Maybe I am just really bad at navigating the JMeter API site.
But lets say I want to find out how long a thread has been running for, in a If Controller or a JSR223 sampler how could I do that? thread group for example doesn't seem to have what I am look for
Maybe, looking into JMeterThread JavaDoc instead. If you use "Scheduler" option of the Thread Group you will be able to use JMeterThread.getStartTime() and JMeterThread.getEndTime() methods.
If you don't use scheduler you could use the following approach:
Add JSR223 Test Element (doesn't really matter which one) to the very beginning of your Thread Group and put the following code into "Script" area:
Add another JSR223 Test Element to the end of your Thread Group and use the following code to get current thread duration:
Demo:
ctx
is a shorthand to JMeterContextService class.See Apache Groovy - Why and How You Should Use It article for more details on using Groovy in JMeter tests.
You can add your test under Transaction Controller
And then in Sampler result you can see Load time: 2771 see Manual