feat: abstract interactions with archive/store

internal/archive/archive.go

@@ -32,13 +32,6 @@ type PackageInfo struct {
 	SHA256  string
 }
 
-func (p *PackageInfo) PkgName() string                 { return p.Name }
-func (p *PackageInfo) PkgVersion() string              { return p.Version }
-func (p *PackageInfo) PkgRevision() int                { return 0 }
-func (p *PackageInfo) PkgArch() string                 { return p.Arch }
-func (p *PackageInfo) PkgDigestKind() cache.DigestKind { return cache.SHA256 }
-func (p *PackageInfo) PkgDigest() string               { return p.SHA256 }
-
 type Options struct {
 	Label      string
 	Version    string

internal/manifestutil/manifestutil.go

@@ -16,8 +16,6 @@ import (
 	"github.com/canonical/chisel/public/manifest"
 )
 
-// PackageInfo describes a package as obtained from its source, abstracting
-// over archives, stores, and any other backend.
 type PackageInfo interface {
 	PkgName() string
 	PkgVersion() string
@@ -26,6 +24,7 @@ type PackageInfo interface {
 	// revisions.
 	PkgRevision() int
 	PkgArch() string
+	PkgStore() string
 	PkgDigestKind() cache.DigestKind
 	PkgDigest() string
 }

internal/manifestutil/manifestutil_test.go

@@ -12,7 +12,7 @@ import (
 	. "gopkg.in/check.v1"
 
 	"github.com/canonical/chisel/internal/apachetestutil"
-	"github.com/canonical/chisel/internal/archive"
+	"github.com/canonical/chisel/internal/cache"
 	"github.com/canonical/chisel/internal/manifestutil"
 	"github.com/canonical/chisel/internal/setup"
 	"github.com/canonical/chisel/public/manifest"
@@ -119,6 +119,24 @@ var slice2 = &setup.Slice{
 	Name:    "slice2",
 }
 
