Fixed critical bugs in the Azure SDK migration (PR #7310)

fix https://github.com/seaweedfs/seaweedfs/issues/5044

weed/remote_storage/azure/azure_storage_client.go

@@ -89,10 +89,10 @@ func (s azureRemoteStorageMaker) Make(conf *remote_pb.RemoteConf) (remote_storag
 	azClient, err := azblob.NewClientWithSharedKeyCredential(serviceURL, credential, &azblob.ClientOptions{
 		ClientOptions: azcore.ClientOptions{
 			Retry: policy.RetryOptions{
-				MaxRetries:    10, // Increased from default 3 to maintain resiliency similar to old SDK's 20
-				TryTimeout:    time.Minute,
-				RetryDelay:    2 * time.Second,
-				MaxRetryDelay: time.Minute,
+				MaxRetries:    3,                // Reasonable retry count - aggressive retries mask configuration errors
+				TryTimeout:    10 * time.Second, // Reduced from 1 minute to fail faster on auth issues
+				RetryDelay:    1 * time.Second,
+				MaxRetryDelay: 10 * time.Second,
 			},
 		},
 	})

weed/remote_storage/azure/azure_storage_client_test.go

@@ -336,7 +336,10 @@ func TestAzureRemoteStorageMaker(t *testing.T) {
 		t.Error("Expected HasBucket() to return true")
 	}
 
-	// Test with missing credentials
+	// Test with missing credentials - unset env vars (auto-restored by t.Setenv)
+	t.Setenv("AZURE_STORAGE_ACCOUNT", "")
+	t.Setenv("AZURE_STORAGE_ACCESS_KEY", "")
+
 	conf := &remote_pb.RemoteConf{
 		Name: "test",
 	}

weed/replication/sink/azuresink/azure_sink.go

@@ -3,9 +3,7 @@ package azuresink
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
-	"net/http"
 	"strings"
 	"time"
 
@@ -78,10 +76,10 @@ func (g *AzureSink) initialize(accountName, accountKey, container, dir string) e
 	client, err := azblob.NewClientWithSharedKeyCredential(serviceURL, credential, &azblob.ClientOptions{
 		ClientOptions: azcore.ClientOptions{
 			Retry: policy.RetryOptions{
-				MaxRetries:    10, // Increased from default 3 for replication sink resiliency
-				TryTimeout:    time.Minute,
-				RetryDelay:    2 * time.Second,
-				MaxRetryDelay: time.Minute,
+				MaxRetries:    3,                // Reasonable retry count - aggressive retries mask configuration errors
+				TryTimeout:    10 * time.Second, // Reduced from 1 minute to fail faster on auth issues
+				RetryDelay:    1 * time.Second,
+				MaxRetryDelay: 10 * time.Second,
 			},
 		},
 	})
@@ -91,6 +89,16 @@ func (g *AzureSink) initialize(accountName, accountKey, container, dir string) e
 
 	g.client = client
 
+	// Validate that the container exists early to catch configuration errors
+	containerClient := client.ServiceClient().NewContainerClient(container)
+	_, err = containerClient.GetProperties(context.Background(), nil)
+	if err != nil {
+		if bloberror.HasCode(err, bloberror.ContainerNotFound) {
+			return fmt.Errorf("Azure container '%s' does not exist. Please create it first", container)
+		}
+		return fmt.Errorf("failed to validate Azure container '%s': %w", container, err)
+	}
+
 	return nil
 }
 
@@ -131,33 +139,51 @@ func (g *AzureSink) CreateEntry(key string, entry *filer_pb.Entry, signatures []
 	// Create append blob client
 	appendBlobClient := g.client.ServiceClient().NewContainerClient(g.container).NewAppendBlobClient(key)
 
-	// Create blob with access conditions
-	accessConditions := &blob.AccessConditions{}
-	if entry.Attributes != nil && entry.Attributes.Mtime > 0 {
-		modifiedTime := time.Unix(entry.Attributes.Mtime, 0)
-		accessConditions.ModifiedAccessConditions = &blob.ModifiedAccessConditions{
-			IfUnmodifiedSince: &modifiedTime,
-		}
-	}
-
-	_, err := appendBlobClient.Create(context.Background(), &appendblob.CreateOptions{
-		AccessConditions: accessConditions,
-	})
+	// Try to create the blob first (without access conditions for initial creation)
+	_, err := appendBlobClient.Create(context.Background(), nil)
 
