avro-cado: Encode and Decode using a schema-registry

Features

• Simple package that implements Avro encoding and decoding
• Written in Typescript
• Follows the Avro serialization conventions of Confluent's Schema Registry. During deserialization, schemas are obtained from the registry using their 4-byte id prefix. When serializing data, schemas are registered to the registry and obtain the corresponding 4-byte id prefix.
• Easy to use interface. All of Confluent's Schema Registry flows are implemented in the package
• Supports evolution. Converts Avro-encoded payloads into a format specified by the application's Avro schema.

Sample use case

• We use this to encode and decode messages when consuming and producing to Kakfa

Installation

npm install avro-cado

Examples

Avro schema

// Avro schema
const avroSchema = {
  type: "record",
  name: "TestMessage",
  namespace: "com.flipp.node.kafka.TestMessage",
  doc: "Properties related to a TestMessage.",
  fields: [
    {
      name: "key",
      type: "string",
      doc: "The the key for the message"
    },
    {
      name: "text",
      type: "string",
      doc: "The text for the message"
    }
  ]
};

Options

// package options
const opts: Options = {
  schemaRegistry: "http://localhost:8081",
  numRetries: 10, // number of attempts to call schemaRegistry
  wrapUnions: "auto", // avsc option
  subject: "test-value", // subject for schema registration
  schema: avroSchema, // schema object as needed for avsc
};

Create Encoder and use it

const encodeFunc = await createEncoder(opts);

// encode a message
const encoded: Buffer = encodeFunc(message);

Create Decoder and use it

const decodeFunc = createDecoder(opts);

// decode a message
const decoded = await decodeFunc(encoded);

Making Changes

• Ensure typescript is installed: npm install -g typescript
• Install all dependencies: npm install
• Make changes
• Run npm run package. This will remove the release directory, run tsc and add the release directory back to git. The release directory needs to be updated every commit to include changes in the library.
• Update the version in package.json
• Add your changes to git, and commit.

Support / Contributing

Before opening an issue or pull request, please read the Contributing guide.