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kontain.me/cmd/buildpack/main.go
2019-05-16 08:48:18 -04:00

262 lines
7.2 KiB
Go

package main
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"strings"
"time"
"cloud.google.com/go/compute/metadata"
"cloud.google.com/go/datastore"
"github.com/google/go-containerregistry/pkg/authn"
"github.com/google/go-containerregistry/pkg/name"
"github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/remote"
"github.com/google/go-containerregistry/pkg/v1/types"
"github.com/imjasonh/kontain.me/pkg/run"
"github.com/imjasonh/kontain.me/pkg/serve"
)
var projectID = ""
func init() {
var err error
projectID, err = metadata.ProjectID()
if err != nil {
log.Fatalf("metadata.ProjectID: %v", err)
}
}
const base = "packs/run:v3alpha2"
func main() {
ctx := context.Background()
ds, err := datastore.NewClient(ctx, projectID)
if err != nil {
log.Fatalf("datastore.NewClient: %v", err)
}
http.Handle("/v2/", &server{
info: log.New(os.Stdout, "I ", log.Ldate|log.Ltime|log.Lshortfile),
error: log.New(os.Stderr, "E ", log.Ldate|log.Ltime|log.Lshortfile),
ds: ds,
})
log.Println("Starting...")
port := os.Getenv("PORT")
if port == "" {
port = "8080"
log.Printf("Defaulting to port %s", port)
}
log.Printf("Listening on port %s", port)
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
}
type server struct {
info, error *log.Logger
ds *datastore.Client
}
func (s *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
s.info.Println("handler:", r.Method, r.URL)
path := strings.TrimPrefix(r.URL.String(), "/v2/")
switch {
case path == "": // API Version check.
w.Header().Set("Docker-Distribution-API-Version", "registry/2.0")
case strings.Contains(path, "/manifests/"):
s.serveBuildpackManifest(w, r)
case strings.Contains(path, "/blobs/"):
serve.Blob(w, r)
default:
serve.Error(w, serve.ErrNotFound)
}
}
func (s *server) serveBuildpackManifest(w http.ResponseWriter, r *http.Request) {
// Prepare workspace.
src, layers, err := s.prepareWorkspace()
if err != nil {
s.error.Println("ERROR:", err)
serve.Error(w, err)
return
}
// Clean up workspace.
defer func() {
for _, path := range []string{
src, layers, os.Getenv("HOME"),
} {
if err := os.RemoveAll(path); err != nil {
s.error.Printf("RemoveAll(%q): %v", path, err)
}
}
os.Setenv("HOME", "/home/")
}()
// Determine source repo and revision.
path := strings.TrimPrefix(r.URL.Path, "/v2/ko/")
parts := strings.Split(path, "/")
repo := strings.Join(parts[2:len(parts)-2], "/")
if repo == "" || repo == "buildpack" {
repo = "buildpack/sample-java-app"
}
revision := parts[len(parts)-1]
if revision == "latest" {
revision = "master"
}
// Resolve branch/tag/whatever -> SHA
revision, err = s.resolveCommit(repo, revision)
if err != nil {
s.error.Println("ERROR(resolveCommit):", err)
serve.Error(w, err)
return
}
// Check whether we have a cached manfiest for this revision.
// If we do, just serve it.
if b := s.checkCachedManifest(revision); len(b) != 0 {
w.Header().Set("Content-Type", string(types.DockerManifestSchema2)) // TODO: don't hard-code
io.Copy(w, bytes.NewReader(b))
return
}
// Fetch, detect and build source.
image, err := s.fetchAndBuild(src, layers, repo, revision)
if err != nil {
s.error.Println("ERROR:", err)
serve.Error(w, err)
return
}
// Serve new image manifest.
img, err := s.getImage(image)
if err != nil {
s.error.Println("ERROR:", err)
serve.Error(w, err)
return
}
// Cache the generated manifest.
if b, _ := img.RawManifest(); len(b) != 0 {
s.putCachedManifest(revision, b)
}
// Serve the manifest.
