# Changelog
## v0.17.0 - 2024-03-20
This release contains significant changes aimed at freeing users
from having to manage their own version of a unique list of members.
Whilst upgrading won't be just trivially bumping the version, it's
expected to be very easy and users will probably find themselves
deleting more code than writing new one when doing it.
Memory and CPU usage should go down since members and cluster
updates are now bound by the number of distinct addresses whereas
previously it would grow with the number of distinct identities.
As this is a large change, users should be more cautious when
upgrading and are welcome to open an issue in case of questions
or problems.
- **BREAKING**: `foca::Identity` has been revamped and now requires
a unique cluster-wide identifier (typically a socket address or a
hostname). When multiple identities appear with the same `Addr`
the conflict is handled by `Identity::win_addr_conflict`
- **BREAKING**: _Custom_ broadcasts wire format has changed and
handler implementations now only need to emit an identifier (Key)
for each value being broadcast instead of managing the allocation
See the `BroadcastHandler` documentation and examples for details
- `Config::periodic_announce_to_down_members`: Foca periodically
tries to join with members it considers down, as an attempt to
recover from a network partition. This setting is **enabled** by
default for `Config::new_wan` and `Config::new_lan`
- There's now `Notification::Rename` that signals whenever an
identity with a conflicting `Addr` in the cluster gets replaced
by a newer one
- There's no need to manage the list of members externally anymore:
Foca does it all for you and `Foca::iter_members` only lists
the unique (by `Identity::Addr`), freshest identities
- `examples/foca_insecure_udp_agent.rs` now comes with a fully working
custom broadcast example
- There's now a simple `runtime::AccumulatingRuntime` that's good
enough for basic usage if you don't want to implement your own
## v0.16.0 - 2023-10-01
- Introduce `Foca::iter_membership_state` that provides a view into the
whole state facilitating state replication scenarios. Previously one
would need to juggle `Notification::MemberDown` and
`Foca::iter_members` to achieve the same
## v0.15.0 - 2023-09-04
- `Foca::leave_cluster` doesn't consume self anymore, so users can keep
using the instance; Even rejoin the cluster if they so wish.
See: https://github.com/caio/foca/issues/30
## v0.14.0 - 2023-09-03
- **BREAKING** Custom broadcast handlers now know which member sent the
data they're handling to facilitate anti-entropy use-cases.
See: https://github.com/caio/foca/issues/28
- Foca now only emits DEBUG and TRACE level traces when using the
`tracing` feature
See: https://github.com/caio/foca/issues/30
- The `foca_insecure_udp_agent` example now contains a more robust timer
handler able to tolerate arbitrary runtime lags
## v0.13.0 - 2023-07-09
- Foca will now gossip upon receiving messages that flag their identity
as suspect
- Foca now resumes probing more quickly when recovering from an incorrect
sequence of Timer events
- The Timer enum now has a very simple Ord implementation to facilitate
dealing with out-of-order delivery. Sorting a slice of Timer events
should leave them in the order they should be handled, starting from
the first index.
See: https://github.com/caio/foca/issues/26
## v0.12.0 - 2023-06-18
- **CRITICAL BUGFIX**: uses of the functionality to notify down members
introduced on v0.6.0 could end up in a situation with a seemingly
endless flood of Message::TurnUndead payloads.
Upgrade is highly recommended.
See: https://github.com/caio/foca/issues/25
## v0.11.0 - 2023-03-22
- config::PeriodicParams is now exposed correctly so users can setup
periodic tasks without relying on and mutating the result from
`Config::new_{wan,lan}`
See: https://github.com/caio/foca/issues/24
## v0.10.1 - 2023-02-26
- Foca now always randomizes the list of members it sends when replying
to announce messages. Previously this shuffling would happen
periodically, so a fast announce rate would end up seeing the same set
of members for a while.
See: https://github.com/caio/foca/issues/22
## v0.10.0 - 2023-01-13
- Traces now include useful information even when running with less
verbose level
- Bugfix: albeit rare, foca could end up choosing an identity with
the same prefix for the indirect probe cycle, leading to a confusing
error in the logs of the target about receiving a message from
itself
## v0.9.0 - 2023-01-07
- **BREAKING**: `iter_members` now yields an iterator of `Member`
structs, previously if would yield `Member::id`. This allows
users to bootstrap a foca instance with existing cluster state
by feeding its output directly to `Foca::apply_many`
- **BREAKING**: `Config::remove_down_after` has been increased to
24h. The previous default value of 2 minutes was still too small
and would lead to unreasonably large updates backlog on large
clusters. See: https://github.com/caio/foca/issues/19
- Performance/Bugfix: now foca doesn't allocate when preparing a
message to be sent
## v0.8.0 - 2022-12-31
- Bugfix: foca would send garbage at the end of the payload when
replying to Announce messages under certain scenarios.
See: https://github.com/caio/foca/issues/18
## v0.7.0 - 2022-11-27
- **BREAKING**: `Config::remove_down_after` now defaults to 2 minutes
instead of 15 seconds: clients _not_ using the auto-rejoin
functionality will take longer to rejoin the cluster after being
declared down. Clients whose identity implement `Identity::renew`
have nothing to worry about.
- Bugfix: A foca instance could end up learning that its previous
identity was as active member on the cluster, adding more false
positives to the cluster chatter
## v0.6.0 - 2022-11-13
- New features:
- `Config::notify_down_members`: foca can now inform down members that
keep talking to the cluster that their messages are being ignored
- `Config::periodic_announce`: you can instruct foca to periodically
ask its peers for more peers, so that it learns about every member
in the cluster faster
- `Config::periodic_gossip`: to help speed up the propagation of
cluster updates
- **BREAKING**: `Config::new_wan` and `Config::new_lan` now _enable_
every new feature in this release
## v0.5.0 - 2022-10-24
- Foca now gracefully resumes probing when it detects an incorrect
probe cycle. https://github.com/caio/foca/pull/13
- Fixed one more instance of missing cleanup when the cluster state
changes mid probe cycle. https://github.com/caio/foca/issues/2
- Public entities now implement `Eq` along with `PartialEq`
## v0.4.1 - 2022-07-23
- Bugfix: "Member not found" trace lowered from warn to debug, only
affects users of the `tracing` feature
## v0.4.0 - 2022-07-02
- Optional feature `postcard-codec` now requires postcard v1.0
## v0.3.1 - 2022-05-29
- Configuration can now be changed at runtime via `Foca::set_config`
- Added `Config::new_wan` and `Config::new_lan` helpers to generate a
good enough configuration based on a given cluster size (requires the
`std` feature)
- Traces (from using the `tracing` feature) are a lot less noisy
## v0.3.0 - 2022-05-29
- **Yanked**, released accidentally
## v0.2.0 - 2022-04-18
- **BREAKING** `BroadcastHandler` now takes a generic parameter:
the identity type used by Foca
- `BroadcastHandler` can now decide which members should receive
custom broadcasts
- You can now ask Foca to disseminate broadcasts only, via
`Foca::broadcast`
- Simple broadcasting example added at `./examples/broadcasting.rs`
- Fixed a bug that could lead to incorrect behaviour when a Foca
instance changed identities in the middle of a probe cycle
https://github.com/caio/foca/issues/2
## v0.1.0 - 2021-11-04
- First release