imagefmt: Move layer blob download logic to blob.go

blob.go

@@ -0,0 +1,61 @@
+package clair
+
+import (
+	"context"
+	"crypto/tls"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func retrieveLayerBlob(ctx context.Context, blobSha256 string, path string, headers map[string]string) (io.ReadCloser, error) {
+	if strings.HasPrefix(path, "http://") || strings.HasPrefix(path, "https://") {
+		return downloadLayerBlob(ctx, blobSha256, path, headers)
+	}
+
+	return loadLayerBlobFromFS(blobSha256)
+}
+
+func downloadLayerBlob(ctx context.Context, blobSha256 string, uri string, headers map[string]string) (io.ReadCloser, error) {
+	request, err := http.NewRequest("GET", uri, nil)
+	if err != nil {
+		return nil, RetrieveBlobError
+	}
+
+	if headers != nil {
+		for k, v := range headers {
+			request.Header.Set(k, v)
+		}
+	}
+
+	tr := &http.Transport{
+		TLSClientConfig: &tls.Config{},
+		Proxy:           http.ProxyFromEnvironment,
+	}
+
+	client := &http.Client{Transport: tr}
+	r, err := client.Do(request)
+	if err != nil {
+		log.WithError(err).Error("could not download layer")
+		return nil, RetrieveBlobError
+	}
+
+	// Fail if we don't receive a 2xx HTTP status code.
+	if is2xx(r.StatusCode) {
+		log.WithField("status", r.StatusCode).Error("could not download layer: expected 2XX")
+		return nil, RetrieveBlobError
+	}
+
+	return r.Body, nil
+}
+
+func is2xx(statusCode int) bool {
+	return statusCode >= 200 && statusCode < 300
+}
+
+func loadLayerBlobFromFS(path string) (io.ReadCloser, error) {
+	return os.Open(path)
+}

ext/imagefmt/driver.go

@@ -21,19 +21,12 @@
 package imagefmt
 
 import (
-	"crypto/tls"
 	"fmt"
 	"io"
-	"math"
-	"net/http"
-	"os"
 	"strings"
 	"sync"
 
-	log "github.com/sirupsen/logrus"
-
 	"github.com/coreos/clair/pkg/commonerr"
-	"github.com/coreos/clair/pkg/strutil"
 	"github.com/coreos/clair/pkg/tarutil"
 )
 
@@ -102,67 +95,22 @@ func UnregisterExtractor(name string) {
 	delete(extractors, name)
 }
 
-// Extract streams an image layer from disk or over HTTP, determines the
+// Extract a set of files as FilesMap from a layer blob.
-// image format, then extracts the files specified.
+func Extract(format string, blobReader io.ReadCloser, filePaths []string) (tarutil.FilesMap, error) {
-func Extract(format, path string, headers map[string]string, toExtract []string) (tarutil.FilesMap, error) {
-	var layerReader io.ReadCloser
-	if strings.HasPrefix(path, "http://") || strings.HasPrefix(path, "https://") {
-		log.WithField("path", strutil.CleanURL(path)).Debug("start downloading layer blob...")
-		request, err := http.NewRequest("GET", path, nil)
-		if err != nil {
-			return nil, ErrCouldNotFindLayer
-		}
-
-		// Set any provided HTTP Headers.
-		if headers != nil {
-			for k, v := range headers {
-				request.Header.Set(k, v)
-			}
-		}
-
-		// Send the request and handle the response.
-		tr := &http.Transport{
-			TLSClientConfig: &tls.Config{InsecureSkipVerify: insecureTLS},
-			Proxy:           http.ProxyFromEnvironment,
-		}
-		client := &http.Client{Transport: tr}
-		r, err := client.Do(request)
-		if err != nil {
-			log.WithError(err).Error("could not download layer")
-			return nil, ErrCouldNotFindLayer
-		}
-
-		// Fail if we don't receive a 2xx HTTP status code.
-		if math.Floor(float64(r.StatusCode/100)) != 2 {
-			log.WithError(ErrCouldNotFindLayer).WithField("status code", r.StatusCode).Error("could not download layer: expected 2XX")
-			return nil, ErrCouldNotFindLayer
-		}
-
-		layerReader = r.Body
-	} else {
-		log.WithField("path", strutil.CleanURL(path)).Debug("start reading layer blob from local file system...")
-		var err error
-		layerReader, err = os.Open(path)
-		if err != nil {
-			log.WithError(ErrCouldNotFindLayer).Error("could not open layer")
-			return nil, ErrCouldNotFindLayer
-		}
-	}
-	defer layerReader.Close()
-
 	if extractor, exists := Extractors()[strings.ToLower(format)]; exists {
-		files, err := extractor.ExtractFiles(layerReader, toExtract)
+		files, err := extractor.ExtractFiles(blobReader, filePaths)
 		if err != nil {
 			return nil, err
 		}
+
 		return files, nil
 	}
 
-	return nil, commonerr.NewBadRequestError(fmt.Sprintf("unsupported image format '%s'", format))
+	return nil, fmt.Errorf("unsupported image format '%s'", format)
 }
 
-// SetInsecureTLS sets the insecureTLS to control whether TLS server's certificate chain
+// IsSupported checks if a format is supported
-// and hostname are verified when pulling layers.
+func IsSupported(format string) bool {
-func SetInsecureTLS(insecure bool) {
+	_, ok := Extractors()[strings.ToLower(format)]
-	insecureTLS = insecure
+	return ok
 }