Add context to many gobuild errors (#1016)

pkg/build/cache.go

@@ -26,6 +26,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/google/go-containerregistry/pkg/logs"
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 	"github.com/google/go-containerregistry/pkg/v1/partial"
 )
@@ -53,12 +54,14 @@ func (c *layerCache) get(ctx context.Context, file string, miss layerFactory) (v
 			desc:       *desc,
 			buildLayer: miss,
 		}, nil
+	} else {
+		logs.Debug.Printf("getMeta(%q): %v", file, err)
 	}
 
 	// Cache miss.
 	layer, err := miss()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("miss(%q): %w", file, err)
 	}
 	if err := c.put(ctx, file, layer); err != nil {
 		log.Printf("failed to cache metadata %s: %v", file, err)
@@ -73,7 +76,7 @@ func (c *layerCache) getMeta(ctx context.Context, file string) (*v1.Hash, *v1.De
 	}
 
 	if buildid == "" {
-		return nil, nil, fmt.Errorf("no buildid for %s", file)
+		return nil, nil, fmt.Errorf("no buildid for %q", file)
 	}
 
 	// TODO: Implement better per-file locking.
@@ -137,13 +140,13 @@ func (c *layerCache) put(ctx context.Context, file string, layer v1.Layer) error
 
 	btodf, err := os.OpenFile(filepath.Join(filepath.Dir(file), "buildid-to-diffid"), os.O_RDWR|os.O_CREATE, 0755)
 	if err != nil {
-		return err
+		return fmt.Errorf("opening buildid-to-diffid: %w", err)
 	}
 	defer btodf.Close()
 
 	dtodf, err := os.OpenFile(filepath.Join(filepath.Dir(file), "diffid-to-descriptor"), os.O_RDWR|os.O_CREATE, 0755)
 	if err != nil {
-		return err
+		return fmt.Errorf("opening diffid-to-descriptor: %w", err)
 	}
 	defer dtodf.Close()
 
@@ -169,7 +172,7 @@ func (c *layerCache) readDiffToDesc(file string) (diffIDToDescriptor, error) {
 
 	dtodf, err := os.Open(filepath.Join(filepath.Dir(file), "diffid-to-descriptor"))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("opening diffid-to-descriptor: %w", err)
 	}
 	defer dtodf.Close()
 
@@ -188,7 +191,7 @@ func (c *layerCache) readBuildToDiff(file string) (buildIDToDiffID, error) {
 
 	btodf, err := os.Open(filepath.Join(filepath.Dir(file), "buildid-to-diffid"))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("opening buildid-to-diffid: %w", err)
 	}
 	defer btodf.Close()
 
@@ -210,7 +213,7 @@ func getBuildID(ctx context.Context, file string) (string, error) {
 
 	if err := cmd.Run(); err != nil {
 		log.Printf("Unexpected error running \"go tool buildid %s\": %v\n%v", err, file, output.String())
-		return "", err
+		return "", fmt.Errorf("go tool buildid %s: %w", file, err)
 	}
 	return strings.TrimSpace(output.String()), nil
 }

pkg/build/gobuild.go

@@ -269,14 +269,14 @@ func build(ctx context.Context, ip string, dir string, platform v1.Platform, con
 		return "", fmt.Errorf("could not create env for %s: %w", ip, err)
 	}
 
-	tmpDir, err := ioutil.TempDir("", "ko")
-	if err != nil {
-		return "", err
-	}
+	tmpDir := ""
 
 	if dir := os.Getenv("KOCACHE"); dir != "" {
 		dirInfo, err := os.Stat(dir)
-		if os.IsNotExist(err) {
+		if err != nil {
+			if !os.IsNotExist(err) {
+				return "", fmt.Errorf("could not stat KOCACHE: %w", err)
+			}
 			if err := os.MkdirAll(dir, os.ModePerm); err != nil && !os.IsExist(err) {
 				return "", fmt.Errorf("could not create KOCACHE dir %s: %w", dir, err)
 			}
@@ -287,6 +287,11 @@ func build(ctx context.Context, ip string, dir string, platform v1.Platform, con
 		// TODO(#264): if KOCACHE is unset, default to filepath.Join(os.TempDir(), "ko").
 		tmpDir = filepath.Join(dir, "bin", ip, platform.String())
 		if err := os.MkdirAll(tmpDir, os.ModePerm); err != nil {
+			return "", fmt.Errorf("creating KOCACHE bin dir: %w", err)
+		}
+	} else {
+		tmpDir, err = ioutil.TempDir("", "ko")
+		if err != nil {
 			return "", err
 		}
 	}
@@ -311,7 +316,7 @@ func build(ctx context.Context, ip string, dir string, platform v1.Platform, con
 			os.RemoveAll(tmpDir)
 		}
 		log.Printf("Unexpected error running \"go build\": %v\n%v", err, output.String())
-		return "", err
+		return "", fmt.Errorf("go build: %w", err)
 	}
 	return file, nil
 }
@@ -326,15 +331,15 @@ func goversionm(ctx context.Context, file string, appPath string, appFileName st
 		cmd.Stdout = sbom
 		cmd.Stderr = os.Stderr
 		if err := cmd.Run(); err != nil {
-			return nil, "", err
+			return nil, "", fmt.Errorf("go version -m %s: %w", file, err)
 		}
 
