mirror of
https://github.com/imjasonh/kontain.me
synced 2026-07-08 09:04:54 +00:00
313 lines
8.9 KiB
Go
313 lines
8.9 KiB
Go
package main
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import (
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"context"
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"crypto/md5"
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"errors"
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"fmt"
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"io/ioutil"
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"log"
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"net/http"
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"os"
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"path/filepath"
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"regexp"
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"strings"
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"time"
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"cloud.google.com/go/compute/metadata"
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"github.com/google/go-containerregistry/pkg/name"
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v1 "github.com/google/go-containerregistry/pkg/v1"
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gauthn "github.com/google/go-containerregistry/pkg/v1/google"
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"github.com/google/go-containerregistry/pkg/v1/remote"
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"github.com/google/go-github/v32/github"
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"github.com/imjasonh/kontain.me/pkg/run"
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"github.com/imjasonh/kontain.me/pkg/serve"
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"golang.org/x/oauth2/google"
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)
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var projectID = ""
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func init() {
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var err error
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projectID, err = metadata.ProjectID()
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if err != nil {
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log.Fatalf("metadata.ProjectID: %v", err)
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}
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}
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var commitRE = regexp.MustCompile("[a-f0-9]{40}")
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const base = "gcr.io/buildpacks/gcp/run:v1"
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func main() {
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ctx := context.Background()
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st, err := serve.NewStorage(ctx)
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if err != nil {
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log.Fatalf("serve.NewStorage: %v", err)
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}
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http.Handle("/v2/", &server{
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info: log.New(os.Stdout, "I ", log.Ldate|log.Ltime|log.Lshortfile),
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error: log.New(os.Stderr, "E ", log.Ldate|log.Ltime|log.Lshortfile),
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storage: st,
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})
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http.Handle("/", http.RedirectHandler("https://github.com/imjasonh/kontain.me/blob/main/cmd/buildpack", http.StatusSeeOther))
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log.Println("Starting...")
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port := os.Getenv("PORT")
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if port == "" {
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port = "8080"
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log.Printf("Defaulting to port %s", port)
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}
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log.Printf("Listening on port %s", port)
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log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
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}
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type server struct {
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info, error *log.Logger
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storage *serve.Storage
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}
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func (s *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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s.info.Println("handler:", r.Method, r.URL)
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path := strings.TrimPrefix(r.URL.String(), "/v2/")
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switch {
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case path == "": // API Version check.
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w.Header().Set("Docker-Distribution-API-Version", "registry/2.0")
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case strings.Contains(path, "/blobs/"),
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strings.Contains(path, "/manifests/sha256:"):
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// Extract requested blob digest and redirect to serve it from GCS.
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// If it doesn't exist, this will return 404.
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parts := strings.Split(r.URL.Path, "/")
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digest := parts[len(parts)-1]
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serve.Blob(w, r, digest)
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case strings.Contains(path, "/manifests/"):
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s.serveBuildpackManifest(w, r)
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default:
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serve.Error(w, serve.ErrNotFound)
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}
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}
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func (s *server) serveBuildpackManifest(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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// Prepare workspace.
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src, layers, err := s.prepareWorkspace()
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if err != nil {
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s.error.Println("ERROR:", err)
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serve.Error(w, err)
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return
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}
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// Clean up workspace.
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defer func() {
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for _, path := range []string{
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src, layers, os.Getenv("HOME"),
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} {
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if err := os.RemoveAll(path); err != nil {
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s.error.Printf("RemoveAll(%q): %v", path, err)
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}
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}
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os.Setenv("HOME", "/home/")
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}()
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// Determine source repo and revision.
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parts := strings.Split(r.URL.Path, "/")
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if len(parts) < 4 {
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serve.Error(w, errors.New("Must specify GitHub repository"))
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return
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}
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ghOwner, ghRepo := parts[2], parts[3]
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path := strings.Join(parts[4:len(parts)-2], "/")
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tagOrDigest := parts[len(parts)-1]
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// If request is for image by digest, try to serve it from GCS.
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if strings.HasPrefix(tagOrDigest, "sha256:") {
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desc, err := s.storage.BlobExists(ctx, tagOrDigest)
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if err != nil {
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s.error.Printf("ERROR (storage.BlobExists): %s", err)
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serve.Error(w, serve.ErrNotFound)
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return
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}
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if r.Method == http.MethodHead {
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w.Header().Set("Docker-Content-Digest", tagOrDigest)
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w.Header().Set("Content-Type", string(desc.MediaType))
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w.Header().Set("Content-Length", fmt.Sprintf("%d", desc.Size))
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return
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}
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serve.Blob(w, r, tagOrDigest)
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return
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}
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// If the image tag looks like a commit SHA, see if we already have a
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// manifest cached for that revision and serve it directly. Otherwise,
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// resolve the branch/tag/whatever to a SHA and redirect to that SHA
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// image tag.
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revision := tagOrDigest
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if commitRE.MatchString(revision) {
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ck := cacheKey(path, revision)
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if _, err := s.storage.BlobExists(ctx, ck); err == nil {
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s.info.Println("serving cached manifest:", ck)
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serve.Blob(w, r, ck)
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return
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}
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} else {
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revision, err = s.resolveCommit(ghOwner, ghRepo, revision)
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if err != nil {
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s.error.Println("ERROR(resolveCommit):", err)
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serve.Error(w, err)
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return
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}
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path := r.URL.Path[:strings.LastIndex(r.URL.Path, "/")+1] + revision
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http.Redirect(w, r, path, http.StatusSeeOther)
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return
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}
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// Fetch, detect and build source.
