Move GSFetcher to internal/client/gcp package

Author: roger2hk

internal/client/fetcher.go

@@ -24,7 +24,6 @@ import (
 	"path"
 	"strings"
 
-	gcs "cloud.google.com/go/storage"
 	"github.com/transparency-dev/tessera/api/layout"
 	"k8s.io/klog/v2"
 )
@@ -124,56 +123,6 @@ func (f FileFetcher) ReadEntryBundle(_ context.Context, i uint64, p uint8) ([]by
 	return os.ReadFile(path.Join(f.Root, ctEntriesPath(i, p)))
 }
 
-// NewGSFetcher creates a new GSFetcher for the Google Cloud Storage bucket, using
-// the provided GCS client.
-//
-// bucket should not contain any slash.
-// c may be nil, in which case a new GCS client will be used.
-func NewGSFetcher(ctx context.Context, bucket string, c *gcs.Client) (*GSFetcher, error) {
-	if c == nil {
-		var err error
-		c, err = gcs.NewClient(ctx, gcs.WithJSONReads())
-		if err != nil {
-			return nil, err
-		}
-	}
-	return &GSFetcher{
-		bucket: bucket,
-		c:      c,
-	}, nil
-}
-
-// GSFetcher knows how to fetch log artifacts from a Google Cloud Storage bucket.
-type GSFetcher struct {
-	bucket string
-	c      *gcs.Client
-}
-
-func (f GSFetcher) fetch(ctx context.Context, p string) ([]byte, error) {
-	r, err := f.c.Bucket(f.bucket).Object(p).NewReader(ctx)
-	if err != nil {
-		return nil, fmt.Errorf("getObject: failed to create reader for object %q in bucket %q: %w", p, f.bucket, err)
-	}
-
-	d, err := io.ReadAll(r)
-	if err != nil {
-		return nil, fmt.Errorf("failed to read %q: %v", p, err)
-	}
-	return d, r.Close()
-}
-
-func (f GSFetcher) ReadCheckpoint(ctx context.Context) ([]byte, error) {
-	return f.fetch(ctx, layout.CheckpointPath)
-}
-
-func (f GSFetcher) ReadTile(ctx context.Context, l, i uint64, p uint8) ([]byte, error) {
-	return f.fetch(ctx, layout.TilePath(l, i, p))
-}
-
-func (f GSFetcher) ReadEntryBundle(ctx context.Context, i uint64, p uint8) ([]byte, error) {
-	return f.fetch(ctx, ctEntriesPath(i, p))
-}
-
 func ctEntriesPath(n uint64, p uint8) string {
 	return fmt.Sprintf("tile/data/%s", layout.NWithSuffix(0, n, p))
 }

internal/client/gcp/fetcher.go

@@ -0,0 +1,74 @@
+// Copyright 2025 The Tessera authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gcp
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	gcs "cloud.google.com/go/storage"
+	"github.com/transparency-dev/tessera/api/layout"
+)
+
+// NewGSFetcher creates a new GSFetcher for the Google Cloud Storage bucket, using
+// the provided GCS client.
+//
+// bucket should not contain any slash.
+// c may be nil, in which case a new GCS client will be used.
+func NewGSFetcher(ctx context.Context, bucket string, c *gcs.Client) (*GSFetcher, error) {
+	if c == nil {
+		var err error
+		c, err = gcs.NewClient(ctx, gcs.WithJSONReads())
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &GSFetcher{
+		bucket: bucket,
+		c:      c,
+	}, nil
+}
+
+// GSFetcher knows how to fetch log artifacts from a Google Cloud Storage bucket.
+type GSFetcher struct {
+	bucket string
+	c      *gcs.Client
+}
+
+func (f GSFetcher) fetch(ctx context.Context, p string) ([]byte, error) {
+	r, err := f.c.Bucket(f.bucket).Object(p).NewReader(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("getObject: failed to create reader for object %q in bucket %q: %w", p, f.bucket, err)
+	}
+
+	d, err := io.ReadAll(r)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read %q: %v", p, err)
+	}
+	return d, r.Close()
+}
+
+func (f GSFetcher) ReadCheckpoint(ctx context.Context) ([]byte, error) {
+	return f.fetch(ctx, layout.CheckpointPath)
+}
+
+func (f GSFetcher) ReadTile(ctx context.Context, l, i uint64, p uint8) ([]byte, error) {
+	return f.fetch(ctx, layout.TilePath(l, i, p))
+}
+
+func (f GSFetcher) ReadEntryBundle(ctx context.Context, i uint64, p uint8) ([]byte, error) {
+	return f.fetch(ctx, fmt.Sprintf("tile/data/%s", layout.NWithSuffix(0, i, p)))
+}

internal/hammer/loadtest/client.go

@@ -29,6 +29,7 @@ import (
 	"time"
 
 	"github.com/transparency-dev/tesseract/internal/client"
+	"github.com/transparency-dev/tesseract/internal/client/gcp"
 	"github.com/transparency-dev/tesseract/internal/types/rfc6962"
 	"github.com/transparency-dev/tesseract/internal/types/staticct"
 	"k8s.io/klog/v2"
@@ -103,7 +104,7 @@ func newFetcher(ctx context.Context, root *url.URL, bearerToken string) fetcher
 	case "file":
 		return client.FileFetcher{Root: root.Path}
 	case "gs":
-		c, err := client.NewGSFetcher(ctx, root.Host, nil)
+		c, err := gcp.NewGSFetcher(ctx, root.Host, nil)
 		if err != nil {
 			klog.Exitf("NewGSFetcher: %v", err)
 		}