# Changes for [`governor`](https://crates.io/crates/governor)

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## [Unreleased] - ReleaseDate

## [[0.10.1](https://docs.rs/governor/0.10.1/governor/)] - 2025-08-06

- Updated code and tests to pass on nightly rust.

## [[0.10.0](https://docs.rs/governor/0.10.0/governor/)] - 2025-03-27

## Changed

- Opting out of the `jitter` feature now disables the `getrandom`
  dependency as well as the `rand` dependency.
  ([#266](https://github.com/boinkor-net/governor/pull/266),
  thanks @sandhose!).

## [[0.9.0](https://docs.rs/governor/0.9.0/governor/)] - 2025-03-24

## Changed

- Governor no longer uses the
  [`no_std_compat` crate](https://crates.io/crates/no-std-compat),
  eliminating a very outdated transitive dependency (on `hashbrown`
  version 0.8).

- Keyed state stores now allow specifying the hasher.
  ([#262](https://github.com/boinkor-net/governor/pull/262) -
  thanks, @0xdeafbeef!)

## [[0.8.1](https://docs.rs/governor/0.8.1/governor/)] - 2025-02-25

## Changed

- Governor can be compiled in a WASM environment now, thanks to the
  [efforts](https://github.com/boinkor-net/governor/pull/255) of
  [@AntoniosBarotsis](https://github.com/AntoniosBarotsis)!

- The `jitter` feature now uses
  [rand v0.9](https://github.com/rust-random/rand/releases/tag/0.9.0)
  and [getrandom v0.3](https://crates.io/crates/getrandom/0.3.0)

## [[0.8.0](https://docs.rs/governor/0.8.0/governor/)] - 2024-12-10

### Changed

- Fixed the long-standing confusion of rate-limiting "tolerance"
  vs. "burst capacity": Tolerance is indicated with one cell less than
  burst capacity would be. The code treated the two as the same thing,
  leading to spurious single cells being allowed through when the
  clock advanced.
  ([#107](https://github.com/boinkor-net/governor/issues/107),
  [#249](https://github.com/boinkor-net/governor/issues/249)). This
  confusion has finally been identified and fixed by @jonasmalacofilho
  in [#251](https://github.com/boinkor-net/governor/pull/251).

  This should not affect the public API, but any clients subject to
  rate-limiting may see a slightly fairer treatment.

### Contributors

- [@jonasmalacofilho](https://github.com/jonasmalacofilho)

## [[0.7.0](https://docs.rs/governor/0.7.0/governor/)] - 2024-10-21

This is a quick bug-fix release to address the semver incompatibility
in 0.6.4. It is functionally identical to 0.6.4, with the exception of
the dashmap version upgrade.

### Changed

- Upgraded dashmap to 6.1.0.

## [[0.6.4](https://docs.rs/governor/0.6.4/governor/)] - 2024-10-19

This release has been yanked because it violates Semantic Versioning
ideals: The Clock argument type in functions like `direct_with_clock`
changed, which breaks existing code.

Instead of 0.6.4, please use 0.7.0.

### Added

- https://docs.rs/governor now lists the features required for
  feature-gated types and functions.

- A
  [`RateLimiter`](https://docs.rs/governor/0.6.4/governor/struct.RateLimiter.html)
  now has a
  [`clock`](https://docs.rs/governor/0.6.4/governor/struct.RateLimiter.html#method.clock)
  method to retrieve the clock providing its timestamps. Added by
  [@max-heller](https://github.com/max-heller) in
  [#232](https://github.com/boinkor-net/governor/pull/232).

### Changed

- [`Clock`](https://docs.rs/governor/0.6.4/governor/clock/trait.Clock.html)s
  no longer need to be `Clone`. Changed by
  [@max-heller](https://github.com/max-heller) in
  [#232](https://github.com/boinkor-net/governor/pull/232).

- governor now depends only on
  [`futures-util`](https://crates.io/crates/futures-util) and
  [`futures-executor`](https://crates.io/crates/futures-executor) instead of
  the much larger `futures` crate. Fixed by
  [@negezor](https://github.com/negezor) in
  [#239](https://github.com/boinkor-net/governor/pull/239).

## [[0.6.3](https://docs.rs/governor/0.6.3/governor/)] - 2024-02-16

### Changed

- Just another bug-fixed release process. This time, it should
  actually release out of github actions.

## [[0.6.2](https://docs.rs/governor/0.6.2/governor/)] - 2024-02-16

### Changed

- New release process: governor can now be automatically released
  using github actions.