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image, err := s.fetchAndBuild(src, layers, ghOwner, ghRepo, revision, path)
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if err != nil {
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s.error.Println("ERROR:", err)
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serve.Error(w, err)
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return
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}
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// Serve new image manifest.
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img, err := s.getImage(ctx, image)
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if err != nil {
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s.error.Println("ERROR:", err)
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serve.Error(w, err)
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return
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}
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// Serve the manifest.
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ck := cacheKey(path, revision)
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if err := s.storage.ServeManifest(w, r, img, ck); err != nil {
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s.error.Printf("ERROR (storage.ServeManifest): %v", err)
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serve.Error(w, err)
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return
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}
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}
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func cacheKey(path, revision string) string {
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ck := []byte(fmt.Sprintf("%s-%s", strings.ReplaceAll(path, "/", "_"), revision))
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return fmt.Sprintf("buildpack-%x", md5.Sum(ck))
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}
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// Resolves a ref (branch, tag, PR, commit) into its SHA.
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// If the image tag is "latest", use the repo's default branch.
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// If the image tag is "latest-release", look up the repo's latest release tag.
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// In any case, resolve the branch/tag/whatever to a commit SHA.
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func (s *server) resolveCommit(owner, repo, ref string) (string, error) {
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ctx := context.Background()
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client := github.NewClient(nil)
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if ref == "latest" {
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repo, _, err := client.Repositories.Get(ctx, owner, repo)
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if err != nil {
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return "", err
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}
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ref = repo.GetDefaultBranch()
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}
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if ref == "latest-release" {
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release, resp, err := client.Repositories.GetLatestRelease(ctx, owner, repo)
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if resp.StatusCode == http.StatusNotFound {
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return "", errors.New("Repository has no releases")
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}
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if err != nil {
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return "", err
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}
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ref = release.GetTagName()
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}
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commit, _, err := client.Repositories.GetCommit(ctx, owner, repo, ref)
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if err != nil {
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return "", err
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}
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s.info.Printf("Resolved %q -> %q\n", ref, commit.GetSHA())
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return commit.GetSHA(), nil
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}
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func (s *server) prepareWorkspace() (string, string, error) {
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// Create tempdir to store app source.
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src, err := ioutil.TempDir("", "")
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if err != nil {
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return "", "", err
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}
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// Create layers dir.
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layers, err := ioutil.TempDir("", "")
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if err != nil {
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return "", "", err
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}
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// Create and set $HOME, which is otherwise not writable.
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home, err := ioutil.TempDir("", "")
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if err != nil {
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return "", "", err
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}
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os.Setenv("HOME", home)
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return src, layers, nil
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}
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func (s *server) fetchAndBuild(src, layers, ghOwner, ghRepo, revision, path string) (string, error) {
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image := fmt.Sprintf("gcr.io/%s/built-%d", projectID, time.Now().Unix())
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source := fmt.Sprintf("https://github.com/%s/%s/archive/%s.tar.gz", ghOwner, ghRepo, revision)
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if resp, err := http.Head(source); err != nil {
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return "", err
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} else if resp.StatusCode == http.StatusNotFound {
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return "", serve.ErrNotFound
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} else if resp.StatusCode != http.StatusOK {
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return "", fmt.Errorf("HEAD %s (%d): %s", source, resp.StatusCode, resp.Status)
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}
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srcpath := filepath.Join(src, path)
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ts, err := google.DefaultTokenSource(context.Background(), "https://www.googleapis.com/auth/cloud-platform")
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if err != nil {
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return "", fmt.Errorf("google.DefaultTokenSource: %v", err)
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}
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tok, err := ts.Token()
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if err != nil {
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return "", fmt.Errorf("credentials.Token: %v", err)
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}
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for _, cmd := range []string{
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fmt.Sprintf("chown -R %d:%d %s", os.Geteuid(), os.Getgid(), src),
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fmt.Sprintf("chown -R %d:%d %s", os.Geteuid(), os.Getgid(), layers),
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fmt.Sprintf("curl -fsSL %s | tar xz --strip-components=1 -C %s", source, src),
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fmt.Sprintf("cd %s", srcpath),
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fmt.Sprintf(`
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mkdir -p ~/.docker/ && cat > ~/.docker/config.json << EOF
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{
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"auths": {
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"gcr.io": {
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"username": "oauth2accesstoken",
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"password": "%s"
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}
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}
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}
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EOF`, tok.AccessToken),
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fmt.Sprintf("/lifecycle/detector -app=%s -group=%s/group.toml -plan=%s/plan.toml", srcpath, layers, layers),
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fmt.Sprintf("/lifecycle/analyzer -layers=%s -group=%s/group.toml %s", layers, layers, image),
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fmt.Sprintf("/lifecycle/builder -layers=%s -app=%s -group=%s/group.toml -plan=%s/plan.toml", layers, srcpath, layers, layers),
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fmt.Sprintf("/lifecycle/exporter -layers=%s -app=%s -image=%s -group=%s/group.toml %s", layers, srcpath, base, layers, image),
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} {
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if err := run.Do(s.info.Writer(), cmd); err != nil {
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return "", fmt.Errorf("Running %q: %v", cmd, err)
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}
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}
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return image, nil
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}
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func (s *server) getImage(ctx context.Context, image string) (v1.Image, error) {
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ref, err := name.NewTag(image, name.WeakValidation)
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if err != nil {
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return nil, err
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}
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authn, err := gauthn.NewEnvAuthenticator()
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if err != nil {
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return nil, err
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}
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return remote.Image(ref, remote.WithAuth(authn), remote.WithContext(ctx))
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}
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