/*
* librdkafka - Apache Kafka C library
*
* Copyright (c) 2015, Magnus Edenhill
* 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.
*/
/**
* Apache Kafka high level consumer example program
* using the Kafka driver from librdkafka
* (https://github.com/edenhill/librdkafka)
*/
#include <ctype.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <syslog.h>
#include <sys/time.h>
#include <errno.h>
#include <getopt.h>
/* Typical include path would be <librdkafka/rdkafka.h>, but this program
* is builtin from within the librdkafka source tree and thus differs. */
#include "rdkafka.h" /* for Kafka driver */
static int run = 1;
static rd_kafka_t *rk;
static int exit_eof = 0;
static int wait_eof = 0; /* number of partitions awaiting EOF */
static int quiet = 0;
static enum {
OUTPUT_HEXDUMP,
OUTPUT_RAW,
} output = OUTPUT_HEXDUMP;
static void stop (int sig) {
if (!run)
exit(1);
run = 0;
fclose(stdin); /* abort fgets() */
}
static void hexdump (FILE *fp, const char *name, const void *ptr, size_t len) {
const char *p = (const char *)ptr;
unsigned int of = 0;
if (name)
fprintf(fp, "%s hexdump (%zd bytes):\n", name, len);
for (of = 0 ; of < len ; of += 16) {
char hexen[16*3+1];
char charen[16+1];
int hof = 0;
int cof = 0;
int i;
for (i = of ; i < (int)of + 16 && i < (int)len ; i++) {
hof += sprintf(hexen+hof, "%02x ", p[i] & 0xff);
cof += sprintf(charen+cof, "%c",
isprint((int)p[i]) ? p[i] : '.');
}
fprintf(fp, "%08x: %-48s %-16s\n",
of, hexen, charen);
}
}
/**
* Kafka logger callback (optional)
*/
static void logger (const rd_kafka_t *rk, int level,
const char *fac, const char *buf) {
struct timeval tv;
gettimeofday(&tv, NULL);
fprintf(stdout, "%u.%03u RDKAFKA-%i-%s: %s: %s\n",
(int)tv.tv_sec, (int)(tv.tv_usec / 1000),
level, fac, rd_kafka_name(rk), buf);
}
/**
* Handle and print a consumed message.
* Internally crafted messages are also used to propagate state from
* librdkafka to the application. The application needs to check
* the `rkmessage->err` field for this purpose.
*/
static void msg_consume (rd_kafka_message_t *rkmessage) {
if (rkmessage->err) {
if (rkmessage->err == RD_KAFKA_RESP_ERR__PARTITION_EOF) {
fprintf(stderr,
"%% Consumer reached end of %s [%"PRId32"] "
"message queue at offset %"PRId64"\n",
rd_kafka_topic_name(rkmessage->rkt),
rkmessage->partition, rkmessage->offset);
if (exit_eof && --wait_eof == 0) {
fprintf(stderr,
"%% All partition(s) reached EOF: "
"exiting\n");
run = 0;
}
return;
}
if (rkmessage->rkt)
fprintf(stderr, "%% Consume error for "
"topic \"%s\" [%"PRId32"] "
"offset %"PRId64": %s\n",
rd_kafka_topic_name(rkmessage->rkt),
rkmessage->partition,
rkmessage->offset,
rd_kafka_message_errstr(rkmessage));
else
fprintf(stderr, "%% Consumer error: %s: %s\n",
rd_kafka_err2str(rkmessage->err),
rd_kafka_message_errstr(rkmessage));
if (rkmessage->err == RD_KAFKA_RESP_ERR__UNKNOWN_PARTITION ||
rkmessage->err == RD_KAFKA_RESP_ERR__UNKNOWN_TOPIC)
run = 0;
return;
}
if (!quiet)
fprintf(stdout, "%% Message (topic %s [%"PRId32"], "
"offset %"PRId64", %zd bytes):\n",
rd_kafka_topic_name(rkmessage->rkt),
rkmessage->partition,
rkmessage->offset, rkmessage->len);
if (rkmessage->key_len) {
if (output == OUTPUT_HEXDUMP)
hexdump(stdout, "Message Key",
rkmessage->key, rkmessage->key_len);
else
printf("Key: %.*s\n",
(int)rkmessage->key_len, (char *)rkmessage->key);
}
if (output == OUTPUT_HEXDUMP)
hexdump(stdout, "Message Payload",
rkmessage->payload, rkmessage->len);
else
printf("%.*s\n",
(int)rkmessage->len, (char *)rkmessage->payload);
}
static void print_partition_list (FILE *fp,
const rd_kafka_topic_partition_list_t
*partitions) {
int i;
for (i = 0 ; i < partitions->cnt ; i++) {
