azure: Use default upload parameters to avoid consuming too much memory (#11251)

A lot of memory is consumed when uploading small files in parallel, use
the default upload parameters and add MINIO_AZURE_UPLOAD_CONCURRENCY for
users to tweak.

cmd/gateway/azure/gateway-azure.go

@@ -51,24 +51,8 @@ import (
 	minio "github.com/minio/minio/cmd"
 )
 
-var (
-	azureUploadChunkSize   = getUploadChunkSizeFromEnv(azureChunkSizeEnvVar, strconv.Itoa(azureDefaultUploadChunkSize/humanize.MiByte))
-	azureSdkTimeout        = time.Duration(azureUploadChunkSize/humanize.MiByte) * azureSdkTimeoutPerMb
-	azureUploadConcurrency = azureUploadMaxMemoryUsage / azureUploadChunkSize
-)
-
 const (
-	// The defaultDialTimeout for communicating with the cloud backends is set
+	azureDefaultUploadChunkSizeMB = 25
-	// to 30 seconds in utils.go; the Azure SDK recommends to set a timeout of 60
-	// seconds per MB of data a client expects to upload so we must transfer less
-	// than 0.5 MB per chunk to stay within the defaultDialTimeout tolerance.
-	// See https://github.com/Azure/azure-storage-blob-go/blob/fc70003/azblob/zc_policy_retry.go#L39-L44 for more details.
-	// To change the upload chunk size, set the environmental variable MINIO_AZURE_CHUNK_SIZE_MB with a (float) value between 0 and 100
-	azureDefaultUploadChunkSize = 25 * humanize.MiByte
-	azureSdkTimeoutPerMb        = 60 * time.Second
-	azureUploadMaxMemoryUsage   = 100 * humanize.MiByte
-	azureChunkSizeEnvVar        = "MINIO_AZURE_CHUNK_SIZE_MB"
-
 	azureDownloadRetryAttempts    = 5
 	azureS3MinPartSize            = 5 * humanize.MiByte
 	metadataObjectNameTemplate    = minio.GatewayMinioSysTmp + "multipart/v1/%s.%x/azure.json"
@@ -77,6 +61,11 @@ const (
 	maxPartsCount                 = 10000
 )
 
+var (
+	azureUploadChunkSize   int
+	azureUploadConcurrency int
+)
+
 func init() {
 	const azureGatewayTemplate = `NAME:
   {{.HelpName}} - {{.Usage}}
@@ -94,7 +83,6 @@ EXAMPLES:
   1. Start minio gateway server for Azure Blob Storage backend on custom endpoint.
      {{.Prompt}} {{.EnvVarSetCommand}} MINIO_ROOT_USER{{.AssignmentOperator}}azureaccountname
      {{.Prompt}} {{.EnvVarSetCommand}} MINIO_ROOT_PASSWORD{{.AssignmentOperator}}azureaccountkey
-     {{.Prompt}} {{.EnvVarSetCommand}} MINIO_AZURE_CHUNK_SIZE_MB {{.AssignmentOperator}}0.25
      {{.Prompt}} {{.HelpName}} https://azureaccountname.blob.custom.azure.endpoint
 
   2. Start minio gateway server for Azure Blob Storage backend with edge caching enabled.
@@ -106,8 +94,8 @@ EXAMPLES:
      {{.Prompt}} {{.EnvVarSetCommand}} MINIO_CACHE_AFTER{{.AssignmentOperator}}3
      {{.Prompt}} {{.EnvVarSetCommand}} MINIO_CACHE_WATERMARK_LOW{{.AssignmentOperator}}75
      {{.Prompt}} {{.EnvVarSetCommand}} MINIO_CACHE_WATERMARK_HIGH{{.AssignmentOperator}}85
-     {{.Prompt}} {{.EnvVarSetCommand}} MINIO_AZURE_CHUNK_SIZE_MB {{.AssignmentOperator}}25
      {{.Prompt}} {{.HelpName}}
+
 `
 
 	minio.RegisterGatewayCommand(cli.Command{
@@ -140,27 +128,6 @@ func azureGatewayMain(ctx *cli.Context) {
 	minio.StartGateway(ctx, &Azure{host})
 }
 
-// getUploadChunkSizeFromEnv returns the parsed chunk size from the environmental variable 'MINIO_AZURE_CHUNK_SIZE_MB'
-// The environmental variable should be a floating point number between 0 and 100 representing the MegaBytes
-// The returned value is an int representing the size in bytes
-func getUploadChunkSizeFromEnv(envvar string, defaultValue string) int {
-	envChunkSize := env.Get(envvar, defaultValue)
-
-	i, err := strconv.ParseFloat(envChunkSize, 64)
-	if err != nil {
-		logger.LogIf(context.Background(), err)
-		return azureDefaultUploadChunkSize
-	}
-
-	if i <= 0 || i > 100 {
-		logger.LogIf(context.Background(), fmt.Errorf("ENV '%v' should be a floating point value between 0 and 100.\n"+
-			"The upload chunk size is set to its default: %s\n", azureChunkSizeEnvVar, defaultValue))
-		return azureDefaultUploadChunkSize
-	}
-
-	return int(i * humanize.MiByte)
-}
-
 // Azure implements Gateway.
 type Azure struct {
 	host string
@@ -188,6 +155,20 @@ func (g *Azure) NewGatewayLayer(creds auth.Credentials) (minio.ObjectLayer, erro
 		return nil, err
 	}
 
