Writing Custom Transforms

Shotover supports implementing your own custom transforms. Shotover exposes an API via a rust crate from which you can both implement your own transforms and build those transforms into a final shotover binary that can be run in production.

Required Knowledge

This approach is taken to make the most of rust's speed and type safety. However this does come at an up front cost of you needing a basic familiarity with rust. If you have never worked with rust before, you should first spend a day familiarising yourself with it.

Start with the template

To get started writing custom transforms first clone this template:

git clone https://github.com/shotover/shotover-custom-transforms-template

The template comes with:

• two example transforms: the valkey-get-rewrite and kafka-fetch-rewrite crates
  • By convention, each transform is its own rust crate
• the final shotover binary: the shotover-bin crate
  • this also contains integration tests in shotover-bin/tests, make sure to utiilize them!

Use an example transform that matches the protocol you are working with as a base. e.g.

• valkey-get-rewrite - for valkey
• kafka-fetch-rewrite - for kafka

Running the project

To run the shotover binary containing your project just run:

cargo run --release

This also creates a binary at target/release/shotover-bin which can be used in production.

To run the integration tests run:

cargo test --release

A little cleanup

Feel free to delete transforms that you do not need. That would involve deleting:

• The entire crate folder
• The members entry in the workspace level Cargo.toml
• The corresponding shotover::import_transform! line in shotover-bin/src/main.rs

Development

To understand your transform you are using as a base you will want to consult the shotover API documentation From there explore the API to find how to