health objects added

pom.xml

@@ -31,7 +31,7 @@
 		<distroDirectory>distro</distroDirectory>
 		<tomcat.version>8.0.42</tomcat.version>
 		<jersey.version>2.25.1</jersey.version>
-		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>	
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<maven.compiler.target>1.8</maven.compiler.target>
 		<maven.compiler.source>1.8</maven.compiler.source>
 	</properties>
@@ -117,11 +117,11 @@
 			<version>4.0.1</version>
 			<scope>provided</scope>
 		</dependency>
-		
+
 		<!-- Added to support Java 11 JDK -->
 		<dependency>
-   			<groupId>javax.xml.bind</groupId>
-   			<artifactId>jaxb-api</artifactId>
+			<groupId>javax.xml.bind</groupId>
+			<artifactId>jaxb-api</artifactId>
 		</dependency>
 		<!-- END Added to support Java 11 JDK -->
 

src/main/java/org/gcube/smartgears/extensions/resource/HealthResource.java

@@ -0,0 +1,44 @@
+package org.gcube.smartgears.extensions.resource;
+
+import static org.gcube.smartgears.Constants.application_json;
+import static org.gcube.smartgears.extensions.HttpExtension.Method.GET;
+
+import java.io.IOException;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.gcube.smartgears.extensions.ApiResource;
+import org.gcube.smartgears.extensions.ApiSignature;
+import org.gcube.smartgears.health.response.HealthResponse;
+
+public class HealthResource extends ApiResource {
+
+	private static final long serialVersionUID = 1L;
+	
+	public static final String mapping = "/health";
+	
+	private static final ApiSignature signature = handles(mapping).with(method(GET).produces(application_json)); 
+		
+	
+	HealthResource() {
+		super(signature);
+	}
+	
+	
+	@Override
+	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+		
+	}
+
+	
+	public HealthResponse liveness() {
+		return null;
+	}
+	
+	public HealthResponse readiness() {
+		return null;
+	}
+	
+}

src/main/java/org/gcube/smartgears/extensions/resource/RemoteResource.java

@@ -1,6 +1,6 @@
 package org.gcube.smartgears.extensions.resource;
 
-import static org.gcube.smartgears.Constants.*;
+import static org.gcube.smartgears.Constants.remote_management;
 
 import javax.xml.bind.annotation.XmlRootElement;
 
@@ -27,7 +27,7 @@ public class RemoteResource extends HttpController {
 	public RemoteResource() {
 		super(remote_management, default_mapping);
 		addResources(new FrontPageResource(), new ConfigurationResource(), new ProfileResource(),
-				new LifecycleResource(), new MetricsResource());
+				new LifecycleResource(), new MetricsResource(), new HealthResource());
 	}
 
 	@Override

src/main/java/org/gcube/smartgears/health/HealthCheck.java

@@ -0,0 +1,9 @@
+package org.gcube.smartgears.health;
+
+import org.gcube.smartgears.health.response.HealthCheckResponse;
+
+public interface HealthCheck {
+
+	HealthCheckResponse check();
+	
+}

src/main/java/org/gcube/smartgears/health/KeyCloakHealthCheck.java

@@ -0,0 +1,25 @@
+package org.gcube.smartgears.health;
+
+import java.util.Set;
+
+import org.gcube.smartgears.health.response.HealthCheckResponse;
+import org.gcube.smartgears.provider.ProviderFactory;
+
+@ReadinessChecker
+public class KeyCloakHealthCheck implements HealthCheck{
+
+	private static final String CHECK_NAME = "authorizationCheck" ;
+	
+	@Override
+	public HealthCheckResponse check() {
+		try {
+			Set<String> contexts = ProviderFactory.provider().containerContext().authorizationProvider().getContexts();
+			if (contexts.isEmpty())
+				return HealthCheckResponse.builder(CHECK_NAME).down().withMessage("no contexts are defined for this server").build();
+			return HealthCheckResponse.builder(CHECK_NAME).up().build();
+		}catch (Exception e) {
+			return HealthCheckResponse.builder(CHECK_NAME).down().withMessage(e.getMessage()).build();
+		}
+	}
+
+}

