chore(workers): improve logging, set header timeouts (#9171)

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

core/cli/worker.go

@@ -476,9 +476,22 @@ func (s *backendSupervisor) startBackend(backend, backendPath string) (string, e
 			return clientAddr, nil
 		}
 		cancel()
+
+		// Check if the process died (e.g. OOM, CUDA error, missing libs)
+		if !proc.IsAlive() {
+			stderrTail := readLastLinesFromFile(proc.StderrPath(), 20)
+			xlog.Warn("Backend process died during startup", "backend", backend, "stderr", stderrTail)
+			s.mu.Lock()
+			delete(s.processes, backend)
+			s.freePorts = append(s.freePorts, port)
+			s.mu.Unlock()
+			return "", fmt.Errorf("backend process %s died during startup. Last stderr:\n%s", backend, stderrTail)
+		}
 	}
 
-	xlog.Warn("Backend gRPC server not ready after waiting, proceeding anyway", "backend", backend, "addr", clientAddr)
+	// Log stderr to help diagnose why the backend isn't responding
+	stderrTail := readLastLinesFromFile(proc.StderrPath(), 20)
+	xlog.Warn("Backend gRPC server not ready after waiting, proceeding anyway", "backend", backend, "addr", clientAddr, "stderr", stderrTail)
 	return clientAddr, nil
 }
 
@@ -525,6 +538,20 @@ func (s *backendSupervisor) stopAllBackends() {
 	}
 }
 
+// readLastLinesFromFile reads the last n lines from a file.
+// Returns an empty string if the file cannot be read.
+func readLastLinesFromFile(path string, n int) string {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return ""
+	}
+	lines := strings.Split(strings.TrimRight(string(data), "\n"), "\n")
+	if len(lines) > n {
+		lines = lines[len(lines)-n:]
+	}
+	return strings.Join(lines, "\n")
+}
+
 // isRunning returns whether a specific backend process is currently running.
 func (s *backendSupervisor) isRunning(backend string) bool {
 	s.mu.Lock()

core/services/nodes/file_stager_http.go

@@ -3,12 +3,17 @@ package nodes
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
+	"sync"
+	"syscall"
 	"time"
 
 	"github.com/mudler/LocalAI/core/services/storage"
@@ -19,25 +24,58 @@ import (
 // Files are transferred between the frontend and backend nodes over a small
 // HTTP server running alongside the gRPC backend process.
 type HTTPFileStager struct {
-	httpAddrFor func(nodeID string) (string, error)
-	token       string
-	client      *http.Client
+	httpAddrFor     func(nodeID string) (string, error)
+	token           string
+	client          *http.Client
+	responseTimeout time.Duration // timeout waiting for server response after upload
+	maxRetries      int           // number of retry attempts for transient failures
 }
 
 // NewHTTPFileStager creates a new HTTP file stager.
 // httpAddrFor should return the HTTP address (host:port) for the given node ID.
 // token is the registration token used for authentication.
 func NewHTTPFileStager(httpAddrFor func(nodeID string) (string, error), token string) *HTTPFileStager {
-	timeout := 30 * time.Minute
+	responseTimeout := 30 * time.Minute
 	if v := os.Getenv("LOCALAI_FILE_TRANSFER_TIMEOUT"); v != "" {
 		if d, err := time.ParseDuration(v); err == nil {
-			timeout = d
+			responseTimeout = d
 		}
 	}
+
+	maxRetries := 3
+	if v := os.Getenv("LOCALAI_FILE_TRANSFER_RETRIES"); v != "" {
+		if n, err := strconv.Atoi(v); err == nil && n >= 0 {
+			maxRetries = n
+		}
+	}
+
+	transport := &http.Transport{
+		DialContext: (&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 15 * time.Second, // aggressive keepalive for LAN transfers
+		}).DialContext,
+		ForceAttemptHTTP2:     false, // HTTP/2 flow control can stall large uploads
+		MaxIdleConns:          10,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+		WriteBufferSize:       256 << 10, // 256 KB
+		ReadBufferSize:        256 << 10, // 256 KB
+	}
+
 	return &HTTPFileStager{
 		httpAddrFor: httpAddrFor,
 		token:       token,
-		client:      &http.Client{Timeout: timeout},
+		client: &http.Client{
+			// No Timeout set — for large uploads, http.Client.Timeout covers the
+			// entire request lifecycle including the body upload. If it fires
+			// mid-write, Go closes the connection causing "connection reset by peer"
+			// on the server. Instead we use ResponseHeaderTimeout on the transport
+			// to cover only the wait-for-server-response phase.
+			Transport: transport,
+		},
+		responseTimeout: responseTimeout,
+		maxRetries:      maxRetries,
 	}
 }
 