+	needsWrite := true
 	if err != nil {
 		if bloberror.HasCode(err, bloberror.BlobAlreadyExists) {
-			// Blob already exists, which is fine for an append blob - we can append to it
-		} else {
-			// Check if this is a precondition failed error (HTTP 412)
-			var respErr *azcore.ResponseError
-			if ok := errors.As(err, &respErr); ok && respErr.StatusCode == http.StatusPreconditionFailed {
-				glog.V(0).Infof("skip overwriting %s/%s: precondition failed", g.container, key)
-				return nil
+			// Blob already exists - check if we should skip based on mtime/size
+			if entry.Attributes != nil && entry.Attributes.Mtime > 0 {
+				props, propErr := appendBlobClient.GetProperties(context.Background(), nil)
+				if propErr == nil && props.LastModified != nil {
+					remoteMtime := props.LastModified.Unix()
+					localMtime := entry.Attributes.Mtime
+
+					// Skip if remote is newer or same, and has content
+					if remoteMtime >= localMtime && props.ContentLength != nil && *props.ContentLength > 0 {
+						glog.V(2).Infof("skip overwriting %s/%s: remote is up-to-date (remote mtime: %d >= local mtime: %d, size: %d)",
+							g.container, key, remoteMtime, localMtime, *props.ContentLength)
+						needsWrite = false
+					}
+				}
+			}
+
+			// If blob exists but is empty or outdated, we need to delete and recreate
+			if needsWrite {
+				// Delete existing blob
+				_, delErr := appendBlobClient.Delete(context.Background(), nil)
+				if delErr != nil && !bloberror.HasCode(delErr, bloberror.BlobNotFound) {
+					return fmt.Errorf("azure delete existing blob %s/%s: %w", g.container, key, delErr)
+				}
+				// Recreate the blob
+				_, createErr := appendBlobClient.Create(context.Background(), nil)
+				if createErr != nil {
+					return fmt.Errorf("azure recreate append blob %s/%s: %w", g.container, key, createErr)
+				}
 			}
+		} else {
 			return fmt.Errorf("azure create append blob %s/%s: %w", g.container, key, err)
 		}
 	}
 
+	// If we don't need to write (blob is up-to-date), return early
+	if !needsWrite {
+		return nil
+	}
+
 	writeFunc := func(data []byte) error {
 		_, writeErr := appendBlobClient.AppendBlock(context.Background(), streaming.NopCloser(bytes.NewReader(data)), &appendblob.AppendBlockOptions{})
 		return writeErr

weed/replication/sink/azuresink/azure_sink_test.go

@@ -1,6 +1,7 @@
 package azuresink
 
 import (
+	"context"
 	"os"
 	"testing"
 	"time"
@@ -320,6 +321,119 @@ func TestAzureSinkPrecondition(t *testing.T) {
 	sink.DeleteEntry(testKey, false, false, nil)
 }
 
