examples: add example for building buildkit itself

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

examples/buildkit/buildkit.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"flag"
+	"os"
+
+	"github.com/tonistiigi/buildkit_poc/client/llb"
+	"github.com/tonistiigi/buildkit_poc/util/system"
+)
+
+func main() {
+	target := flag.String("target", "containerd", "target (standalone, containerd)")
+	flag.Parse()
+
+	bk := buildkit(*target == "containerd")
+	out := bk.Run(llb.Shlex("ls -l /bin")) // debug output
+
+	dt, err := out.Marshal()
+	if err != nil {
+		panic(err)
+	}
+	llb.WriteTo(dt, os.Stdout)
+}
+
+func goBuildBase() *llb.State {
+	goAlpine := llb.Image("docker.io/library/golang:1.8-alpine")
+	return goAlpine.
+		AddEnv("PATH", "/usr/local/go/bin:"+system.DefaultPathEnv).
+		AddEnv("GOPATH", "/go").
+		Run(llb.Shlex("apk add --no-cache g++ linux-headers")).
+		Run(llb.Shlex("apk add --no-cache git make")).Root()
+}
+
+func runc(version string) *llb.State {
+	return goBuildBase().
+		Run(llb.Shlex("git clone https://github.com/opencontainers/runc.git /go/src/github.com/opencontainers/runc")).
+		Dir("/go/src/github.com/opencontainers/runc").
+		Run(llb.Shlex("git checkout -q %s", version)).
+		Run(llb.Shlex("go build -o /usr/bin/runc ./")).Root()
+}
+
+func containerd(version string) *llb.State {
+	return goBuildBase().
+		Run(llb.Shlex("apk add --no-cache btrfs-progs-dev")).
+		Run(llb.Shlex("git clone https://github.com/containerd/containerd.git /go/src/github.com/containerd/containerd")).
+		Dir("/go/src/github.com/containerd/containerd").
+		Run(llb.Shlex("git checkout -q %s", version)).
+		Run(llb.Shlex("make bin/containerd")).Root()
+}
+
+func buildkit(withContainerd bool) *llb.State {
+	src := goBuildBase().
+		Run(llb.Shlex("git clone https://github.com/tonistiigi/buildkit_poc.git /go/src/github.com/tonistiigi/buildkit_poc")).
+		Dir("/go/src/github.com/tonistiigi/buildkit_poc")
+
+	builddStandalone := src.
+		Run(llb.Shlex("go build -o /bin/buildd-standalone -tags standalone ./cmd/buildd"))
+
+	builddContainerd := src.
+		Run(llb.Shlex("go build -o /bin/buildd-containerd -tags containerd ./cmd/buildd"))
+
+	buildctl := src.
+		Run(llb.Shlex("go build -o /bin/buildctl ./cmd/buildctl"))
+
+	r := llb.Image("docker.io/library/alpine:latest")
+	r = copy(buildctl.Root(), "/bin/buildctl", r, "/bin/")
+	r = copy(runc("v1.0.0-rc3"), "/usr/bin/runc", r, "/bin/")
+	if withContainerd {
+		r = copy(containerd("master"), "/go/src/github.com/containerd/containerd/bin/containerd", r, "/bin/")
+		r = copy(builddContainerd.Root(), "/bin/buildd-containerd", r, "/bin/")
+	} else {
+		r = copy(builddStandalone.Root(), "/bin/buildd-standalone", r, "/bin/")
+	}
+	return r
+}
+
+func copy(src *llb.State, srcPath string, dest *llb.State, destPath string) *llb.State {
+	cpImage := llb.Image("docker.io/library/alpine:latest")
+	cp := cpImage.Run(llb.Shlex("cp -a /src%s /dest%s", srcPath, destPath))
+	cp.AddMount("/src", src)
+	return cp.AddMount("/dest", dest)
+}