improvements mid may 2025 (#24)

* General improvements and bug fixes. * Improve tests coverage. * fixup! Improve tests coverage. * Update README.md with latest changes. * Fix the uint32 * Resolve issue with race condition for logging. * fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * Fix the test of the rate limiter * Add default ratelimit.json file * Update dependencies. * Significant refactor. * fixup! Significant refactor. * fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! fixup! fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025 * fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! Merge remote-tracking branch 'origin/main' into improvements-mid-apr-2025
2026-10-12 05:32:36 +00:00 · 2025-09-30 18:27:33 +01:00
parent 3bd96cbd8a
commit cedee416a8
80 changed files with 22799 additions and 647 deletions
@@ -0,0 +1,243 @@
+package main
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+
+	libpack_logger "github.com/lukaszraczylo/graphql-monitoring-proxy/logging"
+	libpack_monitoring "github.com/lukaszraczylo/graphql-monitoring-proxy/monitoring"
+)
+
+// CoalescedResponse represents the shared response
+type CoalescedResponse struct {
+	Body       []byte
+	StatusCode int
+	Headers    map[string]string
+	Err        error
+	CachedAt   time.Time
+}
+
+// RequestCoalescer implements the single-flight pattern to deduplicate identical concurrent requests
+type RequestCoalescer struct {
+	inflight   sync.Map // key: hash, value: *inflightRequest
+	logger     *libpack_logger.Logger
+	monitoring *libpack_monitoring.MetricsSetup
+	enabled    bool
+
+	// Statistics
+	totalRequests     atomic.Int64
+	coalescedRequests atomic.Int64
+	inflightCount     atomic.Int64
+}
+
+// inflightRequest represents a request currently in flight
+type inflightRequest struct {
+	wg        sync.WaitGroup
+	response  *CoalescedResponse
+	waiters   atomic.Int32
+	createdAt time.Time
+	mu        sync.RWMutex
+}
+
+// NewRequestCoalescer creates a new request coalescer
+func NewRequestCoalescer(enabled bool, logger *libpack_logger.Logger, monitoring *libpack_monitoring.MetricsSetup) *RequestCoalescer {
+	rc := &RequestCoalescer{
+		logger:     logger,
+		monitoring: monitoring,
+		enabled:    enabled,
+	}
+
+	if logger != nil && enabled {
+		logger.Info(&libpack_logger.LogMessage{
+			Message: "Request coalescing enabled",
+		})
+	}
+
+	return rc
+}
+
+// Do executes a function, deduplicating concurrent calls with the same key
+func (rc *RequestCoalescer) Do(key string, fn func() (*CoalescedResponse, error)) (*CoalescedResponse, error) {
+	rc.totalRequests.Add(1)
+
+	if !rc.enabled {
+		return fn()
+	}
+
+	// Try to load existing inflight request
+	if existing, loaded := rc.inflight.Load(key); loaded {
+		inflight := existing.(*inflightRequest)
+
+		// Increment waiter count
+		waiters := inflight.waiters.Add(1)
+		rc.coalescedRequests.Add(1)
+
+		if rc.logger != nil {
+			rc.logger.Debug(&libpack_logger.LogMessage{
+				Message: "Request coalesced with in-flight request",
+				Pairs: map[string]interface{}{
+					"key":     key[:min(len(key), 32)] + "...",
+					"waiters": waiters,
+				},
+			})
+		}
+
+		// Wait for the inflight request to complete
+		inflight.wg.Wait()
+
+		// Return the shared response
+		inflight.mu.RLock()
+		defer inflight.mu.RUnlock()
+
+		if rc.monitoring != nil {
+			rc.monitoring.Increment("graphql_proxy_coalesced_requests_total", nil)
+		}
+
+		return inflight.response, nil
+	}
+
+	// Create a new inflight request
+	inflight := &inflightRequest{
+		createdAt: time.Now(),
+	}
+	inflight.wg.Add(1)
+	inflight.waiters.Store(1) // This request is the first waiter
+
