X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/94788532e822ef26b8c9eac7818f03e3a94fb124..380a54a7d97b34119cbaa3bee05d6b6cd241eee5:/services/keepstore/azure_blob_volume_test.go

diff --git a/services/keepstore/azure_blob_volume_test.go b/services/keepstore/azure_blob_volume_test.go
index a240c23e16..8d02def144 100644
--- a/services/keepstore/azure_blob_volume_test.go
+++ b/services/keepstore/azure_blob_volume_test.go
@@ -1,17 +1,24 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
 	"bytes"
+	"context"
+	"crypto/md5"
 	"encoding/base64"
+	"encoding/json"
 	"encoding/xml"
 	"flag"
 	"fmt"
 	"io/ioutil"
-	"log"
 	"math/rand"
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"regexp"
 	"sort"
 	"strconv"
@@ -20,16 +27,26 @@ import (
 	"testing"
 	"time"
 
-	"github.com/curoverse/azure-sdk-for-go/storage"
+	"git.curoverse.com/arvados.git/sdk/go/arvados"
+	"github.com/Azure/azure-sdk-for-go/storage"
+	"github.com/ghodss/yaml"
+	"github.com/prometheus/client_golang/prometheus"
+	check "gopkg.in/check.v1"
 )
 
 const (
-	// The same fake credentials used by Microsoft's Azure emulator
-	emulatorAccountName = "devstoreaccount1"
-	emulatorAccountKey  = "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw=="
+	// This cannot be the fake account name "devstoreaccount1"
+	// used by Microsoft's Azure emulator: the Azure SDK
+	// recognizes that magic string and changes its behavior to
+	// cater to the Azure SDK's own test suite.
+	fakeAccountName = "fakeaccountname"
+	fakeAccountKey  = "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw=="
 )
 
-var azureTestContainer string
+var (
+	azureTestContainer string
+	azureTestDebug     = os.Getenv("ARVADOS_DEBUG") != ""
+)
 
 func init() {
 	flag.StringVar(
@@ -49,8 +66,9 @@ type azBlob struct {
 
 type azStubHandler struct {
 	sync.Mutex
-	blobs map[string]*azBlob
-	race  chan chan struct{}
+	blobs      map[string]*azBlob
+	race       chan chan struct{}
+	didlist503 bool
 }
 
 func newAzStubHandler() *azStubHandler {
@@ -73,6 +91,7 @@ func (h *azStubHandler) PutRaw(container, hash string, data []byte) {
 	h.blobs[container+"|"+hash] = &azBlob{
 		Data:        data,
 		Mtime:       time.Now(),
+		Metadata:    make(map[string]string),
 		Uncommitted: make(map[string][]byte),
 	}
 }
@@ -92,10 +111,14 @@ func (h *azStubHandler) unlockAndRace() {
 	h.Lock()
 }
 
+var rangeRegexp = regexp.MustCompile(`^bytes=(\d+)-(\d+)$`)
+
 func (h *azStubHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 	h.Lock()
 	defer h.Unlock()
-	// defer log.Printf("azStubHandler: %+v", r)
+	if azureTestDebug {
+		defer log.Printf("azStubHandler: %+v", r)
+	}
 