src/main/java/org/gcube/smartgears/health/ReadinessChecker.java

@@ -0,0 +1,12 @@
+package org.gcube.smartgears.health;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+public @interface ReadinessChecker {
+
+}

src/main/java/org/gcube/smartgears/health/Status.java

@@ -0,0 +1,6 @@
+package org.gcube.smartgears.health;
+
+public enum Status {
+
+	UP, DOWN, NOT_CALCULATED
+}

src/main/java/org/gcube/smartgears/health/response/HealthCheckResponse.java

@@ -0,0 +1,30 @@
+package org.gcube.smartgears.health.response;
+
+import org.gcube.com.fasterxml.jackson.annotation.JsonInclude;
+import org.gcube.com.fasterxml.jackson.annotation.JsonInclude.Include;
+import org.gcube.common.validator.annotations.NotEmpty;
+import org.gcube.common.validator.annotations.NotNull;
+import org.gcube.smartgears.health.Status;
+
+@JsonInclude(Include.NON_NULL)
+public class HealthCheckResponse {
+	
+	public static HealthCheckResponseBuilder builder(String checkName) {
+		return new HealthCheckResponseBuilder(checkName);
+	}
+	
+	protected HealthCheckResponse() {}
+	
+	//enum ErrorType {UNRECOVERABLE, RECOVERABLE}
+	
+	@NotNull
+	protected Status status;
+	
+	@NotNull @NotEmpty
+	protected String name;
+	
+	//protected ErrorType errorType;
+	
+	protected String errorMessage;
+	
+}

src/main/java/org/gcube/smartgears/health/response/HealthCheckResponseBuilder.java

@@ -0,0 +1,65 @@
+package org.gcube.smartgears.health.response;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.gcube.common.validator.ValidationError;
+import org.gcube.common.validator.Validator;
+import org.gcube.common.validator.ValidatorFactory;
+import org.gcube.smartgears.health.Status;
+
+public class HealthCheckResponseBuilder {
+
+	private HealthCheckResponse healthCheckResponse = new HealthCheckResponse();
+		
+	protected HealthCheckResponseBuilder(String name) {
+		healthCheckResponse.name = name;
+	}
+	
+	public BuildPart up() {
+		healthCheckResponse.status = Status.UP;
+		return new BuildPart();
+	}
+	
+	public ErrorPart down() {
+		healthCheckResponse.status = Status.DOWN;
+		return new ErrorPart();
+	}
+	
+	private void validateResponse() {
+
+		List<String> msgs = new ArrayList<String>();
+
+		Validator validator = ValidatorFactory.validator();
+
+		for (ValidationError error : validator.validate(healthCheckResponse))
+			msgs.add(error.toString());
+
+		if (!msgs.isEmpty())
+			throw new IllegalStateException("invalid configuration: "+msgs);
+
+	}
+	
+	public class ErrorPart{
+		
+		private ErrorPart() {}
+		
+		public BuildPart withMessage(String message) {
+			healthCheckResponse.errorMessage = message;
+			return new BuildPart();
+		}
+		
+	}
+	
+	public class BuildPart{
+		
+		private BuildPart() {};
+		
+		public HealthCheckResponse build() {
+			validateResponse();
+			return healthCheckResponse;		
+		}
+		
+	}
+	
+}

src/main/java/org/gcube/smartgears/health/response/HealthResponse.java

@@ -0,0 +1,18 @@
+package org.gcube.smartgears.health.response;
+
+import java.util.List;
+
+import org.gcube.smartgears.health.HealthCheck;
+import org.gcube.smartgears.health.Status;
+
+public class HealthResponse {
+
+	Status status;
+	
+	List<HealthCheck> checks;
+	
+	void register(HealthCheck check){
+		checks.add(check);
+	}
+	
+}

src/main/java/org/gcube/smartgears/health/response/HealthResponseBuilder.java

@@ -0,0 +1,13 @@
+package org.gcube.smartgears.health.response;
+
+public class HealthResponseBuilder {
+
+	private HealthResponse healthResponse;
+	
+	public HealthResponse build() {
+		return healthResponse;
+	}
+	
+	
+	
+}