Create Repositories method

This change removes the Catalog Service and replaces it with a more
simplistic Repositories() method for obtaining a catalog of all
repositories.  The Repositories method takes a pre-allocated slice
and fills it up to the size of the slice and returns the amount
filled.  The catalog is returned lexicographically and will start
being filled from the last entry passed to Repositories().  If there
are no more entries to fill, io.EOF will be returned.

Signed-off-by: Patrick Devine <patrick.devine@docker.com>

Conflicts:
	registry/client/repository.go
	registry/handlers/api_test.go

docs/storage/catalog.go

@@ -1,36 +1,38 @@
 package storage
 
 import (
+	"errors"
+	"io"
 	"path"
 	"sort"
 	"strings"
 
-	log "github.com/Sirupsen/logrus"
-	"github.com/docker/distribution"
 	"github.com/docker/distribution/context"
-	storageDriver "github.com/docker/distribution/registry/storage/driver"
+	"github.com/docker/distribution/registry/storage/driver"
 )
 
-type catalogSvc struct {
-	ctx    context.Context
-	driver storageDriver.StorageDriver
-}
-
-var _ distribution.CatalogService = &catalogSvc{}
-
-// Get returns a list, or partial list, of repositories in the registry.
+// Returns a list, or partial list, of repositories in the registry.
 // Because it's a quite expensive operation, it should only be used when building up
 // an initial set of repositories.
-func (c *catalogSvc) Get(maxEntries int, lastEntry string) ([]string, bool, error) {
-	log.Infof("Retrieving up to %d entries of the catalog starting with '%s'", maxEntries, lastEntry)
-	var repos []string
+func (reg *registry) Repositories(ctx context.Context, repos []string, last string) (n int, err error) {
+	var foundRepos []string
+	var errVal error
+
+	if len(repos) == 0 {
+		return 0, errors.New("no space in slice")
+	}
 
 	root, err := defaultPathMapper.path(repositoriesRootPathSpec{})
 	if err != nil {
-		return repos, false, err
+		return 0, err
 	}
 
-	Walk(c.ctx, c.driver, root, func(fileInfo storageDriver.FileInfo) error {
+	// Walk each of the directories in our storage.  Unfortunately since there's no
+	// guarantee that storage will return files in lexigraphical order, we have
+	// to store everything another slice, sort it and then copy it back to our
+	// passed in slice.
+
+	Walk(ctx, reg.blobStore.driver, root, func(fileInfo driver.FileInfo) error {
 		filePath := fileInfo.Path()
 
 		// lop the base path off
@@ -39,8 +41,8 @@ func (c *catalogSvc) Get(maxEntries int, lastEntry string) ([]string, bool, erro
 		_, file := path.Split(repoPath)
 		if file == "_layers" {
 			repoPath = strings.TrimSuffix(repoPath, "/_layers")
-			if repoPath > lastEntry {
-				repos = append(repos, repoPath)
+			if repoPath > last {
+				foundRepos = append(foundRepos, repoPath)
 			}
 			return ErrSkipDir
 		} else if strings.HasPrefix(file, "_") {
@@ -50,13 +52,14 @@ func (c *catalogSvc) Get(maxEntries int, lastEntry string) ([]string, bool, erro
 		return nil
 	})
 
-	sort.Strings(repos)
+	sort.Strings(foundRepos)
+	n = copy(repos, foundRepos)
 
-	moreEntries := false
-	if len(repos) > maxEntries {
-		moreEntries = true
-		repos = repos[0:maxEntries]
+	// Signal that we have no more entries by setting EOF
+	if len(foundRepos) <= len(repos) {
+		errVal = io.EOF
 	}
 
-	return repos, moreEntries, nil
+	return n, errVal
+
 }

docs/storage/catalog_test.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"io"
 	"testing"
 
 	"github.com/docker/distribution"
@@ -15,7 +16,6 @@ type setupEnv struct {
 	driver   driver.StorageDriver
 	expected []string
 	registry distribution.Namespace
-	catalog  distribution.CatalogService
 }
 
 func setupFS(t *testing.T) *setupEnv {
@@ -41,8 +41,6 @@ func setupFS(t *testing.T) *setupEnv {
 		}
 	}
 
