avro_derive

A proc-macro module for automatically deriving the avro schema for structs or enums. The macro produces the logic necessary to implement the AvroSchema trait for the type.

pub trait AvroSchema {
    // constructs the schema for the type
    fn get_schema() -> Schema;
}

How-to use

Add the "derive" feature to your apache-avro dependency inside cargo.toml

apache-avro = { version = "X.Y.Z", features = ["derive"] }

Add to your data model

#[derive(AvroSchema)]
struct Test {
    a: i64,
    b: String,
}

Example

use apache_avro::Writer;

#[derive(Debug, Serialize, AvroSchema)]
struct Test {
    a: i64,
    b: String,
}
// derived schema, always valid or code fails to compile with a descriptive message
let schema = Test::get_schema();

let mut writer = Writer::new(&schema, Vec::new());
let test = Test {
    a: 27,
    b: "foo".to_owned(),
};
writer.append_ser(test).unwrap();
let encoded = writer.into_inner();

Compatibility Notes

This module is designed to work in concert with the Serde implementation. If your use case dictates needing to manually convert to a Value type in order to encode then the derived schema may not be correct.