assigned
* according to the partition.assignment.strategy
* (consumer config property) to the consumers in the group. */
if (rd_kafka_conf_set(conf, "group.id", groupid,
errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK) {
fprintf(stderr, "%s\n", errstr);
rd_kafka_conf_destroy(conf);
return 1;
}
/* If there is no previously committed offset for a partition
* the auto.offset.reset strategy will be used to decide where
* in the partition to start fetching messages.
* By setting this to earliest the consumer will read all messages
* in the partition if there was no previously committed offset. */
if (rd_kafka_conf_set(conf, "auto.offset.reset", "earliest",
errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK) {
fprintf(stderr, "%s\n", errstr);
rd_kafka_conf_destroy(conf);
return 1;
}
/*
* Create consumer instance.
*
* NOTE: rd_kafka_new() takes ownership of the conf object
* and the application must not reference it again after
* this call.
*/
rk = rd_kafka_new(RD_KAFKA_CONSUMER, conf, errstr, sizeof(errstr));
if (!rk) {
fprintf(stderr,
"%% Failed to create new consumer: %s\n", errstr);
return 1;
}
conf = NULL; /* Configuration object is now owned, and freed,
* by the rd_kafka_t instance. */
/* Redirect all messages from per-partition queues to
* the main queue so that messages can be consumed with one
* call from all assigned partitions.
*
* The alternative is to poll the main queue (for events)
* and each partition queue separately, which requires setting
* up a rebalance callback and keeping track of the assignment:
* but that is more complex and typically not recommended. */
rd_kafka_poll_set_consumer(rk);
/* Convert the list of topics to a format suitable for librdkafka */
subscription = rd_kafka_topic_partition_list_new(topic_cnt);
for (i = 0; i < topic_cnt; i++)
rd_kafka_topic_partition_list_add(subscription,
topics[i],
/* the partition is ignored
* by subscribe() */
RD_KAFKA_PARTITION_UA);
/* Subscribe to the list of topics */
err = rd_kafka_subscribe(rk, subscription);
if (err) {
fprintf(stderr,
"%% Failed to subscribe to %d topics: %s\n",
subscription->cnt, rd_kafka_err2str(err));
rd_kafka_topic_partition_list_destroy(subscription);
rd_kafka_destroy(rk);
return 1;
}
fprintf(stderr,
"%% Subscribed to %d topic(s), "
"waiting for rebalance and messages...\n",
subscription->cnt);
rd_kafka_topic_partition_list_destroy(subscription);
/* Signal handler for clean shutdown */
signal(SIGINT, stop);
/* Subscribing to topics will trigger a group rebalance
* which may take some time to finish, but there is no need
* for the application to handle this idle period in a special way
* since a rebalance may happen at any time.
* Start polling for messages. */
while (run) {
rd_kafka_message_t* rkm;
rkm = rd_kafka_consumer_poll(rk, 100);
if (!rkm)
continue; /* Timeout: no message within 100ms,
* try again. This short timeout allows
* checking for `run` at frequent intervals.
*/
/* consumer_poll() will return either a proper message
* or a consumer error (rkm->err is set). */
if (rkm->err) {
/* Consumer errors are generally to be considered
* informational as the consumer will automatically
* try to recover from all types of errors. */
fprintf(stderr,
"%% Consumer error: %s\n",
rd_kafka_message_errstr(rkm));
rd_kafka_message_destroy(rkm);
continue;
}
/* Proper message. */
printf("Message on %s [%" PRId32 "] at offset %" PRId64 ":\n",
rd_kafka_topic_name(rkm->rkt), rkm->partition,
rkm->offset);
/* Print the message key. */
if (rkm->key && is_printable((const char*)rkm->key, rkm->key_len))
printf(" Key: %.*s\n",
(int)rkm->key_len, (const char*)rkm->key);
else if (rkm->key)
printf(" Key: (%d bytes)\n", (int)rkm->key_len);
/* Print the message value/payload. */
if (rkm->payload && is_printable((const char*)rkm->payload, rkm->len))
printf(" Value:%.*s\n",
(int)rkm->len, (const char*)rkm->payload);
else if (rkm->payload)
printf(" Value: (%d bytes)\n", (int)rkm->len);
rd_kafka_message_destroy(rkm);
}
/* Close the consumer: commit final offsets and leave the group. */
fprintf(stderr, "%% Closing consumer\n");
rd_kafka_consumer_close(rk);
/* Destroy the consumer */
rd_kafka_destroy(rk);
return 0;
}