 	path := strings.Split(r.URL.Path, "/")
 	container := path[1]
@@ -110,6 +133,11 @@ func (h *azStubHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if (r.Method == "PUT" || r.Method == "POST") && r.Header.Get("Content-Length") == "" {
+		rw.WriteHeader(http.StatusLengthRequired)
+		return
+	}
+
 	body, err := ioutil.ReadAll(r.Body)
 	if err != nil {
 		return
@@ -133,14 +161,23 @@ func (h *azStubHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 			h.blobs[container+"|"+hash] = &azBlob{
 				Mtime:       time.Now(),
 				Uncommitted: make(map[string][]byte),
+				Metadata:    make(map[string]string),
 				Etag:        makeEtag(),
 			}
 			h.unlockAndRace()
 		}
+		metadata := make(map[string]string)
+		for k, v := range r.Header {
+			if strings.HasPrefix(strings.ToLower(k), "x-ms-meta-") {
+				name := k[len("x-ms-meta-"):]
+				metadata[strings.ToLower(name)] = v[0]
+			}
+		}
 		h.blobs[container+"|"+hash] = &azBlob{
 			Data:        body,
 			Mtime:       time.Now(),
 			Uncommitted: make(map[string][]byte),
+			Metadata:    metadata,
 			Etag:        makeEtag(),
 		}
 		rw.WriteHeader(http.StatusCreated)
@@ -193,22 +230,46 @@ func (h *azStubHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 		blob.Metadata = make(map[string]string)
 		for k, v := range r.Header {
 			if strings.HasPrefix(strings.ToLower(k), "x-ms-meta-") {
-				blob.Metadata[k] = v[0]
+				name := k[len("x-ms-meta-"):]
+				blob.Metadata[strings.ToLower(name)] = v[0]
 			}
 		}
 		blob.Mtime = time.Now()
 		blob.Etag = makeEtag()
+	case (r.Method == "GET" || r.Method == "HEAD") && r.Form.Get("comp") == "metadata" && hash != "":
+		// "Get Blob Metadata" API
+		if !blobExists {
+			rw.WriteHeader(http.StatusNotFound)
+			return
+		}
+		for k, v := range blob.Metadata {
+			rw.Header().Set(fmt.Sprintf("x-ms-meta-%s", k), v)
+		}
+		return
 	case (r.Method == "GET" || r.Method == "HEAD") && hash != "":
 		// "Get Blob" API
 		if !blobExists {
 			rw.WriteHeader(http.StatusNotFound)
 			return
 		}
+		data := blob.Data
+		if rangeSpec := rangeRegexp.FindStringSubmatch(r.Header.Get("Range")); rangeSpec != nil {
+			b0, err0 := strconv.Atoi(rangeSpec[1])
+			b1, err1 := strconv.Atoi(rangeSpec[2])
+			if err0 != nil || err1 != nil || b0 >= len(data) || b1 >= len(data) || b0 > b1 {
+				rw.Header().Set("Content-Range", fmt.Sprintf("bytes */%d", len(data)))
+				rw.WriteHeader(http.StatusRequestedRangeNotSatisfiable)
+				return
+			}
+			rw.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", b0, b1, len(data)))
+			rw.WriteHeader(http.StatusPartialContent)
+			data = data[b0 : b1+1]
+		}
 		rw.Header().Set("Last-Modified", blob.Mtime.Format(time.RFC1123))
-		rw.Header().Set("Content-Length", strconv.Itoa(len(blob.Data)))
+		rw.Header().Set("Content-Length", strconv.Itoa(len(data)))
 		if r.Method == "GET" {
-			if _, err := rw.Write(blob.Data); err != nil {
-				log.Printf("write %+q: %s", blob.Data, err)
+			if _, err := rw.Write(data); err != nil {
+				log.Printf("write %+q: %s", data, err)
 			}
 		}
 		h.unlockAndRace()
@@ -222,6 +283,11 @@ func (h *azStubHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 		rw.WriteHeader(http.StatusAccepted)
 	case r.Method == "GET" && r.Form.Get("comp") == "list" && r.Form.Get("restype") == "container":
 		// "List Blobs" API
+		if !h.didlist503 {
+			h.didlist503 = true
+			rw.WriteHeader(http.StatusServiceUnavailable)
+			return
+		}
 		prefix := container + "|" + r.Form.Get("prefix")
 		marker := r.Form.Get("marker")
 
@@ -249,14 +315,20 @@ func (h *azStubHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 			}
 			if len(resp.Blobs) > 0 || marker == "" || marker == hash {
 				blob := h.blobs[container+"|"+hash]
-				resp.Blobs = append(resp.Blobs, storage.Blob{
+				bmeta := map[string]string(nil)
+				if r.Form.Get("include") == "metadata" {
+					bmeta = blob.Metadata
+				}
+				b := storage.Blob{
 					Name: hash,
 					Properties: storage.BlobProperties{
-						LastModified:  blob.Mtime.Format(time.RFC1123),
+						LastModified:  storage.TimeRFC1123(blob.Mtime),
 						ContentLength: int64(len(blob.Data)),
 						Etag:          blob.Etag,
 					},
-				})
+					Metadata: bmeta,
+				}
+				resp.Blobs = append(resp.Blobs, b)
 			}
 		}
 		buf, err := xml.Marshal(resp)
@@ -282,7 +354,9 @@ var localHostPortRe = regexp.MustCompile(`(127\.0\.0\.1|localhost|\[::1\]):\d+`)
 
