feat: migrate backend from rust to go

This commit replaces the Axum/Rust backend with a Gin/Go implementation. The original Rust code has been archived in the 'rust' branch.

internal/server/logging.go

@@ -0,0 +1,113 @@
+package server
+
+import (
+	"log"
+	"time"
+
+	"llm-proxy/internal/db"
+)
+
+type RequestLog struct {
+	Timestamp        time.Time `json:"timestamp"`
+	ClientID         string    `json:"client_id"`
+	Provider         string    `json:"provider"`
+	Model            string    `json:"model"`
+	PromptTokens     uint32    `json:"prompt_tokens"`
+	CompletionTokens uint32    `json:"completion_tokens"`
+	ReasoningTokens  uint32    `json:"reasoning_tokens"`
+	TotalTokens      uint32    `json:"total_tokens"`
+	CacheReadTokens  uint32    `json:"cache_read_tokens"`
+	CacheWriteTokens uint32    `json:"cache_write_tokens"`
+	Cost             float64   `json:"cost"`
+	HasImages        bool      `json:"has_images"`
+	Status           string    `json:"status"`
+	ErrorMessage     string    `json:"error_message,omitempty"`
+	DurationMS       int64     `json:"duration_ms"`
+}
+
+type RequestLogger struct {
+	database *db.DB
+	hub      *Hub
+	logChan  chan RequestLog
+}
+
+func NewRequestLogger(database *db.DB, hub *Hub) *RequestLogger {
+	return &RequestLogger{
+		database: database,
+		hub:      hub,
+		logChan:  make(chan RequestLog, 100),
+	}
+}
+
+func (l *RequestLogger) Start() {
+	go func() {
+		for entry := range l.logChan {
+			l.processLog(entry)
+		}
+	}()
+}
+
+func (l *RequestLogger) LogRequest(entry RequestLog) {
+	select {
+	case l.logChan <- entry:
+	default:
+		log.Println("Request log channel full, dropping log entry")
+	}
+}
+
+func (l *RequestLogger) processLog(entry RequestLog) {
+	// Broadcast to dashboard
+	l.hub.broadcast <- map[string]interface{}{
+		"type":    "request",
+		"channel": "requests",
+		"payload": entry,
+	}
+
+	// Insert into DB
+	tx, err := l.database.Begin()
+	if err != nil {
+		log.Printf("Failed to begin transaction for logging: %v", err)
+		return
+	}
+	defer tx.Rollback()
+
+	// Ensure client exists
+	_, _ = tx.Exec("INSERT OR IGNORE INTO clients (client_id, name, description) VALUES (?, ?, 'Auto-created from request')", 
+		entry.ClientID, entry.ClientID)
+
+	// Insert log
+	_, err = tx.Exec(`
+		INSERT INTO llm_requests 
+		(timestamp, client_id, provider, model, prompt_tokens, completion_tokens, reasoning_tokens, total_tokens, cache_read_tokens, cache_write_tokens, cost, has_images, status, error_message, duration_ms)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+	`, entry.Timestamp, entry.ClientID, entry.Provider, entry.Model, 
+		entry.PromptTokens, entry.CompletionTokens, entry.ReasoningTokens, entry.TotalTokens, 
+		entry.CacheReadTokens, entry.CacheWriteTokens, entry.Cost, entry.HasImages, 
+		entry.Status, entry.ErrorMessage, entry.DurationMS)
+
+	if err != nil {
+		log.Printf("Failed to insert request log: %v", err)
+		return
+	}
+
+	// Update client stats
+	_, _ = tx.Exec(`
+		UPDATE clients SET 
+			total_requests = total_requests + 1,
+			total_tokens = total_tokens + ?,
+			total_cost = total_cost + ?,
+			updated_at = CURRENT_TIMESTAMP
+		WHERE client_id = ?
+	`, entry.TotalTokens, entry.Cost, entry.ClientID)
+
+	// Update provider balance
+	if entry.Cost > 0 {
+		_, _ = tx.Exec("UPDATE provider_configs SET credit_balance = credit_balance - ? WHERE id = ? AND (billing_mode IS NULL OR billing_mode != 'postpaid')",
+			entry.Cost, entry.Provider)
+	}
+
+	err = tx.Commit()
+	if err != nil {
+		log.Printf("Failed to commit logging transaction: %v", err)
+	}
+}