问题：我正在尝试遍历 JSON 内容并呈现键值对等结果。
我编写了一些读取 hcl 文件的代码，然后使用 hcldec.Decode 对这些代码进行解码，然后将结果转换为 JSON。这些 hcl 文件为应用程序定义源和目标，如下所示：
源.hcl：
source json "namefile" {
attr firstName {
type = "varchar"
expr = "$.firstName"
length = "30"
}
attr lastName {
type = "varchar"
expr = "$.lastName"
length = "40"
}
attr gender {
type = "varchar"
expr = "$.gender"
length = "10"
}
attr age {
type = "varchar"
expr = "$.age"
length = "2"
}
}
目标.hcl
target table {
cols firstName {
name=source.json.namefile.attr.firstName.expr
type=source.json.namefile.attr.firstName.type
length=source.json.namefile.attr.firstName.length
}
cols lastName {
name=source.json.namefile.attr.lastName.expr
type=source.json.namefile.attr.lastName.type
length=source.json.namefile.attr.lastName.length
}
}
解码是这样完成的：
tspec := hcldec.ObjectSpec{
"target": &hcldec.BlockMapSpec{
TypeName: "target",
LabelNames: []string{"table"},
Nested: hcldec.ObjectSpec{
"cols": &hcldec.BlockMapSpec{
TypeName: "cols",
LabelNames: []string{"name"},
Nested: &hcldec.ObjectSpec{
"name": &hcldec.AttrSpec{
Name: "name",
Type: cty.String, //cty.List(cty.String),
Required: false,
},
"type": &hcldec.AttrSpec{
Name: "type",
Type: cty.String, //cty.List(cty.String),
Required: false,
},
"length": &hcldec.AttrSpec{
Name: "length",
Type: cty.String, //cty.List(cty.String),
Required: false,
},
},
},
},
},
}
targ, _ := hcldec.Decode(body, tspec, &hcl.EvalContext{
Variables: map[string]cty.Value{
"source": val.GetAttr("source"),
},
Functions: nil,
})
j := decodeCtyToJson(targ, true)
log.Debugf("targ -j (spec): %s", string(j)) // debug info
decodeCtyToJson 像这样返回 []byte 的地方：
func decodeCtyToJson(value cty.Value, pretty bool) []byte {
jsonified, err := ctyjson.Marshal(value, cty.DynamicPseudoType)
if err != nil {
log.Debugf("Error: #v", err)
return nil
}
if pretty {
return jsonPretty.Pretty(jsonified)
}
return jsonified
}
现在，当我尝试测试打印 JSON 内容时，我没有得到我正在寻找的内容：
var result map[string]interface{}
json.Unmarshal(j, &result)
log.Debugf("result: %# v", result)
tgtfil := result["value"].(map[string]interface{})
log.Debugf("tgtfil: %v", tgtfil)
log.Debugf("len(tgtfil): %# v", len(tgtfil))
for key, value := range tgtfil {
log.Debugf("key: %# v", key)
log.Debugf("value: %# v", value)
}
我正在尝试获取键值对。但是我得到了这个（首先是整个 JSON 的漂亮打印，然后我试图遍历 JSON）：
DEBU[0000] targ -j (spec): {
"value": {
"target": {
"table": {
"cols": {
"firstName": {
"length": "30",
"name": "$.firstName",
"type": "varchar"
},
"lastName": {
"length": "40",
"name": "$.lastName",
"type": "varchar"
}
}
}
}
},
"type": [
"object",
{
"target": [
"map",
[
"object",
{
"cols": [
"map",
[
"object",
{
"length": "string",
"name": "string",
"type": "string"
}
]
]
}
]
]
}
]
}
DEBU[0000] result: map[string]interface {}{"type":[]interface {}{"object", map[string]interface {}{"target":[]interface {}{"map", []interface {}{"object", map[string]interface {}{"cols":[]interface {}{"map", []interface {}{"object", map[string]interface {}{"length":"string", "name":"string", "type":"string"}}}}}}}}, "value":map[string]interface {}{"target":map[string]interface {}{"table":map[string]interface {}{"cols":map[string]interface {}{"firstName":map[string]interface {}{"length":"30", "name":"$.firstName", "type":"varchar"}, "lastName":map[string]interface {}{"length":"40", "name":"$.lastName", "type":"varchar"}}}}}}
DEBU[0000] tgtfil: map[target:map[table:map[cols:map[firstName:map[length:30 name:$.firstName type:varchar] lastName:map[length:40 name:$.lastName type:varchar]]]]]
DEBU[0000] len(tgtfil): 1
DEBU[0000] key: "target"
DEBU[0000] value: map[string]interface {}{"table":map[string]interface {}{"cols":map[string]interface {}{"firstName":map[string]interface {}{"length":"30", "name":"$.firstName", "type":"varchar"}, "lastName":map[string]interface {}{"length":"40", "name":"$.lastName", "type":"varchar"}}}}
Process finished with exit code 0
我的目标是最终能够遍历 target.hcl 中定义的所有属性（在这种情况下，每个 cols 的长度、名称和类型）。然后根据这些信息生成 DDL 代码，最后在 Presto 中实现 DDL。
但截至目前，我无法隔离这些信息。
任何有关如何执行此操作的指示都值得赞赏。
谢谢，/b