docs: fix docs

docs/src/en/filter/function.md

@@ -2,17 +2,17 @@
 outline: deep
 ---
 
-# 什么是 function
+# What is function
 
-RedisShake 通过提供 function 功能，实现了的 [ETL(提取-转换-加载)](https://en.wikipedia.org/wiki/Extract,_transform,_load) 中的 `transform` 能力。通过利用 function 可以实现类似功能：
-* 更改数据所属的 `db`，比如将源端的 `db 0` 写入到目的端的 `db 1`。
-* 对数据进行筛选，例如，只将 key 以 `user:` 开头的源数据写入到目标端。
-* 改变 Key 的前缀，例如，将源端的 key `prefix_old_key` 写入到目标端的 key `prefix_new_key`。
+RedisShake provides a function feature that implements the `transform` capability in [ETL (Extract-Transform-Load)](https://en.wikipedia.org/wiki/Extract,_transform,_load). By utilizing functions, you can achieve similar functionalities:
+* Change the `db` to which data belongs, for example, writing data from source `db 0` to destination `db 1`.
+* Filter data, for instance, only writing source data with keys starting with `user:` to the destination.
+* Modify key prefixes, such as writing a source key `prefix_old_key` to a destination key `prefix_new_key`.
 * ...
 
-要使用 function 功能，只需编写一份 lua 脚本。RedisShake 在从源端获取数据后，会将数据转换为 Redis 命令。然后，它会处理这些命令，从中解析出 `KEYS`、`ARGV`、`SLOTS`、`GROUP` 等信息，并将这些信息传递给 lua 脚本。lua 脚本会处理这些数据，并返回处理后的命令。最后，RedisShake 会将处理后的数据写入到目标端。
+To use the function feature, you only need to write a Lua script. After RedisShake retrieves data from the source, it converts the data into Redis commands. Then, it processes these commands, parsing information such as `KEYS`, `ARGV`, `SLOTS`, `GROUP`, and passes this information to the Lua script. The Lua script processes this data and returns the processed commands. Finally, RedisShake writes the processed data to the destination.
 
-以下是一个具体的例子：
+Here's a specific example:
 ```toml
 function = """
 shake.log(DB)
@@ -29,28 +29,119 @@ address = "127.0.0.1:6379"
 [redis_writer]
 address = "127.0.0.1:6380"
 ```
-`DB` 是 RedisShake 提供的信息，表示当前数据所属的 db。`shake.log` 用于打印日志，`shake.call` 用于调用 Redis 命令。上述脚本的目的是丢弃源端 `db` 0 的数据，将其他 `db` 的数据写入到目标端。
+`DB` is information provided by RedisShake, indicating the db to which the current data belongs. `shake.log` is used for logging, and `shake.call` is used to call Redis commands. The purpose of the above script is to discard data from source `db 0` and write data from other `db`s to the destination.
 
-除了 `DB`，还有其他信息如 `KEYS`、`ARGV`、`SLOTS`、`GROUP` 等，可供调用的函数有 `shake.log` 和 `shake.call`，具体请参考 [function API](#function-api)。
-
-关于更多的示例，可以参考 [最佳实践](./best_practices.md)。
+In addition to `DB`, there is other information such as `KEYS`, `ARGV`, `SLOTS`, `GROUP`, and available functions include `shake.log` and `shake.call`. For details, please refer to [function API](#function-api).
 
 ## function API
 
-### 变量
+### Variables
 
-因为有些命令中含有多个 key，比如 `mset` 等命令。所以，`KEYS`、`KEY_INDEXES`、`SLOTS` 这三个变量都是数组类型。如果确认命令只有一个 key，可以直接使用 `KEYS[1]`、`KEY_INDEXES[1]`、`SLOTS[1]`。
+Because some commands contain multiple keys, such as the `mset` command, the variables `KEYS`, `KEY_INDEXES`, and `SLOTS` are all array types. If you are certain that a command has only one key, you can directly use `KEYS[1]`, `KEY_INDEXES[1]`, `SLOTS[1]`.
 