 func (d *azStubDialer) Dial(network, address string) (net.Conn, error) {
 	if hp := localHostPortRe.FindString(address); hp != "" {
-		log.Println("azStubDialer: dial", hp, "instead of", address)
+		if azureTestDebug {
+			log.Println("azStubDialer: dial", hp, "instead of", address)
+		}
 		address = hp
 	}
 	return d.Dialer.Dial(network, address)
@@ -292,10 +366,10 @@ type TestableAzureBlobVolume struct {
 	*AzureBlobVolume
 	azHandler *azStubHandler
 	azStub    *httptest.Server
-	t         *testing.T
+	t         TB
 }
 
-func NewTestableAzureBlobVolume(t *testing.T, readonly bool, replication int) *TestableAzureBlobVolume {
+func NewTestableAzureBlobVolume(t TB, readonly bool, replication int) *TestableAzureBlobVolume {
 	azHandler := newAzStubHandler()
 	azStub := httptest.NewServer(azHandler)
 
@@ -306,7 +380,7 @@ func NewTestableAzureBlobVolume(t *testing.T, readonly bool, replication int) *T
 		// Connect to stub instead of real Azure storage service
 		stubURLBase := strings.Split(azStub.URL, "://")[1]
 		var err error
-		if azClient, err = storage.NewClient(emulatorAccountName, emulatorAccountKey, stubURLBase, storage.DefaultAPIVersion, false); err != nil {
+		if azClient, err = storage.NewClient(fakeAccountName, fakeAccountKey, stubURLBase, storage.DefaultAPIVersion, false); err != nil {
 			t.Fatal(err)
 		}
 		container = "fakecontainername"
@@ -321,8 +395,18 @@ func NewTestableAzureBlobVolume(t *testing.T, readonly bool, replication int) *T
 			t.Fatal(err)
 		}
 	}
-
-	v := NewAzureBlobVolume(azClient, container, readonly, replication)
+	azClient.Sender = &singleSender{}
+
+	bs := azClient.GetBlobService()
+	v := &AzureBlobVolume{
+		ContainerName:        container,
+		ReadOnly:             readonly,
+		AzureReplication:     replication,
+		ListBlobsMaxAttempts: 2,
+		ListBlobsRetryDelay:  arvados.Duration(time.Millisecond),
+		azClient:             azClient,
+		container:            &azureContainer{ctr: bs.GetContainerReference(container)},
+	}
 
 	return &TestableAzureBlobVolume{
 		AzureBlobVolume: v,
@@ -332,6 +416,29 @@ func NewTestableAzureBlobVolume(t *testing.T, readonly bool, replication int) *T
 	}
 }
 
+var _ = check.Suite(&StubbedAzureBlobSuite{})
+
+type StubbedAzureBlobSuite struct {
+	volume            *TestableAzureBlobVolume
+	origHTTPTransport http.RoundTripper
+}
+
+func (s *StubbedAzureBlobSuite) SetUpTest(c *check.C) {
+	s.origHTTPTransport = http.DefaultTransport
+	http.DefaultTransport = &http.Transport{
+		Dial: (&azStubDialer{}).Dial,
+	}
+	azureWriteRaceInterval = time.Millisecond
+	azureWriteRacePollTime = time.Nanosecond
+
+	s.volume = NewTestableAzureBlobVolume(c, false, 3)
+}
+
+func (s *StubbedAzureBlobSuite) TearDownTest(c *check.C) {
+	s.volume.Teardown()
+	http.DefaultTransport = s.origHTTPTransport
+}
+
 func TestAzureBlobVolumeWithGeneric(t *testing.T) {
 	defer func(t http.RoundTripper) {
 		http.DefaultTransport = t
@@ -341,11 +448,32 @@ func TestAzureBlobVolumeWithGeneric(t *testing.T) {
 	}
 	azureWriteRaceInterval = time.Millisecond
 	azureWriteRacePollTime = time.Nanosecond
-	DoGenericVolumeTests(t, func(t *testing.T) TestableVolume {
+	DoGenericVolumeTests(t, func(t TB) TestableVolume {
 		return NewTestableAzureBlobVolume(t, false, azureStorageReplication)
 	})
 }
 
