c - 如何减少连接的等待时间？

Question

连接服务器的简单脚本：

#include "hiredis.h"
int main(void) {
    int fd;

    unsigned int j;
    redisReply *reply;
    reply = redisConnect(&fd, "test.com", 6379);

    if (reply != NULL) {
        printf("Connection error: %s", reply->reply);
        exit(1);
    }

    reply = redisCommand(fd,"PING");
    printf("PONG: %s\n", reply->reply);
    freeReplyObject(reply);
}

如果服务器可用- 一切正常。如果没有 - 有很长的停顿。例如，如何将等待时间减少到 2 秒？

Answer 1

我对redis了解不多。但我假设，redisConnect 内部基本上也只是在阻塞 fd 上调用 connect()。

所以尝试使用setsockopt预先设置超时：

struct timeval timeout;
timeout.tv_usec = 0;
timeout.tv_sec = 2;
setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, (void *)&timeout, sizeof(timeout));

这将发送超时设置为 2 秒，对于接收，您基本上也这样做。

干杯，

Answer 2

You'll need to modify the hiredis library, and the anetTcpGenericConnect function to make connect timeout aware. There's an example here of how to do it.