如何从接口中提取数据

Question

我正在使用 Redigo 从 Redis 检索指标。虽然该包有一些内置的帮助程序来解析某些格式的响应中的数据，但我有一个我需要解析的格式，它没有被涵盖。

该命令的结果是接口类型，包含一个长度不确定的数组，每个数组中包含一组数据。如果我将结果作为字符串打印出来，我会得到（添加换行符以提高可读性）......

[

      [name cgroup1 consumers %!s(int64=2) pending %!s(int64=90) last-delivered-id 1582572156729-0] 

      [name cgroup2 consumers %!s(int64=2) pending %!s(int64=110) last-delivered-id 1582572156729-0]

]

我将如何在 Go 中迭代这样的响应并访问数据。我发现了很多处理 JSON 和解组的示例，但没有发现与上述类似的示例。

使用的redis命令是...

xinfo groups <stream name>

Redis 中的数据，看起来是这样的……

1) 1) "name"

   2) "cgroup1"

   3) "consumers"

   4) (integer) 2

   5) "pending"

   6) (integer) 90

   7) "last-delivered-id"

   8) "1582572156729-0"

2) 1) "name"

   2) "cgroup2"

   3) "consumers"

   4) (integer) 2

   5) "pending"

   6) (integer) 110

   7) "last-delivered-id"

   8) "1582572156729-0"

如果我打印出它显示的类型...

[]interface {}

另一个问题是如何提取嵌套更深的信息。

例如

XINFO STREAM <stream name>

我可以使用 ScanStruct 从第一级获取所有内容，但似乎无法获取第一个条目下的信息。

我的信息结构

type Stream struct {

    Length int    `redis:"length"`

    Groups int    `redis:"groups"`

    LastID string `redis:"last-generated-id"`

}

如果我尝试从下面添加第一个条目，我不确定要使用什么类型或如何获取值 12[1] (1582572131616-0)

示例 Redis 输出

127.0.0.1:6379> xinfo stream stream1

 1) "length"

 2) (integer) 1200

 3) "radix-tree-keys"

 4) (integer) 12

 5) "radix-tree-nodes"

 6) (integer) 30

 7) "groups"

 8) (integer) 2

 9) "last-generated-id"

10) "1582642828055-10"

11) "first-entry"

12) 1) "1582572131616-0"

    2) 1) "payload"

       2) "message:0"

13) "last-entry"

14) 1) "1582642828055-10"

    2) 1) "payload"

       2) "message:99"

Answer 1

使用redis.Values转换interface{}为切片。使用redis.ScanStruct从名称-值对的切片中设置结构字段。type Group struct {&nbsp; &nbsp; Name&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; string `redis:"name"`&nbsp; &nbsp; Consumers&nbsp; &nbsp; &nbsp; &nbsp;int&nbsp; &nbsp; `redis:"consumers"`&nbsp; &nbsp; Pending&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;int&nbsp; &nbsp; `redis:"pending"`&nbsp; &nbsp; LastDeliveredID string `redis:"last-delivered-id"`}func scanGroups(resp interface{}, err error) ([]*Group, error) {&nbsp; &nbsp; // Get slice from resp&nbsp; &nbsp; groups, err := redis.Values(resp, err)&nbsp; &nbsp; if err != nil {&nbsp; &nbsp; &nbsp; &nbsp; return nil, err&nbsp; &nbsp; }&nbsp; &nbsp; var result []*Group&nbsp; &nbsp; // For each group&nbsp; &nbsp; for _, g := range groups {&nbsp; &nbsp; &nbsp; &nbsp; // Get slice for group&nbsp; &nbsp; &nbsp; &nbsp; v, err := redis.Values(g, nil)&nbsp; &nbsp; &nbsp; &nbsp; if err != nil {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return nil, err&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; // Scan slice to struct&nbsp; &nbsp; &nbsp; &nbsp; var group Group&nbsp; &nbsp; &nbsp; &nbsp; err = redis.ScanStruct(v, &group)&nbsp; &nbsp; &nbsp; &nbsp; if err != nil {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return nil, err&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; // Accumlate result&nbsp; &nbsp; &nbsp; &nbsp; result = append(result, &group)&nbsp; &nbsp; }&nbsp; &nbsp; return result, nil}像这样使用它：&nbsp;groups, err := scanGroups(conn.Do("XINFO", "GROUPS", "mystream"))