api: "YAML JSON TOON Database"
version: "1.0.0"
format: "json"
dataset:
  id: 20
  slug: "go-concurrency-patterns"
  title: "Go Concurrency Patterns"
  description: "Goroutines, channels, select, sync primitives, and common concurrency patterns in Go."
  category: "Programming Languages"
  category_slug: "programming-languages"
  tags: "go,golang,concurrency,goroutines,channels"
  view_count: 0
  created_at: 1777673262
  updated_at: 1777673262
data:
  concepts:
    - name: "Goroutines"
      keyword: "go"
      description: "Lightweight threads managed by Go runtime; cheap to create (few KB stack)."
      example: "go func() { fmt.Println(\"running in goroutine\") }()"
      notes: " thousands of concurrent goroutines possible; multiplexed onto OS threads"
    - name: "Channels"
      keyword: "chan"
      description: "Typed conduits for communication between goroutines; synchronous or buffered."
      example: "ch := make(chan int); go func() { ch <- 42 }(); val := <-ch"
      notes: "Blocking by default; unbuffered channels synchronize goroutines"
    - name: "Buffered Channels"
      keyword: "make(chan T, n)"
      description: "Channels with capacity; sender blocks only when buffer full."
      example: "bufCh := make(chan string, 5); bufCh <- \"msg\"; // non-blocking if space"
      notes: "Useful for queue-like patterns; decouples sender/receiver rates"
    - name: "Select Statement"
      keyword: "select"
      description: "Wait on multiple channel operations; like switch for channels."
      example: "select { case msg := <-ch1: fmt.Println(msg) case msg := <-ch2: fmt.Println(msg) case <-time.After(time.Second): fmt.Println(\"timeout\") }"
      notes: "Random choice if multiple ready; default case non-blocking"
    - name: "WaitGroup"
      keyword: "sync.WaitGroup"
      description: "Wait for a collection of goroutines to finish; Add, Done, Wait."
      example: "var wg sync.WaitGroup; wg.Add(2); go func(){ defer wg.Done(); ... }(); wg.Wait()"
      notes: "Must call Done exactly once per Add; typically defer wg.Done()"
    - name: "Mutex (Mutual Exclusion)"
      keyword: "sync.Mutex"
      description: "Protect shared memory; Lock/Unlock ensure exclusive access."
      example: "var mu sync.Mutex; mu.Lock(); counter++; mu.Unlock()"
      notes: "Prefer channels over mutexes when possible (communicating vs sharing)"
    - name: "Worker Pool Pattern"
      pattern: "Fan-out / Fan-in"
      description: "Distribute work across multiple workers; collect results."
      example: "jobs := make(chan Job); results := make(chan Result); for w:=1; w<=3; w++ { go worker(jobs, results) }; for j:=range jobs { jobs <- j }; close(results); for r:=range results { ... }"
      notes: "Classic pipeline: distribute tasks, process concurrently, collect"
    - name: "Context Package"
      keyword: "context.Context"
      description: "Carry deadlines, cancellation signals, and request-scoped values across API boundaries."
      example: "ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second); defer cancel(); select { case <-ctx.Done(): fmt.Println(\"timeout\") }"
      notes: "Use for cancellation, timeouts, and passing request-scoped data"