Concurrency

RWMutex

RWMutex allows all the readers to access the map at the same time, but a writer will lock out everyone else

package main

import (

"fmt"

"sync"

)

func main() {

m := map[int]int{}

mux := &sync.RWMutex{}

go writeLoop(m, mux)

go readLoop(m, mux)

go readLoop(m, mux)

go readLoop(m, mux)

go readLoop(m, mux)

// stop program from exiting, must be killed

block := make(chan struct{})

<-block

}

func writeLoop(m map[int]int, mux *sync.RWMutex) {

for {

for i := 0; i < 100; i++ {

mux.Lock()

m[i] = i

mux.Unlock()

}

}

}

func readLoop(m map[int]int, mux *sync.RWMutex) {

for {

mux.RLock()

for k, v := range m {

fmt.Println(k, "-", v)

}

mux.RUnlock()

}

}

Range over a channel

Range will automatically break the loop when a channel is closed

for integer := range intChannel {

fmt.Printf("%v ", integer)

}

Buffered channel

Buffered channels are channels that are given a capacity when they're instatiated. If no reads are perfomred on the channel,a goroutine can still performs n write, where n is the capacity of the bufferd channel

If a goroutine making writes to a channel has knowledge of how many writes it will make. It can be useful to create a bufferd channel whose capacity is the number of writes to be made, and then make those writes as quickly as possible