## [[0.6.1](https://docs.rs/governor/0.6.1/governor/)] - 2024-02-16

### Changed

- The governor repo now lives in the `boinkor-net` github
  organization. No ownership has changed (@antifuchs still manages
  this org), but this makes it easier to securely manage the CI and
  release setup.

- The `.per_second` constructor for `Quota` now constructs a quota
  that ensures all rate-limiting calls succeed when given values in
  excess of 1 billion (previously, this would result in rate limiters
  that would incorrectly reject values). Reported in
  [#203](https://github.com/antifuchs/governor/issues/203).

- `QuantaUpkeepInstant` now [properly advances
  forward](https://github.com/boinkor-net/governor/pull/223).

- `no_std` is now [properly
  supported](https://github.com/boinkor-net/governor/pull/222):
  Instead of parking-lot, governor now uses the spinning_top crate in
  `no_std` mode.

### Contributors

- [@rkd-msw](https://github.com/rkd-msw)
- [@Serene-Arc](https://github.com/Serene-Arc)
- [@waynerobinson](https://github.com/waynerobinson)
- [@mammothbane](https://github.com/mammothbane)

## [[0.6.0](https://docs.rs/governor/0.6.0/governor/)] - 2023-07-12

### Added

- Type aliases `DefaultDirectRateLimiter` and
  `DefaultKeyedRateLimiter` to cut down on type-typing of typical rate
  limiters in struct and function definitions. Requested in
  [#85](https://github.com/antifuchs/governor/issues/85).

### Changed

- The API for `.check_n` and `.until_n` (and their keyed counterpart)
  have changed to return a nested `Result` - the outer indicating
  whether the check could ever succeed and the inner one indicating
  the rate limiting result, if it could succeed.
- Updated the [quanta dependency to
  0.11.1](https://github.com/metrics-rs/quanta/blob/main/CHANGELOG.md#0110---2023-03-24).
  This change also adds a reference u64 instant to all instances of
  the `QuantaUpkeepClock` structure. All lower-resolution quanta
  timekeeping used by governor will now be relative to that reference
  instant.
- Some parts of the documentation for burst sizes has been rephrased
  to be less confusing.

### Contributors

- [@brprkr](https://github.com/brprkr)

## [[0.5.1](https://docs.rs/governor/0.5.1/governor/)] - 2022-11-29

### Changed

- Fixed quota reporting for positive rate limiting decisions when
  `StateInformationMiddleware` is in use with a real clock. Reported
  in [#157](https://github.com/antifuchs/governor/issues/157)

### Contributors

- [@AaronErhardt](https://github.com/AaronErhardt)

## [[0.5.0](https://docs.rs/governor/0.5.0/governor/)] - 2022-09-19

### Changed

- Fixed a bug in `StateSnapshot::remaining_burst_capacity`: Now
  returns the correct number of cells after enough time has
  passed. Thanks to [@holmesmr](https://github.com/holmesmr) for
  reporting [#102](https://github.com/antifuchs/governor/issues/102)!

- Dropped a `From<(&_ Gcra, Nanos)>` impl for `StateSnapshot`.

## [[0.4.2](https://docs.rs/governor/0.4.2/governor/)] - 2022-02-09

### Changed

- Upgraded `dashmap` back [to 5.1.0](https://github.com/antifuchs/governor/pull/110).
- Upgraded `parking_lot` [to 0.12.0](https://github.com/antifuchs/governor/pull/109).

### Internal

- Migrated the `governor` code base to [cargo
  workspaces](https://doc.rust-lang.org/book/ch14-03-cargo-workspaces.html).

## [[0.4.1](https://docs.rs/governor/0.4.1/governor/)] - 2022-01-21

### Changed

- Downgraded `dashmap` to 4.0.2 as a remediation for
  [RUSTSEC-2022-0002](https://rustsec.org/advisories/RUSTSEC-2022-0002)
  via [#104](https://github.com/antifuchs/governor/pull/104).

### Contributors

- [@kim](https://github.com/kim)

## [[0.4.0](https://docs.rs/governor/0.4.0/governor/)] - 2021-12-28

### Added

- You can now alter&expand the information returned from a rate
  limiter by attaching middleware to it using
  `.with_middleware::<YourClass>()` at construction time.

  This is an incompatible change, as the type signature of RateLimiter
  gained an additional generic parameter. See the [pull
  request](https://github.com/antifuchs/governor/pull/67) and
  [issue #66](https://github.com/antifuchs/governor/issues/66) for
  details.