 		// In order to get deterministics SBOMs replace our randomized
 		// file name with the path the app will get inside of the container.
 		s := []byte(strings.Replace(sbom.String(), file, appPath, 1))
 
 		if err := writeSBOM(s, appFileName, dir, "go.version-m"); err != nil {
-			return nil, "", err
+			return nil, "", fmt.Errorf("writing sbom: %w", err)
 		}
 
 		return s, "application/vnd.go.version-m", nil
@@ -513,13 +518,13 @@ func tarBinary(name, binary string, platform *v1.Platform) (*bytes.Buffer, error
 			// 0444, or 0666, none of which are executable.
 			Mode: 0555,
 		}); err != nil {
-			return nil, fmt.Errorf("writing dir %q: %w", dir, err)
+			return nil, fmt.Errorf("writing dir %q to tar: %w", dir, err)
 		}
 	}
 
 	file, err := os.Open(binary)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("opening binary: %w", err)
 	}
 	defer file.Close()
 	stat, err := file.Stat()
@@ -544,11 +549,11 @@ func tarBinary(name, binary string, platform *v1.Platform) (*bytes.Buffer, error
 	}
 	// write the header to the tarball archive
 	if err := tw.WriteHeader(header); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("writing tar header: %w", err)
 	}
 	// copy the file data to the tarball
 	if _, err := io.Copy(tw, file); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("copying file to tar: %w", err)
 	}
 
 	return buf, nil
@@ -828,7 +833,7 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 	// Do the build into a temporary file.
 	file, err := g.build(ctx, ref.Path(), g.dir, *platform, g.configForImportPath(ref.Path()))
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("build: %w", err)
 	}
 	if os.Getenv("KOCACHE") == "" {
 		defer os.RemoveAll(filepath.Dir(file))
@@ -839,7 +844,7 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 	// Create a layer from the kodata directory under this import path.
 	dataLayerBuf, err := g.tarKoData(ref, platform)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("tarring kodata: %w", err)
 	}
 	dataLayerBytes := dataLayerBuf.Bytes()
 	dataLayer, err := tarball.LayerFromOpener(func() (io.ReadCloser, error) {
@@ -868,7 +873,7 @@ func (g *gobuild) buildOne(ctx context.Context, refStr string, base v1.Image, pl
 
 	binaryLayer, err := g.cache.get(ctx, file, miss)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("cache.get(%q): %w", file, err)
 	}
 
 	layers = append(layers, mutate.Addendum{
@@ -948,7 +953,7 @@ func buildLayer(appPath, file string, platform *v1.Platform, layerMediaType type
 	// Construct a tarball with the binary and produce a layer.
 	binaryLayerBuf, err := tarBinary(appPath, file, platform)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("tarring binary: %w", err)
 	}
 	binaryLayerBytes := binaryLayerBuf.Bytes()
 	return tarball.LayerFromOpener(func() (io.ReadCloser, error) {
@@ -987,7 +992,7 @@ func (g *gobuild) Build(ctx context.Context, s string) (Result, error) {
 	// early, and we lazily use the ctx within ggcr's remote package.
 	baseRef, base, err := g.getBase(g.ctx, s)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("fetching base image: %w", err)
 	}
 
 	// Determine what kind of base we have and if we should publish an image or an index.
@@ -1069,7 +1074,7 @@ func (g *gobuild) buildAll(ctx context.Context, ref string, baseRef name.Referen
 	// Build an image for each matching platform from the base and append
 	// it to a new index to produce the result. We use the indices to
 	// preserve the base image ordering here.
-	errg, ctx := errgroup.WithContext(ctx)
+	errg, gctx := errgroup.WithContext(ctx)
 	adds := make([]ocimutate.IndexAddendum, len(matches))
 	for i, desc := range matches {
 		i, desc := i, desc
@@ -1101,7 +1106,7 @@ func (g *gobuild) buildAll(ctx context.Context, ref string, baseRef name.Referen
 				specsv1.AnnotationBaseImageName:   baseRef.Name(),
 			}).(v1.Image)
 
-			img, err := g.buildOne(ctx, ref, baseImage, desc.Platform)
+			img, err := g.buildOne(gctx, ref, baseImage, desc.Platform)
 			if err != nil {
 				return err
 			}