Human operators

The primary use case for the JSON response payload is to provide a way for operators to investigate the application state. To support this, health checks allow for additional data to be attached to a health check response as we have seen in the CheckDiskspace and ServiceCheck examples. Consider the following fragment:

[...]
return HealthCheckResponse
           .named("memory-check")
           .withData("free-heap", "64mb")
           .up()
           .build();
[...]

Here, the additional information about free-heap is provided and will become part of the response payload, as shown in this response fragment. The JSON response fragment showing memory-check procedure content is as follows:

{
...
   "checks": [
       {
           "name": "memory-check",
           "state": "UP",
           "data": {
               "free-heap": "64mb"
           }
       }
   ],
   "outcome": "UP"
}

Here, we see the memory-check procedure with its UP state and additional free-heap data item of the string type with the value of 64mb.