package main import ( "fmt" "image" "os" "strconv" "github.com/disintegration/imaging" "gitlab.com/gitlab-org/gitlab-workhorse/cmd/gitlab-resize-image/png" ) func main() { if err := _main(); err != nil { fmt.Fprintf(os.Stderr, "%s: fatal: %v\n", os.Args[0], err) os.Exit(1) } } func _main() error { widthParam := os.Getenv("GL_RESIZE_IMAGE_WIDTH") requestedWidth, err := strconv.Atoi(widthParam) if err != nil { return fmt.Errorf("GL_RESIZE_IMAGE_WIDTH: %w", err) } pngReader, err := png.NewReader(os.Stdin) if err != nil { return fmt.Errorf("construct PNG reader: %w", err) } src, formatName, err := image.Decode(pngReader) if err != nil { return fmt.Errorf("decode: %w", err) } imagingFormat, err := imaging.FormatFromExtension(formatName) if err != nil { return fmt.Errorf("find imaging format: %w", err) } image := imaging.Resize(src, requestedWidth, 0, imaging.Lanczos) return imaging.Encode(os.Stdout, image, imagingFormat) }