hcl，json，go :我如何迭代JSON？
hcl，json，go :我如何迭代JSON？
提问于 2020-04-29 15:39:34
问题:我试图遍历JSON-content并像键、值对一样显示结果。
我已经写了一些读取hcl文件的代码，然后用hcldec.Decode解码这些文件，然后将结果转换成JSON。这些hcl文件定义应用程序的源和目标，如下所示：
source.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"
}
}target.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
}
}解码过程如下所示：
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其中decodeCtyToJson返回[]字节，如下所示：
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，当我尝试打印JSON-content时，我没有得到我想要的东西：
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(首先是想要的整个JSON漂亮的打印，然后我尝试遍历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我在这里的目标是最终能够遍历target.hcl中定义的所有属性(在本例中是每个cols的长度、名称和类型)。然后从该信息生成DDL代码，并最终在例如Presto中实现DDL。
但到目前为止，我还不能分离出这些信息。
任何关于如何做到这一点的建议都是值得感谢的。
谢谢，/b
回答 1
Stack Overflow用户
回答已采纳
发布于 2020-05-05 15:42:20
我的解决方案是为目标创建一个结构，而不是使用目标规范。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/61496581
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