commit 60f4d82fce8299eb5642a9ab76905c13943eefe2
Author: Jason Hall <jasonhall@google.com>
Date:   Mon Dec 3 17:02:39 2018 -0500

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4874312
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+blobs/*
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..4cbee58
--- /dev/null
+++ b/main.go
@@ -0,0 +1,223 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/google/go-containerregistry/pkg/ko/build"
+	"github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/empty"
+	"github.com/google/go-containerregistry/pkg/v1/random"
+)
+
+func main() {
+	http.HandleFunc("/", handler)
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	log.Println(r.Method, r.URL)
+	if !strings.HasPrefix(r.URL.String(), "/v2/") {
+		http.Error(w, "not found", http.StatusNotFound)
+		return
+	}
+	path := strings.TrimPrefix(r.URL.String(), "/v2/")
+
+	switch {
+	case path == "":
+		// API Version check.
+		w.Header().Set("Docker-Distribution-API-Version", "registry/2.0")
+		return
+	case strings.HasPrefix(path, "random/manifests/"):
+		log.Println("serving random manifest...")
+		serveRandomManifest(w, r)
+	case strings.HasPrefix(path, "ko/manifests/"):
+		serveKoManifest(w, r)
+	case strings.HasPrefix(path, "random/blobs/"), strings.HasPrefix(path, "ko/blobs/"):
+		serveBlob(w, r)
+	}
+}
+
+// TODO: serve blobs by redirecting to GCS.
+func serveBlob(w http.ResponseWriter, r *http.Request) {
+	// Extract requested blob digest and serve it.
+	// If it doesn't exist, this will return 404.
+	parts := strings.Split(r.URL.Path, "/")
+	digest := parts[len(parts)-1]
+	http.ServeFile(w, r, "blobs/"+digest)
+}
+
+// TODO: write blobs to GCS.
+func writeBlob(h v1.Hash, rc io.ReadCloser) error {
+	path := "blobs/" + h.String()
+	// Check if file exists already.
+	if _, err := os.Stat(path); err == nil {
+		return nil
+	}
+
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	if _, err := io.Copy(f, rc); err != nil {
+		return err
+	}
+	if err := rc.Close(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func getDefaultBaseImage(string) (v1.Image, error) {
+	return empty.Image, nil
+	/*
+		ref, err := name.ParseReference("gcr.io/distroless/base", name.WeakValidation)
+		if err != nil {
+			return nil, err
+		}
+		return remote.Image(ref)
+	*/
+}
+
+// registry.lol/ko/github.com/knative/build/cmd/controller -> ko build and serve
+func serveKoManifest(w http.ResponseWriter, r *http.Request) {
+	path := strings.TrimPrefix(r.URL.Path, "/v2/ko/manifests/")
+	parts := strings.Split(path, "/")
+	pkg := strings.Join(parts[:len(parts)-1], "/")
+
+	tag := parts[len(parts)-1]
+	log.Printf("requested image tag :%s", tag)
+
+	// go get the package.
+	log.Printf("go get %s...", pkg)
+	if err := exec.Command("go", "get", pkg).Run(); err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	// TODO: Check image tag for version, resolve branches -> commits and redirect to img:<commit>
+	// TODO: For requests for commit SHAs, check if it's already built and serve that instead.
+	// TODO: Look for $GOPATH/$importPath/.ko.yaml and up, to base image config.
+
+	// ko build the package.
+	g, err := build.NewGo(
+		build.WithBaseImages(getDefaultBaseImage),
+		build.WithCreationTime(v1.Time{time.Unix(0, 0)}),
+	)
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if !g.IsSupportedReference(pkg) {
+		log.Println("ERROR: %s", err)
+		http.Error(w, fmt.Sprintf("%q is not a supported reference", pkg), http.StatusBadRequest)
+		return
+	}
+	img, err := g.Build(pkg)
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	serveManifest(w, img)
+}
+
+// Capture up to 99 layers of up to <1GB each.
+var randomTagRE = regexp.MustCompile("([0-9]{1,2})x([0-9]{1,6})")
+
+// registry.lol/random:3x10mb
+// registry.lol/random(:latest) -> 1x10mb
+func serveRandomManifest(w http.ResponseWriter, r *http.Request) {
+	tag := strings.TrimPrefix(r.URL.Path, "/v2/random/manifests/")
+	var num, size int64 = 1, 100000 // 10MB
+
+	// Captured requested num + size from tag.
+	all := randomTagRE.FindStringSubmatch(tag)
+	if len(all) >= 3 {
+		num, _ = strconv.ParseInt(all[1], 10, 64)
+		size, _ = strconv.ParseInt(all[2], 10, 64)
+	}
+	log.Printf("generating random image with %d layers of %d bytes", num, size)
+
+	// Generate a random image.
+	img, err := random.Image(size, num)
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	serveManifest(w, img)
+}
+
+// serveManifest writes config and layer blobs for the image, then serves the
+// manifest contents pointing to those blobs.
+func serveManifest(w http.ResponseWriter, img v1.Image) {
+	// Write config blob for later serving.
+	ch, err := img.ConfigName()
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	cb, err := img.RawConfigFile()
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	log.Printf("writing config blob %q", ch)
+	if err := writeBlob(ch, ioutil.NopCloser(bytes.NewReader(cb))); err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Write layer blobs for later serving.
+	layers, err := img.Layers()
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	for _, l := range layers {
+		rc, err := l.Compressed()
+		if err != nil {
+			log.Println("ERROR: %s", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		lh, err := l.Digest()
+		if err != nil {
+			log.Println("ERROR: %s", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		log.Printf("writing layer blob %q", lh)
+		if err := writeBlob(lh, rc); err != nil {
+			log.Println("ERROR: %s", err)
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
+
+	// Serve the manifest.
+	b, err := img.RawManifest()
+	if err != nil {
+		log.Println("ERROR: %s", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.Write(b)
+}