kube_core/duration.rs
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//! Kubernetes [`Duration`]s.
use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
use std::{cmp::Ordering, fmt, str::FromStr, time};
/// A Kubernetes duration.
///
/// This is equivalent to the [`metav1.Duration`] type in the Go Kubernetes
/// apimachinery package. A [`metav1.Duration`] is serialized in YAML and JSON
/// as a string formatted in the format accepted by the Go standard library's
/// [`time.ParseDuration()`] function. This type is a similar wrapper around
/// Rust's [`std::time::Duration`] that can be serialized and deserialized using
/// the same format as `metav1.Duration`.
///
/// # On Signedness
///
/// Go's [`time.Duration`] type is a signed integer type, while Rust's
/// [`std::time::Duration`] is unsigned. Therefore, this type is also capable of
/// representing both positive and negative durations. This is implemented by
/// storing whether or not the parsed duration was negative as a boolean field
/// in the wrapper type. The [`Duration::is_negative`] method returns this
/// value, and when a [`Duration`] is serialized, the negative sign is included
/// if the duration is negative.
///
/// [`Duration`]s can be compared with [`std::time::Duration`]s. If the
/// [`Duration`] is negative, it will always be considered less than the
/// [`std::time::Duration`]. Similarly, because [`std::time::Duration`]s are
/// unsigned, a negative [`Duration`] will never be equal to a
/// [`std::time::Duration`], even if the wrapped [`std::time::Duration`] (the
/// negative duration's absolute value) is equal.
///
/// When converting a [`Duration`] into a [`std::time::Duration`], be aware that
/// *this information is lost*: if a negative [`Duration`] is converted into a
/// [`std::time::Duration`] and then that [`std::time::Duration`] is converted
/// back into a [`Duration`], the second [`Duration`] will *not* be negative.
///
/// [`metav1.Duration`]: https://pkg.go.dev/k8s.io/apimachinery/pkg/apis/meta/v1#Duration
/// [`time.Duration`]: https://pkg.go.dev/time#Duration
/// [`time.ParseDuration()`]: https://pkg.go.dev/time#ParseDuration
#[derive(Copy, Clone, PartialEq, Eq)]
pub struct Duration {
duration: time::Duration,
is_negative: bool,
}
/// Errors returned by the [`FromStr`] implementation for [`Duration`].
#[derive(Debug, thiserror::Error, Eq, PartialEq)]
#[non_exhaustive]
pub enum ParseError {
/// An invalid unit was provided. Units must be one of 'ns', 'us', 'μs',
/// 's', 'ms', 's', 'm', or 'h'.
#[error("invalid unit: {}", EXPECTED_UNITS)]
InvalidUnit,
/// No unit was provided.
#[error("missing a unit: {}", EXPECTED_UNITS)]
NoUnit,
/// The number associated with a given unit was invalid.
#[error("invalid floating-point number: {}", .0)]
NotANumber(#[from] std::num::ParseFloatError),
}
const EXPECTED_UNITS: &str = "expected one of 'ns', 'us', '\u{00b5}s', 'ms', 's', 'm', or 'h'";
impl From<time::Duration> for Duration {
fn from(duration: time::Duration) -> Self {
Self {
duration,
is_negative: false,
}
}
}
impl From<Duration> for time::Duration {
fn from(Duration { duration, .. }: Duration) -> Self {
duration
}
}
impl Duration {
/// Returns `true` if this `Duration` is negative.
