add metrics and optimize query

internal/postgres/client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"sync/atomic"
 
 	"github.com/jackc/pgx/v5/pgxpool"
 	"golang.org/x/exp/slog"
@@ -16,12 +17,40 @@ type DatabaseStats struct {
 	IdleConnections     int32
 }
 
+type Metrics struct {
+	EnqueuedMessages uint64
+	DequeuedMessages uint64
+	Acked            uint64
+	Nacked           uint64
+}
+
+func (m *Metrics) Clone() Metrics {
+	return *m
+}
+
+func (m *Metrics) Enqueue() {
+	atomic.AddUint64(&m.EnqueuedMessages, 1)
+}
+
+func (m *Metrics) Dequeue() {
+	atomic.AddUint64(&m.DequeuedMessages, 1)
+}
+
+func (m *Metrics) Ack() {
+	atomic.AddUint64(&m.Acked, 1)
+}
+
+func (m *Metrics) Nack() {
+	atomic.AddUint64(&m.Nacked, 1)
+}
+
 type Client interface {
 	io.Closer
 
 	Queue() QueueClient
 
-	GetStats() DatabaseStats
+	GetMetrics() Metrics
+	GetDBStats() DatabaseStats
 }
 
 type Config struct {
@@ -31,8 +60,9 @@ type Config struct {
 }
 
 type client struct {
-	pool *pgxpool.Pool
-	log  *slog.Logger
+	pool    *pgxpool.Pool
+	metrics *Metrics
+	log     *slog.Logger
 }
 
 func New(ctx context.Context, config Config, logger *slog.Logger) (*client, error) {
@@ -61,7 +91,7 @@ func (c *client) Close() error {
 	return nil
 }
 
-func (c *client) GetStats() DatabaseStats {
+func (c *client) GetDBStats() DatabaseStats {
 	stat := c.pool.Stat()
 
 	return DatabaseStats{
@@ -71,3 +101,7 @@ func (c *client) GetStats() DatabaseStats {
 		IdleConnections:     stat.IdleConns(),
 	}
 }
+
+func (c *client) GetMetrics() Metrics {
+	return c.metrics.Clone()
+}