Struct smart_config::de::WithUnit

pub struct WithUnit;

Default deserializer for Durations and ByteSizes.

Values can be deserialized from 2 formats:

• String consisting of an integer, optional whitespace and a unit, such as “30 secs” or “500ms” (for Duration) / “4 MiB” (for ByteSize). The unit must correspond to a TimeUnit / SizeUnit.
• Object with a single key and an integer value, such as { "hours": 3 } (for Duration) / { "kb": 512 } (for SizeUnit).

Thanks to nesting of object params, the second approach automatically means that a duration can be parsed from a param name suffixed with a unit. For example, a value latency_ms: 500 for parameter latency will be recognized as 500 ms.

Examples

#[derive(DescribeConfig, DeserializeConfig)]
struct TestConfig {
    latency: Duration,
    disk: ByteSize,
}

// Parsing from a string
let source = smart_config::config!("latency": "30 secs", "disk": "256 MiB");
let config: TestConfig = testing::test(source)?;
assert_eq!(config.latency, Duration::from_secs(30));
assert_eq!(config.disk, ByteSize(256 << 20));

// Parsing from an object
let source = smart_config::config!(
    "latency": serde_json::json!({ "hours": 3 }),
    "disk": serde_json::json!({ "gigabytes": 2 }),
);
let config: TestConfig = testing::test(source)?;
assert_eq!(config.latency, Duration::from_secs(3 * 3_600));
assert_eq!(config.disk, ByteSize(2 << 30));

// Parsing from a suffixed parameter name
let source = Environment::from_iter("", [("LATENCY_SEC", "15"), ("DISK_GB", "10")]);
let config: TestConfig = testing::test(source)?;
assert_eq!(config.latency, Duration::from_secs(15));
assert_eq!(config.disk, ByteSize(10 << 30));

Trait Implementations

impl Clone for WithUnit

fn clone(&self) -> WithUnit

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WithUnit

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl DeserializeParam<ByteSize> for WithUnit

const EXPECTING: BasicTypes = Self::EXPECTED_TYPES

Describes which parameter this deserializer is expecting.

fn describe(&self, description: &mut TypeDescription)

Additional info about the deserialized type, e.g., extended description.

fn deserialize_param( &self, ctx: DeserializeContext<'_>, param: &'static ParamMetadata, ) -> Result<ByteSize, ErrorWithOrigin>

Performs deserialization given the context and param metadata.

fn serialize_param(&self, param: &ByteSize) -> Value

Serializes the provided parameter to the JSON model.

impl DeserializeParam<Duration> for WithUnit

const EXPECTING: BasicTypes = Self::EXPECTED_TYPES

Describes which parameter this deserializer is expecting.

fn describe(&self, description: &mut TypeDescription)

Additional info about the deserialized type, e.g., extended description.

fn deserialize_param( &self, ctx: DeserializeContext<'_>, param: &'static ParamMetadata, ) -> Result<Duration, ErrorWithOrigin>

Performs deserialization given the context and param metadata.

fn serialize_param(&self, param: &Duration) -> Value

Serializes the provided parameter to the JSON model.

impl DeserializeParam<Option<ByteSize>> for WithUnit

const EXPECTING: BasicTypes = Self::EXPECTED_TYPES

Describes which parameter this deserializer is expecting.

fn describe(&self, description: &mut TypeDescription)

Additional info about the deserialized type, e.g., extended description.

fn deserialize_param( &self, ctx: DeserializeContext<'_>, param: &'static ParamMetadata, ) -> Result<Option<ByteSize>, ErrorWithOrigin>

Performs deserialization given the context and param metadata.

fn serialize_param(&self, param: &Option<ByteSize>) -> Value

Serializes the provided parameter to the JSON model.

impl DeserializeParam<Option<Duration>> for WithUnit

const EXPECTING: BasicTypes = Self::EXPECTED_TYPES

Describes which parameter this deserializer is expecting.

fn describe(&self, description: &mut TypeDescription)

Additional info about the deserialized type, e.g., extended description.

fn deserialize_param( &self, ctx: DeserializeContext<'_>, param: &'static ParamMetadata, ) -> Result<Option<Duration>, ErrorWithOrigin>

Performs deserialization given the context and param metadata.

fn serialize_param(&self, param: &Option<Duration>) -> Value

Serializes the provided parameter to the JSON model.

impl Copy for WithUnit