The Go Programming Language

8.5 Looping in Parallel

In this section, we’ll explore some common concurrency patterns for executing all the iterations of a loop in parallel. We’ll consider the problem of producing thumbnail-size images from a set of full-size ones. The gopl.io/ch8/thumbnail package provides an ImageFile function that can scale a single image. We won’t show its implementation but it can be downloaded from gopl.io.

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gopl.io/ch8/thumbnail

package thumbnail

// ImageFile reads an image from infile and writes
// a thumbnail-size version of it in the same directory.
// It returns the generated file name, e.g., "foo.thumb.jpg".
func ImageFile(infile string) (string, error)

The program below loops over a list of image file names and ...