ARC-1238: Added health endpoint

Dockerfile

@@ -26,4 +26,7 @@ COPY --chown=1001 ehealthid-rp/target/ehealthid-rp-jar-with-dependencies.jar /de
 
 USER 1001
 
+# The default port, configurable though.
+EXPOSE 1234
+
 ENTRYPOINT [ "/deployments/run-java.sh" ]

ehealthid-rp/src/main/java/com/oviva/ehealthid/relyingparty/ws/App.java

@@ -44,7 +44,8 @@ public Set<Object> getSingletons() {
         new AuthEndpoint(
             config.baseUri(), config.relyingParty(), sessionRepo, tokenIssuer, authenticationFlow),
         new OpenIdEndpoint(config.baseUri(), config.relyingParty(), keyStore),
-        new JacksonJsonProvider(configureObjectMapper()));
+        new JacksonJsonProvider(configureObjectMapper()),
+        new HealthEndpoint());
   }
 
   @Override

ehealthid-rp/src/main/java/com/oviva/ehealthid/relyingparty/ws/HealthEndpoint.java

@@ -0,0 +1,19 @@
+package com.oviva.ehealthid.relyingparty.ws;
+
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.core.MediaType;
+import jakarta.ws.rs.core.Response;
+
+@Path("/health")
+public class HealthEndpoint {
+
+  private static final String STATUS_UP = "{\"status\":\"UP\"}";
+
+  @GET
+  public Response get() {
+    // For now if this endpoint is reachable then the service is up. There is no hard dependency
+    // that could be down.
+    return Response.ok(STATUS_UP).type(MediaType.APPLICATION_JSON_TYPE).build();
+  }
+}

ehealthid-rp/src/test/java/com/oviva/ehealthid/relyingparty/ws/HealthEndpointTest.java

@@ -0,0 +1,20 @@
+package com.oviva.ehealthid.relyingparty.ws;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import jakarta.ws.rs.core.Response.Status;
+import org.junit.jupiter.api.Test;
+
+class HealthEndpointTest {
+
+  @Test
+  void get() {
+    var sut = new HealthEndpoint();
+
+    // when
+    var res = sut.get();
+
+    // then
+    assertEquals(Status.OK.getStatusCode(), res.getStatus());
+  }
+}