+	azureUploadChunkSize, err = env.GetInt("MINIO_AZURE_CHUNK_SIZE_MB", azureDefaultUploadChunkSizeMB)
+	if err != nil {
+		return nil, err
+	}
+	azureUploadChunkSize *= humanize.MiByte
+	if azureUploadChunkSize <= 0 || azureUploadChunkSize > 100*humanize.MiByte {
+		return nil, fmt.Errorf("MINIO_AZURE_CHUNK_SIZE_MB should be an integer value between 0 and 100")
+	}
+
+	azureUploadConcurrency, err = env.GetInt("MINIO_AZURE_UPLOAD_CONCURRENCY", 4)
+	if err != nil {
+		return nil, err
+	}
+
 	credential, err := azblob.NewSharedKeyCredential(creds.AccessKey, creds.SecretKey)
 	if err != nil {
 		if _, ok := err.(base64.CorruptInputError); ok {
@@ -208,7 +189,9 @@ func (g *Azure) NewGatewayLayer(creds auth.Credentials) (minio.ObjectLayer, erro
 
 	pipeline := azblob.NewPipeline(credential, azblob.PipelineOptions{
 		Retry: azblob.RetryOptions{
-			TryTimeout: azureSdkTimeout,
+			// Azure SDK recommends to set a timeout of 60 seconds per MB of data so we
+			// calculate here the timeout for the configured upload chunck size.
+			TryTimeout: time.Duration(azureUploadChunkSize/humanize.MiByte) * 60 * time.Second,
 		},
 		HTTPSender: pipeline.FactoryFunc(func(next pipeline.Policy, po *pipeline.PolicyOptions) pipeline.PolicyFunc {
 			return func(ctx context.Context, request pipeline.Request) (pipeline.Response, error) {
@@ -914,7 +897,6 @@ func (a *azureObjects) PutObject(ctx context.Context, bucket, object string, r *
 	blobURL := a.client.NewContainerURL(bucket).NewBlockBlobURL(object)
 
 	_, err = azblob.UploadStreamToBlockBlob(ctx, data, blobURL, azblob.UploadStreamToBlockBlobOptions{
-		BufferSize:      azureUploadChunkSize,
 		MaxBuffers:      azureUploadConcurrency,
 		BlobHTTPHeaders: properties,
 		Metadata:        metadata,

cmd/gateway/azure/gateway-azure_test.go

@@ -20,13 +20,9 @@ import (
 	"encoding/base64"
 	"fmt"
 	"net/http"
-	"os"
 	"reflect"
-	"strconv"
 	"testing"
 
-	"github.com/dustin/go-humanize"
-
 	"github.com/Azure/azure-storage-blob-go/azblob"
 	minio "github.com/minio/minio/cmd"
 )
@@ -268,36 +264,3 @@ func TestCheckAzureUploadID(t *testing.T) {
 		}
 	}
 }
-
-func TestParsingUploadChunkSize(t *testing.T) {
-	key := "MINIO_AZURE_CHUNK_SIZE_MB"
-	invalidValues := []string{
-		"",
-		"0,3",
-		"100.1",
-		"-1",
-	}
-
-	for i, chunkValue := range invalidValues {
-		os.Setenv(key, chunkValue)
-		result := getUploadChunkSizeFromEnv(key, strconv.Itoa(azureDefaultUploadChunkSize/humanize.MiByte))
-		if result != azureDefaultUploadChunkSize {
-			t.Errorf("Test %d: expected: %d, got: %d", i+1, azureDefaultUploadChunkSize, result)
-		}
-	}
-
-	validValues := []string{
-		"1",
-		"1.25",
-		"50",
-		"99",
-	}
-	for i, chunkValue := range validValues {
-		os.Setenv(key, chunkValue)
-		result := getUploadChunkSizeFromEnv(key, strconv.Itoa(azureDefaultUploadChunkSize/humanize.MiByte))
-		if result == azureDefaultUploadChunkSize {
-			t.Errorf("Test %d: expected: %d, got: %d", i+1, azureDefaultUploadChunkSize, result)
-		}
-	}
-
-}

pkg/env/env.go

@@ -18,6 +18,7 @@
 package env
 
 import (
+	"strconv"
 	"strings"
 	"sync"
 )
@@ -75,6 +76,16 @@ func Get(key, defaultValue string) string {
 	return defaultValue
 }
 
+// GetInt returns an integer if found in the environment
+// and returns the default value otherwise.
+func GetInt(key string, defaultValue int) (int, error) {
+	v := Get(key, "")
+	if v == "" {
+		return defaultValue, nil
+	}
+	return strconv.Atoi(v)
+}
+
 // List all envs with a given prefix.
 func List(prefix string) (envs []string) {
 	for _, env := range Environ() {