Add logging

netstack2/http_request_log.go

@@ -0,0 +1,175 @@
+package netstack2
+
+import (
+	"bytes"
+	"compress/zlib"
+	"encoding/base64"
+	"encoding/json"
+	"sync"
+	"time"
+
+	"github.com/fosrl/newt/logger"
+)
+
+// HTTPRequestLog represents a single HTTP/HTTPS request proxied through the handler.
+type HTTPRequestLog struct {
+	RequestID  string    `json:"requestId"`
+	ResourceID int       `json:"resourceId"`
+	Timestamp  time.Time `json:"timestamp"`
+	Method     string    `json:"method"`
+	Scheme     string    `json:"scheme"`
+	Host       string    `json:"host"`
+	Path       string    `json:"path"`
+	RawQuery   string    `json:"rawQuery,omitempty"`
+	UserAgent  string    `json:"userAgent,omitempty"`
+	SourceAddr string    `json:"sourceAddr"`
+	TLS        bool      `json:"tls"`
+}
+
+// HTTPRequestLogger buffers HTTP request logs and periodically flushes them
+// to the server via a configurable SendFunc.
+type HTTPRequestLogger struct {
+	mu        sync.Mutex
+	pending   []HTTPRequestLog
+	sendFn    SendFunc
+	stopCh    chan struct{}
+	flushDone chan struct{}
+}
+
+// NewHTTPRequestLogger creates a new HTTPRequestLogger and starts its background flush loop.
+func NewHTTPRequestLogger() *HTTPRequestLogger {
+	rl := &HTTPRequestLogger{
+		pending:   make([]HTTPRequestLog, 0),
+		stopCh:    make(chan struct{}),
+		flushDone: make(chan struct{}),
+	}
+	go rl.backgroundLoop()
+	return rl
+}
+
+// SetSendFunc sets the callback used to send compressed HTTP request log batches
+// to the server. This can be called after construction once the websocket
+// client is available.
+func (rl *HTTPRequestLogger) SetSendFunc(fn SendFunc) {
+	rl.mu.Lock()
+	defer rl.mu.Unlock()
+	rl.sendFn = fn
+}
+
+// LogRequest adds an HTTP request log entry to the buffer. If the buffer
+// reaches maxBufferedSessions entries a flush is triggered immediately.
+func (rl *HTTPRequestLogger) LogRequest(log HTTPRequestLog) {
+	if log.RequestID == "" {
+		log.RequestID = generateSessionID()
+	}
+
+	rl.mu.Lock()
+	rl.pending = append(rl.pending, log)
+	shouldFlush := len(rl.pending) >= maxBufferedSessions
+	rl.mu.Unlock()
+
+	if shouldFlush {
+		rl.flush()
+	}
+}
+
+// backgroundLoop handles periodic flushing of buffered request logs.
+func (rl *HTTPRequestLogger) backgroundLoop() {
+	defer close(rl.flushDone)
+
+	ticker := time.NewTicker(flushInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-rl.stopCh:
+			return
+		case <-ticker.C:
+			rl.flush()
+		}
+	}
+}
+
+// flush drains the pending buffer, compresses with zlib, and sends via the SendFunc.
+// On send failure the batch is re-queued, capped at maxBufferedSessions*5 entries
+// to prevent unbounded memory growth when the server is unreachable.
+func (rl *HTTPRequestLogger) flush() {
+	rl.mu.Lock()
+	if len(rl.pending) == 0 {
+		rl.mu.Unlock()
+		return
+	}
+	batch := rl.pending
+	rl.pending = make([]HTTPRequestLog, 0)
+	sendFn := rl.sendFn
+	rl.mu.Unlock()
+
+	if sendFn == nil {
+		logger.Debug("HTTP request logger: no send function configured, discarding %d requests", len(batch))
+		return
+	}
+
+	compressed, err := compressRequestLogs(batch)
+	if err != nil {
+		logger.Error("HTTP request logger: failed to compress %d requests: %v", len(batch), err)
+		return
+	}
+
+	if err := sendFn(compressed); err != nil {
+		logger.Error("HTTP request logger: failed to send %d requests: %v", len(batch), err)
+		// Re-queue the batch so we don't lose data
+		rl.mu.Lock()
+		rl.pending = append(batch, rl.pending...)
+		// Cap re-queued data to prevent unbounded growth if server is unreachable
+		if len(rl.pending) > maxBufferedSessions*5 {
+			dropped := len(rl.pending) - maxBufferedSessions*5
+			rl.pending = rl.pending[:maxBufferedSessions*5]
+			logger.Warn("HTTP request logger: buffer overflow, dropped %d oldest requests", dropped)
+		}
+		rl.mu.Unlock()
+		return
+	}
+
+	logger.Info("HTTP request logger: sent %d requests to server", len(batch))
+}
+
+// compressRequestLogs JSON-encodes the request logs, compresses with zlib, and
+// returns a base64-encoded string suitable for embedding in a JSON message.
+func compressRequestLogs(logs []HTTPRequestLog) (string, error) {
+	jsonData, err := json.Marshal(logs)
+	if err != nil {
+		return "", err
+	}
+
+	var buf bytes.Buffer
+	w, err := zlib.NewWriterLevel(&buf, zlib.BestCompression)
+	if err != nil {
+		return "", err
+	}
+	if _, err := w.Write(jsonData); err != nil {
+		w.Close()
+		return "", err
+	}
+	if err := w.Close(); err != nil {
+		return "", err
+	}
+
+	return base64.StdEncoding.EncodeToString(buf.Bytes()), nil
+}
+
+// Close shuts down the background loop and performs one final flush to send
+// any remaining buffered requests to the server.
+func (rl *HTTPRequestLogger) Close() {
+	select {
+	case <-rl.stopCh:
+		// Already closed
+		return
+	default:
+		close(rl.stopCh)
+	}
+
+	// Wait for the background loop to exit so we don't race on flush
+	<-rl.flushDone
+
+	rl.flush()
+}