#[inline]
#[must_use]
pub fn is_negative(&self) -> bool {
self.is_negative
}
}
impl fmt::Debug for Duration {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use std::fmt::Write;
if self.is_negative {
f.write_char('-')?;
}
fmt::Debug::fmt(&self.duration, f)
}
}
impl fmt::Display for Duration {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use std::fmt::Write;
if self.is_negative {
f.write_char('-')?;
}
fmt::Debug::fmt(&self.duration, f)
}
}
impl FromStr for Duration {
type Err = ParseError;
fn from_str(mut s: &str) -> Result<Self, Self::Err> {
// implements the same format as
// https://cs.opensource.google/go/go/+/refs/tags/go1.20.4:src/time/format.go;l=1589
const MINUTE: time::Duration = time::Duration::from_secs(60);
// Go durations are signed. Rust durations aren't.
let is_negative = s.starts_with('-');
s = s.trim_start_matches('+').trim_start_matches('-');
let mut total = time::Duration::from_secs(0);
while !s.is_empty() && s != "0" {
let unit_start = s.find(|c: char| c.is_alphabetic()).ok_or(ParseError::NoUnit)?;
let (val, rest) = s.split_at(unit_start);
let val = val.parse::<f64>()?;
let unit = if let Some(next_numeric_start) = rest.find(|c: char| !c.is_alphabetic()) {
let (unit, rest) = rest.split_at(next_numeric_start);
s = rest;
unit
} else {
s = "";
rest
};
// https://cs.opensource.google/go/go/+/refs/tags/go1.20.4:src/time/format.go;l=1573
let base = match unit {
"ns" => time::Duration::from_nanos(1),
// U+00B5 is the "micro sign" while U+03BC is "Greek letter mu"
"us" | "\u{00b5}s" | "\u{03bc}s" => time::Duration::from_micros(1),
"ms" => time::Duration::from_millis(1),
"s" => time::Duration::from_secs(1),
"m" => MINUTE,
"h" => MINUTE * 60,
_ => return Err(ParseError::InvalidUnit),
};
total += base.mul_f64(val);
}
Ok(Duration {
duration: total,
is_negative,
})
}
}
impl Serialize for Duration {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
serializer.collect_str(self)
}
}
impl<'de> Deserialize<'de> for Duration {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
struct Visitor;
impl de::Visitor<'_> for Visitor {
type Value = Duration;
fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("a string in Go `time.Duration.String()` format")
}
fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
where
E: de::Error,
{
let val = value.parse::<Duration>().map_err(de::Error::custom)?;
Ok(val)
}
}
deserializer.deserialize_str(Visitor)
}
}
impl PartialEq<time::Duration> for Duration {
fn eq(&self, other: &time::Duration) -> bool {
// Since `std::time::Duration` is unsigned, a negative `Duration` is
// never equal to a `std::time::Duration`.
if self.is_negative {
return false;
}
self.duration == *other
}
}
impl PartialEq<time::Duration> for &'_ Duration {
fn eq(&self, other: &time::Duration) -> bool {
// Since `std::time::Duration` is unsigned, a negative `Duration` is
// never equal to a `std::time::Duration`.
if self.is_negative {
return false;
}
self.duration == *other
}
}
impl PartialEq<Duration> for time::Duration {
fn eq(&self, other: &Duration) -> bool {
// Since `std::time::Duration` is unsigned, a negative `Duration` is
// never equal to a `std::time::Duration`.
if other.is_negative {
return false;
}
self == &other.duration
}
}
impl PartialEq<Duration> for &'_ time::Duration {
fn eq(&self, other: &Duration) -> bool {
// Since `std::time::Duration` is unsigned, a negative `Duration` is
// never equal to a `std::time::Duration`.
if other.is_negative {
return false;
}
*self == &other.duration
}
}
impl PartialOrd for Duration {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl Ord for Duration {
fn cmp(&self, other: &Self) -> Ordering {
match (self.is_negative, other.is_negative) {
(true, false) => Ordering::Less,
(false, true) => Ordering::Greater,
// if both durations are negative, the "higher" Duration value is
// actually the lower one
(true, true) => self.duration.cmp(&other.duration).reverse(),
(false, false) => self.duration.cmp(&other.duration),
}
}
}
impl PartialOrd<time::Duration> for Duration {
fn partial_cmp(&self, other: &time::Duration) -> Option<Ordering> {
// Since `std::time::Duration` is unsigned, a negative `Duration` is
// always less than the `std::time::Duration`.
