Avro Schema and Arrays - avro

Question

In C# I can define these two POCOs to define generations
public class Family
{
public List<Person> FamilyMembers {get; set;}
}
public class Person
{
public string FirstName {get; set;}
public string LastName {get; set;}
public List<Person> Children {get; set;}
}
I am attempting to define an AVRO schema to serialize FamilyMembers to. Is it possible in Avro to define a recursive array (not sure if that's the proper term), rather than having to specify each generation in the schema like below.
{
"type": "record",
"name": "family",
"namespace": "com.family.my",
"fields": [
{
"name":"familymember",
"type":{
"type": "array",
"items":{
"name":"person",
"type":"record",
"fields":[
{"name":"firstname", "type":"string"},
{"name":"lastname", "type":"string"},
{"name":"children",
"type":{
"type": "array",
"items":{
"name":"children",
"type":"record",
"fields":[
{"name":"firstname", "type":"string"},
{"name":"lastname", "type":"string"},
{"name":"grandchildren",
"type":{
"type": "array",
"items":{
"name":"greatgrandchildren",
"type":"record",
"fields":[
{"name":"firstname", "type":"string"},
{"name":"lastname", "type":"string"}
]
}
}}
]
}
}}
]
}
}
}
]
}

Answer 1

Yes! After you define person, you may use it as the item type in the children array. For example:
{
"type": "record",
"name": "family",
"namespace": "com.family.my",
"fields": [{
"name":"familymember",
"type":{
"type": "array",
"items":{
"name":"person",
"type":"record",
"fields":[
{"name":"firstname", "type":"string"},
{"name":"lastname", "type":"string"},
{"name":"children", "type": { "type": "array", "items": "person" }}
]
}
}
}]
}
This sort of recursive schema is demonstrated by the LongList from the Avro spec:
{
"type": "record",
"name": "LongList",
"aliases": ["LinkedLongs"],
"fields" : [
{"name": "value", "type": "long"},
{"name": "next", "type": ["null", "LongList"]}
]
}