@@ -49,25 +87,69 @@ func (h *HTTPFileStager) EnsureRemote(ctx context.Context, nodeID, localPath, ke
 		return "", fmt.Errorf("resolving HTTP address for node %s: %w", nodeID, err)
 	}
 
+	fi, err := os.Stat(localPath)
+	if err != nil {
+		return "", fmt.Errorf("stat local file %s: %w", localPath, err)
+	}
+	fileSize := fi.Size()
+
+	url := fmt.Sprintf("http://%s/v1/files/%s", addr, key)
+	xlog.Info("Uploading file to remote node", "node", nodeID, "file", filepath.Base(localPath), "size", humanFileSize(fileSize), "url", url)
+
+	var lastErr error
+	attempts := h.maxRetries + 1 // maxRetries=3 means 4 total attempts (1 initial + 3 retries)
+	for attempt := 1; attempt <= attempts; attempt++ {
+		if attempt > 1 {
+			backoff := time.Duration(5<<(attempt-2)) * time.Second // 5s, 10s, 20s
+			xlog.Warn("Retrying file upload", "node", nodeID, "file", filepath.Base(localPath),
+				"attempt", attempt, "of", attempts, "backoff", backoff, "lastError", lastErr)
+			select {
+			case <-ctx.Done():
+				return "", fmt.Errorf("upload cancelled during retry backoff: %w", ctx.Err())
+			case <-time.After(backoff):
+			}
+		}
+
+		result, err := h.doUpload(ctx, addr, nodeID, localPath, key, url, fileSize)
+		if err == nil {
+			if attempt > 1 {
+				xlog.Info("File upload succeeded after retry", "node", nodeID, "file", filepath.Base(localPath), "attempt", attempt)
+			}
+			return result, nil
+		}
+		lastErr = err
+
+		if !isTransientError(err) {
+			xlog.Error("File upload failed with non-transient error", "node", nodeID, "file", filepath.Base(localPath), "error", err)
+			return "", err
+		}
+		xlog.Warn("File upload failed with transient error", "node", nodeID, "file", filepath.Base(localPath),
+			"attempt", attempt, "of", attempts, "error", err)
+	}
+
+	return "", fmt.Errorf("uploading %s to node %s failed after %d attempts: %w", localPath, nodeID, attempts, lastErr)
+}
+
+// doUpload performs a single upload attempt.
+func (h *HTTPFileStager) doUpload(ctx context.Context, addr, nodeID, localPath, key, url string, fileSize int64) (string, error) {
 	f, err := os.Open(localPath)
 	if err != nil {
 		return "", fmt.Errorf("opening local file %s: %w", localPath, err)
 	}
 	defer f.Close()
 
-	fi, _ := f.Stat()
-	var fileSize int64
-	if fi != nil {
-		fileSize = fi.Size()
+	var body io.Reader = f
+	// For files > 100MB, wrap with progress logging
+	const progressThreshold = 100 << 20
+	if fileSize > progressThreshold {
+		body = newProgressReader(f, fileSize, filepath.Base(localPath), nodeID)
 	}
 
-	url := fmt.Sprintf("http://%s/v1/files/%s", addr, key)
-	xlog.Debug("HTTP upload starting", "node", nodeID, "url", url, "localPath", localPath, "fileSize", fileSize)
-
-	req, err := http.NewRequestWithContext(ctx, http.MethodPut, url, f)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPut, url, body)
 	if err != nil {
 		return "", fmt.Errorf("creating request: %w", err)
 	}
+	req.ContentLength = fileSize // explicit Content-Length for progress tracking
 	req.Header.Set("Content-Type", "application/octet-stream")
 	if h.token != "" {
 		req.Header.Set("Authorization", "Bearer "+h.token)
@@ -75,13 +157,15 @@ func (h *HTTPFileStager) EnsureRemote(ctx context.Context, nodeID, localPath, ke
 
