Best practices in go channels

Channels initialization

Channels in Go serve as a potent instrument for enabling communication and synchronization among goroutines. To optimize channel usage and ensure efficient and dependable concurrent programming, it is crucial to adhere to some recommended practices.

In Go, you can create a channel using the built-in make function with the chan keyword and a specified element type. Go provides the chan keyword to create a channel. A channel can only transmit data of one type, data of other types cannot be transmitted through this channel. The make function takes a type and returns a channel of that type. Here's an example:

package main

import "fmt"

func main() {
    var c chan int
    fmt.Println(c)
}         

This creates a channel ch that can transmit values of type int. We can then send and receive values on the channel using the <- operator:

ch <- 10// send 10 on the channel
value := <-ch // receive a value from the channel        

Channels usage on practice

We have declared the function greet, which takes channel c as an argument. In this function, we read data from channel c and output it to the console.

In the main function, the programme first outputs ‘main() started’.

Then we use make to create channel c with data type string.

We put channel c into the function greet and run the function as a goroutine using the keyword go.

Now we have two goroutines main and greet, main is still active.

We put data into channel c and at this point main is blocked until the other goroutine (greet) reads the data from channel c. The Go scheduler schedules greet to run and does what was described in the first point.

After that main becomes active again and displays ‘main() stopped’ in the console.

package main

import "fmt"

func greet(c chan string) {
    fmt.Println("Hello " + <-c + "!")
}

func main() {
    fmt.Println("main() started")
    c := make(chan string)

    go greet(c)

    c <- "John"
    fmt.Println("main() stopped")
}        

In Go it is also possible to close a channel, it will be impossible to send or receive data through a closed channel. Gorutina can check if a channel is closed or not by using the following construct: val, ok := <- channel, where ok will be true if the channel is open and a read operation can be performed, otherwise ok will be false if the channel is closed and there is no data to read from it. You can close a channel using the inbuilt close function using the following close(channel) syntax. Let's look at the following example:

package main

import "fmt"

func greet(c chan string) {
    <-c // for John
    <-c // for Mike
}

func main() {
    fmt.Println("main() started")

    c := make(chan string, 1)

    go greet(c)
    c <- "John"

    close(c) // closing channel

    c <- "Mike"
    fmt.Println("main() stopped")
}        

Sending and receiving on a channel will block until both a sender and a receiver are ready. This ensures that values are transmitted safely and correctly between goroutines. Here are guidelines for effectively employing channels in Go:

1. Make Judicious Use of Buffered Channels

Buffered channels can enhance performance by enabling goroutines to transmit multiple values without blocking until the buffer reaches capacity. Nonetheless, employing excessively large buffers can result in heightened memory usage. Utilize buffered channels when there is a temporary need to separate senders and receivers, while being mindful of buffer size.

2. Steer Clear of Nil Channels

Nil channels can trigger panics when utilized. Always initialize channels prior to usage to avert unexpected runtime errors. Employ the make function to generate a new channel:

ch := make(chan int)
        

3. Close Channels Appropriately

If a sender knows that no further data will be transmitted through a channel, it should close the channel to signal to the receiver(s) that no additional data will be forthcoming. Receivers can utilize the second value returned by a receive operation to detect if a channel has been closed.

close(ch)
        

4. Employ select for Non-blocking Operations

The select statement in Go permits simultaneous waiting on multiple channel operations. It proves beneficial for managing multiple channels and timeouts. Utilize select to prevent goroutines from blocking indefinitely.

5. Document Channel Usage

Thoroughly document the purpose of channels, the parties involved in sending and receiving data, and any specific synchronization requirements. This documentation aids other developers in comprehending the code and prevents channel misuse.

6. Mitigate Data Races

Channels are engineered to mitigate data races in Go. By utilizing channels for goroutine communication, you can circumvent numerous common concurrency issues. Always prioritize channels over shared memory for communication.

7. Employ the default Case in select

When utilizing select, consider integrating a default case to handle scenarios where no channel operation is ready. This inclusion can prevent goroutines from needlessly blocking and furnish fallback behavior.

8. Validate Concurrent Code

Craft tests for concurrent code incorporating channels to verify correct functionality across various scenarios. Leverage tools such as the sync package and the testing package to formulate comprehensive tests for your concurrent code.

By adhering to these recommended practices, you can harness the capabilities of channels in Go for efficient communication and synchronization among goroutines, culminating in more resilient and dependable concurrent programs.