使用zookeeper获取brokers的信息
Table of Contents
- 1. 在ArchLinux上安装libzookeeper
- 2. include 头文件
- 3. 现在编写代码
- 4. 运行程序
- 5. 后续要解决
1 在ArchLinux上安装libzookeeper
yaourt -S libzookeeper
这样会安装最新版本3.4.7-1, 由于 3.4客户端兼容3.3 server，所以应该问题不大。如果不幸，可以下载源代码自己编译。
2 include 头文件
上面的方式会将头文件安装到/usr/include/zookeeper/目录
#include <zookeeper/zookeeper.h> #include <zookeeper/zookeeper.jute.h>
3 现在编写代码
读取zookeeper的例子来源于rdkafkazookeeperexample.c(0.8 branch), 为了和C++代码一起使用做了修改。 这是main函数的部份代码。
int main (int argc, char **argv) {
/*
* Process kill signal, quit from the loop
*/
signal(SIGINT, sigterm);
signal(SIGTERM, sigterm);
/*
* Create configuration objects
*/
RdKafka::Conf * global_conf = RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL);
RdKafka::Conf * topic_conf = RdKafka::Conf::create(RdKafka::Conf::CONF_TOPIC);
/** Initialize zookeeper */
string zookeeper("localhost:2181");
zhandle_t * zh = initialize_zookeeper(zookeeper);
/*
* Set configuration properties
*/
char brokers[1024];
set_brokerlist_from_zookeeper(zh, brokers);
string errstr;
cout << "brokers from zookeeper is: " << brokers << endl;
global_conf->set("metadata.broker.list", brokers, errstr);
几个C函数代码实现
#include "librdkafka/rdkafka.h" /* for Kafka driver */
#include <zookeeper/zookeeper.h>
#include <zookeeper/zookeeper.jute.h>
#include <jansson.h>
using std::string;
using std::list;
using std::cout;
using std::endl;
static bool run = true;
static bool exit_eof = true;
static rd_kafka_t *rk;
#define BROKER_PATH "/brokers/ids"
static void set_brokerlist_from_zookeeper(zhandle_t *zzh, char *brokers) {
if (zzh) {
struct String_vector brokerlist;
if (zoo_get_children(zzh, BROKER_PATH, 1, &brokerlist) != ZOK) {
fprintf(stderr, "No brokers found on path %s\n", BROKER_PATH);
return;
}
int i;
char *brokerptr = brokers;
for (i = 0; i < brokerlist.count; i++) {
char path[255], cfg[1024];
sprintf(path, "/brokers/ids/%s", brokerlist.data[i]);
int len = sizeof(cfg);
zoo_get(zzh, path, 0, cfg, &len, NULL);
if (len > 0) {
cfg[len] = '\0';
json_error_t jerror;
json_t *jobj = json_loads(cfg, 0, &jerror);
if (jobj) {
json_t *jhost = json_object_get(jobj, "host");
json_t *jport = json_object_get(jobj, "port");
if (jhost && jport) {
const char *host = json_string_value(jhost);
const int port = json_integer_value(jport);
sprintf(brokerptr, "%s:%d", host, port);
brokerptr += strlen(brokerptr);
if (i < brokerlist.count - 1) {
*brokerptr++ = ',';
}
}
json_decref(jobj);
}
}
}
deallocate_String_vector(&brokerlist);
printf("Found brokers %s\n", brokers);
}
}
static void watcher(zhandle_t *zh, int type, int state, const char *path, void *watcherCtx)
{
char brokers[1024];
if (type == ZOO_CHILD_EVENT && strncmp(path, BROKER_PATH, sizeof(BROKER_PATH) - 1) == 0)
{
brokers[0] = '\0';
set_brokerlist_from_zookeeper(zh, brokers);
if (brokers[0] != '\0' && rk != NULL)
{
rd_kafka_brokers_add(rk, brokers);
rd_kafka_poll(rk, 10);
}
}
}
static zhandle_t* initialize_zookeeper(string const& zookeeper) {
zhandle_t * zh = zookeeper_init(zookeeper.c_str(), watcher, 10000, 0, 0, 0);
if (zh == NULL) {
fprintf(stderr, "Zookeeper connection not established.");
exit(1);
}
return zh;
}
4 运行程序
可以看到打印出从zookeeper中读取到的broker list, broker之间用,隔开
brokers from zookeeper is: localhost.localdomain:9093,localhost.localdomain:9094
5 后续要解决
读取topic的partition等信息，能够自动获取所有partition的消息。