pub struct Data<F>where
    F: Format,
{ pub profile: Option<Profile>, /* private fields */ }
Expand description

A Provider that sources values from a file or string in a given Format.

Constructing

A Data provider is typically constructed indirectly via a type that implements the Format trait via the Format::file() and Format::string() methods which in-turn defer to Data::file() and Data::string() by default:

// The `Format` trait must be in-scope to use its methods.
use figment::providers::{Format, Data, Json};

// These two are equivalent, except the former requires the explicit type.
let json = Data::<Json>::file("foo.json");
let json = Json::file("foo.json");

Provider Details

  • Profile

    This provider does not set a profile.

  • Metadata

    This provider is named ${NAME} file (when constructed via Data::file()) or ${NAME} source string (when constructed via Data::string()), where ${NAME} is Format::NAME. When constructed from a file, the file’s path is specified as file Source. Path interpolation is unchanged from the default.

  • Data (Unnested, default)

    When nesting is not specified, the source file or string is read and parsed, and the parsed dictionary is emitted into the profile configurable via Data::profile(), which defaults to Profile::Default. If the source is a file and the file is not present, an empty dictionary is emitted.

  • Data (Nested)

    When nesting is specified, the source value is expected to be a dictionary. It’s top-level keys are emitted as profiles, and the value corresponding to each key as the profile data.

Fields

profile: Option<Profile>

The profile data will be emitted to if nesting is disabled. Defaults to Profile::Default.

Implementations

Returns a Data provider that sources its values by parsing the file at path as format F. If path is relative, the file is searched for in the current working directory and all parent directories until the root, and the first hit is used.

Nesting is not enabled by default; use Data::nested() to enable nesting.

use serde::Deserialize;
use figment::{Figment, Jail, providers::{Format, Toml}, value::Map};

#[derive(Debug, PartialEq, Deserialize)]
struct Config {
    numbers: Vec<usize>,
    untyped: Map<String, usize>,
}

Jail::expect_with(|jail| {
    jail.create_file("Config.toml", r#"
        numbers = [1, 2, 3]

        [untyped]
        key = 1
        other = 4
    "#)?;

    let config: Config = Figment::from(Toml::file("Config.toml")).extract()?;
    assert_eq!(config, Config {
        numbers: vec![1, 2, 3],
        untyped: figment::util::map!["key".into() => 1, "other".into() => 4],
    });

    Ok(())
});

Returns a Data provider that sources its values by parsing the string string as format F. Nesting is not enabled by default; use Data::nested() to enable nesting.

use serde::Deserialize;
use figment::{Figment, Jail, providers::{Format, Toml}, value::Map};

#[derive(Debug, PartialEq, Deserialize)]
struct Config {
    numbers: Vec<usize>,
    untyped: Map<String, usize>,
}

Jail::expect_with(|jail| {
    let source = r#"
        numbers = [1, 2, 3]
        untyped = { key = 1, other = 4 }
    "#;

    let config: Config = Figment::from(Toml::string(source)).extract()?;
    assert_eq!(config, Config {
        numbers: vec![1, 2, 3],
        untyped: figment::util::map!["key".into() => 1, "other".into() => 4],
    });

    Ok(())
});

Enables nesting on self, which results in top-level keys of the sourced data being treated as profiles.

use serde::Deserialize;
use figment::{Figment, Jail, providers::{Format, Toml}, value::Map};

#[derive(Debug, PartialEq, Deserialize)]
struct Config {
    numbers: Vec<usize>,
    untyped: Map<String, usize>,
}

Jail::expect_with(|jail| {
    jail.create_file("Config.toml", r#"
        [global.untyped]
        global = 0
        hi = 7

        [staging]
        numbers = [1, 2, 3]

        [release]
        numbers = [6, 7, 8]
    "#)?;

    // Enable nesting via `nested()`.
    let figment = Figment::from(Toml::file("Config.toml").nested());

    let figment = figment.select("staging");
    let config: Config = figment.extract()?;
    assert_eq!(config, Config {
        numbers: vec![1, 2, 3],
        untyped: figment::util::map!["global".into() => 0, "hi".into() => 7],
    });

    let config: Config = figment.select("release").extract()?;
    assert_eq!(config, Config {
        numbers: vec![6, 7, 8],
        untyped: figment::util::map!["global".into() => 0, "hi".into() => 7],
    });

    Ok(())
});

Set the profile to emit data to when nesting is disabled.

use serde::Deserialize;
use figment::{Figment, Jail, providers::{Format, Toml}, value::Map};

#[derive(Debug, PartialEq, Deserialize)]
struct Config { value: u8 }

Jail::expect_with(|jail| {
    let provider = Toml::string("value = 123").profile("debug");
    let config: Config = Figment::from(provider).select("debug").extract()?;
    assert_eq!(config, Config { value: 123 });

    Ok(())
});

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Returns the Metadata for this provider, identifying itself and its configuration sources. Read more
Returns the configuration data.
Optionally returns a profile to set on the Figment this provider is merged into. The profile is only set if self is merged. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Converts self into a collection.
Should always be Self
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more