fprintf(stderr, "%s %s [%"PRId32"] offset %"PRId64,
i > 0 ? ",":"",
partitions->elems[i].topic,
partitions->elems[i].partition,
partitions->elems[i].offset);
}
fprintf(stderr, "\n");
}
static void rebalance_cb (rd_kafka_t *rk,
rd_kafka_resp_err_t err,
rd_kafka_topic_partition_list_t *partitions,
void *opaque) {
fprintf(stderr, "%% Consumer group rebalanced: ");
switch (err)
{
case RD_KAFKA_RESP_ERR__ASSIGN_PARTITIONS:
fprintf(stderr, "assigned:\n");
print_partition_list(stderr, partitions);
rd_kafka_assign(rk, partitions);
wait_eof += partitions->cnt;
break;
case RD_KAFKA_RESP_ERR__REVOKE_PARTITIONS:
fprintf(stderr, "revoked:\n");
print_partition_list(stderr, partitions);
rd_kafka_assign(rk, NULL);
wait_eof = 0;
break;
default:
fprintf(stderr, "failed: %s\n",
rd_kafka_err2str(err));
rd_kafka_assign(rk, NULL);
break;
}
}
static int describe_groups (rd_kafka_t *rk, const char *group) {
rd_kafka_resp_err_t err;
const struct rd_kafka_group_list *grplist;
int i;
err = rd_kafka_list_groups(rk, group, &grplist, 10000);
if (err) {
fprintf(stderr, "%% Failed to acquire group list: %s\n",
rd_kafka_err2str(err));
return -1;
}
for (i = 0 ; i < grplist->group_cnt ; i++) {
const struct rd_kafka_group_info *gi = &grplist->groups[i];
int j;
printf("Group \"%s\" in state %s on broker %d (%s:%d)\n",
gi->group, gi->state,
gi->broker.id, gi->broker.host, gi->broker.port);
if (gi->err)
printf(" Error: %s\n", rd_kafka_err2str(gi->err));
printf(" Protocol type \"%s\", protocol \"%s\", "
"with %d member(s):\n",
gi->protocol_type, gi->protocol, gi->member_cnt);
for (j = 0 ; j < gi->member_cnt ; j++) {
const struct rd_kafka_group_member_info *mi;
mi = &gi->members[j];
printf(" \"%s\", client id \"%s\" on host %s\n",
mi->member_id, mi->client_id, mi->client_host);
printf(" metadata: %d bytes\n",
mi->member_metadata_size);
printf(" assignment: %d bytes\n",
mi->member_assignment_size);
}
printf("\n");
}
if (group && !grplist->group_cnt)
fprintf(stderr, "%% No matching group (%s)\n", group);
rd_kafka_group_list_destroy(grplist);
return 0;
}
static void sig_usr1 (int sig) {
rd_kafka_dump(stdout, rk);
}
int main (int argc, char **argv) {
char mode = 'C';
char *brokers = "localhost:9092";
int opt;
rd_kafka_conf_t *conf;
rd_kafka_topic_conf_t *topic_conf;
char errstr[512];
const char *debug = NULL;
int do_conf_dump = 0;
char tmp[16];
rd_kafka_resp_err_t err;
char *group = NULL;
rd_kafka_topic_partition_list_t *topics;
int is_subscription;
int i;
quiet = !isatty(STDIN_FILENO);
/* Kafka configuration */
conf = rd_kafka_conf_new();
/* Set logger */
rd_kafka_conf_set_log_cb(conf, logger);
/* Quick termination */
snprintf(tmp, sizeof(tmp), "%i", SIGIO);
rd_kafka_conf_set(conf, "internal.termination.signal", tmp, NULL, 0);
/* Topic configuration */
topic_conf = rd_kafka_topic_conf_new();
while ((opt = getopt(argc, argv, "g:b:qd:eX:ADO")) != -1) {
switch (opt) {
case 'b':
brokers = optarg;
break;
case 'g':
group = optarg;
break;
case 'e':
exit_eof = 1;
break;
case 'd':
debug = optarg;
break;
case 'q':
quiet = 1;
break;
case 'A':
output = OUTPUT_RAW;
break;
case 'X':
{
char *name, *val;
rd_kafka_conf_res_t res;
if (!strcmp(optarg, "list") ||
!strcmp(optarg, "help")) {
rd_kafka_conf_properties_show(stdout);
exit(0);
}
if (!strcmp(optarg, "dump")) {
do_conf_dump = 1;
continue;
}
name = optarg;
if (!(val = strchr(name, '='))) {
fprintf(stderr, "%% Expected "
"-X property=value, not %s\n", name);
exit(1);
}
*val = '\0';
val++;
res = RD_KAFKA_CONF_UNKNOWN;
/* Try "topic." prefixed properties on topic
* conf first, and then fall through to global if
* it didnt match a topic configuration property. */
if (!strncmp(name, "topic.", strlen("topic.")))
