Sri Lanka is definitely NOT safe to travel now. It is recommended that you only travel there if you have to. Only if the travel is essential should anyone go there for any reason due to the current and constantly evolving high alert security situation which is a direct result of the attacks on 21 April 2019.
The Foreign office has actually urged all of those who are on the island to contact relatives in the UK so they can warn them and tell them that although the airport is operating, it is not really operating as normal and there will be increased security. Friends and family of those who live there are not really safe to come visit and neither are tourists.