From 8f8efa4592a2891dd9c1efa3f031f73a36862a93 Mon Sep 17 00:00:00 2001
From: John Poth <poth.john@gmail.com>
Date: Thu, 16 Dec 2021 22:41:06 +0100
Subject: [PATCH] Artifacts (#7)

* fix: don't forget to close writer when finished

* Support empty base image

* Support files as well as directories as input

* Update GO version
---
 .github/workflows/release.yml |  4 +--
 go.mod                        |  2 +-
 pkg/builder/build.go          | 59 +++++++++++++++++++++++------------
 pkg/builder/image.go          |  4 +++
 4 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 7f55800..d1bd1c2 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -38,7 +38,7 @@ jobs:
     - name: Set Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.13.x
+        go-version: 1.16.x
     - name: Start Docker Registry
       run: |
         docker run -d -p "5000:5000" --restart=always --name "registry" registry:2
@@ -69,7 +69,7 @@ jobs:
     - name: Set Go
       uses: actions/setup-go@v1
       with:
-        go-version: 1.13.x
+        go-version: 1.16.x
     - name: Tag Release
       uses: mathieudutour/github-tag-action@v4
       with:
diff --git a/go.mod b/go.mod
index 3c3d5c7..937fc31 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/container-tools/spectrum
 
-go 1.13
+go 1.16
 
 require (
 	github.com/docker/cli v20.10.11+incompatible
diff --git a/pkg/builder/build.go b/pkg/builder/build.go
index b7f4337..5bd0bbd 100644
--- a/pkg/builder/build.go
+++ b/pkg/builder/build.go
@@ -7,6 +7,7 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/mutate"
 	"github.com/google/go-containerregistry/pkg/v1/tarball"
 	"io"
+	"io/fs"
 	"io/ioutil"
 	"log"
 	"os"
@@ -76,7 +77,7 @@ func configureLogging(options Options) {
 	logs.Warn = log.New(stderr, LogPrefix, log.LstdFlags)
 }
 
-func tarPackage(dirName, targetPath string, recursive bool) (file string, err error) {
+func tarPackage(name, targetPath string, recursive bool) (file string, err error) {
 	layerFile, err := ioutil.TempFile("", "spectrum-layer-*.tar")
 	if err != nil {
 		return "", err
@@ -84,14 +85,24 @@ func tarPackage(dirName, targetPath string, recursive bool) (file string, err er
 	defer layerFile.Close()
 
 	writer := tar.NewWriter(layerFile)
+	defer writer.Close()
+	fileInfo, err := os.Stat(name)
+	if err != nil {
+		return "", err
+	}
 
-	if recursive {
-		err = tarPackageRecursive(dirName, targetPath, writer)
+	if !fileInfo.IsDir() {
+		err := writeFileToTar(name, targetPath, writer, fileInfo)
+		if err != nil {
+			return "", err
+		}
+	} else if recursive {
+		err = tarPackageRecursive(name, targetPath, writer)
 		if err != nil {
 			return "", err
 		}
 	} else {
-		err = tarPackageNonRecursive(dirName, targetPath, writer)
+		err = tarPackageNonRecursive(name, targetPath, writer)
 		if err != nil {
 			return "", err
 		}
@@ -117,28 +128,36 @@ func tarPackageNonRecursive(dirName, targetPath string, writer *tar.Writer) erro
 			continue
 		}
 
-		file, err := os.Open(dir.Name() + string(filepath.Separator) + fileInfo.Name())
+		err := writeFileToTar(dir.Name()+string(filepath.Separator)+fileInfo.Name(), targetPath, writer, fileInfo)
 		if err != nil {
 			return err
 		}
-		defer file.Close()
+	}
+	return nil
+}
+
+func writeFileToTar(name, targetPath string, writer *tar.Writer, fileInfo fs.FileInfo) error {
+	file, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
 
-		// prepare the tar header
-		header := new(tar.Header)
-		header.Name = path.Join(targetPath, filepath.Base(file.Name()))
-		header.Size = fileInfo.Size()
-		header.Mode = int64(fileInfo.Mode())
-		header.ModTime = fileInfo.ModTime()
+	// prepare the tar header
+	header := new(tar.Header)
+	header.Name = path.Join(targetPath, filepath.Base(file.Name()))
+	header.Size = fileInfo.Size()
+	header.Mode = int64(fileInfo.Mode())
+	header.ModTime = fileInfo.ModTime()
 
-		err = writer.WriteHeader(header)
-		if err != nil {
-			return err
-		}
+	err = writer.WriteHeader(header)
+	if err != nil {
+		return err
+	}
 
-		_, err = io.Copy(writer, file)
-		if err != nil {
-			return err
-		}
+	_, err = io.Copy(writer, file)
+	if err != nil {
+		return err
 	}
 	return nil
 }
diff --git a/pkg/builder/image.go b/pkg/builder/image.go
index 587fb36..9ad2c5e 100644
--- a/pkg/builder/image.go
+++ b/pkg/builder/image.go
@@ -6,10 +6,14 @@ import (
 	"github.com/google/go-containerregistry/pkg/authn"
 	"github.com/google/go-containerregistry/pkg/name"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
+	"github.com/google/go-containerregistry/pkg/v1/empty"
 	"github.com/google/go-containerregistry/pkg/v1/remote"
 )
 
 func Pull(options Options) (v1.Image, error) {
+	if options.Base == "" || options.Base == "scratch" {
+		return empty.Image, nil
+	}
 	nameOptions := makeNameOptions(options.PullInsecure)
 	ref, err := name.ParseReference(options.Base, nameOptions...)
 	if err != nil {