Release v1.2.0

Full Changelog: v1.1.0...v1.2.0

Release v1.1.0

Full Changelog: v1.0.0...v1.1.0

Release v1.0.0

Cirreum.Coordination 1.0.0 — standalone atomic-coordination primitives

Dependency-light primitives for the two atomic operations distributed systems keep
reaching for: a single-use claim (IReplayGuard) and an atomic fixed-window counter
(IRequestThrottle). Usable by any consumer — authentication, messaging, command
pipelines, or an unrelated application — to share one set of primitives and a single
chosen backend.

Strictly additive — initial release. Depends only on
Microsoft.Extensions.DependencyInjection.Abstractions (no Cirreum dependencies).

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Why this release exists

Replay protection, nonce single-use, idempotency keys, message de-duplication, and
rate limiting all reduce to one of two atomic operations: claim-if-absent and
increment-within-a-window. Re-implementing those per feature (and per backend) is
where subtle races creep in. Cirreum.Coordination gives them one contract, one
in-memory default, and a single place to swap in a distributed backend.

It has no Cirreum dependencies — so it is usable outside Cirreum entirely, and
within Cirreum it is a shared primitive rather than an authentication-only detail.

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What's new

IReplayGuard

// Atomic set-if-absent: the first caller to claim a token wins; a replay loses.
bool firstUse = await replayGuard.TryClaimAsync(nonce, ttl, ct);

A single-use claim for replay / nonce protection, idempotency keys, and message
de-duplication.

IRequestThrottle

// Atomic fixed-window counter — returns the post-increment count + an allow/block verdict.
ThrottleOutcome outcome = await throttle.RecordAsync(clientId, window, limit, ct);
if (!outcome.Allowed) { /* outcome.RetryAfter hints when to try again */ }

An atomic fixed-window counter for rate limiting.

In-memory backend + AddCoordination

services.AddCoordination(c => c.UseInMemory());

A lock-free in-memory backend (monotonic TickCount64 deadlines, single-sweeper
eviction) — correct for single-instance and development. Registration is idempotent
and order-independent: a component that needs coordination pulls it (registering a
fail-closed sentinel if no backend is chosen yet), and the application chooses the
backend; the chosen backend always wins.

CoordinationPostureValidator

CoordinationPostureValidator.Validate(services);

A boot-time check that fails fast when coordination was pulled but no backend was
chosen — turning a silent mis-configuration into a clear startup error.

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Compatibility

• Strictly additive. Initial release.
• One dependency: Microsoft.Extensions.DependencyInjection.Abstractions. No Cirreum
  dependencies.
• Fail-closed throughout: the sentinel throws rather than silently allow; non-positive
  TTL / window / limit and null / blank token / key are rejected before any work.

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Coordinated downstream work

Cirreum.Coordination.Redis provides a distributed backend over the same contracts
(services.AddCoordination(c => c.UseRedis(...))). Cirreum's authentication track uses
these primitives for SignedRequest replay-nonce protection and request throttling.

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See also

• Cirreum.Coordination.Redis — a distributed (Redis) backend for the same primitives