App Engine Instance ID

Question

Is it possible to get info on what instance you're running on? I want to output just a simple identifier for which instance the code is currently running on for logging purposes.

Answer 1

Since there is no language tag, and seeing your profile history, I assume you are using GAE/J?

In that case, the instance ID information is embedded in one of the environment attributes that you could get via ApiProxy.getCurrentEnvironment() method. You could then extract the instance id from the resulting map using key BackendService.INSTANCE_ID_ENV_ATTRIBUTE.

Even though the key is stored in BackendService, this approach will also work for frontend instances. So in summary, the following code would fetch the instance ID for you:

String tInstanceId = ApiProxy.getCurrentEnvironment()
                             .getAttributes()
                             .get( BackendService.INSTANCE_ID_ENV_ATTRIBUTE )
                             .toString();

Please keep in mind that this approach is quite undocumented by Google, and might subject to change without warning in the future. But since your use case is only for logging, I think it would be sufficient for now.

Answer 2

With the advent of Modules, you can get the current instance id in a more elegant way:

ModulesServiceFactory.getModulesService().getCurrentInstanceId()