Is it possible to simulate connection timeout using wiremock tools?

Checkout https://github.com/tomakehurst/saboteur which allows you to simulate network issues. Or you can do it your self with iptables.

It seems that the answer to this question has been "No", since version 2.0.8-beta.

Tom (author of WireMock) explains why in this GitHub issue:

It's basically impossible to reliably force connection timeouts in pure Java at the moment.

It used to be the case that you could inject a delay before calling .accept() on the socket, but that stopped working a while back, I guess due to a change in the implementation internals.

My recommendation at the moment would be to use a tool that works at the level of the network stack. iptables ... -j DROP type commands will do the trick, or if you want a level of automation over this you can use tools such as https://github.com/tomakehurst/saboteur or https://github.com/alexei-led/pumba.

He also goes on to explain that just stopping WireMock doesn't achieve the same thing:

shutting down WireMock won't have the same effect - when a port is not being listened on, you get a TCP RST (reset) packet back, whereas a connection timeout happens when you get nothing back from the server in the timeout window after your initial SYN packet.

Yes it is possible to do this with WireMock by calling addDelayBeforeProcessingRequests(300) against the Java API or posting the following to http://<host>:<port>/__admin/socket-delay:

{ "milliseconds": 300 }

(Obviously replacing 300 with however many milliseconds you'd like to delay by)