Push the rest

backend/analytics/internal/db/postgres.go

@@ -0,0 +1,28 @@
+package db
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// OpenPostgres creates a pgx connection pool and validates connectivity.
+func OpenPostgres(ctx context.Context, dsn string) (*pgxpool.Pool, error) {
+	cfg, err := pgxpool.ParseConfig(dsn)
+	if err != nil {
+		return nil, fmt.Errorf("parse postgres DSN: %w", err)
+	}
+
+	pool, err := pgxpool.NewWithConfig(ctx, cfg)
+	if err != nil {
+		return nil, fmt.Errorf("create postgres pool: %w", err)
+	}
+	if err := pool.Ping(ctx); err != nil {
+		pool.Close()
+		return nil, fmt.Errorf("ping postgres: %w", err)
+	}
+	slog.Info("postgres connected", "max_conns", cfg.MaxConns)
+	return pool, nil
+}