 	resp, err := h.client.Do(req)
 	if err != nil {
+		xlog.Error("File upload failed", "node", nodeID, "file", filepath.Base(localPath), "size", humanFileSize(fileSize), "error", err)
 		return "", fmt.Errorf("uploading %s to node %s: %w", localPath, nodeID, err)
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		body, _ := io.ReadAll(resp.Body)
-		return "", fmt.Errorf("upload to node %s failed with status %d: %s", nodeID, resp.StatusCode, string(body))
+		respBody, _ := io.ReadAll(resp.Body)
+		xlog.Error("File upload rejected by remote node", "node", nodeID, "file", filepath.Base(localPath), "status", resp.StatusCode, "response", string(respBody))
+		return "", fmt.Errorf("upload to node %s failed with status %d: %s", nodeID, resp.StatusCode, string(respBody))
 	}
 
 	var result struct {
@@ -91,10 +175,113 @@ func (h *HTTPFileStager) EnsureRemote(ctx context.Context, nodeID, localPath, ke
 		return "", fmt.Errorf("decoding upload response: %w", err)
 	}
 
-	xlog.Debug("HTTP upload complete", "node", nodeID, "remotePath", result.LocalPath, "fileSize", fileSize)
+	xlog.Info("File upload complete", "node", nodeID, "file", filepath.Base(localPath), "size", humanFileSize(fileSize), "remotePath", result.LocalPath)
 	return result.LocalPath, nil
 }
 
+// isTransientError returns true if the error is likely transient and worth retrying.
+func isTransientError(err error) bool {
+	if err == nil {
+		return false
+	}
+	// Connection reset by peer
+	if errors.Is(err, syscall.ECONNRESET) {
+		return true
+	}
+	// Broken pipe
+	if errors.Is(err, syscall.EPIPE) {
+		return true
+	}
+	// Connection refused (worker might be restarting)
+	if errors.Is(err, syscall.ECONNREFUSED) {
+		return true
+	}
+	// Context deadline exceeded (but not cancelled — cancelled means the caller gave up)
+	if errors.Is(err, context.DeadlineExceeded) {
+		return true
+	}
+	// net.Error timeout
+	var netErr net.Error
+	if errors.As(err, &netErr) && netErr.Timeout() {
+		return true
+	}
+	// Check for "connection reset" in the error string as a fallback
+	// (some wrapped errors lose the syscall.Errno)
+	msg := err.Error()
+	if strings.Contains(msg, "connection reset") ||
+		strings.Contains(msg, "broken pipe") ||
+		strings.Contains(msg, "connection refused") ||
+		strings.Contains(msg, "EOF") {
+		return true
+	}
+	return false
+}
+
+// progressReader wraps an io.Reader and logs upload progress periodically.
+type progressReader struct {
+	reader   io.Reader
+	total    int64
+	read     int64
+	file     string
+	node     string
+	lastLog  time.Time
+	lastPct  int
+	start    time.Time
+	mu       sync.Mutex
+}
+
+func newProgressReader(r io.Reader, total int64, file, node string) *progressReader {
+	return &progressReader{
+		reader:  r,
+		total:   total,
+		file:    file,
+		node:    node,
+		start:   time.Now(),
+		lastLog: time.Now(),
+	}
+}
+
+func (pr *progressReader) Read(p []byte) (int, error) {
+	n, err := pr.reader.Read(p)
+	if n > 0 {
+		pr.mu.Lock()
+		pr.read += int64(n)
+		pct := int(pr.read * 100 / pr.total)
+		now := time.Now()
+		// Log every 10% or every 30 seconds
+		if pct/10 > pr.lastPct/10 || now.Sub(pr.lastLog) >= 30*time.Second {
+			elapsed := now.Sub(pr.start)
+			var speed string
+			if elapsed > 0 {
+				bytesPerSec := float64(pr.read) / elapsed.Seconds()
+				speed = humanFileSize(int64(bytesPerSec)) + "/s"
+			}
+			xlog.Info("Upload progress", "node", pr.node, "file", pr.file,
+				"progress", fmt.Sprintf("%d%%", pct),
+				"sent", humanFileSize(pr.read), "total", humanFileSize(pr.total),
+				"speed", speed)
+			pr.lastLog = now
+			pr.lastPct = pct
+		}
+		pr.mu.Unlock()
+	}
+	return n, err
+}
+
+// humanFileSize returns a human-readable file size string.
+func humanFileSize(b int64) string {
+	const unit = 1024
+	if b < unit {
+		return fmt.Sprintf("%d B", b)
+	}
+	div, exp := int64(unit), 0
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGTPE"[exp])
+}
+
 func (h *HTTPFileStager) FetchRemote(ctx context.Context, nodeID, remotePath, localDst string) error {
 	// For staging files (not under models/ or data/), the worker's file transfer
 	// server resolves the key as a relative path under its staging directory.

