entrypoint

eliminate main function boilerplate with this opinionated application framework/wrapper

About

entrypoint has the following design goals:

eliminate application startup/configuration boilerplate
help enforce application best practices

What does this crate actually do?

entrypoint essentially wraps a user defined function with automatic configuration/setup/processing of:

logging (via tracing)
command-line arguments (via clap)
.dotenv file(s), environment variable population/overrides (via dotenvy)
easy application error handling (via anyhow)

The user defined function is intended to be/replace main().

Thus, the main/entrypoint function can be written as if all the configuration/processing/boilerplate is ready-to-use. More explicitly:

clap::Parser struct has been parsed & populated
.dotenv files have been parsed; environment variables are ready to go
tracing has been configured & the global subscriber has been registered

Using the default behavior is totally reasonable, but overwriting some traits' default impl(s) can provide customization.

Usage

Include the entrypoint prelude:
```
use entrypoint::prelude::*;
```

Define a clap struct:

#[derive(entrypoint::clap::Parser, Debug)]
#[command(version, about, long_about = None)]
struct Args {
    #[arg(short, long)]
    debug: bool,
}

Define an entrypoint/main function:

#[entrypoint::entrypoint]
fn main(args: Args) -> entrypoint::anyhow::Result<()> {
    // env::vars() already loaded-from/merged-with .dotenv file(s)
    let _dev_secret  = env::vars("SECRET_KEY");

    // logging is ready to use
    entrypoint::tracing::info!("entrypoint::entrypoint");

    // args is already parsed and ready to use
    entrypoint::tracing::info!("w/ {:#?}", args);

    Ok(())
}

This function must:

accept a clap::Parser as an input
return entrypoint::anyhow::Result<()>

Note: #[entrypoint::entrypoint] should be first when used with other attribute macros. e.g.:

#[entrypoint::entrypoint]
#[tokio::main]
async fn main(args: Args) -> entrypoint::anyhow::Result<()> { Ok(()) }

For more information, refer to:

Crates

entrypoint is divided into the following crates:

entrypoint: core traits & functionality
entrypoint_macros: convienence macros to further reduce boilerplate

Contributing