+	// Try to store it (another goroutine might have just done the same)
+	actual, loaded := rc.inflight.LoadOrStore(key, inflight)
+	if loaded {
+		// Someone else beat us to it, wait for their result
+		existingInflight := actual.(*inflightRequest)
+		waiters := existingInflight.waiters.Add(1)
+		rc.coalescedRequests.Add(1)
+
+		if rc.logger != nil {
+			rc.logger.Debug(&libpack_logger.LogMessage{
+				Message: "Request coalesced (race condition)",
+				Pairs: map[string]interface{}{
+					"key":     key[:min(len(key), 32)] + "...",
+					"waiters": waiters,
+				},
+			})
+		}
+
+		existingInflight.wg.Wait()
+
+		existingInflight.mu.RLock()
+		defer existingInflight.mu.RUnlock()
+
+		if rc.monitoring != nil {
+			rc.monitoring.Increment("graphql_proxy_coalesced_requests_total", nil)
+		}
+
+		return existingInflight.response, nil
+	}
+
+	// We're the primary request, execute the function
+	rc.inflightCount.Add(1)
+	defer rc.inflightCount.Add(-1)
+
+	// Execute the request
+	response, err := fn()
+
+	// Store the result
+	inflight.mu.Lock()
+	if err != nil {
+		inflight.response = &CoalescedResponse{
+			Err: err,
+		}
+	} else {
+		inflight.response = response
+	}
+	inflight.mu.Unlock()
+
+	// Clean up and notify waiters
+	rc.inflight.Delete(key)
+	inflight.wg.Done()
+
+	// Log statistics
+	waiters := inflight.waiters.Load()
+	duration := time.Since(inflight.createdAt)
+
+	if rc.logger != nil && waiters > 1 {
+		rc.logger.Info(&libpack_logger.LogMessage{
+			Message: "Request completed, served coalesced waiters",
+			Pairs: map[string]interface{}{
+				"key":         key[:min(len(key), 32)] + "...",
+				"waiters":     waiters,
+				"duration_ms": duration.Milliseconds(),
+				"saved_calls": waiters - 1,
+			},
+		})
+	}
+
+	if rc.monitoring != nil {
+		rc.monitoring.Increment("graphql_proxy_primary_requests_total", nil)
+		if waiters > 1 {
+			rc.monitoring.Update("graphql_proxy_coalescing_wait_duration", nil, duration.Seconds())
+		}
+	}
+
+	return inflight.response, nil
+}
+
+// GetStats returns coalescing statistics
+func (rc *RequestCoalescer) GetStats() map[string]interface{} {
+	totalRequests := rc.totalRequests.Load()
+	coalescedRequests := rc.coalescedRequests.Load()
+
+	var coalescingRate float64
+	if totalRequests > 0 {
+		coalescingRate = float64(coalescedRequests) / float64(totalRequests) * 100
+	}
+
+	primaryRequests := totalRequests - coalescedRequests
+
+	var savings float64
+	if primaryRequests > 0 {
+		savings = float64(coalescedRequests) / float64(primaryRequests) * 100
+	}
+
+	return map[string]interface{}{
+		"enabled":             rc.enabled,
+		"total_requests":      totalRequests,
+		"primary_requests":    primaryRequests,
+		"coalesced_requests":  coalescedRequests,
+		"inflight_count":      rc.inflightCount.Load(),
+		"coalescing_rate_pct": coalescingRate,
+		"backend_savings_pct": savings,
+	}
+}
+
+// Reset resets coalescing statistics
+func (rc *RequestCoalescer) Reset() {
+	rc.totalRequests.Store(0)
+	rc.coalescedRequests.Store(0)
+}
+
+// Global request coalescer
+var (
+	requestCoalescer     *RequestCoalescer
+	requestCoalescerOnce sync.Once
+)
+
+// InitializeRequestCoalescer initializes the global request coalescer
+func InitializeRequestCoalescer(enabled bool, logger *libpack_logger.Logger, monitoring *libpack_monitoring.MetricsSetup) *RequestCoalescer {
+	requestCoalescerOnce.Do(func() {
+		requestCoalescer = NewRequestCoalescer(enabled, logger, monitoring)
+	})
+	return requestCoalescer
+}
+
+// GetRequestCoalescer returns the global request coalescer
+func GetRequestCoalescer() *RequestCoalescer {
+	return requestCoalescer
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}