How to Measure Function Runtime in Go Using the Defer Feature?

Measuring Function Runtime in Go

In Go, a simple way to measure the execution time of a function is to leverage the defer feature.

Implementation

1. Define the following helper functions:

func trace(s string) (string, time.Time) {
    log.Println("START:", s)
    return s, time.Now()
}

func un(s string, startTime time.Time) {
    endTime := time.Now()
    log.Println("  END:", s, "ElapsedTime in seconds:", endTime.Sub(startTime))
}

2. Use these functions in the target function:

func someFunction() {
    defer un(trace("SOME_ARBITRARY_STRING_SO_YOU_CAN_KEEP_TRACK"))

    // Perform the function's intended operations here...
}

Explanation

• The trace() function is called at the beginning of the function and returns the function name and the current time.
• The defer un statement defers the execution of un() until the end of the function.
• When un() is executed, it calculates the elapsed time using the difference between the current time and the start time obtained from trace().
• The time is logged in milliseconds.

Note:

• This approach is not atomic-clock accurate due to the logging statements. For more precise timing, consider using specific profiling tools.

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