kacerrandClaude Fable 5
7219eb5a23
Includes solved 02-worker-pool and 09-safe-counter (mutex, atomic, sharded). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GbnJj9ZqEx9nUvzkjdwfMq
62 lines
1.5 KiB
Go
62 lines
1.5 KiB
Go
// Exercise 02 — Worker Pool
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//
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// ASSIGNMENT
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// ----------
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// Implement Pool so that it:
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//
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// 1. Spawns exactly `workers` goroutines.
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// 2. Each worker consumes jobs from `jobs` until the channel is closed.
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// 3. Results of fn(job) are sent to the returned channel.
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// 4. The returned channel is CLOSED after ALL workers finish.
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// (Whoever ranges over the output must terminate — no deadlocks.)
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// 5. No goroutines may leak.
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//
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// Run the tests: go test -race ./02-worker-pool/
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package main
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import (
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"fmt"
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"sync"
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)
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// Pool fans `jobs` out to `workers` goroutines running fn, fans results in.
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// TODO: implement me.
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func Pool[T, R any](jobs <-chan T, workers int, fn func(T) R) <-chan R {
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out := make(chan R)
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var wg sync.WaitGroup
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// start all the workers and increment the waitgroup
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for i := 0; i < workers; i++ {
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wg.Add(1)
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go func() {
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defer wg.Done()
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for j := range jobs {
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out <- fn(j)
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}
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}()
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}
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// TODO:
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// - start `workers` goroutines, each: for j := range jobs { out <- fn(j) }
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// - close(out) exactly once, only after every worker returned
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// (hint: sync.WaitGroup + one extra "closer" goroutine)
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// start go routine that closes out channel when all workers are done
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go func() {
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wg.Wait()
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close(out)
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}()
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return out
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}
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func main() {
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jobs := make(chan int)
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go func() {
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for i := 1; i <= 9; i++ {
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jobs <- i
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}
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close(jobs)
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}()
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for r := range Pool(jobs, 3, func(n int) int { return n * n }) {
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fmt.Println(r)
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}
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}
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