# Changelog

## [0.2.1] - 2026-03-12

Patch release focused on HTTP retry semantics, registry durability, and
concurrency safety across shared limiters.

### Added

- Method-aware HTTP retry classification via `Foundation.Retry.HTTP.retryable_status_for_method?/3`
- Method-aware retry decisions via `Foundation.Retry.HTTP.should_retry_for_method?/3`
- Support for `Retry-After` HTTP-date values in `Foundation.Retry.HTTP.parse_retry_after/2`
- Backoff policy aliases (`:base_delay_ms`, `:max_delay_ms`) and string strategy names
- Shared internal ETS registry helpers used by circuit breakers, rate-limit windows, and counting semaphores

### Changed

- Circuit breaker registry calls now reserve half-open probes with CAS updates to enforce concurrency limits
- Dispatch snapshots now reflect backoff applied directly to the shared limiter
- Backoff windows now extend active deadlines instead of shortening them, and `wait/2` re-checks after wakeups
- Default ETS registries are reused or recreated more safely across owner exits
- ExDoc was updated to `0.40.0`

### Fixed

- HTTP-date parsing now degrades gracefully when `:httpd_util` is unavailable at runtime
- Release docs and package metadata now explicitly clarify the 0.2.x rewrite and 0.1.x incompatibility

## [0.2.0] - 2026-01-08

Complete rewrite focusing on lightweight, composable resilience primitives.

This release is not compatible with the 0.1.x series, and there is no direct
upgrade path.

### Added

#### Backoff (`Foundation.Backoff`)
- Configurable backoff policies with exponential, linear, and constant strategies
- Jitter support: none, factor, additive, and range strategies
- Pluggable random functions for deterministic testing

#### Retry (`Foundation.Retry`)
- Generic retry orchestration with `Policy` and `State` structs
- Configurable max attempts, elapsed time limits, and progress timeouts
- Support for custom `retry_on` predicates and `retry_after_ms_fun` callbacks

#### Retry Helpers (`Foundation.Retry.*`)
- `Config` - retry configuration struct with sensible defaults
- `Handler` - stateful retry handler built from config
- `HTTP` - HTTP-specific utilities: status classification, `Retry-After` parsing
- `Runner` - generic retry runner with telemetry hooks and exception handling

#### Polling (`Foundation.Poller`)
- Generic polling loop with backoff, timeout, and max-attempts controls
- Async execution via `Task` with graceful shutdown
- Custom exception handlers

#### Rate Limiting (`Foundation.RateLimit.BackoffWindow`)
- Shared backoff windows for rate-limited APIs
- ETS-backed per-key limiter registry using atomic backoff deadlines

#### Circuit Breaker (`Foundation.CircuitBreaker`)
- Pure functional circuit breaker state machine (closed/open/half-open)
- Configurable failure threshold, reset timeout, and half-open call limits
- `Foundation.CircuitBreaker.Registry` - ETS-backed registry with heir support

#### Semaphores (`Foundation.Semaphore.*`)
- `Counting` - ETS-backed counting semaphore with blocking acquire
- `Weighted` - GenServer-backed weighted semaphore for byte budgets
- `Limiter` - simple process-based semaphore for quick concurrency limits

#### Dispatch (`Foundation.Dispatch`)
- Layered dispatch limiter combining concurrency, throttling, and byte budgets
- Automatic throttle mode under backoff pressure
- Configurable byte penalty multipliers

#### Telemetry (`Foundation.Telemetry`)
- Lightweight wrappers around `:telemetry.execute/3`
- `measure/3` helper for timing function execution
- Optional `telemetry_reporter` integration for reporter lifecycle management

### Changed
- Minimum Elixir version is now 1.15
- Only runtime dependency is `telemetry ~> 1.2`

### Removed
- Legacy infrastructure wrappers (fuse, hammer, poolboy integrations)
- Configuration server and event store services
- Process registry and service registry modules
- All 0.1.x application supervision tree and runtime services

## [0.1.5] - 2025-06-12

### Added
- Service lifecycle integration tests
- Config logic unit tests
- Additional event store tests
- Utils test coverage improvements

### Changed
- Flagged slow tests for better CI performance
- Updated test helper infrastructure

### Fixed
- Resolved various issues discovered from expanded test coverage

## [0.1.4] - 2025-06-06

### Fixed
- Connection manager test reliability improvements (Fixes #4)

## [0.1.3] - 2025-06-06

### Added
- CHANGELOG.md updates

### Fixed
- Event store query and validation improvements (Fixes #2)
- Event validator enhancements

## [0.1.2] - 2025-06-06

### Added
- Telemetry service with histogram API support
- Circuit breaker initialization tests
- Infrastructure module enhancements
- Documentation for Python bridge integration

### Fixed
- Race condition in connection manager tests (Fixes #1)
- Dialyzer warnings cleanup

## [0.1.1] - 2025-06-05

### Fixed
- GitHub CI configuration bug
- Test infrastructure improvements for graceful degradation tests
- Chaos resilience test stability

## [0.1.0] - 2025-06-05

Initial release of Foundation - an Elixir infrastructure library.

### Added

#### Core Infrastructure
- Circuit breaker pattern implementation via Fuse integration
- Rate limiting via Hammer integration
- Connection pooling via Poolboy integration
- Configuration management with ConfigServer GenServer
- Event store for application events

#### Services
- `Foundation.Config` - Runtime configuration management
- `Foundation.Events` - Event publishing and querying
- `Foundation.Infrastructure` - Circuit breakers, rate limiting, connection pools

#### Testing
- Comprehensive test suite with 506 tests and 49 property-based tests
- Test helpers and mock infrastructure
- Integration and stress tests

#### Documentation
- Architecture documentation
- API documentation with ExDoc