arbitrary buildpack support

cli/cmd/pack/pack.go

@@ -3,12 +3,15 @@ package pack
 import (
 	"context"
 	"fmt"
+	"net/url"
 	"path/filepath"
 	"strings"
 
 	"github.com/buildpacks/pack"
 	"github.com/porter-dev/porter/api/types"
 	"github.com/porter-dev/porter/cli/cmd/docker"
+	"github.com/porter-dev/porter/cli/cmd/github"
+	"k8s.io/client-go/util/homedir"
 )
 
 type Agent struct{}
@@ -41,8 +44,34 @@ func (a *Agent) Build(opts *docker.BuildOpts, buildConfig *types.BuildConfig) er
 
 	if buildConfig != nil {
 		buildOpts.Builder = buildConfig.Builder
-		if len(buildConfig.Buildpacks) > 0 {
-			buildOpts.Buildpacks = buildConfig.Buildpacks
+		for i := range buildConfig.Buildpacks {
+			bp := buildConfig.Buildpacks[i]
+			u, err := url.Parse(bp)
+			if err == nil {
+				// could be a git repository containing the buildpack
+				dstDir := filepath.Join(homedir.HomeDir(), ".porter")
+				bpCustomName := strings.ReplaceAll(u.Path, "/", "-")
+				downloader := &github.ZIPDownloader{
+					ZipFolderDest:       dstDir,
+					AssetFolderDest:     dstDir,
+					ZipName:             fmt.Sprintf("%s.zip", bpCustomName),
+					RemoveAfterDownload: true,
+				}
+
+				err = downloader.DownloadToFile(bp)
+				if err != nil {
+					return err
+				}
+
+				err = downloader.UnzipToDir()
+				if err != nil {
+					return err
+				}
+
+				buildOpts.Buildpacks = append(buildOpts.Buildpacks, bpCustomName)
+			} else {
+				buildOpts.Buildpacks = append(buildOpts.Buildpacks, bp)
+			}
 		}
 		// FIXME: use all the config vars
 	}