refactoring copy task to use build vfs func

Updated comments for copytask, still need to translate URL.

upup/pkg/fi/assettasks/copyfile.go

@@ -132,20 +132,26 @@ func transferFile(c *fi.Context, source string, target string, sha string) error
 		return fmt.Errorf("error downloading file %q: %v", source, err)
 	}
 
-	uploadVFS, err := buildVFSPath(target)
+	objectStore, err := buildVFSPath(target)
 	if err != nil {
 		return err
 	}
 
-	shaVFS, err := buildVFSPath(target + ".sha1")
+	uploadVFS, err := vfs.Context.BuildVfsPath(objectStore)
 	if err != nil {
-		return err
+		return fmt.Errorf("error building path %q: %v", objectStore, err)
+	}
+
+	shaTarget := objectStore + ".sha1"
+	shaVFS, err := vfs.Context.BuildVfsPath(shaTarget)
+	if err != nil {
+		return fmt.Errorf("error building path %q: %v", shaTarget, err)
 	}
 
 	in := bytes.NewReader(data)
 	dataHash, err := hashing.HashAlgorithmSHA1.Hash(in)
 	if err != nil {
-		return fmt.Errorf("unable to parse sha from file %q downloaded: %v", target+".sha1", err)
+		return fmt.Errorf("unable to parse sha from file %q downloaded: %v", sha, err)
 	}
 
 	shaHash, err := hashing.FromString(strings.TrimSpace(sha))
@@ -154,43 +160,38 @@ func transferFile(c *fi.Context, source string, target string, sha string) error
 	}
 
 	if !shaHash.Equal(dataHash) {
-		return fmt.Errorf("the sha value in %q does not match %q calculated value %q", target+".sha1", source, dataHash.String())
+		return fmt.Errorf("the sha value in %q does not match %q calculated value %q", shaTarget, source, dataHash.String())
 	}
 
-	glog.Infof("uploading %q to %q", source, target)
+	glog.Infof("uploading %q to %q", source, objectStore)
 	if err := writeFile(c, uploadVFS, data); err != nil {
-		return fmt.Errorf("error uploading file %q: %v", uploadVFS, err)
+		return err
 	}
 
 	b := []byte(shaHash.Hex())
 	if err := writeFile(c, shaVFS, b); err != nil {
-		return fmt.Errorf("error uploading sha %q: %v", shaVFS, err)
+		return err
 	}
 
 	return nil
 }
 
-func writeFile(c *fi.Context, vfsPath string, data []byte) error {
-	glog.V(2).Infof("uploading to %q", vfsPath)
-	p, err := vfs.Context.BuildVfsPath(vfsPath)
-	if err != nil {
-		return fmt.Errorf("error building path %q: %v", vfsPath, err)
-	}
+func writeFile(c *fi.Context, p vfs.Path, data []byte) error {
 
 	acl, err := acls.GetACL(p, c.Cluster)
 	if err != nil {
 		return err
 	}
 
 	if err = p.WriteFile(data, acl); err != nil {
-		return fmt.Errorf("error writing path %q: %v", vfsPath, err)
+		return fmt.Errorf("error writing path %v: %v", p, err)
 	}
 
-	glog.V(2).Infof("upload complete: %q", vfsPath)
-
 	return nil
 }
 
+// buildVFSPath task a recognizable https url and transforms that URL into the equivalent url with the the object
+// store prefix.
 func buildVFSPath(target string) (string, error) {
 	if !strings.Contains(target, "://") || strings.HasPrefix(target, "memfs://") {
 		return target, nil
@@ -203,20 +204,20 @@ func buildVFSPath(target string) (string, error) {
 
 	var vfsPath string
 
-	// I am not a huge fan of this, but it does work.  We could have two urls, one for vfs and one for https?
+	// These matches only cover a subset of the URLs that you can use, but I am uncertain how to cover more of the possible
+	// options.
 	// This code parses the HOST and determines to use s3 or gs.
+	// URLs.  For instance you can have the bucket name in the s3 url hostname.
 	// We are translating known https urls such as https://s3.amazonaws.com/example-kops to vfs path like
 	// s3://example-kops
 	if u.Host == "s3.amazonaws.com" {
 		vfsPath = "s3:/" + u.Path
 	} else if u.Host == "storage.googleapis.com" {
 		vfsPath = "gs:/" + u.Path
-	}
-
-	if vfsPath == "" {
+	} else {
 		glog.Errorf("unable to determine vfs path s3, google storage, and file paths are supported")
-		glog.Errorf("for s3 use s3.amazonaws.com and for google storage use storage.googleapis.com hostnames.")
-		return "", fmt.Errorf("unable to determine vfs for %q", target)
+		glog.Errorf("URLs starting with https://s3.amazonaws.com and http://storage.googleapis.com are transformed into s3 and gs URLs")
+		return "", fmt.Errorf("unable to determine vfs type for %q", target)
 	}
 
 	return vfsPath, nil