Preparation of e2eutils for Thanos indexheader unit tests. (#1982)

We want to pull in the indexheader package from Thanos so that we can add some experimental alternative implementations of BinaryReader. In order to also pull in the unit tests for this package, we need the replacements for e2eutil.Copy and e2eutil.CreateBlock. This change does two things:

1. Copy in e2eutil/copy.go and fix it up accordingly.
2. Move CreateBlock into a package to avoid circular imports.

pkg/storegateway/bucket_e2e_test.go

@@ -27,6 +27,7 @@ import (
 
 	mimir_tsdb "github.com/grafana/mimir/pkg/storage/tsdb"
 	"github.com/grafana/mimir/pkg/storegateway/indexcache"
+	"github.com/grafana/mimir/pkg/storegateway/testhelper"
 
 	"github.com/thanos-io/thanos/pkg/block"
 	"github.com/thanos-io/thanos/pkg/block/metadata"
@@ -90,9 +91,9 @@ func prepareTestBlocks(t testing.TB, now time.Time, count int, dir string, bkt o
 
 		// Create two blocks per time slot. Only add 10 samples each so only one chunk
 		// gets created each. This way we can easily verify we got 10 chunks per series below.
-		id1, err := CreateBlock(ctx, dir, series[:4], 10, mint, maxt, extLset, 0, metadata.NoneFunc)
+		id1, err := testhelper.CreateBlock(ctx, dir, series[:4], 10, mint, maxt, extLset, 0, metadata.NoneFunc)
 		assert.NoError(t, err)
-		id2, err := CreateBlock(ctx, dir, series[4:], 10, mint, maxt, extLset, 0, metadata.NoneFunc)
+		id2, err := testhelper.CreateBlock(ctx, dir, series[4:], 10, mint, maxt, extLset, 0, metadata.NoneFunc)
 		assert.NoError(t, err)
 
 		dir1, dir2 := filepath.Join(dir, id1.String()), filepath.Join(dir, id2.String())

pkg/storegateway/helpers_test.go → pkg/storegateway/testhelper/testhelper.go

@@ -2,7 +2,7 @@
 // Provenance-includes-location: https://github.com/thanos-io/thanos/blob/main/pkg/testutil/e2eutil/prometheus.go
 // Provenance-includes-license: Apache-2.0
 // Provenance-includes-copyright: The Thanos Authors.
-package storegateway
+package testhelper
 
 import (
 	"context"

pkg/util/test/copy.go

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// Provenance-includes-location: https://github.com/thanos-io/thanos/blob/main/pkg/testutil/e2eutil/copy.go
+// Provenance-includes-license: Apache-2.0
+// Provenance-includes-copyright: The Thanos Authors.
+
+package test
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/grafana/dskit/runutil"
+	"github.com/pkg/errors"
+	"github.com/stretchr/testify/require"
+)
+
+func Copy(t testing.TB, src, dst string) {
+	require.NoError(t, copyRecursive(src, dst))
+}
+
+func copyRecursive(src, dst string) error {
+	return filepath.Walk(src, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		relPath, err := filepath.Rel(src, path)
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			return os.MkdirAll(filepath.Join(dst, relPath), os.ModePerm)
+		}
+
+		if !info.Mode().IsRegular() {
+			return errors.Errorf("%s is not a regular file", path)
+		}
+
+		source, err := os.Open(filepath.Clean(path))
+		if err != nil {
+			return err
+		}
+		defer runutil.CloseWithErrCapture(&err, source, "close file")
+
+		destination, err := os.Create(filepath.Join(dst, relPath))
+		if err != nil {
+			return err
+		}
+		defer runutil.CloseWithErrCapture(&err, destination, "close file")
+
+		_, err = io.Copy(destination, source)
+		return err
+	})
+}