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Example explaining RWMutex composition on a struct
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| package main | |
| import ( | |
| "fmt" | |
| "sync" | |
| "net/url" | |
| "math/rand" | |
| "strconv" | |
| "time" | |
| ) | |
| type MutexHolder struct { | |
| sync.RWMutex | |
| Fields url.Values | |
| } | |
| func main() { | |
| start := time.Now() | |
| var wg sync.WaitGroup | |
| wait := 3 * time.Second | |
| for i:=0; i<5; i++ { | |
| m := MutexHolder { | |
| Fields: map[string][]string{"key": {"value", "value2"}}, | |
| } | |
| wg.Add(3) | |
| go printByReference(&m, i, wait, &wg) | |
| go printByReference(&m, i, wait, &wg) | |
| go printByReference(&m, i, wait, &wg) | |
| // Goroutines will finish in `wait * count(printByReference calls)` seconds because RWMutex is shared | |
| //wg.Add(3) | |
| //go printByValue(m, i, wait, &wg) | |
| //go printByValue(m, i, wait, &wg) | |
| //go printByValue(m, i, wait, &wg) | |
| // Goroutines will finish in `wait` seconds because RWMutex is shared | |
| } | |
| wg.Wait() | |
| fmt.Println("Took: ", time.Since(start)) | |
| } | |
| func printByReference(mh *MutexHolder, i int, wait time.Duration, wg *sync.WaitGroup) { | |
| defer wg.Done() | |
| mh.Lock() | |
| time.Sleep(wait) | |
| mh.Fields.Add("RandInt", strconv.Itoa(rand.Intn(100))) | |
| mh.Fields.Add("MyAddress", fmt.Sprintf("%p", &mh)) | |
| mh.Fields.Set("LoopIndex", strconv.Itoa(i)) | |
| fmt.Println(mh) | |
| mh.Unlock() | |
| } | |
| func printByValue(mh MutexHolder, i int, wait time.Duration, wg *sync.WaitGroup) { | |
| defer wg.Done() | |
| mh.Lock() | |
| time.Sleep(wait) | |
| mh.Fields.Add("RandInt", strconv.Itoa(rand.Intn(100))) | |
| mh.Fields.Add("MyAddress", fmt.Sprintf("%p", &mh)) | |
| mh.Fields.Set("LoopIndex", strconv.Itoa(i)) | |
| fmt.Println(mh) | |
| mh.Unlock() | |
| } |
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