if self.is_negative {
return Some(Ordering::Less);
}
self.duration.partial_cmp(other)
}
}
#[cfg(feature = "schema")]
impl schemars::JsonSchema for Duration {
// see
// https://github.com/kubernetes/apimachinery/blob/756e2227bf3a486098f504af1a0ffb736ad16f4c/pkg/apis/meta/v1/duration.go#L61
fn schema_name() -> String {
"Duration".to_owned()
}
fn is_referenceable() -> bool {
false
}
fn json_schema(_: &mut schemars::gen::SchemaGenerator) -> schemars::schema::Schema {
schemars::schema::SchemaObject {
instance_type: Some(schemars::schema::InstanceType::String.into()),
// the format should *not* be "duration", because "duration" means
// the duration is formatted in ISO 8601, as described here:
// https://datatracker.ietf.org/doc/html/draft-handrews-json-schema-validation-02#section-7.3.1
format: None,
..Default::default()
}
.into()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn parses_the_same_as_go() {
const MINUTE: time::Duration = time::Duration::from_secs(60);
const HOUR: time::Duration = time::Duration::from_secs(60 * 60);
// from Go:
// https://cs.opensource.google/go/go/+/refs/tags/go1.20.4:src/time/time_test.go;l=891-951
// ```
// var parseDurationTests = []struct {
// in string
// want time::Duration
// }{
let cases: &[(&str, Duration)] = &[
// // simple
// {"0", 0},
("0", time::Duration::from_secs(0).into()),
// {"5s", 5 * Second},
("5s", time::Duration::from_secs(5).into()),
// {"30s", 30 * Second},
("30s", time::Duration::from_secs(30).into()),
// {"1478s", 1478 * Second},
("1478s", time::Duration::from_secs(1478).into()),
// // sign
// {"-5s", -5 * Second},
("-5s", Duration {
duration: time::Duration::from_secs(5),
is_negative: true,
}),
// {"+5s", 5 * Second},
("+5s", time::Duration::from_secs(5).into()),
// {"-0", 0},
("-0", Duration {
duration: time::Duration::from_secs(0),
is_negative: true,
}),
// {"+0", 0},
("+0", time::Duration::from_secs(0).into()),
// // decimal
// {"5.0s", 5 * Second},
("5s", time::Duration::from_secs(5).into()),
// {"5.6s", 5*Second + 600*Millisecond},
(
"5.6s",
(time::Duration::from_secs(5) + time::Duration::from_millis(600)).into(),
),
// {"5.s", 5 * Second},
("5.s", time::Duration::from_secs(5).into()),
// {".5s", 500 * Millisecond},
(".5s", time::Duration::from_millis(500).into()),
// {"1.0s", 1 * Second},
("1.0s", time::Duration::from_secs(1).into()),
// {"1.00s", 1 * Second},
("1.00s", time::Duration::from_secs(1).into()),
// {"1.004s", 1*Second + 4*Millisecond},
(
"1.004s",
(time::Duration::from_secs(1) + time::Duration::from_millis(4)).into(),
),
// {"1.0040s", 1*Second + 4*Millisecond},
(
"1.0040s",
(time::Duration::from_secs(1) + time::Duration::from_millis(4)).into(),
),
// {"100.00100s", 100*Second + 1*Millisecond},
(
"100.00100s",
(time::Duration::from_secs(100) + time::Duration::from_millis(1)).into(),
),
// // different units
// {"10ns", 10 * Nanosecond},
("10ns", time::Duration::from_nanos(10).into()),
// {"11us", 11 * Microsecond},
("11us", time::Duration::from_micros(11).into()),
// {"12µs", 12 * Microsecond}, // U+00B5
("12µs", time::Duration::from_micros(12).into()),
// {"12μs", 12 * Microsecond}, // U+03BC
