[#585] Add ListBuckets pagination

Signed-off-by: Nikita Zinkevich <n.zinkevich@yadro.com>

api/handler/bucket_list.go

@@ -0,0 +1,70 @@
+package handler
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/layer"
+	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/middleware"
+)
+
+const maxBucketList = 10000
+
+// ListBucketsHandler handles bucket listing requests.
+func (h *handler) ListBucketsHandler(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	reqInfo := middleware.GetReqInfo(ctx)
+
+	params, err := parseListBucketParams(r)
+	if err != nil {
+		h.logAndSendError(ctx, w, "failed to parse params", reqInfo, err)
+		return
+	}
+
+	resp, err := h.obj.ListBuckets(ctx, params)
+	if err != nil {
+		h.logAndSendError(ctx, w, "something went wrong", reqInfo, err)
+		return
+	}
+
+	if err = middleware.EncodeToResponse(w, encodeListBuckets(reqInfo.User, resp, params)); err != nil {
+		h.logAndSendError(ctx, w, "something went wrong", reqInfo, err)
+	}
+}
+
+func encodeListBuckets(owner string, resp layer.ListBucketsResult, params layer.ListBucketsParams) *ListBucketsResponse {
+	res := &ListBucketsResponse{
+		Owner: Owner{
+			ID:          owner,
+			DisplayName: owner,
+		},
+		ContinuationToken: resp.ContinuationToken,
+		Prefix:            params.Prefix,
+	}
+
+	for _, item := range resp.Containers {
+		res.Buckets.Buckets = append(res.Buckets.Buckets, Bucket{
+			Name:         item.Name,
+			CreationDate: item.Created.UTC().Format(time.RFC3339),
+			BucketRegion: item.LocationConstraint,
+		})
+	}
+	return res
+}
+
+func parseListBucketParams(r *http.Request) (prm layer.ListBucketsParams, err error) {
+	prm.MaxBuckets = maxBucketList
+	strMaxBuckets := r.URL.Query().Get(middleware.QueryMaxBuckets)
+	if strMaxBuckets != "" {
+		if prm.MaxBuckets, err = strconv.Atoi(strMaxBuckets); err != nil || prm.MaxBuckets < 0 {
+			return layer.ListBucketsParams{}, errors.GetAPIError(errors.ErrInvalidMaxKeys)
+		}
+	}
+	prm.Prefix = r.URL.Query().Get(middleware.QueryPrefix)
+	prm.BucketRegion = r.URL.Query().Get(middleware.QueryBucketRegion)
+	prm.ContinuationToken = r.URL.Query().Get(middleware.QueryContinuationToken)
+
+	return
+}

api/handler/list.go

@@ -1,49 +0,0 @@
-package handler
-
-import (
-	"net/http"
-	"time"
-
-	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/middleware"
-	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/user"
-)
-
-const maxObjectList = 1000 // Limit number of objects in a listObjectsResponse/listObjectsVersionsResponse.
-
-// ListBucketsHandler handles bucket listing requests.
-func (h *handler) ListBucketsHandler(w http.ResponseWriter, r *http.Request) {
-	var (
-		own     user.ID
-		res     *ListBucketsResponse
-		ctx     = r.Context()
-		reqInfo = middleware.GetReqInfo(ctx)
-	)
-
-	list, err := h.obj.ListBuckets(ctx)
-	if err != nil {
-		h.logAndSendError(ctx, w, "something went wrong", reqInfo, err)
-		return
-	}
-
-	if len(list) > 0 {
-		own = list[0].Owner
-	}
-
-	res = &ListBucketsResponse{
-		Owner: Owner{
-			ID:          own.String(),
-			DisplayName: own.String(),
-		},
-	}
-
-	for _, item := range list {
-		res.Buckets.Buckets = append(res.Buckets.Buckets, Bucket{
-			Name:         item.Name,
-			CreationDate: item.Created.UTC().Format(time.RFC3339),
-		})
-	}
-
-	if err = middleware.EncodeToResponse(w, res); err != nil {
-		h.logAndSendError(ctx, w, "something went wrong", reqInfo, err)
-	}
-}

api/handler/object_list.go

@@ -15,6 +15,8 @@ import (
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
 )
 