### Changed

- Updated the [`Arc` guide section](https://docs.rs/governor/0.3.3/governor/_guide/index.html#wrapping-the-limiter-in-an-arc) to use `Arc::clone()` instead of `limiter.clone()`.
- Updated the [`quanta` dependency](https://crates.io/crates/quanta)
  to 0.8.0, speeding up the quanta clock by a bit. This changes the
  upkeep clock interface incompatibly: The quanta upkeep Builder
  structure got renamed to `quanta::Upkeep`.
- The `nanos` module is now public, allowing other crates to implement
  the `Clock` trait.
- When using the `std` feature, governor will no longer pull in the
  `hashbrown` crate.

### Contributors

- [@bradfier](https://github.com/bradfier)
- [@izik1](https://github.com/izik1)
- [@ldm0](https://github.com/ldm0)

## [[0.3.2](https://docs.rs/governor/0.3.2/governor/)] - 2021-01-28

## [[0.3.1](https://docs.rs/governor/0.3.1/governor/)] - 2020-07-26

### Added

- A little section to the
  [guide](https://docs.rs/governor/0.3.1/governor/_guide/index.html)
  explaining how to use keyed rate limiters.

### Changed

Several dependencies' minimum versions were bumped, including a
version bump of
[`smallvec`](https://github.com/servo/rust-smallvec), a transitive
dependency which could previously result in trees using `governor`
pulling in a vulnerable smallvec version.

### Contributors

- [@AaronErhardt](https://github.com/AaronErhardt)
- [@FintanH](https://github.com/FintanH)

## [[0.3.0](https://docs.rs/governor/0.3.0/governor/)] - 2020-07-25

### Added

- The `ShrinkableKeyedStateStore` trait now has required `len` and
  `is_empty` methods, which are also made available on any
  `RateLimiter` that uses a shrinkable (Hashmap / Dashmap backed)
  state store. Thanks to [@lytefast](https://github.com/lytefast) for
  the idea and [pull request](https://github.com/antifuchs/ratelimit_meter/pull/38)
  on `ratelimit_meter`!

### Changed

- The `MonotonicClock` and `SystemClock` struct definitions now are
  proper "empty" structs. Any non-`Default` construction of these clocks
  must now use `MonotonicClock` instead of `MonotonicClock()`.
- The `clock::ReasonablyRealtime` trait got simplified and no longer
  has any required methods to implement, only one default method.
- Replaced the `spin` crate with `parking_lot` for `no_std` contexts.

### Contributors

- [@Restioson](https://github.com/Restioson)
- [@korrat](https://github.com/korrat)
- [@lytefast](https://github.com/lytefast)

## [[0.2.0](https://docs.rs/governor/0.2.0/governor/)] - 2020-03-01

### Added

- This changelog!

- New type `RateLimiter`, superseding the `DirectRateLimiter` type.

- Support for keyed rate limiting in `RateLimiter`, which allows users
  to keep a distict rate limit state based on the value of a hashable
  element.

- Support for different state stores:

  - The direct in-memory state store
  - A keyed state store based on [dashmap](https://crates.io/crates/dashmap)
  - A keyed state store based on a mutex-locked [HashMap](https://doc.rust-lang.org/nightly/std/collections/struct.HashMap.html).

- Support for different clock kinds:

  - [Quanta](https://crates.io/crates/quanta) (the default), a high-performance clock
  - [Instant](https://doc.rust-lang.org/nightly/std/time/struct.Instant.html), the stdlib monotonic clock
  - A fake releative clock, useful for tests or in non-std environments.

- `Quota` constructors now support a separate `.allow_burst` method
  that specifies a maximum burst capacity that diverges from the
  default.

- New constructor `Quota::with_period` allows specifying the exact
  amount of time it takes to replenish a single element.

### Deprecated

- The `Quota::new` constructor has some very confusing modalities, and
  should not be used as-is.

### Fixed

- An off-by-one error in `check_n`, causing calls with `n =
burst_size + 1` to return a "not yet" result instead of a "this will
  never work" result.

### Contributors

- [@jean-airoldie](https://github.com/jean-airoldie)
- [@antifuchs](https://github.com/antifuchs)

## [0.1.2](https://docs.rs/governor/0.1.2/governor/) - 2019-11-17

Initial release: A "direct" (a single rate-limiting state per
structure) rate limiter that works in an async context, using atomic
operations.