+func TestAzureBlobVolumeConcurrentRanges(t *testing.T) {
+	defer func(b int) {
+		azureMaxGetBytes = b
+	}(azureMaxGetBytes)
+
+	defer func(t http.RoundTripper) {
+		http.DefaultTransport = t
+	}(http.DefaultTransport)
+	http.DefaultTransport = &http.Transport{
+		Dial: (&azStubDialer{}).Dial,
+	}
+	azureWriteRaceInterval = time.Millisecond
+	azureWriteRacePollTime = time.Nanosecond
+	// Test (BlockSize mod azureMaxGetBytes)==0 and !=0 cases
+	for _, azureMaxGetBytes = range []int{2 << 22, 2<<22 - 1} {
+		DoGenericVolumeTests(t, func(t TB) TestableVolume {
+			return NewTestableAzureBlobVolume(t, false, azureStorageReplication)
+		})
+	}
+}
+
 func TestReadonlyAzureBlobVolumeWithGeneric(t *testing.T) {
 	defer func(t http.RoundTripper) {
 		http.DefaultTransport = t
@@ -355,11 +483,54 @@ func TestReadonlyAzureBlobVolumeWithGeneric(t *testing.T) {
 	}
 	azureWriteRaceInterval = time.Millisecond
 	azureWriteRacePollTime = time.Nanosecond
-	DoGenericVolumeTests(t, func(t *testing.T) TestableVolume {
+	DoGenericVolumeTests(t, func(t TB) TestableVolume {
 		return NewTestableAzureBlobVolume(t, true, azureStorageReplication)
 	})
 }
 
+func TestAzureBlobVolumeRangeFenceposts(t *testing.T) {
+	defer func(t http.RoundTripper) {
+		http.DefaultTransport = t
+	}(http.DefaultTransport)
+	http.DefaultTransport = &http.Transport{
+		Dial: (&azStubDialer{}).Dial,
+	}
+
+	v := NewTestableAzureBlobVolume(t, false, 3)
+	defer v.Teardown()
+
+	for _, size := range []int{
+		2<<22 - 1, // one <max read
+		2 << 22,   // one =max read
+		2<<22 + 1, // one =max read, one <max
+		2 << 23,   // two =max reads
+		BlockSize - 1,
+		BlockSize,
+	} {
+		data := make([]byte, size)
+		for i := range data {
+			data[i] = byte((i + 7) & 0xff)
+		}
+		hash := fmt.Sprintf("%x", md5.Sum(data))
+		err := v.Put(context.Background(), hash, data)
+		if err != nil {
+			t.Error(err)
+		}
+		gotData := make([]byte, len(data))
+		gotLen, err := v.Get(context.Background(), hash, gotData)
+		if err != nil {
+			t.Error(err)
+		}
+		gotHash := fmt.Sprintf("%x", md5.Sum(gotData))
+		if gotLen != size {
+			t.Errorf("length mismatch: got %d != %d", gotLen, size)
+		}
+		if gotHash != hash {
+			t.Errorf("hash mismatch: got %s != %s", gotHash, hash)
+		}
+	}
+}
+
 func TestAzureBlobVolumeReplication(t *testing.T) {
 	for r := 1; r <= 4; r++ {
 		v := NewTestableAzureBlobVolume(t, false, r)
@@ -384,10 +555,14 @@ func TestAzureBlobVolumeCreateBlobRace(t *testing.T) {
 	azureWriteRaceInterval = time.Second
 	azureWriteRacePollTime = time.Millisecond
 
