调试

调试 Redis 堆栈函数的方法

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概述

您可以使用两种方法来调试 Redis Stack 函数：

明智地使用redis.log函数，该函数写入 Redis 日志文件。
使用 Redis pub/sub。

用`redis.log`

如果您有权访问 Redis 日志文件，redis.log是调试时使用的好方法。但是，有一个缺点。Redis Cloud 用户无权访问 Redis 日志文件，在自托管安装中，只有系统管理员才能访问这些文件，这很常见。幸运的是，您还可以使用 Redis pub/sub，这将在下一节中讨论。

您无需执行任何特殊作即可使用redis.log，因为它始终可用。下面是一个示例：

#!js api_version=1.0 name=lib

redis.registerFunction('hello', ()=> {
  redis.log('Hello log')
  return 'Hello from an external file'
})

After loading the library and executing the function with TFCALL, you'll see something like the following in your Redis log file:


45718:M 01 Nov 2023 07:02:40.593 * <redisgears_2> Hello log
Use Redis pub/sub
If you don't have access to your Redis database log files, you can use pub/sub. The following example demonstrates how to use the client.call API to publish to a pub/sub channel.
#!js api_version=1.0 name=lib

const logChannel = 'tfLogChannel'

function publog(client, message) {
  client.call('publish', logChannel, message)
}

redis.registerFunction('tflog', (client) => {
  publog(client, 'sample pub/sub log message')
  return 'sample'
})
In a CLI session, subscribe to the tfLogChannel channel and watch for messages.

$ redis-cli
127.0.0.1:6379> subscribe tfLogChannel
1) "subscribe"
2) "tfLogChannel"
3) (integer) 1
Reading messages... (press Ctrl-C to quit or any key to type command)
In another CLI session, load the library, replacing what was already there, and then call the new function:
127.0.0.1:6379> TFCALL lib.tflog 0
"sample"
You'll see the following in the previous CLI session:
1) "message"
2) "tfLogChannel"
3) "sample pub/sub log message"
There is a downside to using pub/sub. Redis pub/sub provides at-most-once message delivery semantics, which means that once a message is sent, it won't be sent again. So, if a message isn't consumed, it's gone forever. This is likely okay for debugging, but for the longer term, redis.log is the better solution for log persistence.

调试

概述

用redis.log

Use Redis pub/sub

On this page

用`redis.log`