res = rd_kafka_topic_conf_set(topic_conf,
name+
strlen("topic."),
val,
errstr,
sizeof(errstr));
if (res == RD_KAFKA_CONF_UNKNOWN)
res = rd_kafka_conf_set(conf, name, val,
errstr, sizeof(errstr));
if (res != RD_KAFKA_CONF_OK) {
fprintf(stderr, "%% %s\n", errstr);
exit(1);
}
}
break;
case 'D':
case 'O':
mode = opt;
break;
default:
goto usage;
}
}
if (do_conf_dump) {
const char **arr;
size_t cnt;
int pass;
for (pass = 0 ; pass < 2 ; pass++) {
if (pass == 0) {
arr = rd_kafka_conf_dump(conf, &cnt);
printf("# Global config\n");
} else {
printf("# Topic config\n");
arr = rd_kafka_topic_conf_dump(topic_conf,
&cnt);
}
for (i = 0 ; i < (int)cnt ; i += 2)
printf("%s = %s\n",
arr[i], arr[i+1]);
printf("\n");
rd_kafka_conf_dump_free(arr, cnt);
}
exit(0);
}
if (strchr("OC", mode) && optind == argc) {
usage:
fprintf(stderr,
"Usage: %s [options] <topic[:part]> <topic[:part]>..\n"
"\n"
"librdkafka version %s (0x%08x)\n"
"\n"
" Options:\n"
" -g <group> Consumer group (%s)\n"
" -b <brokers> Broker address (%s)\n"
" -e Exit consumer when last message\n"
" in partition has been received.\n"
" -D Describe group.\n"
" -O Get commmitted offset(s)\n"
" -d [facs..] Enable debugging contexts:\n"
" %s\n"
" -q Be quiet\n"
" -A Raw payload output (consumer)\n"
" -X <prop=name> Set arbitrary librdkafka "
"configuration property\n"
" Properties prefixed with \"topic.\" "
"will be set on topic object.\n"
" Use '-X list' to see the full list\n"
" of supported properties.\n"
"\n"
"For balanced consumer groups use the 'topic1 topic2..'"
