xiaozan-dev / hystrix-demo

A sample repo to demonstrate how hystrix works as well as the threads that the commands execute on under different conditions.

hystrix-demo

A sample application which goes some way to highlighting which threads execution occurs on depending on the failure scenario.

This demo hopes to also demonstrate the effect structuring your Hystrix Commands has on your overall execution time.

Unless specifically set in the start of the test, all Hystrix default configuration is used. i.e. 1000ms command timeout. Defaults described here

See more on the accompanying blog post here

Scenarios

All scenarios can be executed via tests in HystrixControllerTest

1. Immediate failure in run() and slow execution in fallback to simulate IO blocking call in fallback()
2. Slow run() which results in timing out, and fallback() return immediately
3. Slow run() which results in timing out, as well as a slow fallback()
4. Slow run() which results in timing out, and a deterministic fallback() by means of wrapping the call in a HystrixCommand
5. Slow run() which results in timing out, and a fallback() which will execute on calling thread by means of some lambda magic

IntelliJ IDEA users

Installing the GrepConsole plugin is suggested if you would like to follow along with the diagram in the blog post mentioned above. The below grep console configuration will highlight the appropriate thread executions which correlate to the diagram.

Diagram from blog: ![Diagram from blog] (https://kevinpotgieter.files.wordpress.com/2016/10/hystrix-thread-execution.jpg)

GrepConsole configuration: ![GrepConsole configuration] (https://kevinpotgieter.files.wordpress.com/2016/10/screen-shot-2016-10-31-at-09-34-30.png)