("12μs", time::Duration::from_micros(12).into()),
// {"13ms", 13 * Millisecond},
("13ms", time::Duration::from_millis(13).into()),
// {"14s", 14 * Second},
("14s", time::Duration::from_secs(14).into()),
// {"15m", 15 * Minute},
("15m", (15 * MINUTE).into()),
// {"16h", 16 * Hour},
("16h", (16 * HOUR).into()),
// // composite durations
// {"3h30m", 3*Hour + 30*Minute},
("3h30m", (3 * HOUR + 30 * MINUTE).into()),
// {"10.5s4m", 4*Minute + 10*Second + 500*Millisecond},
(
"10.5s4m",
(4 * MINUTE + time::Duration::from_secs(10) + time::Duration::from_millis(500)).into(),
),
// {"-2m3.4s", -(2*Minute + 3*Second + 400*Millisecond)},
("-2m3.4s", Duration {
duration: 2 * MINUTE + time::Duration::from_secs(3) + time::Duration::from_millis(400),
is_negative: true,
}),
// {"1h2m3s4ms5us6ns", 1*Hour + 2*Minute + 3*Second + 4*Millisecond + 5*Microsecond + 6*Nanosecond},
(
"1h2m3s4ms5us6ns",
(1 * HOUR
+ 2 * MINUTE
+ time::Duration::from_secs(3)
+ time::Duration::from_millis(4)
+ time::Duration::from_micros(5)
+ time::Duration::from_nanos(6))
.into(),
),
// {"39h9m14.425s", 39*Hour + 9*Minute + 14*Second + 425*Millisecond},
(
"39h9m14.425s",
(39 * HOUR + 9 * MINUTE + time::Duration::from_secs(14) + time::Duration::from_millis(425))
.into(),
),
// // large value
// {"52763797000ns", 52763797000 * Nanosecond},
("52763797000ns", time::Duration::from_nanos(52763797000).into()),
// // more than 9 digits after decimal point, see https://golang.org/issue/6617
// {"0.3333333333333333333h", 20 * Minute},
("0.3333333333333333333h", (20 * MINUTE).into()),
// // 9007199254740993 = 1<<53+1 cannot be stored precisely in a float64
// {"9007199254740993ns", (1<<53 + 1) * Nanosecond},
(
"9007199254740993ns",
time::Duration::from_nanos((1 << 53) + 1).into(),
),
// Rust Durations can handle larger durations than Go's
// representation, so skip these tests for their precision limits
// // largest duration that can be represented by int64 in nanoseconds
// {"9223372036854775807ns", (1<<63 - 1) * Nanosecond},
// ("9223372036854775807ns", time::Duration::from_nanos((1 << 63) - 1).into()),
// {"9223372036854775.807us", (1<<63 - 1) * Nanosecond},
// ("9223372036854775.807us", time::Duration::from_nanos((1 << 63) - 1).into()),
// {"9223372036s854ms775us807ns", (1<<63 - 1) * Nanosecond},
// {"-9223372036854775808ns", -1 << 63 * Nanosecond},
// {"-9223372036854775.808us", -1 << 63 * Nanosecond},
// {"-9223372036s854ms775us808ns", -1 << 63 * Nanosecond},
// // largest negative value
// {"-9223372036854775808ns", -1 << 63 * Nanosecond},
// // largest negative round trip value, see https://golang.org/issue/48629
// {"-2562047h47m16.854775808s", -1 << 63 * Nanosecond},
// // huge string; issue 15011.
// {"0.100000000000000000000h", 6 * Minute},
("0.100000000000000000000h", (6 * MINUTE).into()), // // This value tests the first overflow check in leadingFraction.
// {"0.830103483285477580700h", 49*Minute + 48*Second + 372539827*Nanosecond},
// }
// ```
];
for (input, expected) in cases {
let parsed = dbg!(input).parse::<Duration>().unwrap();
assert_eq!(&dbg!(parsed), expected);
}
}
}