Module serde_units 

serde adapters, so a config or API struct can hold quantities.

uom’s own Serialize/Deserialize encodes the raw base-unit float: a timeout as 30.0, and a size as 536870912.0. An operator does not write that in YAML, and an admin API should not return it. Use these modules through #[serde(with = ...)]. They give a choice of two encodings:

• human — the operator-facing string form ("512MiB", "30s", "10MiB/s"), for config files.
• numeric — an exact integer in a named unit (30000 milliseconds, 536870912 bytes), for JSON APIs and anything mirroring a Kafka wire field.

use krabka_units::{prelude::*, serde_units};
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize)]
struct TopicConfig {
    #[serde(with = "serde_units::human::byte_size")]
    segment_size: ByteSize,
    #[serde(with = "serde_units::numeric::millis_i64")]
    retention: Time,
}

let parsed: TopicConfig =
    serde_json::from_str(r#"{"segment_size":"512MiB","retention":604800000}"#)?;
assert_eq!(parsed.segment_size, mebibytes(512));
assert_eq!(parsed.retention, days(7));

A dimensioned field in human form must carry its unit. These modules reject a bare number and never assume seconds or bytes, because that guess is the failure this crate prevents. human::ratio is the exception. A fraction’s unit is “none”, so it accepts 0.25 as well as "25%".

Modules

human

The operator-facing string encoding: "512MiB", "30s", "10MiB/s", "25%".

numeric

The exact integer encoding, in an explicitly named unit.