feat: use postgres

pkg/postgres/health.go

@@ -0,0 +1,30 @@
+package postgres
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// Ping bounds db.PingContext under timeout and returns a wrapped error so
+// startup failures are easy to spot in service logs.
+//
+// timeout is typically taken from Config.OperationTimeout.
+func Ping(ctx context.Context, db *sql.DB, timeout time.Duration) error {
+	if db == nil {
+		return errors.New("ping postgres: nil db")
+	}
+	if timeout <= 0 {
+		return errors.New("ping postgres: timeout must be positive")
+	}
+
+	pingCtx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	if err := db.PingContext(pingCtx); err != nil {
+		return fmt.Errorf("ping postgres: %w", err)
+	}
+	return nil
+}