-	allDone := make(chan struct{})
+	var wg sync.WaitGroup
+
 	v.azHandler.race = make(chan chan struct{})
+
+	wg.Add(1)
 	go func() {
-		err := v.Put(TestHash, TestBlock)
+		defer wg.Done()
+		err := v.Put(context.Background(), TestHash, TestBlock)
 		if err != nil {
 			t.Error(err)
 		}
@@ -395,22 +570,22 @@ func TestAzureBlobVolumeCreateBlobRace(t *testing.T) {
 	continuePut := make(chan struct{})
 	// Wait for the stub's Put to create the empty blob
 	v.azHandler.race <- continuePut
+	wg.Add(1)
 	go func() {
-		buf, err := v.Get(TestHash)
+		defer wg.Done()
+		buf := make([]byte, len(TestBlock))
+		_, err := v.Get(context.Background(), TestHash, buf)
 		if err != nil {
 			t.Error(err)
-		} else {
-			bufs.Put(buf)
 		}
-		close(allDone)
 	}()
 	// Wait for the stub's Get to get the empty blob
 	close(v.azHandler.race)
 	// Allow stub's Put to continue, so the real data is ready
 	// when the volume's Get retries
 	<-continuePut
-	// Wait for volume's Get to return the real data
-	<-allDone
+	// Wait for Get() and Put() to finish
+	wg.Wait()
 }
 
 func TestAzureBlobVolumeCreateBlobRaceDeadline(t *testing.T) {
@@ -435,20 +610,20 @@ func TestAzureBlobVolumeCreateBlobRaceDeadline(t *testing.T) {
 		t.Errorf("Index %+q should be empty", buf.Bytes())
 	}
 
-	v.TouchWithDate(TestHash, time.Now().Add(-1982 * time.Millisecond))
+	v.TouchWithDate(TestHash, time.Now().Add(-1982*time.Millisecond))
 
 	allDone := make(chan struct{})
 	go func() {
 		defer close(allDone)
-		buf, err := v.Get(TestHash)
+		buf := make([]byte, BlockSize)
+		n, err := v.Get(context.Background(), TestHash, buf)
 		if err != nil {
 			t.Error(err)
 			return
 		}
-		if len(buf) != 0 {
-			t.Errorf("Got %+q, expected empty buf", buf)
+		if n != 0 {
+			t.Errorf("Got %+q, expected empty buf", buf[:n])
 		}
-		bufs.Put(buf)
 	}()
 	select {
 	case <-allDone:
@@ -463,18 +638,139 @@ func TestAzureBlobVolumeCreateBlobRaceDeadline(t *testing.T) {
 	}
 }
 
