goavro无法使用架构验证json数据

Question

I'm new to go and avro and struggling with validating data.I have this avro schema

{
  "namespace": "com.input",
  "name": "parent",
  "type": "record",
  "fields": [
{
  "name": "field1",
  "type": [
    "null",
    {
      "type": "record",
      "name": "child",
      "fields": [
        {
          "name": "child1",
          "type": "string"
        },
        {
          "name": "child2",
          "type": "string"
        }
      ]
    }
  ]
}
]
}

Data to be validated:

{
 "field1": {
 "child1": "1",
 "child2": "abc"
}
}

This is the code which i'm using to validate using goavro library:

func loadMockData() (stringFormatData string) {
    mockData, err := ioutil.ReadFile("sample.json")
    if err != nil {
        log.Println(err)
    }
    return string(mockData)
}

func loadSchema() (stringFormatData string) {
    mockSchema, err := ioutil.ReadFile("schema.avsc")
    if err != nil {
        log.Println(err)
    }
    return string(mockSchema)
}

avroSchema := loadSchema()
jsonString := loadMockData()

codec, err := goavro.NewCodec(avroSchema)
decoded, _, err := codec.NativeFromTextual([]byte(jsonString))

This gives me following error: NativeFromTextual error: cannot decode textual record "com.input.parent": cannot decode textual union: cannot decode textual map: cannot determine codec: "parentid"

I tried debugging the goavro library, seems that fieldcodec remains nil for parentid in map.go. With simple fields this setting works fine. Problem is with nested data its not able to get codec for parentid.

Any help is much appreciated.