Is it possible to create Avro schema for Dictionary object

Question

Trying to implement avro serialization and deserialization in .net for kafka messages. Message model as follows.

public class SampleMessage
{
    public string Hash{ get; set; }
    public string FileName { get; set; }
    public string Data { get; set; }
    public Dictionary<string, string> Content { get; set; }
    public string LineDetails { get; set; }
}

So, Is it possible to create Avro schema for Dictionary in c#?

Answer 1

Yes. For that, you should use the complex type "map" (https://avro.apache.org/docs/current/spec.html#Maps

Maps use the type name "map" and support one attribute:

values: the schema of the map's values.

Map keys are assumed to be strings.

Given the example, your .avsc would look something like this:

{
    "type": "record",
    "name": "SampleMessage",
    "namespace": "samplemessage",
    "fields": [
        {
            "name": "hash",
            "type": "string"
        },
        {
            "name": "fileName",
            "type": "string"
        },
        {
            "name": "data",
            "type": "string"
        },
        {
            "name": "content",
            "type": {
                "type": "map",
                "values": "string"
            }
        },
        {
            "name": "lineDetails",
            "type": "string"
        }
    ]
}