channels

Creation and usage

channel := make(chan type)
 
// send to channel
go func() { channel <- val1 }()
go func() { channel <- val2 }()
...
 
// receive
first := <-channel
second := <-channel
...

Buffered vs Unbuffered channels

Unbuffered: Channels will block when sending until a reader is available Buffered: channels have a specific capacity and can send messages up to that capacity even without a reader

Buffered example

channel := make(chan int, BUFFER_SIZE)
 
// these will be buffered
channel <- 1
channel <- 2
 
go func() { channel <- 3}() // this will wait until 1 is read to be placed in the channel

Select keyword

• Allows you to work with two potentially blocking channels
• If one is blocking then reads from 2 and vice versa

one := make(chan int)
two := make(chan int)
 
for {
	select {
	case o := <-one:
		fmt.Println(o)
	case t := <-two
		fmt.Println(t)
	default:
		fmt.Println("No data received")
	}
	
	// timeout case
	select {
	case o := <-one:
		fmt.Println(o)
	case t := <-two:
		fmt.Printn(t)
	case <-time.After(300 * time.Millisecond):
		fmt.Println("timed out")
		return
	}
}