Failsafe

The OpenAPI and Swagger API description format are becoming important standards to specify API contracts for RESTful web services and the Microservices trend pushes the need for such contracts even further. Therefore arises the need for software architects, testers and developers to write tests to verify if an exposed API follows such a specified contract. In the following tutorial I will demonstrate a setup with Java, Maven, JUnit and the designated contract-testing-library, assertj-swagger that verifies the validity of such a contract exposed by a Spring Boot application against a local stored definition. ...

When implementing distributed systems, client-server architectures and simple applications with network related functionalities, everything is fine when we’re in the development or in the testing stage because the network is reliable and the communicating systems are not as stressed as they are in production. But to sleep well we want to validate how resilient we have implemented our systems, how they behave when the network fails, the latency rises, the bandwidth is limited, connections time out and so on. ...

When dealing with remote services or APIs there is always the risk of latency issues, failures or connection losses. The worst thing to happen is when the remote service is down and our application hangs until the underlying protocol’s (e.g. TCP) connection timeout is reached and we’re receiving an exception. Until this moment is reached, our application might hang, memory is allocated for threads or bound objects and at last, our continuous requests might prevent the remote system from recovering. ...

Remote Debug a Pod’s Java Process Simple steps for remote debugging a Java process running on a k8 pod: Edit deployment and add the following parameters to the Java start line: -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=127.0.0.1:5005 Also add the following port mapping at the section container → ports in the deployment: - containerPort: 5005 protocol: TCP Safe, wait for the new pods and then add a port forward for port 5005 for this pod: kubectl port-forward podname 5005 ...

Define and Configure Log Groups This allows to configure a group of loggers at the same time Define a log group named myaspect with two packages application.properties logging.group.myaspect=com.hascode.package1,com.hascode.package2 Configure the log group and set all loggers to level TRACE application.properties logging.level.myaspect=TRACE This is also possible as parameter on startup java -Dlogging.level.myaspect=TRACE myapp.jar Use JUnit 5 with Spring Boot Use newer versions of Surefire and Failsafe plugins: <properties> [..] <maven-failsafe-plugin.version>2.22.0</maven-failsafe-plugin.version> <maven-surefire-plugin.version>2.22.0</maven-surefire-plugin.version> </properties> ...