-| 变量 | 类型 | 示例 | 描述 |
+| Variable | Type | Example | Description |
 |-|-|-|-----|
-| DB | number | 1 | 命令所属的 `db` |
-| GROUP | string | "LIST" | 命令所属的 `group`，符合 [Command key specifications](https://redis.io/docs/reference/key-specs/)，可以在 [commands](https://github.com/tair-opensource/RedisShake/tree/v4/scripts/commands) 中查询每个命令的 `group` 字段 |
-| CMD | string | "XGROUP-DELCONSUMER" | 命令的名称 |
-| KEYS | table | \{"key1", "key2"\} | 命令的所有 Key |
-| KEY_INDEXES | table | \{2, 4\} | 命令的所有 Key 在 `ARGV` 中的索引 |
-| SLOTS | table | \{9189, 4998\} | 当前命令的所有 Key 所属的 [slot](https://redis.io/docs/reference/cluster-spec/#key-distribution-model) |
-| ARGV | table | \{"mset", "key1", "value1", "key2", "value2"\} | 命令的所有参数 |
-
-### 函数
-* `shake.call(DB, ARGV)`：返回一个 Redis 命令，RedisShake 会将该命令写入目标端。
-* `shake.log(msg)`：打印日志。
+| DB | number | 1 | The `db` to which the command belongs |
+| GROUP | string | "LIST" | The `group` to which the command belongs, conforming to [Command key specifications](https://redis.io/docs/reference/key-specs/). You can check the `group` field for each command in [commands](https://github.com/tair-opensource/RedisShake/tree/v4/scripts/commands) |
+| CMD | string | "XGROUP-DELCONSUMER" | The name of the command |
+| KEYS | table | {"key1", "key2"} | All keys of the command |
+| KEY_INDEXES | table | {2, 4} | The indexes of all keys in `ARGV` |
+| SLOTS | table | {9189, 4998} | The [slots](https://redis.io/docs/reference/cluster-spec/#key-distribution-model) to which all keys of the current command belong |
+| ARGV | table | {"mset", "key1", "value1", "key2", "value2"} | All parameters of the command |
+
+### Functions
+* `shake.call(DB, ARGV)`: Returns a Redis command that RedisShake will write to the destination.
+* `shake.log(msg)`: Prints logs.
+
+## Best Practices
+
+
+### Filtering Keys
+
+```lua
+local prefix = "user:"
+local prefix_len = #prefix
+
+if string.sub(KEYS[1], 1, prefix_len) ~= prefix then
+  return
+end
+
+shake.call(DB, ARGV)
+```
+
+The effect is to only write source data with keys starting with `user:` to the destination. This doesn't consider cases of multi-key commands like `mset`.
+
+### Filtering DB
+
+```lua
+shake.log(DB)
+if DB == 0
+then
+    return
+end
+shake.call(DB, ARGV)
+```
+
+The effect is to discard data from source `db 0` and write data from other `db`s to the destination.
+
+
+### Filtering Certain Data Structures
+
+You can use the `GROUP` variable to determine the data structure type. Supported data structure types include: `STRING`, `LIST`, `SET`, `ZSET`, `HASH`, `SCRIPTING`, etc.
+
+#### Filtering Hash Type Data
+```lua
+if GROUP == "HASH" then
+  return
+end
+shake.call(DB, ARGV)
+```
+
+The effect is to discard `hash` type data from the source and write other data to the destination.
+
+#### Filtering [LUA Scripts](https://redis.io/docs/interact/programmability/eval-intro/)
+
+```lua
+if GROUP == "SCRIPTING" then
+  return
+end
+shake.call(DB, ARGV)
+```
+
+The effect is to discard `lua` scripts from the source and write other data to the destination. This is common when synchronizing from master-slave to cluster, where there are LUA scripts not supported by the cluster.
+
+### Modifying Key Prefixes
+
+```lua
+local prefix_old = "prefix_old_"
+local prefix_new = "prefix_new_"
+
+shake.log("old=" .. table.concat(ARGV, " "))
+
+for i, index in ipairs(KEY_INDEXES) do
+  local key = ARGV[index]
+  if string.sub(key, 1, #prefix_old) == prefix_old then
+    ARGV[index] = prefix_new .. string.sub(key, #prefix_old + 1)
+  end
+end
+
+shake.log("new=" .. table.concat(ARGV, " "))
+shake.call(DB, ARGV)
+```
+The effect is to write the source key `prefix_old_key` to the destination key `prefix_new_key`.
+
+### Swapping DBs
+
+```lua
+local db1 = 1
+local db2 = 2
+
+if DB == db1 then
+  DB = db2
+elseif DB == db2 then
+  DB = db1
+end
+shake.call(DB, ARGV)
+```
+
+The effect is to write source `db 1` to destination `db 2`, write source `db 2` to destination `db 1`, and leave other `db`s unchanged.

docs/src/en/guide/introduction.md

@@ -32,7 +32,7 @@ Versions (configurations are not interchangeable between different versions):
 
 - The [RedisShake 2.x](https://github.com/tair-opensource/RedisShake/tree/v2) version brought a series of improvements and updates, enhancing its overall stability and performance.
 - The [RedisShake 3.x](https://github.com/tair-opensource/RedisShake/tree/v3) version was a significant milestone, with the entire codebase being completely rewritten and optimized for better efficiency and availability.
-- The [RedisShake 4.x](https://github.com/tair-opensource/RedisShake/tree/v4) version further enhanced features related to the [Reader](../reader/scan_reader.md), configuration, observability, and [function](../function/introduction.md).
+- The [RedisShake 4.x](https://github.com/tair-opensource/RedisShake/tree/v4) version further enhanced features related to the [Reader](../reader/scan_reader.md), configuration, observability, and `function`.
 
 ## License
 

docs/src/zh/filter/function.md

@@ -33,8 +33,6 @@ address = "127.0.0.1:6380"
 
 除了 `DB`，还有其他信息如 `KEYS`、`ARGV`、`SLOTS`、`GROUP` 等，可供调用的函数有 `shake.log` 和 `shake.call`，具体请参考 [function API](#function-api)。
 
-关于更多的示例，可以参考 [最佳实践](./best_practices.md)。
-
 ## function API
 
 ### 变量

docs/src/zh/guide/introduction.md

@@ -36,7 +36,7 @@ RedisShake 是阿里云 [Tair 团队](https://github.com/tair-opensource)
 - [RedisShake 2.x](https://github.com/tair-opensource/RedisShake/tree/v2) 版本带来了一系列的改进和更新，提高了其整体稳定性和性能。
 - [RedisShake 3.x](https://github.com/tair-opensource/RedisShake/tree/v3) 版本是一个重要的里程碑，整个代码库被完全重写和优化，具有更好的效率和可用性。
 - [RedisShake 4.x](https://github.com/tair-opensource/RedisShake/tree/v4) 版本
-  ，进一步增强了 [Reader](../reader/scan_reader.md)、配置、可观察性和 [function](../function/introduction.md) 相关的特性。
+  ，进一步增强了 [Reader](../reader/scan_reader.md)、配置、可观察性和 function 相关的特性。
 
 ## 许可证