cli-app-base/README.md

# clappconfig - CLI app config boilerplate

```none
Clap
  App
     Config
-----------
clappconfig
```

This crate provides a simple CLI app boilerplate that takes care of 
the most repetitive init tasks:

- Load JSON5 config from a custom or default path (or use `Default::default()`)
- Set up logging, with CLI and config-based overrides
- Optionally print the loaded or default config
- Show help / version on demand, courtesy of `clap`
- Optional start-up banner print

Supports custom `clap` arguments as well.

-> The repository is open to improvement PRs.

## Logging

- uses `env_logger` by default
- level can be set in the config file
- log level can be overridden by the `--log` CLI flag
- log level can be increased by repeated use of `-v` or `--verbose`

## Re-exports

The crates re-exports crates used in public API: `clap`, `anyhow`, `log`.

## Example

See the examples directory.

The example called "rotn" implements rot13 as a command-line tool.

```none
$ cargo run --example rotn -- -h

Rot-N 0.1.0 by Ondřej Hruška <ondra@ondrovo.com>

USAGE:
    rotn [FLAGS] [OPTIONS] --input <FILE>

FLAGS:
        --default-config    Print the default config JSON for reference (or to be piped to a file)
        --dump-config       Print the loaded config struct
    -h, --help              Prints help information
    -V, --version           Prints version information
    -v, --verbose           Increase logging verbosity (repeat to increase)

OPTIONS:
    -c, --config <FILE>    Sets a custom config file (JSON5)
    -i, --input <FILE>     Input file
        --log <LEVEL>      Set logging verbosity (error,warning,info,debug,trace)
    -n, --shift <N>        Positive or negative shift, default 13
```

To get rot13 of this README, run `cargo run --example rotn -- -iREADME.md`.