Add Health indicator (#10)

build.gradle

@@ -9,7 +9,7 @@ plugins {
 }
 
 group 'uk.gov.hmcts.reform'
-version '0.0.4'
+version '0.0.5'
 
 checkstyle {
     maxWarnings = 0
@@ -120,6 +120,7 @@ ext {
 
 dependencies {
     compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-feign'
+    compile group: 'org.springframework.boot', name: 'spring-boot-starter-actuator'
     compile group: 'com.netflix.feign', name: 'feign-jackson', version: '8.18.0'
     compile group: 'com.google.guava', name: 'guava', version: '23.0'
     compile group: 'com.warrenstrange', name: 'googleauth', version: '1.1.2'

src/main/java/uk/gov/hmcts/reform/authorisation/ServiceAuthorisationApi.java

@@ -5,9 +5,14 @@
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RequestParam;
+import uk.gov.hmcts.reform.authorisation.healthcheck.InternalHealth;
 
 import static org.springframework.http.HttpHeaders.AUTHORIZATION;
+import static org.springframework.http.HttpHeaders.CONTENT_TYPE;
+import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8_VALUE;
 
 @EnableFeignClients
 @FeignClient(name = "idam-s2s-auth", url = "${idam.s2s-auth.url}")
@@ -19,4 +24,11 @@ String serviceToken(@RequestParam("microservice") final String microservice,
     @GetMapping(value = "/authorisation-check")
     void authorise(@RequestHeader(AUTHORIZATION) final String authHeader,
                    @RequestParam("role") final String[] roles);
+
+    @RequestMapping(
+            method = RequestMethod.GET,
+            value = "/health",
+            headers = CONTENT_TYPE + "=" + APPLICATION_JSON_UTF8_VALUE
+    )
+    InternalHealth health();
 }

src/main/java/uk/gov/hmcts/reform/authorisation/healthcheck/InternalHealth.java

@@ -0,0 +1,29 @@
+package uk.gov.hmcts.reform.authorisation.healthcheck;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import org.springframework.boot.actuate.health.Status;
+
+import java.util.Map;
+
+public class InternalHealth {
+    private final Status status;
+    private final Map<String, Object> details;
+
+    @JsonCreator
+    public InternalHealth(
+        @JsonProperty("status") Status status,
+        @JsonProperty("details") Map<String, Object> details
+    ) {
+        this.status = status;
+        this.details = details;
+    }
+
+    public Status getStatus() {
+        return status;
+    }
+
+    public Map<String, Object> getDetails() {
+        return details;
+    }
+}

src/main/java/uk/gov/hmcts/reform/authorisation/healthcheck/ServiceAuthHealthIndicator.java

@@ -0,0 +1,33 @@
+package uk.gov.hmcts.reform.authorisation.healthcheck;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.stereotype.Component;
+import uk.gov.hmcts.reform.authorisation.ServiceAuthorisationApi;
+
+@Component
+public class ServiceAuthHealthIndicator implements HealthIndicator {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ServiceAuthHealthIndicator.class);
+
+    private final ServiceAuthorisationApi serviceAuthorisationApi;
+
+    @Autowired
+    public ServiceAuthHealthIndicator(final ServiceAuthorisationApi serviceAuthorisationApi) {
+        this.serviceAuthorisationApi = serviceAuthorisationApi;
+    }
+
+    @Override
+    public Health health() {
+        try {
+            InternalHealth internalHealth = this.serviceAuthorisationApi.health();
+            return new Health.Builder(internalHealth.getStatus()).build();
+        } catch (Exception ex) {
+            LOGGER.error("Error on service auth healthcheck", ex);
+            return Health.down(ex).build();
+        }
+    }
+}