Kafka Client C --Producer && Consumer
运行环境：Windows 10 64位、Visual Stdio 2017 Community、kafka_2.12-3.3.1.tgz
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一、Kafka Client C库
Kafka官网只提供Java版本的Client 库，不过有第三方维护的其他语言版本的Client库。
博主选择下载C版本的Client 库，还需要下载example 的源文件，下载链接如下：
???? librdkafka.redist/1.9.2(包含Client库 和 依赖文件； 注意：下载的压缩包后缀.nupkg，需要修改后缀为.zip)
???? librdkafka（包含producer.c、comsumer.c等源文件）
二、Producer
???? 第一步
在Visual Stdio 2017创建空项目，添加producer.c源文件
???? 第二步
???? 第三步
-
项目-->属性-->添加头文件目录
-
项目-->属性-->添加库文件目录
-
项目-->属性-->添加库文件
???? 第三步
将librdkafka\examples\producer.c文件内容复制到项目源文件producer.c中，并作部分修改
/*
* librdkafka - Apache Kafka C library
*
* Copyright (c) 2017, 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.
*/
/**
* Simple Apache Kafka producer
* using the Kafka driver from librdkafka
* (https://github.com/edenhill/librdkafka)
*/
#include
#include
#include
/* Typical include path would be , but this program
* is builtin from within the librdkafka source tree and thus differs. */
#include "rdkafka.h"
static volatile sig_atomic_t run = 1;
/**
* @brief Signal termination of program
*/
static void stop(int sig) {
run = 0;
fclose(stdin); /* abort fgets() */
}
/**
* @brief Message delivery report callback.
*
* This callback is called exactly once per message, indicating if
* the message was succesfully delivered
* (rkmessage->err == RD_KAFKA_RESP_ERR_NO_ERROR) or permanently
* failed delivery (rkmessage->err != RD_KAFKA_RESP_ERR_NO_ERROR).
*
* The callback is triggered from rd_kafka_poll() and executes on
* the application's thread.
*/
static void
dr_msg_cb(rd_kafka_t *rk, const rd_kafka_message_t *rkmessage, void *opaque) {
if (rkmessage->err)
fprintf(stderr, "%% Message delivery failed: %s\n",
rd_kafka_err2str(rkmessage->err));
else
fprintf(stderr,
"%% Message delivered (%zd bytes, "
"partition %" PRId32 ")\n",
rkmessage->len, rkmessage->partition);
/* The rkmessage is destroyed automatically by librdkafka */
}
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 */
const char *brokers = "10.8.198.62:9092"; /* Argument: broker list */
const char *topic = "data-time"; /* Argument: topic to produce to */
/*
* Argument validation
*/
//if (argc != 3) {
// fprintf(stderr, "%% Usage: %s \n", argv[0]);
// return 1;
//}
//brokers = argv[1];
//topic = argv[2];
/*
* 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,
"%% 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 && fgets(buf, sizeof(buf), stdin)) {
size_t len = strlen(buf);
rd_kafka_resp_err_t err;
if (buf[len - 1] == '\n') /* Remove newline */
buf[--len] = '\0';
if (len == 0) {
/* Empty line: only serve delivery reports */
rd_kafka_poll(rk, 0 /*non-blocking */);
continue;
}
/*
* Send/Produce message.
* This is an asynchronous call, on success it will only
* enqueue the message on the internal producer queue.
* The actual delivery attempts to the broker are handled
* by background threads.
* The previously registered delivery report callback
* (dr_msg_cb) is used to signal back to the application
* when the message has been delivered (or failed).
*/
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(buf, 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;
}
???? 第四步
编译、运行(项目路径下生成了Debug文件夹)：
出现报错，原因是：未将.dll文件放置到.exe相同文件夹下。
解决方法：将librdkafka.redist.1.9.2\runtimes\win-x86\native文件夹下所有.dll文件复制到Kafka_Producer\Debug文件夹下
再次编译、运行，结果成功
???? 第五步
验证生产者发布消息，命令行启动消费者订阅主题：data-time，如下启动消费者订阅，请参考Kafka Server的运行
出现上图结果，说明生产者成功发布消息
三、Consumer
???? 第一步
在Visual Stdio 2017创建空项目，添加Consumer.c源文件
???? 第二步
???? 第三步（详细操作过程，请参考Producer）
-
项目-->属性-->添加头文件目录
-
项目-->属性-->添加库文件目录
-
项目-->属性-->添加库文件
???? 第四步
将librdkafka\examples\consumer.c文件内容复制到项目源文件consumer.c中，并作部分修改
/*
* librdkafka - Apache Kafka C library
*
* Copyright (c) 2019, 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.
*/
/**
* Simple high-level balanced Apache Kafka consumer
* using the Kafka driver from librdkafka
* (https://github.com/edenhill/librdkafka)
*/
#include
#include
#include
#include
/* Typical include path would be , but this program
* is builtin from within the librdkafka source tree and thus differs. */
//#include
#include "rdkafka.h"
static volatile sig_atomic_t run = 1;
/**
* @brief Signal termination of program
*/
static void stop(int sig) {
run = 0;
}
/**
* @returns 1 if all bytes are printable, else 0.
*/
static int is_printable(const char *buf, size_t size) {
size_t i;
for (i = 0; i < size; i++)
if (!isprint((int)buf[i]))
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 = "10.8.198.62:9092"; /* Argument: broker list */
const char *groupid = "ClientConsumer"; /* Argument: Consumer group id */
char *topic = "data-time";
char **topics = &topic; /* Argument: list of topics to subscribe to */
int topic_cnt = 1; /* Number of topics to subscribe to */
rd_kafka_topic_partition_list_t *subscription; /* Subscribed topics */
int i;
/*
* Argument validation
*/
//if (argc < 4) {
// fprintf(stderr,
// "%% Usage: "
// "%s ..\n",
// argv[0]);
// return 1;
//}
//brokers = argv[1];
//groupid = argv[2];
//topics = &argv[3];
//topic_cnt = argc - 3;
/*
* 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(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(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;
}
???? 第五步
编译、运行，producer发布消息（利用编译好的producer.exe），consumer订阅消息
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