Add methods to retrieve raw bundle bytes

Add this BundleBytes method to Bundle interface and BundleDataSource

In Juju, we have come across a need to run some extra parsing +
verification which we do not want to do in juju/charm. We want to keep
the data model clean in juju/charm.

As such, we need to way to keep the raw bundle data around for later
parsing

Add this to BundleDataSource, as this is what we use in Juju

However, we also implement our own BundleDataSource in Juju. built with
the Bundle interface here. So we need to add this method to Bundle as
well

bundle.go

@@ -15,6 +15,8 @@ import (
 type Bundle interface {
 	// Data returns the contents of the bundle's bundle.yaml file.
 	Data() *BundleData
+	// BundleBytes returns the raw bytes content of a bundle
+	BundleBytes() []byte
 	// ReadMe returns the contents of the bundle's README.md file.
 	ReadMe() string
 	// ContainsOverlays returns true if the bundle contains any overlays.

bundle_test.go

@@ -4,6 +4,9 @@
 package charm_test
 
 import (
+	"os"
+	"path/filepath"
+
 	"github.com/juju/testing"
 	jc "github.com/juju/testing/checkers"
 	gc "gopkg.in/check.v1"
@@ -23,7 +26,7 @@ func (*BundleSuite) TestReadBundleDir(c *gc.C) {
 	c.Assert(err, gc.IsNil)
 	c.Assert(b.ContainsOverlays(), jc.IsFalse)
 	c.Assert(b, gc.FitsTypeOf, (*charm.BundleDir)(nil))
-	checkWordpressBundle(c, b, path)
+	checkWordpressBundle(c, b, path, "wordpress-simple")
 }
 
 func (*BundleSuite) TestReadMultiDocBundleDir(c *gc.C) {
@@ -32,7 +35,7 @@ func (*BundleSuite) TestReadMultiDocBundleDir(c *gc.C) {
 	c.Assert(err, gc.IsNil)
 	c.Assert(b.ContainsOverlays(), jc.IsTrue)
 	c.Assert(b, gc.FitsTypeOf, (*charm.BundleDir)(nil))
-	checkWordpressBundle(c, b, path)
+	checkWordpressBundle(c, b, path, "wordpress-simple-multidoc")
 }
 
 func (*BundleSuite) TestReadBundleArchive(c *gc.C) {
@@ -41,7 +44,7 @@ func (*BundleSuite) TestReadBundleArchive(c *gc.C) {
 	c.Assert(err, gc.IsNil)
 	c.Assert(b.ContainsOverlays(), jc.IsFalse)
 	c.Assert(b, gc.FitsTypeOf, (*charm.BundleDir)(nil))
-	checkWordpressBundle(c, b, path)
+	checkWordpressBundle(c, b, path, "wordpress-simple")
 }
 
 func (*BundleSuite) TestReadMultiDocBundleArchive(c *gc.C) {
@@ -50,10 +53,10 @@ func (*BundleSuite) TestReadMultiDocBundleArchive(c *gc.C) {
 	c.Assert(err, gc.IsNil)
 	c.Assert(b.ContainsOverlays(), jc.IsTrue)
 	c.Assert(b, gc.FitsTypeOf, (*charm.BundleDir)(nil))
-	checkWordpressBundle(c, b, path)
+	checkWordpressBundle(c, b, path, "wordpress-simple-multidoc")
 }
 
-func checkWordpressBundle(c *gc.C, b charm.Bundle, path string) {
+func checkWordpressBundle(c *gc.C, b charm.Bundle, path string, bundleName string) {
 	// Load the charms required by the bundle.
 	wordpressCharm := readCharmDir(c, "wordpress")
 	mysqlCharm := readCharmDir(c, "mysql")
@@ -87,6 +90,11 @@ func checkWordpressBundle(c *gc.C, b charm.Bundle, path string) {
 	case *charm.BundleDir:
 		c.Assert(b.Path, gc.Equals, path)
 	}
+
+	bundlePath := filepath.Join("internal/test-charm-repo/bundle", bundleName, "bundle.yaml")
+	raw, err := os.ReadFile(bundlePath)
+	c.Assert(err, jc.ErrorIsNil)
+	c.Assert(string(b.BundleBytes()), gc.Equals, string(raw))
 }
 
 func verifyOk(string) error {

bundlearchive.go

@@ -6,17 +6,17 @@ package charm
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 
 	ziputil "github.com/juju/utils/v4/zip"
 )
 
 type BundleArchive struct {
 	zopen zipOpener
 
-	Path   string
-	data   *BundleData
-	readMe string
+	Path        string
+	data        *BundleData
+	bundleBytes []byte
+	readMe      string
 
 	containsOverlays bool
 }
@@ -61,7 +61,12 @@ func readBundleArchive(zopen zipOpener) (*BundleArchive, error) {
 	if err != nil {
 		return nil, err
 	}
-	a.data, a.containsOverlays, err = readBaseFromMultidocBundle(reader)
+	b, err := io.ReadAll(reader)
+	if err != nil {
+		return nil, err
+	}
+	a.bundleBytes = b
+	a.data, a.containsOverlays, err = readBaseFromMultidocBundle(b)
 	reader.Close()
 	if err != nil {
 		return nil, err
@@ -70,7 +75,7 @@ func readBundleArchive(zopen zipOpener) (*BundleArchive, error) {
 	if err != nil {
 		return nil, err
 	}
-	readMe, err := ioutil.ReadAll(reader)
+	readMe, err := io.ReadAll(reader)
 	if err != nil {
 		return nil, err
 	}
@@ -83,6 +88,11 @@ func (a *BundleArchive) Data() *BundleData {
 	return a.data
 }
 