+type testPackageInfo struct {
+	Name       string
+	Version    string
+	Revision   int
+	Arch       string
+	Store      string
+	DigestKind cache.DigestKind
+	Digest     string
+}
+
+func (p *testPackageInfo) PkgName() string                 { return p.Name }
+func (p *testPackageInfo) PkgVersion() string              { return p.Version }
+func (p *testPackageInfo) PkgRevision() int                { return p.Revision }
+func (p *testPackageInfo) PkgArch() string                 { return p.Arch }
+func (p *testPackageInfo) PkgStore() string                { return p.Store }
+func (p *testPackageInfo) PkgDigestKind() cache.DigestKind { return p.DigestKind }
+func (p *testPackageInfo) PkgDigest() string               { return p.Digest }
+
 var generateManifestTests = []struct {
 	summary     string
 	report      *manifestutil.Report
@@ -149,17 +167,19 @@ var generateManifestTests = []struct {
 		},
 	},
 	packageInfo: []manifestutil.PackageInfo{
-		&archive.PackageInfo{
-			Name:    "package1",
-			Version: "v1",
-			Arch:    "a1",
-			SHA256:  "s1",
+		&testPackageInfo{
+			Name:       "package1",
+			Version:    "v1",
+			Arch:       "a1",
+			DigestKind: cache.SHA256,
+			Digest:     "s1",
 		},
-		&archive.PackageInfo{
-			Name:    "package2",
-			Version: "v2",
-			Arch:    "a2",
-			SHA256:  "s2",
+		&testPackageInfo{
+			Name:       "package2",
+			Version:    "v2",
+			Arch:       "a2",
+			DigestKind: cache.SHA256,
+			Digest:     "s2",
 		},
 	},
 	expected: &apachetestutil.ManifestContents{
@@ -399,11 +419,12 @@ var generateManifestTests = []struct {
 		},
 	},
 	packageInfo: []manifestutil.PackageInfo{
-		&archive.PackageInfo{
-			Name:    "package1",
-			Version: "v1",
-			Arch:    "a1",
-			SHA256:  "s1",
+		&testPackageInfo{
+			Name:       "package1",
+			Version:    "v1",
+			Arch:       "a1",
+			DigestKind: cache.SHA256,
+			Digest:     "s1",
 		},
 	},
 	expected: &apachetestutil.ManifestContents{
@@ -500,37 +521,40 @@ var generateManifestTests = []struct {
 }, {
 	summary: "Invalid package: missing name",
 	packageInfo: []manifestutil.PackageInfo{
-		&archive.PackageInfo{
-			Version: "v1",
-			Arch:    "a1",
-			SHA256:  "s1",
+		&testPackageInfo{
+			Version:    "v1",
+			Arch:       "a1",
+			DigestKind: cache.SHA256,
+			Digest:     "s1",
 		},
 	},
 	error: `internal error: invalid manifest: package name not set`,
 }, {
 	summary: "Invalid package: missing version",
 	packageInfo: []manifestutil.PackageInfo{
-		&archive.PackageInfo{
-			Name:   "package-1",
-			Arch:   "a1",
-			SHA256: "s1",
+		&testPackageInfo{
+			Name:       "package-1",
+			Arch:       "a1",
+			DigestKind: cache.SHA256,
+			Digest:     "s1",
 		},
 	},
 	error: `internal error: invalid manifest: package "package-1" missing version`,
 }, {
 	summary: "Invalid package: missing arch",
 	packageInfo: []manifestutil.PackageInfo{
-		&archive.PackageInfo{
-			Name:    "package-1",
-			Version: "v1",
-			SHA256:  "s1",
+		&testPackageInfo{
+			Name:       "package-1",
+			Version:    "v1",
+			DigestKind: cache.SHA256,
+			Digest:     "s1",
 		},
 	},
 	error: `internal error: invalid manifest: package "package-1" missing arch`,
 }, {
 	summary: "Invalid package: missing sha256",
 	packageInfo: []manifestutil.PackageInfo{
-		&archive.PackageInfo{
+		&testPackageInfo{
 			Name:    "package-1",
 			Version: "v1",
 			Arch:    "a1",
@@ -547,11 +571,12 @@ func (s *S) TestGenerateManifests(c *C) {
 		}
 		if test.packageInfo == nil {
 			test.packageInfo = []manifestutil.PackageInfo{
-				&archive.PackageInfo{
-					Name:    "package1",
-					Version: "v1",
-					Arch:    "a1",
-					SHA256:  "s1",
+				&testPackageInfo{
+					Name:       "package1",
+					Version:    "v1",
+					Arch:       "a1",
+					DigestKind: cache.SHA256,
+					Digest:     "s1",
 				},
 			}
 		}

internal/slicer/package_remote.go

@@ -0,0 +1,62 @@
+package slicer
+
+import (
+	"io"
+
+	"github.com/canonical/chisel/internal/archive"
+	"github.com/canonical/chisel/internal/cache"
+)
+
+// RemotePackageInfo describes a package as reported by its provider.
+type RemotePackageInfo struct {
+	Name       string
+	Version    string
+	Revision   int
+	Arch       string
+	Store      string
+	DigestKind cache.DigestKind
+	Digest     string
+}
+
+func (p *RemotePackageInfo) PkgName() string                 { return p.Name }
+func (p *RemotePackageInfo) PkgVersion() string              { return p.Version }
+func (p *RemotePackageInfo) PkgRevision() int                { return p.Revision }
+func (p *RemotePackageInfo) PkgArch() string                 { return p.Arch }
+func (p *RemotePackageInfo) PkgStore() string                { return p.Store }
+func (p *RemotePackageInfo) PkgDigestKind() cache.DigestKind { return p.DigestKind }
+func (p *RemotePackageInfo) PkgDigest() string               { return p.Digest }
+
+// PackageRemote represents the remote from which a package is obtained.
+type PackageRemote interface {
+	// Arch returns the architecture the remote serves packages for, which is
+	// the target architecture used to request the package, not the
+	// architecture of the fetched package itself (which may be "all", for
+	// example).
+	Arch() string
+	Fetch() (io.ReadSeekCloser, *RemotePackageInfo, error)
+}
+
+var _ PackageRemote = (*archiveRemote)(nil)
+
+type archiveRemote struct {
+	archive archive.Archive
+	name    string
+}
+
+func (d *archiveRemote) Arch() string {
+	return d.archive.Options().Arch
+}
+
+func (d *archiveRemote) Fetch() (io.ReadSeekCloser, *RemotePackageInfo, error) {
+	reader, info, err := d.archive.Fetch(d.name)
+	if err != nil {
+		return nil, nil, err
+	}
+	return reader, &RemotePackageInfo{
+		Name:       info.Name,
+		Version:    info.Version,
+		Arch:       info.Arch,
+		DigestKind: cache.SHA256,
+		Digest:     info.SHA256,
+	}, nil
+}

internal/slicer/slicer.go

@@ -90,7 +90,7 @@ func Run(options *RunOptions) error {
 		targetDir = filepath.Join(dir, targetDir)
 	}
 
