Using Golang TimeTicker for a set duration

Problem: As part of me learning and experimenting with golang and working on a small gauge-reportserver plugin, I stumbled across a problem where I had to repeat a task for a certain period.

Solution:

1. Create a time.Ticker so that it can hold a channel that ticks at set intervals.
2. Use a time.Timer to stop the ticker after a set period of time.

Timers and Tickers let you execute code in the future, once or repeatedly.

Ticker

The following will create a new ticker and tick tick with a 500 milliseconds interval.

ticker := time.NewTicker(500 * time.Millisecond)
defer func() { ticker.Stop() }()
for {
    select {
    case <-ticker.C:
        fmt.Printf("tick tick")
}

The above will go on forever unless stopped, but we needed to timeout the ticker after a set duration which can easily be achieved by time.After that waits for a specified duration and then sends the current time on the returned channel.

Timer

We can add time.After(10 * time.Second) to the select to end the ticker after 10 seconds.

ticker := time.NewTicker(500 * time.Millisecond)
defer func() { ticker.Stop() }()
for {
    select {
    case <-ticker.C:
        fmt.Printf("tick tick")
    case <-time.After(10 * time.Second):
        fmt.Println("10 seconds! End Ticker")
        return
    }
}

However, running the above would still tick forever because a select blocks until one of it’s cases is ready and then it executes the case but time.After(10 * time.Second) was never getting a chance to be ready due to interval being shorter, that would only work if that was less than 5 seconds.

This can be resolved by by having timer declared before starting the for loop.

The final solution looks like this where a ticker is created that ticks every 500 milliseconds and timer added to stop the ticker after 10 seconds have elapsed.

ticker := time.NewTicker(500 * time.Millisecond)
defer func() { ticker.Stop() }()
timer := time.After(10 * time.Second)
for {
    select {
    case <-ticker.C:
        fmt.Printf("tick tick")
    case <-timer:
        fmt.Println("10 seconds! End Ticker")
        return
    }
}

Hopefully, the above is helpful to others. Good Luck! :)