Add catalog to minio (#1040)

* Implement cataloger interface for Minio

* Catalog fix

* Implemented Catalog method in the Minio storage package

* code fmt fix

* fmt fix

* remove unused channel

pkg/storage/minio/cataloger.go

@@ -0,0 +1,84 @@
+package minio
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/gomods/athens/pkg/errors"
+	"github.com/gomods/athens/pkg/observ"
+	"github.com/gomods/athens/pkg/paths"
+	"github.com/minio/minio-go"
+)
+
+// Catalog implements the (./pkg/storage).Cataloger interface
+// It returns a list of modules and versions contained in the storage
+func (s *storageImpl) Catalog(ctx context.Context, token string, pageSize int) ([]paths.AllPathParams, string, error) {
+	const op errors.Op = "minio.Catalog"
+	ctx, span := observ.StartSpan(ctx, op.String())
+	defer span.End()
+	queryToken := token
+	res := make([]paths.AllPathParams, 0)
+	startAfter := token
+	token = ""
+
+	count := pageSize
+	for count > 0 {
+		loo, err := s.minioCore.ListObjectsV2(s.bucketName, token, "", false, "", 0, startAfter)
+		if err != nil {
+			return nil, "", errors.E(op, err)
+		}
+
+		m, lastKey := fetchModsAndVersions(loo.Contents, count)
+
+		res = append(res, m...)
+		count -= len(m)
+		queryToken = lastKey
+
+		if !loo.IsTruncated { // not truncated, there is no point in asking more
+			if count > 0 { // it means we reached the end, no subsequent requests are necessary
+				queryToken = ""
+			}
+			break
+		}
+	}
+
+	return res, queryToken, nil
+}
+
+func fetchModsAndVersions(objects []minio.ObjectInfo, elementsNum int) ([]paths.AllPathParams, string) {
+	res := make([]paths.AllPathParams, 0)
+	lastKey := ""
+
+	for _, o := range objects {
+		if !strings.HasSuffix(o.Key, ".info") {
+			continue
+		}
+
+		p, err := parseMinioKey(&o)
+		if err != nil {
+			continue
+		}
+
+		res = append(res, p)
+		lastKey = o.Key
+
+		elementsNum--
+		if elementsNum == 0 {
+			break
+		}
+	}
+	return res, lastKey
+}
+
+func parseMinioKey(o *minio.ObjectInfo) (paths.AllPathParams, error) {
+	const op errors.Op = "minio.parseMinioKey"
+	parts := strings.Split(o.Key, "/")
+	v := parts[len(parts)-2]
+	m := strings.Replace(o.Key, v, "", -2)
+	m = strings.Replace(m, "//.info", "", -1)
+	if m == "" || v == "" {
+		return paths.AllPathParams{}, errors.E(op, fmt.Errorf("invalid object key format %s", o.Key))
+	}
+	return paths.AllPathParams{m, v}, nil
+}

pkg/storage/minio/lister.go

@@ -18,8 +18,9 @@ func (l *storageImpl) List(ctx context.Context, module string) ([]string, error)
 	doneCh := make(chan struct{})
 	defer close(doneCh)
 	searchPrefix := module + "/"
-	objectCh := l.minioClient.ListObjectsV2(l.bucketName, searchPrefix, false, doneCh)
-	for object := range objectCh {
+	objectCh, _ := l.minioCore.ListObjectsV2(l.bucketName, searchPrefix, "", false, "", 0, "")
+
+	for _, object := range objectCh.Contents {
 		if object.Err != nil {
 			return nil, errors.E(op, object.Err, errors.M(module))
 		}

pkg/storage/minio/minio.go

@@ -12,6 +12,7 @@ import (
 
 type storageImpl struct {
 	minioClient *minio.Client
+	minioCore   *minio.Core
 	bucketName  string
 }
 
@@ -29,6 +30,7 @@ func NewStorage(conf *config.MinioConfig, timeout time.Duration) (storage.Backen
 	bucketName := conf.Bucket
 	region := conf.Region
 	useSSL := conf.EnableSSL
+	minioCore, err := minio.NewCore(endpoint, accessKeyID, secretAccessKey, useSSL)
 	minioClient, err := minio.New(endpoint, accessKeyID, secretAccessKey, useSSL)
 	if err != nil {
 		return nil, errors.E(op, err)
@@ -42,5 +44,5 @@ func NewStorage(conf *config.MinioConfig, timeout time.Duration) (storage.Backen
 			return nil, errors.E(op, err)
 		}
 	}
-	return &storageImpl{minioClient, bucketName}, nil
+	return &storageImpl{minioClient, minioCore, bucketName}, nil
 }

pkg/storage/minio/minio_test.go

@@ -19,10 +19,8 @@ func BenchmarkBackend(b *testing.B) {
 }
 
 func (s *storageImpl) clear() error {
-	doneCh := make(chan struct{})
-	defer close(doneCh)
-	objectCh := s.minioClient.ListObjectsV2(s.bucketName, "", true, doneCh)
-	for object := range objectCh {
+	objectCh, _ := s.minioCore.ListObjectsV2(s.bucketName, "", "", false, "", 0, "")
+	for _, object := range objectCh.Contents {
 		if object.Err != nil {
 			return object.Err
 		}