coalesce

Documentation

Index

• func Coalesce(ctx context.Context, quiet, max time.Duration, f func(context.Context))

Functions

func Coalesce

func Coalesce(ctx context.Context, quiet, max time.Duration, f func(context.Context))

Coalesce will wait until the given function blocks for at least `quiet` time or is returning for at least `max` time. This enables easy and safe data coalescing.

`quiet` is the time waited between `f` returns, and is reset on each return. If quiet is reached, then Coalesce returns and `f` is not called anymore. `max` is the maximum time to wait for `f` to return. This does not reset.

The callback f must be well-behaved with the context passed in. The context will be cancelled prior to Coalesce returning, and Coalesce will block until the function call returns. This ensures that there are no data races once Coalesce returns.

If the given ctx is cancelled, this function also cancels. It follows the same behavior as if the timeout were reached.

Real world example: imagine you have a function processing input data, and you'd like to accumulate as much input data as possible to batch process it. The logic you'd say is: keep receiving data until I don't receive any within Q time or at most M time passes. Q is usually much shorter than M. This means if the data input is "quiet" enough, continue, otherwise wait until some maximum amount of time and still continue. This is what this function does generally.