DiscoveryClientHealthIndicator active but discovery client not initialized

[dkroehan]

We just updated to Spring Boot 2.2.0 and also moved to the Hoxton Release Train.

We have the following integration test for our custom health checks:

@RunWith(SpringRunner.class)
@EnableAutoConfiguration
@SpringBootTest(classes = {LivenessCheckAutoConfiguration.class}, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@TestPropertySource(properties = {"management.endpoint.health.custom: false"})
public class CustomReadinessCheckDisabledIntTest {

    @Autowired
    private TestRestTemplate restTemplate;

    @Test
    public void testCustomHealthCheckDisabled() {
        String body = this.restTemplate.getForObject("/health", String.class);
        assertThat(body, is(notNullValue()));

        assertThat(body, is("{\"status\":\"UP\",\"components\":{\"ping\":{\"status\":\"UP\"}}}"));
    }
}

We also have the following properties set:
management.health.defaults.enabled: false and management.health.ping.enabled: true

Since the Hoxton.M3 Release the DiscoveryClientHealthIndicator is now active which results in the test to fail with:

java.lang.AssertionError:
Expected: is "{\"status\":\"UP\",\"components\":{\"ping\":{\"status\":\"UP\"}}}"
     but: was "{\"status\":\"UP\",\"components\":{\"discoveryComposite\":{\"description\":\"Discovery Client not initialized\",\"status\":\"UNKNOWN\",\"components\":{\"discoveryClient\":{\"description\":\"Discovery Client not initialized\",\"status\":\"UNKNOWN\"}}},\"ping\":{\"status\":\"UP\"}}}"

Is this intended behaviour or a bug?
Should the DiscoveryClientHealthIndicator be affected by management.health.defaults.enabled: false?
There was a related change in the Spring Boot 2.2.0 Update: See: spring-projects/spring-boot#17926 and spring-projects/spring-boot#18676

If it is an issue:
We tracked it down to the DiscoveryClientHealthIndicator bean that is registered in CommonsClientAutoConfiguration.DiscoveryLoadBalancerConfiguration.

In Greenwich.SR2 and Hoxton.M2 the CommonsClientAutoConfiguration.DiscoveryLoadBalancerConfiguration is not loaded, because of:

   CommonsClientAutoConfiguration.DiscoveryLoadBalancerConfiguration:
      Did not match:
         - @ConditionalOnBean (types: org.springframework.cloud.client.discovery.DiscoveryClient; SearchStrategy: all) did not find any beans of type org.springframework.cloud.client.discovery.DiscoveryClient (OnBeanCondition)
      Matched:
         - @ConditionalOnClass found required class 'org.springframework.boot.actuate.health.HealthIndicator' (OnClassCondition)
         - @ConditionalOnProperty (spring.cloud.discovery.enabled) matched (OnPropertyCondition)

Now this bean is loaded due the change of the @AutoConfigureBefore in SimpleDiscoveryClientAutoConfiguration.
See:

spring-cloud-commons/spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/simple/SimpleDiscoveryClientAutoConfiguration.java

Line 43 in c437379

CommonsClientAutoConfiguration.class })

[OlgaMaciaszek]

Hello @dkroehan , I think this is something that the team has to discuss.

In the meantime, as stated in the docs:

Commons creates a Spring Boot HealthIndicator that DiscoveryClient implementations can participate in by implementing DiscoveryHealthIndicator.
To disable the composite HealthIndicator, set spring.cloud.discovery.client.composite-indicator.enabled=false.
A generic HealthIndicator based on DiscoveryClient is auto-configured (DiscoveryClientHealthIndicator).

Would that work as a workaround for you?

[dkroehan]

Yes, the workaround works for us. So far we used spring.cloud.discovery.enabled=false in our tests.

[spencergibb]

fixed in previous commits