+// BundleBytes implements Bundle.BundleBytes.
+func (a *BundleArchive) BundleBytes() []byte {
+	return a.bundleBytes
+}
+
 // ReadMe implements Bundle.ReadMe.
 func (a *BundleArchive) ReadMe() string {
 	return a.readMe

bundlearchive_test.go

@@ -5,7 +5,6 @@ package charm_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -21,35 +20,37 @@ type BundleArchiveSuite struct {
 	archivePath string
 }
 
+const bundleName = "wordpress-simple"
+
 func (s *BundleArchiveSuite) SetUpSuite(c *gc.C) {
-	s.archivePath = archivePath(c, readBundleDir(c, "wordpress-simple"))
+	s.archivePath = archivePath(c, readBundleDir(c, bundleName))
 }
 
 func (s *BundleArchiveSuite) TestReadBundleArchive(c *gc.C) {
 	archive, err := charm.ReadBundleArchive(s.archivePath)
 	c.Assert(err, gc.IsNil)
-	checkWordpressBundle(c, archive, s.archivePath)
+	checkWordpressBundle(c, archive, s.archivePath, bundleName)
 }
 
 func (s *BundleArchiveSuite) TestReadBundleArchiveBytes(c *gc.C) {
-	data, err := ioutil.ReadFile(s.archivePath)
+	data, err := os.ReadFile(s.archivePath)
 	c.Assert(err, gc.IsNil)
 
 	archive, err := charm.ReadBundleArchiveBytes(data)
 	c.Assert(err, gc.IsNil)
 	c.Assert(archive.ContainsOverlays(), jc.IsFalse)
-	checkWordpressBundle(c, archive, "")
+	checkWordpressBundle(c, archive, "", bundleName)
 }
 
 func (s *BundleArchiveSuite) TestReadMultiDocBundleArchiveBytes(c *gc.C) {
 	path := archivePath(c, readBundleDir(c, "wordpress-simple-multidoc"))
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	c.Assert(err, gc.IsNil)
 
 	archive, err := charm.ReadBundleArchiveBytes(data)
 	c.Assert(err, gc.IsNil)
 	c.Assert(archive.ContainsOverlays(), jc.IsTrue)
-	checkWordpressBundle(c, archive, "")
+	checkWordpressBundle(c, archive, "", "wordpress-simple-multidoc")
 }
 
 func (s *BundleArchiveSuite) TestReadBundleArchiveFromReader(c *gc.C) {
@@ -61,7 +62,7 @@ func (s *BundleArchiveSuite) TestReadBundleArchiveFromReader(c *gc.C) {
 
 	archive, err := charm.ReadBundleArchiveFromReader(f, info.Size())
 	c.Assert(err, gc.IsNil)
-	checkWordpressBundle(c, archive, "")
+	checkWordpressBundle(c, archive, "", bundleName)
 }
 
 func (s *BundleArchiveSuite) TestReadBundleArchiveWithoutBundleYAML(c *gc.C) {

bundledata.go

@@ -49,12 +49,10 @@ type BundleData struct {
 	// Series holds the default series to use when
 	// the bundle deploys applications. A series defined for an application
 	// takes precedence.
-	// Series and Base cannot be mixed.
 	Series string `bson:",omitempty" json:",omitempty" yaml:",omitempty"`
 
 	// Base holds the default base to use when the bundle deploys
 	// applications. A base defined for an application takes precedence.
-	// Series and Base cannot be mixed.
 	DefaultBase string `bson:"default-base,omitempty" json:"default-base,omitempty" yaml:"default-base,omitempty"`
 
 	// Relations holds a slice of 2-element slices,
@@ -104,11 +102,9 @@ type ApplicationSpec struct {
 	Revision *int `bson:"revision,omitempty" yaml:"revision,omitempty" json:"revision,omitempty"`
 
 	// Series is the series to use when deploying the application.
-	// Series and Base cannot be mixed.
 	Series string `bson:",omitempty" yaml:",omitempty" json:",omitempty"`
 
 	// Base is the base to use when deploying the application.
-	// Series and Base cannot be mixed.
 	Base string `bson:",omitempty" yaml:",omitempty" json:",omitempty"`
 