+// Test that repeated creates don't result in zero-byte files (regression test for critical bug)
+func TestAzureSinkIdempotentCreate(t *testing.T) {
+	accountName := os.Getenv("AZURE_STORAGE_ACCOUNT")
+	accountKey := os.Getenv("AZURE_STORAGE_ACCESS_KEY")
+	testContainer := os.Getenv("AZURE_TEST_CONTAINER")
+
+	if accountName == "" || accountKey == "" {
+		t.Skip("Skipping Azure sink idempotent create test: credentials not set")
+	}
+	if testContainer == "" {
+		testContainer = "seaweedfs-test"
+	}
+
+	sink := &AzureSink{}
+	err := sink.initialize(accountName, accountKey, testContainer, "/test")
+	if err != nil {
+		t.Fatalf("Failed to initialize: %v", err)
+	}
+
+	testKey := "/test-idempotent-" + time.Now().Format("20060102-150405") + ".txt"
+	testContent := []byte("This is test content that should never be empty!")
+
+	// Clean up at the end
+	defer sink.DeleteEntry(testKey, false, false, nil)
+
+	// Test 1: Create a file with content
+	t.Run("FirstCreate", func(t *testing.T) {
+		entry := &filer_pb.Entry{
+			Content: testContent,
+			Attributes: &filer_pb.FuseAttributes{
+				Mtime: time.Now().Unix(),
+			},
+		}
+		err := sink.CreateEntry(testKey, entry, nil)
+		if err != nil {
+			t.Fatalf("Failed to create entry: %v", err)
+		}
+
+		// Verify the file has content (not zero bytes)
+		containerClient := sink.client.ServiceClient().NewContainerClient(sink.container)
+		blobClient := containerClient.NewAppendBlobClient(cleanKey(testKey))
+		props, err := blobClient.GetProperties(context.Background(), nil)
+		if err != nil {
+			t.Fatalf("Failed to get blob properties: %v", err)
+		}
+		if props.ContentLength == nil || *props.ContentLength == 0 {
+			t.Errorf("File has zero bytes after creation! Expected %d bytes", len(testContent))
+		} else if *props.ContentLength != int64(len(testContent)) {
+			t.Errorf("File size mismatch: expected %d, got %d", len(testContent), *props.ContentLength)
+		} else {
+			t.Logf("✓ File created with correct size: %d bytes", *props.ContentLength)
+		}
+	})
+
+	// Test 2: Create the same file again (idempotent operation - simulates replication running multiple times)
+	// This is where the zero-byte bug occurred: blob existed, precondition failed, returned early without writing data
+	t.Run("IdempotentCreate", func(t *testing.T) {
+		entry := &filer_pb.Entry{
+			Content: testContent,
+			Attributes: &filer_pb.FuseAttributes{
+				Mtime: time.Now().Unix(), // Same or newer mtime
+			},
+		}
+		err := sink.CreateEntry(testKey, entry, nil)
+		if err != nil {
+			t.Fatalf("Failed on idempotent create: %v", err)
+		}
+
+		// CRITICAL: Verify the file STILL has content (not zero bytes)
+		containerClient := sink.client.ServiceClient().NewContainerClient(sink.container)
+		blobClient := containerClient.NewAppendBlobClient(cleanKey(testKey))
+		props, err := blobClient.GetProperties(context.Background(), nil)
+		if err != nil {
+			t.Fatalf("Failed to get blob properties after idempotent create: %v", err)
+		}
+		if props.ContentLength == nil || *props.ContentLength == 0 {
+			t.Errorf("❌ ZERO-BYTE BUG: File became empty after idempotent create! Expected %d bytes", len(testContent))
+		} else if *props.ContentLength < int64(len(testContent)) {
+			t.Errorf("File lost content: expected at least %d bytes, got %d", len(testContent), *props.ContentLength)
+		} else {
+			t.Logf("✓ File still has content after idempotent create: %d bytes", *props.ContentLength)
+		}
+	})
+
+	// Test 3: Try creating with older mtime (should skip but not leave zero bytes)
+	t.Run("CreateWithOlderMtime", func(t *testing.T) {
+		entry := &filer_pb.Entry{
+			Content: []byte("This content should be skipped"),
+			Attributes: &filer_pb.FuseAttributes{
+				Mtime: time.Now().Add(-1 * time.Hour).Unix(), // Older timestamp
+			},
+		}
+		err := sink.CreateEntry(testKey, entry, nil)
+		// Should succeed (operation is idempotent)
+		if err != nil {
+			t.Logf("Create with older mtime: %v", err)
+		}
+
+		// Verify file STILL has content
+		containerClient := sink.client.ServiceClient().NewContainerClient(sink.container)
+		blobClient := containerClient.NewAppendBlobClient(cleanKey(testKey))
+		props, err := blobClient.GetProperties(context.Background(), nil)
+		if err != nil {
+			t.Fatalf("Failed to get blob properties: %v", err)
+		}
+		if props.ContentLength == nil || *props.ContentLength == 0 {
+			t.Errorf("❌ File became empty after create with older mtime!")
+		} else {
+			t.Logf("✓ File preserved content despite older mtime: %d bytes", *props.ContentLength)
+		}
+	})
+}
+
 // Benchmark tests
 func BenchmarkCleanKey(b *testing.B) {
 	keys := []string{