-	catalog := registry.Catalog(ctx)
-
 	expected := []string{
 		"bar/c",
 		"bar/d",
@@ -56,20 +54,21 @@ func setupFS(t *testing.T) *setupEnv {
 		driver:   d,
 		expected: expected,
 		registry: registry,
-		catalog:  catalog,
 	}
 }
 
 func TestCatalog(t *testing.T) {
 	env := setupFS(t)
 
-	repos, more, _ := env.catalog.Get(100, "")
+	p := make([]string, 50)
 
-	if !testEq(repos, env.expected) {
+	numFilled, err := env.registry.Repositories(env.ctx, p, "")
+
+	if !testEq(p, env.expected, numFilled) {
 		t.Errorf("Expected catalog repos err")
 	}
 
-	if more {
+	if err != io.EOF {
 		t.Errorf("Catalog has more values which we aren't expecting")
 	}
 }
@@ -78,50 +77,46 @@ func TestCatalogInParts(t *testing.T) {
 	env := setupFS(t)
 
 	chunkLen := 2
+	p := make([]string, chunkLen)
 
-	repos, more, _ := env.catalog.Get(chunkLen, "")
-	if !testEq(repos, env.expected[0:chunkLen]) {
+	numFilled, err := env.registry.Repositories(env.ctx, p, "")
+	if err == io.EOF || numFilled != len(p) {
+		t.Errorf("Expected more values in catalog")
+	}
+
+	if !testEq(p, env.expected[0:chunkLen], numFilled) {
 		t.Errorf("Expected catalog first chunk err")
 	}
 
-	if !more {
+	lastRepo := p[len(p)-1]
+	numFilled, err = env.registry.Repositories(env.ctx, p, lastRepo)
+
+	if err == io.EOF || numFilled != len(p) {
 		t.Errorf("Expected more values in catalog")
 	}
 
-	lastRepo := repos[len(repos)-1]
-	repos, more, _ = env.catalog.Get(chunkLen, lastRepo)
-
-	if !testEq(repos, env.expected[chunkLen:chunkLen*2]) {
+	if !testEq(p, env.expected[chunkLen:chunkLen*2], numFilled) {
 		t.Errorf("Expected catalog second chunk err")
 	}
 
-	if !more {
-		t.Errorf("Expected more values in catalog")
-	}
+	lastRepo = p[len(p)-1]
+	numFilled, err = env.registry.Repositories(env.ctx, p, lastRepo)
 
-	lastRepo = repos[len(repos)-1]
-	repos, more, _ = env.catalog.Get(chunkLen, lastRepo)
-
-	if !testEq(repos, env.expected[chunkLen*2:chunkLen*3-1]) {
-		t.Errorf("Expected catalog third chunk err")
-	}
-
-	if more {
+	if err != io.EOF {
 		t.Errorf("Catalog has more values which we aren't expecting")
 	}
 
-}
-
-func testEq(a, b []string) bool {
-	if len(a) != len(b) {
-		return false
+	if !testEq(p, env.expected[chunkLen*2:chunkLen*3-1], numFilled) {
+		t.Errorf("Expected catalog third chunk err")
 	}
 
-	for count := range a {
-		if a[count] != b[count] {
+}
+
+func testEq(a, b []string, size int) bool {
+	for cnt := 0; cnt < size-1; cnt++ {
+		if a[cnt] != b[cnt] {
 			return false
 		}
 	}
-
 	return true
 }

docs/storage/registry.go

@@ -55,15 +55,6 @@ func (reg *registry) Scope() distribution.Scope {
 	return distribution.GlobalScope
 }
 
-// Catalog returns an instance of the catalog service which can be
-// used to dump all of the repositories in a registry
-func (reg *registry) Catalog(ctx context.Context) distribution.CatalogService {
-	return &catalogSvc{
-		ctx:    ctx,
-		driver: reg.blobStore.driver,
-	}
-}
-
 // Repository returns an instance of the repository tied to the registry.
 // Instances should not be shared between goroutines but are cheap to
 // allocate. In general, they should be request scoped.