Rene Nochebuena
631c98396e
worker depends on launcher (now correctly Tier 2) and logz (Tier 1), placing it at Tier 3. The previous docs cited launcher as Tier 1 and logz as Tier 0, both of which were wrong.
30 lines
2.5 KiB
Markdown
30 lines
2.5 KiB
Markdown
# Changelog
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All notable changes to this module will be documented in this file.
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The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
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and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
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## [0.9.0] - 2026-03-18
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### Added
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- `Task` type — `func(ctx context.Context) error`; the unit of work dispatched to the pool
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- `Config` struct — pool settings loaded from environment variables: `WORKER_POOL_SIZE` (number of concurrent goroutines, default `5`), `WORKER_BUFFER_SIZE` (task queue channel capacity, default `100`), `WORKER_TASK_TIMEOUT` (per-task context deadline; `0` means no deadline, default `0s`), `WORKER_SHUTDOWN_TIMEOUT` (time to wait for workers to drain on stop, default `30s`)
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- `Provider` interface — `Dispatch(task Task) bool`; for callers that only dispatch tasks; returns `false` immediately when the queue is full (backpressure, non-blocking)
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- `Component` interface — embeds `launcher.Component` and `Provider`; the full lifecycle-managed surface registered with the launcher
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- `New(logger logz.Logger, cfg Config) Component` — constructor; applies safe defaults (`PoolSize <= 0` → 5, `BufferSize <= 0` → 100); returns a `Component` ready for `lc.Append`
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- `OnInit` — logs pool configuration; initialises the buffered task channel
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- `OnStart` — spawns `PoolSize` worker goroutines, each ranging over the task channel
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- `OnStop` — closes the task channel (drain signal), cancels the pool context, then waits up to `ShutdownTimeout` for all goroutines to finish; logs an error on timeout but returns `nil` so the launcher continues
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- Per-task timeout — when `TaskTimeout > 0`, each worker creates a `context.WithTimeout` child before invoking the task; tasks also receive a cancellation signal when the pool is stopping via the pool context
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- Error logging — task errors are logged with the worker ID; errors are not surfaced to the dispatcher
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### Design Notes
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- A single buffered `chan Task` is shared by all workers; closing it during `OnStop` is the drain signal, avoiding a separate done channel or additional synchronisation primitives.
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- `Dispatch` is deliberately non-blocking: a `false` return means the task has been dropped, not queued; the caller owns the retry or overflow decision, keeping backpressure handling out of the pool itself.
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- `Provider` / `Component` split follows the framework pattern: inject `Provider` into callers that only dispatch tasks, inject `Component` only at the lifecycle registration site.
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[0.9.0]: https://code.nochebuena.dev/go/worker/releases/tag/v0.9.0
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