VRL WASM Web Playground

This directory houses the exposed VRL function to WASM run_vrl() used to power Vector Remap Language Playground, or VRL Playground for short. Although there is already a local REPL supported for use within the terminal, this playground will support running VRL in the web browser and test input via uploading event files, or specifying an event via a text input field.

Setup

To build the project we need to use wasm-pack. This compiles our Rust code to WebAssembly which can then be used within the browser. Install it by running:

cargo install 0.10.3 wasm-pack

After installing wasm-pack we must compile our project by running:

wasm-pack build --target web

Notice a pkg directory was created which contains wasm_bg.wasm, wasm.js, these are the files that will be used by the web browser to run the compiled Rust code.

For more information on Rust and WebAssembly please visit the mozilla docs or the Rust book wasm chapter

The lib.rs file is the entry point of the web-playground library. This will make it so we can use the run_vrl function in the console. Notice our index.html imports the VRL wasm module from /pkg/ and sets the window.run_vrl function so that we can test VRL within the web browser console. To test out index.html we need to host it locally, for example by running:

python3 -m http.server

Remember to be in the directory where index.html is located for it to function properly.

Support

Some functions of VRL are not supported or don't function as expected at the moment due to WASM compatibility with some dependencies that functions use, in the future we will modify the functions so that it is supported.

List of functions that aren't supported at the moment:

• log()
• decrypt()
• encrypt()
• get_hostname()
• parse_groks()
• random_bytes()
• reverse_dns()

It is worth checking out this issue which has some functions written in a way that would make it be WASM compatible.