These proc macros help you to implement the envir::Serialize and envir::Deserialize traits.

Attributes

By default, these macro use the uppercase field name as environment variable name.

use envir::Deserialize;

#[derive(envir::Deserialize, Debug)]
struct Config {
    home: String,
}

let config = Config::from_env();
dbg!(config);

$ cargo run
[src/main.rs:12] config = Ok(
    Config {
        home: "/home/sanpi",
    }
)

Container

• prefix: sets this attributes to add this prefix at the field name.

use envir::Deserialize;

#[derive(envir::Deserialize, Debug)]
#[envir(prefix = "APP_")]
struct Config {
    dir: String,
}

let config = Config::from_env();
dbg!(config);

$ export APP_DIR=~/.config/app
$ cargo run
[src/main.rs:12] config = Ok(
    Config {
        dir: "/home/sanpi/.config/app",
    }
)

Field

• name: use this name for the environment variable instead of the name of the field. If prefix is defined, it also prepend to this name;
• export_with: use this function to export this field. The given function must be callable as fn (T) -> HashMap<String, String>;
• load_with: use this function to load this field. The given function must be callable as fn (Hashmap<String, String>) -> envir::Result<T>;
• noprefix: doesn’t add the prefix for this field;
• nested: this field should be de/serialized recursively;
• skip: skip this field, don’t load or export it;
• skip_load: don’t load this field;
• skip_export: don’t export this field;
• skip_export_if: call a function to determine whether to export this field or not. The given function must be callable as fn(&T) -> bool.

use envir::Deserialize;

#[derive(envir::Deserialize, Debug)]
#[envir(prefix = "APP_")]
struct Config {
    dir: String,
}

let config = Config::from_env();
dbg!(config);

$ export APP_DIR=~/.config/app
$ cargo run
[src/main.rs:12] config = Ok(
    Config {
        dir: "/home/sanpi/.config/app",
    }
)