-	pkgArchive, err := selectPkgArchives(options.Archives, options.Selection)
+	pkgRemotes, err := selectPkgRemotes(options.Archives, options.Selection)
 	if err != nil {
 		return err
 	}
@@ -108,7 +108,7 @@ func Run(options *RunOptions) error {
 			extractPackage = make(map[string][]tarball.ExtractInfo)
 			extract[slice.Package] = extractPackage
 		}
-		arch := pkgArchive[slice.Package].Options().Arch
+		arch := pkgRemotes[slice.Package].Arch()
 		for targetPath, pathInfo := range slice.Contents {
 			if targetPath == "" {
 				continue
@@ -153,7 +153,7 @@ func Run(options *RunOptions) error {
 			continue
 		}
 		pkg := options.Selection.Release.Packages[slice.Package]
-		reader, info, err := pkgArchive[slice.Package].Fetch(pkg.RealName)
+		reader, info, err := pkgRemotes[pkg.Name].Fetch()
 		if err != nil {
 			return err
 		}
@@ -270,7 +270,7 @@ func Run(options *RunOptions) error {
 	// them to the appropriate slices.
 	relPaths := map[string][]*setup.Slice{}
 	for _, slice := range options.Selection.Slices {
-		arch := pkgArchive[slice.Package].Options().Arch
+		arch := pkgRemotes[slice.Package].Arch()
 		for relPath, pathInfo := range slice.Contents {
 			if len(pathInfo.Arch) > 0 && !slices.Contains(pathInfo.Arch, arch) {
 				continue
@@ -490,10 +490,12 @@ func createFile(targetDir, relPath string, pathInfo setup.PathInfo) (*fsutil.Ent
 	})
 }
 
-// selectPkgArchives selects the highest priority archive containing the package
-// unless a particular archive is pinned within the slice definition file. It
-// returns a map of archives indexed by package names.
-func selectPkgArchives(archives map[string]archive.Archive, selection *setup.Selection) (map[string]archive.Archive, error) {
+// selectPkgRemotes determines the remote for each package in the selection.
+// For packages from an archive it selects the highest priority archive
+// containing the package unless a particular archive is pinned within the
+// package slices file. Packages from a store are not supported yet.
+// It returns a map of PackageRemote indexed by package names.
+func selectPkgRemotes(archives map[string]archive.Archive, selection *setup.Selection) (map[string]PackageRemote, error) {
 	sortedArchives := make([]*setup.Archive, 0, len(selection.Release.Archives))
 	for _, archive := range selection.Release.Archives {
 		if archive.Priority < 0 {
@@ -507,9 +509,9 @@ func selectPkgArchives(archives map[string]archive.Archive, selection *setup.Sel
 		return b.Priority - a.Priority
 	})
 
-	pkgArchive := make(map[string]archive.Archive)
+	pkgRemotes := make(map[string]PackageRemote)
 	for _, s := range selection.Slices {
-		if _, ok := pkgArchive[s.Package]; ok {
+		if _, ok := pkgRemotes[s.Package]; ok {
 			continue
 		}
 		pkg := selection.Release.Packages[s.Package]
@@ -538,7 +540,10 @@ func selectPkgArchives(archives map[string]archive.Archive, selection *setup.Sel
 		if chosen == nil {
 			return nil, fmt.Errorf("cannot find package %q in archive(s)", pkg.RealName)
 		}
-		pkgArchive[pkg.Name] = chosen
+		pkgRemotes[pkg.Name] = &archiveRemote{
+			archive: chosen,
+			name:    pkg.RealName,
+		}
 	}
-	return pkgArchive, nil
+	return pkgRemotes, nil
 }