 	// Resources is the set of resource revisions to deploy for the
@@ -355,7 +351,11 @@ type OfferSpec struct {
 // The returned data is not verified - call Verify to ensure
 // that it is OK.
 func ReadBundleData(r io.Reader) (*BundleData, error) {
-	bd, _, err := readBaseFromMultidocBundle(r)
+	b, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	bd, _, err := readBaseFromMultidocBundle(b)
 	if err != nil {
 		return nil, err
 	}
@@ -370,8 +370,8 @@ func ReadBundleData(r io.Reader) (*BundleData, error) {
 //
 // Clients that are interested in reading multi-doc bundle data should use the
 // new helpers: LocalBundleDataSource and StreamBundleDataSource.
-func readBaseFromMultidocBundle(r io.Reader) (*BundleData, bool, error) {
-	parts, err := parseBundleParts(r)
+func readBaseFromMultidocBundle(b []byte) (*BundleData, bool, error) {
+	parts, err := parseBundleParts(b)
 	if err != nil {
 		return nil, false, err
 	}

bundledatasrc.go

@@ -6,7 +6,6 @@ package charm
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -55,19 +54,25 @@ type BundleDataPart struct {
 // list of composable parts.
 type BundleDataSource interface {
 	Parts() []*BundleDataPart
+	BundleBytes() []byte
 	BasePath() string
 	ResolveInclude(path string) ([]byte, error)
 }
 
 type resolvedBundleDataSource struct {
-	basePath string
-	parts    []*BundleDataPart
+	basePath    string
+	bundleBytes []byte
+	parts       []*BundleDataPart
 }
 
 func (s *resolvedBundleDataSource) Parts() []*BundleDataPart {
 	return s.parts
 }
 
+func (s *resolvedBundleDataSource) BundleBytes() []byte {
+	return s.bundleBytes
+}
+
 func (s *resolvedBundleDataSource) BasePath() string {
 	return s.basePath
 }
@@ -95,7 +100,7 @@ func (s *resolvedBundleDataSource) ResolveInclude(path string) ([]byte, error) {
 		return nil, errors.Errorf("include path %q resolves to a folder", absPath)
 	}
 
-	data, err := ioutil.ReadFile(absPath)
+	data, err := os.ReadFile(absPath)
 	if err != nil {
 		return nil, errors.Annotatef(err, "reading include file at %q", absPath)
 	}
@@ -131,15 +136,20 @@ func LocalBundleDataSource(path string) (BundleDataSource, error) {
 	}
 	defer func() { _ = f.Close() }()
 
-	parts, pErr := parseBundleParts(f)
+	b, err := io.ReadAll(f)
+	if err != nil {
+		return nil, err
+	}
+	parts, pErr := parseBundleParts(b)
 	if pErr == nil {
 		absPath, err := filepath.Abs(path)
 		if err != nil {
 			return nil, errors.Annotatef(err, "resolve absolute path to %s", path)
 		}
 		return &resolvedBundleDataSource{
-			basePath: filepath.Dir(absPath),
-			parts:    parts,
+			basePath:    filepath.Dir(absPath),
+			parts:       parts,
+			bundleBytes: b,
 		}, nil
 	}
 
@@ -159,10 +169,15 @@ func LocalBundleDataSource(path string) (BundleDataSource, error) {
 	}
 	defer func() { _ = r.Close() }()
 
-	if parts, pErr = parseBundleParts(r); pErr == nil {
+	b, err = io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	if parts, pErr = parseBundleParts(b); pErr == nil {
 		return &resolvedBundleDataSource{
-			basePath: "", // use empty base path for archives
-			parts:    parts,
+			basePath:    "", // use empty base path for archives
+			parts:       parts,
+			bundleBytes: b,
 		}, nil
 	}
 
@@ -185,20 +200,19 @@ func isNotExistsError(err error) bool {
 // StreamBundleDataSource reads a (potentially multi-part) bundle from r and
 // returns a BundleDataSource for it.
 func StreamBundleDataSource(r io.Reader, basePath string) (BundleDataSource, error) {
-	parts, err := parseBundleParts(r)
+	b, err := io.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	parts, err := parseBundleParts(b)
 	if err != nil {
 		return nil, errors.NotValidf("cannot unmarshal bundle contents: %v", err)
 	}
 
-	return &resolvedBundleDataSource{parts: parts, basePath: basePath}, nil
+	return &resolvedBundleDataSource{parts: parts, bundleBytes: b, basePath: basePath}, nil
 }
 
-func parseBundleParts(r io.Reader) ([]*BundleDataPart, error) {
-	b, err := ioutil.ReadAll(r)
-	if err != nil {
-		return nil, err
-	}
-
+func parseBundleParts(b []byte) ([]*BundleDataPart, error) {
 	var (
 		// Ideally, we would be using a single reader and we would
 		// rewind it to read each block in structured and raw mode.
@@ -216,7 +230,7 @@ func parseBundleParts(r io.Reader) ([]*BundleDataPart, error) {
 	for docIdx := 0; ; docIdx++ {
 		var part BundleDataPart
 
-		err = structDec.Decode(&part.Data)
+		err := structDec.Decode(&part.Data)
 		if err == io.EOF {
 			break
 		} else if err != nil && !strings.HasPrefix(err.Error(), "yaml: unmarshal errors:") {