" format\n"
"and for static assignment use "
"'topic1:part1 topic1:part2 topic2:part1..'\n"
"\n",
argv[0],
rd_kafka_version_str(), rd_kafka_version(),
group, brokers,
RD_KAFKA_DEBUG_CONTEXTS);
exit(1);
}
signal(SIGINT, stop);
signal(SIGUSR1, sig_usr1);
if (debug &&
rd_kafka_conf_set(conf, "debug", debug, errstr, sizeof(errstr)) !=
RD_KAFKA_CONF_OK) {
fprintf(stderr, "%% Debug configuration failed: %s: %s\n",
errstr, debug);
exit(1);
}
/*
* Client/Consumer group
*/
if (strchr("CO", mode)) {
/* Consumer groups require a group id */
if (!group)
group = "rdkafka_consumer_example";
if (rd_kafka_conf_set(conf, "group.id", group,
errstr, sizeof(errstr)) !=
RD_KAFKA_CONF_OK) {
fprintf(stderr, "%% %s\n", errstr);
exit(1);
}
/* Consumer groups always use broker based offset storage */
if (rd_kafka_topic_conf_set(topic_conf, "offset.store.method",
"broker",
errstr, sizeof(errstr)) !=
RD_KAFKA_CONF_OK) {
fprintf(stderr, "%% %s\n", errstr);
exit(1);
}
/* Set default topic config for pattern-matched topics. */
rd_kafka_conf_set_default_topic_conf(conf, topic_conf);
/* Callback called on partition assignment changes */
rd_kafka_conf_set_rebalance_cb(conf, rebalance_cb);
}
/* Create Kafka handle */
if (!(rk = rd_kafka_new(RD_KAFKA_CONSUMER, conf,
errstr, sizeof(errstr)))) {
fprintf(stderr,
"%% Failed to create new consumer: %s\n",
errstr);
exit(1);
}
/* Add brokers */
if (rd_kafka_brokers_add(rk, brokers) == 0) {
fprintf(stderr, "%% No valid brokers specified\n");
exit(1);
}
if (mode == 'D') {
int r;
/* Describe groups */
r = describe_groups(rk, group);
rd_kafka_destroy(rk);
exit(r == -1 ? 1 : 0);
}
/* Redirect rd_kafka_poll() to consumer_poll() */
rd_kafka_poll_set_consumer(rk);
topics = rd_kafka_topic_partition_list_new(argc - optind);
is_subscription = 1;
for (i = optind ; i < argc ; i++) {
/* Parse "topic[:part] */
char *topic = argv[i];
char *t;
int32_t partition = -1;
if ((t = strstr(topic, ":"))) {
*t = '\0';
partition = atoi(t+1);
is_subscription = 0; /* is assignment */
wait_eof++;
}
rd_kafka_topic_partition_list_add(topics, topic, partition);
}
if (mode == 'O') {
/* Offset query */
err = rd_kafka_committed(rk, topics, 5000);
if (err) {
fprintf(stderr, "%% Failed to fetch offsets: %s\n",
rd_kafka_err2str(err));
exit(1);
}
for (i = 0 ; i < topics->cnt ; i++) {
rd_kafka_topic_partition_t *p = &topics->elems[i];
printf("Topic \"%s\" partition %"PRId32,
p->topic, p->partition);
if (p->err)
printf(" error %s",
rd_kafka_err2str(p->err));
else {
printf(" offset %"PRId64"",
p->offset);
if (p->metadata_size)
printf(" (%d bytes of metadata)",
(int)p->metadata_size);
}
printf("\n");
}
goto done;
}
if (is_subscription) {
fprintf(stderr, "%% Subscribing to %d topics\n", topics->cnt);
if ((err = rd_kafka_subscribe(rk, topics))) {
fprintf(stderr,
"%% Failed to start consuming topics: %s\n",
rd_kafka_err2str(err));
exit(1);
}
} else {
fprintf(stderr, "%% Assigning %d partitions\n", topics->cnt);
if ((err = rd_kafka_assign(rk, topics))) {
fprintf(stderr,
"%% Failed to assign partitions: %s\n",
rd_kafka_err2str(err));
}
}
while (run) {
rd_kafka_message_t *rkmessage;
rkmessage = rd_kafka_consumer_poll(rk, 1000);
if (rkmessage) {
msg_consume(rkmessage);
rd_kafka_message_destroy(rkmessage);
}
}
done:
err = rd_kafka_consumer_close(rk);
if (err)
fprintf(stderr, "%% Failed to close consumer: %s\n",
rd_kafka_err2str(err));
else
fprintf(stderr, "%% Consumer closed\n");
rd_kafka_topic_partition_list_destroy(topics);
/* Destroy handle */
rd_kafka_destroy(rk);
/* Let background threads clean up and terminate cleanly. */
run = 5;
while (run-- > 0 && rd_kafka_wait_destroyed(1000) == -1)
printf("Waiting for librdkafka to decommission\n");
if (run <= 0)
rd_kafka_dump(stdout, rk);
return 0;
}