Crate coalesced

coalesced supports reading configs from multiple sources

Usage

[dependencies]
coalesced = { git = "https://github.com/hayas1/coalesced" }

Examples

Coalesce::prior will return the last confirmed value. Coalesce::posterior will return the first confirmed value.

Config	file	env	cli	→	prior	posterior
opt_num	10	100		→	100	10
opt_str		hundred	thousand	→	thousand	hundred
boolean	true	false	true	→	true	true

use coalesced::Coalesce;

#[derive(Coalesce)]
pub struct Config<'a> {
    opt_num: Option<i32>,
    opt_str: Option<&'a str>,
    boolean: bool
}

let from_file = Config {
    opt_num: Some(10),
    opt_str: None,
    boolean: true,
};
let from_env = Config {
    opt_num: Some(100),
    opt_str: Some("hundred"),
    boolean: false,
};
let from_cli = Config {
    opt_num: None,
    opt_str: Some("thousand"),
    boolean: true,
};
let config = from_file.prior(from_env).prior(from_cli);
assert!(matches!(config, Config {
    opt_num: Some(100),
    opt_str: Some("thousand"),
    boolean: true,
}));

let from_file = Config {
    opt_num: Some(10),
    opt_str: None,
    boolean: true,
};
let from_env = Config {
    opt_num: Some(100),
    opt_str: Some("hundred"),
    boolean: false,
};
let from_cli = Config {
    opt_num: None,
    opt_str: Some("thousand"),
    boolean: true,
};
let config = from_file.posterior(from_env).posterior(from_cli);
assert!(matches!(config, Config {
    opt_num: Some(10),
    opt_str: Some("hundred"),
    boolean: true,
}));

Lazy Evaluation

Related to crate::Coalesced. Lazy evaluation is supported so we can follow the changes until the value is confirmed.

use coalesced::{Coalesce, History, IntoHistory};

#[derive(Coalesce)]
pub struct Config<'a> {
    opt_num: Option<i32>,
    opt_str: Option<&'a str>,
    boolean: bool,
}

let from_file = Config {
    opt_num: Some(10),
    opt_str: None,
    boolean: true,
};
let from_env = Config {
    opt_num: Some(100),
    opt_str: Some("hundred"),
    boolean: false,
};
let from_cli = Config {
    opt_num: None,
    opt_str: Some("thousand"),
    boolean: true,
};

let config = from_file.into_history().prior(from_env).prior(from_cli);
assert!(matches!(
    config.base(),
    Config {
        opt_num: Some(10),
        opt_str: None,
        boolean: true,
    }
));
assert!(matches!(config.into(), Config {
    opt_num: Some(100),
    opt_str: Some("thousand"),
    boolean: true,
}));

Extensions metadata

Related to crate::WithExt. Extensions metadata is supported so we can follow the source of the confirmed value.

use coalesced::{Coalesce, Extension};

#[derive(Coalesce)]
pub struct Config<'a> {
    opt_num: Option<i32>,
    opt_str: Option<&'a str>,
    boolean: bool,
}

let from_file = Config {
    opt_num: Some(10),
    opt_str: None,
    boolean: true,
};
let from_env = Config {
    opt_num: Some(100),
    opt_str: Some("hundred"),
    boolean: false,
};
let from_cli = Config {
    opt_num: None,
    opt_str: Some("thousand"),
    boolean: true,
};

let (file, env, cli) = (
    from_file.with_extension(&"file"),
    from_env.with_extension(&"env"),
    from_cli.with_extension(&"cli"),
);

let config = file.prior(env).prior(cli);
assert_eq!(config.opt_num.extension, &"env");
assert_eq!(config.opt_str.extension, &"cli");
assert_eq!(config.boolean.extension, &"cli");
assert!(matches!(config.into(), Config {
    opt_num: Some(100),
    opt_str: Some("thousand"),
    boolean: true
}));

Documents

https://hayas1.github.io/coalesced/coalesced

Testing

Benchmarks

TODO

Coverage

https://hayas1.github.io/coalesced/coalesced/tarpaulin-report.html

Structs

Coalesced

Some values for lazy evaluation

WithExt

A value with an extension

Traits

Coalesce

Extension

History

IntoHistory