core/services/nodes/file_transfer_server.go

@@ -97,7 +97,10 @@ func StartFileTransferServerWithListener(lis net.Listener, stagingDir, modelsDir
 	}
 
 	addr := lis.Addr().String()
-	server := &http.Server{Handler: mux}
+	server := &http.Server{
+		Handler:           mux,
+		ReadHeaderTimeout: 30 * time.Second, // prevent slowloris; does not affect body reads
+	}
 
 	go func() {
 		xlog.Info("HTTP file transfer server started", "addr", addr, "stagingDir", stagingDir, "modelsDir", modelsDir, "dataDir", dataDir)
@@ -119,6 +122,8 @@ func handleUpload(w http.ResponseWriter, r *http.Request, stagingDir, modelsDir,
 		r.Body = http.MaxBytesReader(w, r.Body, maxUploadSize)
 	}
 
+	xlog.Info("Receiving file upload", "key", key, "contentLength", r.ContentLength, "remote", r.RemoteAddr)
+
 	// Route keyed files to the appropriate directory
 	targetDir, relName := resolveKeyToDir(key, stagingDir, modelsDir, dataDir)
 
@@ -144,11 +149,12 @@ func handleUpload(w http.ResponseWriter, r *http.Request, stagingDir, modelsDir,
 	n, err := io.Copy(f, r.Body)
 	if err != nil {
 		os.Remove(dstPath)
+		xlog.Error("File upload failed", "key", key, "bytesReceived", n, "contentLength", r.ContentLength, "remote", r.RemoteAddr, "error", err)
 		http.Error(w, fmt.Sprintf("writing file: %v", err), http.StatusInternalServerError)
 		return
 	}
 
-	xlog.Debug("HTTP file upload complete", "key", key, "path", dstPath, "size", n)
+	xlog.Info("File upload complete", "key", key, "path", dstPath, "size", n)
 
 	w.Header().Set("Content-Type", "application/json")
 	if err := json.NewEncoder(w).Encode(map[string]string{"local_path": dstPath}); err != nil {

core/services/nodes/router.go

@@ -368,7 +368,7 @@ func (r *SmartRouter) buildClientForAddr(node *BackendNode, addr string, paralle
 // simply remove the {ModelsPath}/{trackingKey}/ directory.
 func (r *SmartRouter) stageModelFiles(ctx context.Context, node *BackendNode, opts *pb.ModelOptions, trackingKey string) (*pb.ModelOptions, error) {
 	opts = proto.Clone(opts).(*pb.ModelOptions)
-	xlog.Debug("Staging model files for remote node", "node", node.Name, "modelFile", opts.ModelFile, "trackingKey", trackingKey)
+	xlog.Info("Staging model files for remote node", "node", node.Name, "modelFile", opts.ModelFile, "trackingKey", trackingKey)
 
 	// Derive the frontend models directory from ModelFile and Model.
 	// Example: ModelFile="/models/sd-cpp/models/flux.gguf", Model="sd-cpp/models/flux.gguf"
@@ -419,6 +419,7 @@ func (r *SmartRouter) stageModelFiles(ctx context.Context, node *BackendNode, op
 		if err != nil {
 			// ModelFile is required — fail the whole operation
 			if f.name == "ModelFile" {
+				xlog.Error("Failed to stage model file for remote node", "node", node.Name, "field", f.name, "path", localPath, "error", err)
 				return nil, fmt.Errorf("staging model file: %w", err)
 			}
 			// Optional files: clear the path so the backend doesn't try a non-existent frontend path