gha_main

Write GitHub Actions in Rust!

This crate provides two convenience macros to make it easier to write GitHub Actions in Rust.

How to use: 1. Annotate your main() function with #[gha_main]. 2. Add return type GitHubActionResult. 3. Use the ? operator to propagate errors. 3. Return outputs (anything that implements Display) wrapped in gha_output!() to return it the action runner so that it can be used in later workflow steps or other actions.

Example usage: ```rust use std::env; use ghamain::{ghamain, gha_output, GitHubActionResult};

[gha_main]

fn main() -> GitHubActionResult { let args: Vec = env::args().collect(); let input = &args[1]; let parsedu32 = input.parse::()?; ghaoutput!(parsed_u32) } ```

Values returned in gha_output!() are returned to the runner with the output name equal to the Rust variable name. In the example above, if the action is called with input "5", the parsed_u32 output will be set to 5.

Errors propagated via the ? operator are returned to the runner as the error output. The error values are formatted using [anyhow::Error]'s Display implementation.

Example actions

The /example-actions folder contains two actions that demonstrate how to use this crate in a GitHub Action: 1. /example-actions/container is a docker Action. GitHub currently does not apply docker layer caching when running a container based action so without publishing your image to a registry your code will be recompiled on every workflow run. If your crate has a lot of dependenies you probably want to use the second example. 2. /example-actions/composite is a composite action that manually runs the docker commands. This allows using another action to utilize docker layer caching. Fetching layers from the GitHub Action cache can take ~30 seconds and updating the cache at the end of the run when the layers have changed (or no cache exists) can take up to a couple of minutes.

The best approach strongly depends on the compile time of your crate.

License: Apache-2.0 OR MIT