+func TestAzureBlobVolumeContextCancelGet(t *testing.T) {
+	testAzureBlobVolumeContextCancel(t, func(ctx context.Context, v *TestableAzureBlobVolume) error {
+		v.PutRaw(TestHash, TestBlock)
+		_, err := v.Get(ctx, TestHash, make([]byte, BlockSize))
+		return err
+	})
+}
+
+func TestAzureBlobVolumeContextCancelPut(t *testing.T) {
+	testAzureBlobVolumeContextCancel(t, func(ctx context.Context, v *TestableAzureBlobVolume) error {
+		return v.Put(ctx, TestHash, make([]byte, BlockSize))
+	})
+}
+
+func TestAzureBlobVolumeContextCancelCompare(t *testing.T) {
+	testAzureBlobVolumeContextCancel(t, func(ctx context.Context, v *TestableAzureBlobVolume) error {
+		v.PutRaw(TestHash, TestBlock)
+		return v.Compare(ctx, TestHash, TestBlock2)
+	})
+}
+
+func testAzureBlobVolumeContextCancel(t *testing.T, testFunc func(context.Context, *TestableAzureBlobVolume) error) {
+	defer func(t http.RoundTripper) {
+		http.DefaultTransport = t
+	}(http.DefaultTransport)
+	http.DefaultTransport = &http.Transport{
+		Dial: (&azStubDialer{}).Dial,
+	}
+
+	v := NewTestableAzureBlobVolume(t, false, 3)
+	defer v.Teardown()
+	v.azHandler.race = make(chan chan struct{})
+
+	ctx, cancel := context.WithCancel(context.Background())
+	allDone := make(chan struct{})
+	go func() {
+		defer close(allDone)
+		err := testFunc(ctx, v)
+		if err != context.Canceled {
+			t.Errorf("got %T %q, expected %q", err, err, context.Canceled)
+		}
+	}()
+	releaseHandler := make(chan struct{})
+	select {
+	case <-allDone:
+		t.Error("testFunc finished without waiting for v.azHandler.race")
+	case <-time.After(10 * time.Second):
+		t.Error("timed out waiting to enter handler")
+	case v.azHandler.race <- releaseHandler:
+	}
+
+	cancel()
+
+	select {
+	case <-time.After(10 * time.Second):
+		t.Error("timed out waiting to cancel")
+	case <-allDone:
+	}
+
+	go func() {
+		<-releaseHandler
+	}()
+}
+
+func (s *StubbedAzureBlobSuite) TestStats(c *check.C) {
+	stats := func() string {
+		buf, err := json.Marshal(s.volume.InternalStats())
+		c.Check(err, check.IsNil)
+		return string(buf)
+	}
+
+	c.Check(stats(), check.Matches, `.*"Ops":0,.*`)
+	c.Check(stats(), check.Matches, `.*"Errors":0,.*`)
+
+	loc := "acbd18db4cc2f85cedef654fccc4a4d8"
+	_, err := s.volume.Get(context.Background(), loc, make([]byte, 3))
+	c.Check(err, check.NotNil)
+	c.Check(stats(), check.Matches, `.*"Ops":[^0],.*`)
+	c.Check(stats(), check.Matches, `.*"Errors":[^0],.*`)
+	c.Check(stats(), check.Matches, `.*"storage\.AzureStorageServiceError 404 \(404 Not Found\)":[^0].*`)
+	c.Check(stats(), check.Matches, `.*"InBytes":0,.*`)
+
+	err = s.volume.Put(context.Background(), loc, []byte("foo"))
+	c.Check(err, check.IsNil)
+	c.Check(stats(), check.Matches, `.*"OutBytes":3,.*`)
+	c.Check(stats(), check.Matches, `.*"CreateOps":1,.*`)
+
+	_, err = s.volume.Get(context.Background(), loc, make([]byte, 3))
+	c.Check(err, check.IsNil)
+	_, err = s.volume.Get(context.Background(), loc, make([]byte, 3))
+	c.Check(err, check.IsNil)
+	c.Check(stats(), check.Matches, `.*"InBytes":6,.*`)
+}
+
+func (s *StubbedAzureBlobSuite) TestConfig(c *check.C) {
+	var cfg Config
+	err := yaml.Unmarshal([]byte(`
+Volumes:
+  - Type: Azure
+    StorageClasses: ["class_a", "class_b"]
+`), &cfg)
+
+	c.Check(err, check.IsNil)
+	c.Check(cfg.Volumes[0].GetStorageClasses(), check.DeepEquals, []string{"class_a", "class_b"})
+}
+
 func (v *TestableAzureBlobVolume) PutRaw(locator string, data []byte) {
-	v.azHandler.PutRaw(v.containerName, locator, data)
+	v.azHandler.PutRaw(v.ContainerName, locator, data)
 }
 
 func (v *TestableAzureBlobVolume) TouchWithDate(locator string, lastPut time.Time) {
-	v.azHandler.TouchWithDate(v.containerName, locator, lastPut)
+	v.azHandler.TouchWithDate(v.ContainerName, locator, lastPut)
 }
 
 func (v *TestableAzureBlobVolume) Teardown() {
 	v.azStub.Close()
 }
 
+func (v *TestableAzureBlobVolume) ReadWriteOperationLabelValues() (r, w string) {
+	return "get", "create"
+}
+
+func (v *TestableAzureBlobVolume) DeviceID() string {
+	// Dummy device id for testing purposes
+	return "azure://azure_blob_volume_test"
+}
+
+func (v *TestableAzureBlobVolume) Start(vm *volumeMetricsVecs) error {
+	// Override original Start() to be able to assign CounterVecs with a dummy DeviceID
+	v.container.stats.opsCounters, v.container.stats.errCounters, v.container.stats.ioBytes = vm.getCounterVecsFor(prometheus.Labels{"device_id": v.DeviceID()})
+	return nil
+}
+
 func makeEtag() string {
 	return fmt.Sprintf("0x%x", rand.Int63())
 }