+const maxObjectList = 1000 // Limit number of objects in a listObjectsResponse/listObjectsVersionsResponse.
+
 // ListObjectsV1Handler handles objects listing requests for API version 1.
 func (h *handler) ListObjectsV1Handler(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()

api/handler/response.go

@@ -15,6 +15,9 @@ type ListBucketsResponse struct {
 	Buckets struct {
 		Buckets []Bucket `xml:"Bucket"`
 	} // Buckets are nested
+
+	ContinuationToken string `xml:"ContinuationToken,omitempty"`
+	Prefix            string `xml:"Prefix,omitempty"`
 }
 
 // ListObjectsV1Response -- format for ListObjectsV1 response.
@@ -51,8 +54,9 @@ type ListObjectsV2Response struct {
 
 // Bucket container for bucket metadata.
 type Bucket struct {
-	Name         string
+	Name         string `xml:"Name"`
-	CreationDate string // time string of format "2006-01-02T15:04:05.000Z"
+	CreationDate string `xml:"CreationDate"` // time string of format "2006-01-02T15:04:05.000Z"
+	BucketRegion string `xml:"BucketRegion,omitempty"`
 }
 
 // PolicyStatus contains status of bucket policy.

api/layer/container.go

@@ -3,7 +3,9 @@ package layer
 import (
 	"context"
 	"fmt"
+	"sort"
 	"strconv"
+	"strings"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api"
 	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/data"
@@ -76,7 +78,7 @@ func (n *Layer) containerInfo(ctx context.Context, prm frostfs.PrmContainer) (*d
 	return info, nil
 }
 
-func (n *Layer) containerList(ctx context.Context) ([]*data.BucketInfo, error) {
+func (n *Layer) containerList(ctx context.Context, listParams ListBucketsParams) ([]*data.BucketInfo, error) {
 	stoken := n.SessionTokenForRead(ctx)
 
 	prm := frostfs.PrmUserContainers{
@@ -102,10 +104,34 @@ func (n *Layer) containerList(ctx context.Context) ([]*data.BucketInfo, error) {
 			continue
 		}
 
+		if shouldSkipBucket(info, listParams) {
+			continue
+		}
+
 		list = append(list, info)
 	}
 
-	return list, nil
+	sort.Slice(list, func(i, j int) bool {
+		return list[i].Name < list[j].Name
+	})
+
+	for i, info := range list {
+		if listParams.ContinuationToken != "" && info.Name != listParams.ContinuationToken {
+			continue
+		}
+		return list[i:], nil
+	}
+
+	return nil, nil
+}
+
+func shouldSkipBucket(info *data.BucketInfo, prm ListBucketsParams) bool {
+	if !strings.HasPrefix(info.Name, prm.Prefix) ||
+		(prm.BucketRegion != "" && info.LocationConstraint != prm.BucketRegion) {
+		return true
+	}
+
+	return false
 }
 
 func (n *Layer) createContainer(ctx context.Context, p *CreateBucketParams) (*data.BucketInfo, error) {

api/layer/layer.go

@@ -195,6 +195,18 @@ type (
 		Encode          string
 	}
 
+	ListBucketsParams struct {
+		MaxBuckets        int
+		Prefix            string
+		ContinuationToken string
+		BucketRegion      string
+	}
+
+	ListBucketsResult struct {
+		Containers        []*data.BucketInfo
+		ContinuationToken string
+	}
+
 	// VersionedObject stores info about objects to delete.
 	VersionedObject struct {
 		Name              string
@@ -371,8 +383,24 @@ func (n *Layer) ResolveCID(ctx context.Context, name string) (cid.ID, error) {
 
 // ListBuckets returns all user containers. The name of the bucket is a container
 // id. Timestamp is omitted since it is not saved in frostfs container.
-func (n *Layer) ListBuckets(ctx context.Context) ([]*data.BucketInfo, error) {
+func (n *Layer) ListBuckets(ctx context.Context, params ListBucketsParams) (ListBucketsResult, error) {
-	return n.containerList(ctx)
+	var result ListBucketsResult
+	var err error
+
+	if params.MaxBuckets == 0 {
+		return result, nil
+	}
+
+	result.Containers, err = n.containerList(ctx, params)
+	if err != nil {
+		return ListBucketsResult{}, err
+	}
+	if len(result.Containers) > params.MaxBuckets {
+		result.ContinuationToken = result.Containers[params.MaxBuckets].Name
+		result.Containers = result.Containers[:params.MaxBuckets]
+	}
+
+	return result, nil
 }
 
 // GetObject from storage.