This program is to demo the potential disaster brought by cyclic references between services.

This program contains 3 applications:

1. Application A
   • It has a web controller: Controller A, which contains 2 services:
     • a1
     • a2
2. Application B
   • It has a web controller: Controller B, which contains 2 services:
     • b1
     • b2
3. Application C
   • It has a web controller: Controller C, which contains 2 services:
     • c1
     • c2

To demonstrate the issue with cyclic references, we designed 2 scenarios:

1. Cyclic scenario, which has the invocation hierarchy as follows:

   • a1 -> b1
   • b2 -> a2
   • To trigger the disaster, 2 burst requests to a1 and b2 will be injected in the 5th second

2. Non cyclic scenario, which has the invocation hierarchy as follows:

   • a1 -> c1
   • b2 -> c2

You need to install Apache Jmeter first, and then install plugin Throughput Shaping Timer.

For your simplicity, the Throughput Shaping Timer plugin is included in this project as Throughput-Shaping-Timer-Plugin.zip.

1. Make sure test.enable-cyclic in application.properties is set to true
2. Run service.cyclic.demo.service.a.ApplicationA
3. Run service.cyclic.demo.service.b.ApplicationB
4. Run cyclic-demo.jmx with Apache Jmeter
5. You will find the invocations start to fail since the 15th second, and will continue to fail even all the burst requests are gone, i.e. Application A and Application B can not recover from such scenarios by themselves due to the cyclic references between them

1. Make sure test.enable-cyclic in application.properties is set to false
2. Run service.cyclic.demo.service.a.ApplicationA
3. Run service.cyclic.demo.service.b.ApplicationB
4. Run service.cyclic.demo.service.c.ApplicationC
5. Run cyclic-demo.jmx with Apache Jmeter
6. You will find the result is satisfying. Only a very small jitter happened in the 15th second