serve.Manifest(w, img)
}
type cachedManifest struct {
Manifest []byte `datastore:",noindex"`
}
func (s *server) checkCachedManifest(revision string) []byte {
k := datastore.NameKey("Manifests", revision, nil)
var e cachedManifest
ctx := context.Background() // TODO
if err := s.ds.Get(ctx, k, &e); err == datastore.ErrNoSuchEntity {
s.info.Printf("No cached manifest digest for %q", revision)
} else if err != nil {
s.error.Printf("datastore.Get: %v", err)
}
return e.Manifest
}
func (s *server) putCachedManifest(revision string, manifest []byte) {
k := datastore.NameKey("Manifests", revision, nil)
e := cachedManifest{manifest}
ctx := context.Background() // TODO
if _, err := s.ds.Put(ctx, k, &e); err != nil {
s.error.Printf("datastore.Put: %v", err)
}
}
// Resolves a ref (branch, tag, PR, commit) into its SHA.
// https://developer.github.com/v3/repos/commits/#get-the-sha-1-of-a-commit-reference
func (s *server) resolveCommit(repo, ref string) (string, error) {
url := fmt.Sprintf("https://api.github.com/repos/%s/commits/%s", repo, ref)
resp, err := http.Get(url) // TODO: cache this lookup?
if err != nil {
return "", err
}
if resp.StatusCode == http.StatusNotFound {
return "", serve.ErrNotFound
} else if resp.StatusCode != http.StatusOK {
return "", fmt.Errorf("Error resolving %q (%d): %v", url, resp.StatusCode, resp.Status)
}
defer resp.Body.Close()
var r struct {
SHA string `json:"sha"`
}
if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
return "", err
}
s.info.Printf("Resolved %q -> %q\n", ref, r.SHA)
return r.SHA, nil
}
func (s *server) prepareWorkspace() (string, string, error) {
// Create tempdir to store app source.
src, err := ioutil.TempDir("", "")
if err != nil {
return "", "", err
}
// Create layers dir.
layers, err := ioutil.TempDir("", "")
if err != nil {
return "", "", err
}
// Create and set $HOME, which is otherwise not writable.
home, err := ioutil.TempDir("", "")
if err != nil {
return "", "", err
}
os.Setenv("HOME", home)
return src, layers, nil
}
func (s *server) fetchAndBuild(src, layers, repo, revision string) (string, error) {
image := fmt.Sprintf("gcr.io/%s/built-%d", projectID, time.Now().Unix)
source := fmt.Sprintf("https://github.com/%s/archive/%s.tar.gz", repo, revision)
if resp, err := http.Head(source); err != nil {
return "", err
} else if resp.StatusCode == http.StatusNotFound {
return "", serve.ErrNotFound
} else if resp.StatusCode != http.StatusOK {
return "", fmt.Errorf("HEAD %s (%d): %s", source, resp.StatusCode, resp.Status)
}
for _, cmd := range []string{
fmt.Sprintf("chown -R %d:%d %s", os.Geteuid(), os.Getgid(), src),
fmt.Sprintf("chown -R %d:%d %s", os.Geteuid(), os.Getgid(), layers),
fmt.Sprintf("wget -qO- %s | tar xvz --strip-components=1 -C %s", source, src),
fmt.Sprintf("ls -R %s", src),
fmt.Sprintf("/lifecycle/detector -app=%s -group=%s/group.toml -plan=%s/plan.toml", src, layers, layers),
fmt.Sprintf("/lifecycle/analyzer -layers=%s -helpers=true -group=%s/group.toml %s", layers, layers, image),
fmt.Sprintf("/lifecycle/builder -layers=%s -app=%s -group=%s/group.toml -plan=%s/plan.toml", layers, src, layers, layers),
fmt.Sprintf("/lifecycle/exporter -layers=%s -helpers=true -app=%s -image=%s -group=%s/group.toml %s", layers, src, base, layers, image),
} {
if err := run.Do(s.info.Writer(), cmd); err != nil {
return "", fmt.Errorf("Running %q: %v", cmd, err)
}
}
return image, nil
}
func (s *server) getImage(image string) (v1.Image, error) {
ref, err := name.NewTag(image, name.WeakValidation)
if err != nil {
return nil, err
}
return remote.Image(ref, remote.WithAuthFromKeychain(authn.DefaultKeychain))
}