如何重定向redis订阅的输出 [英] How to redirect the output of redis subscription

问题描述

我正在探索 redis 以进行发布/订阅.我想编写一个脚本，使用 redis-cli 订阅频道并将发布的任何内容转储到文件中.然而，我注意到的是 redis-cli 订阅频道 > 输出不太工作.

I am exploring redis to do pub/sub. I wanted to write a script that uses redis-cli to subscribe to a channel and dump whatever is published to a file. What I notice however is that redis-cli subscripe channel > output does not quite work.

非常感谢您的帮助.

问候，卡夏普

推荐答案

这是因为当 redis-cli 显示与订阅关联的消息时，没有自动刷新 stdout.所以停止redis-cli之前的最后一条消息不会出现在输出文件中.

This is because there is no automatic flush of stdout when redis-cli displays the messages associated to the subscription. So the last messages before stopping redis-cli do not appear in the output file.

没有选项可用于强制执行系统刷新，需要修补 redis-cli.c.在Redis源码中，编辑src/redis-cli.c，找到如下一段代码.添加缺少的 fflush 行.

There is no option you can use to enforce a systematic flush, redis-cli.c needs to be patched. In Redis source code, edit src/redis-cli.c, and find the following piece of code. Add the missing fflush line.

    if (config.pubsub_mode) {
        if (config.output != OUTPUT_RAW)
            printf("Reading messages... (press Ctrl-C to quit)\n");
        while (1) {
            if (cliReadReply(output_raw) != REDIS_OK) exit(1);
            // The following line must be added
            fflush(stdout);
        }
    }

重新编译 redis-cli 后，它应该可以正常工作.

Once redis-cli has been compiled again, it should work as expected.

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