Quick Start

Failify is a Java-based end-to-end testing framework. So, you will need to write your test cases In Java, or languages that can use Java libraries like the ones that can run on JVM, e.g. Scala. Failify can be used alongside the popular testing frameworks in your programming language of choice e.g. JUnit in Java. Here, we use Java and JUnit . We also use Maven as the build system.

Adding dependencies

First, create a simple Maven application and add Failify’s dependency to your pom file.

<dependency>
    <groupId>io.failify</groupId>
    <artifactId>failify</artifactId>
    <version>0.2.2</version>
</dependency>

Also add failsafe plugin to your pom file to be able to run integration tests.

<project>
  [...]
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-failsafe-plugin</artifactId>
        <version>3.0.0-M3</version>
        <executions>
          <execution>
            <goals>
              <goal>integration-test</goal>
              <goal>verify</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

Creating a Dockerfile

Next, you need to create a Dockerfile for your application and that Dockerfile should add any dependency that may be needed by your application. In case you want to use the network partition capability of Failify, you need to install iptables package as well. Network delay and loss will also need the iproute package to be installed. Here, we assume the application under test is written in Java. So, we create a Dockerfile in the docker/Dockerfile address with the following content:

FROM java:8-jre
RUN apt update && apt install -y iptables iproute

Important

In case you are using Docker Toolbox (and consequently boot2docker) on Windows or Mac, be aware that your currently installed boot2docker image may be missing sched_netem kernel module which is included in most of the linux distributions and is needed for tc command in the iproute package to work. So, unless you upgrade your boot2docker image (normally through running docker-machine upgrade [machine_name], you won’t be able to use the network operation capabilities of Failify.

Adding a Test Case

Now, create a JUnit integration test case (ending with IT so failsafe picks it up) in the project’s test directory. Here, we are assuming the final distribution of the project is a zipfile in the Maven’s target directory. Also, we are assuming the zip file contains a project-[PROJECT_VERSION] directory and that directory itself contains a bin directory which contains a start.sh file to start the application.

public class SampleTestIT {
    protected static FailifyRunner runner;

    @BeforeClass
    public static void before() throws RuntimeEngineException {
        String projectVersion = "0.2.1";
        Deployment deployment = Deployment.builder("sampleTest")
            // Service Definition
            .withService("service1")
                .applicationPath("target/project.zip", "/project", PathAttr.COMPRESSED)
                .startCommand("/project/project-" + projectVersion +
                     "/bin/start.sh -conf /config.cfg")
                .dockerImage("project/sampleTest:" + projectVersion)
                .dockerFileAddress("docker/Dockerfile", false)
                .tcpPort(8765)
                .serviceType(ServiceType.JAVA).and()
            // Node Definitions
            .withNode("n1", "service1")
                .applicationPath("config/n1.cfg", "/config.cfg".and()
            .withNode("n2", "service1")
                .applicationPath("config/n2.cfg", "/config.cfg".and()
            .withNode("n3", "service1")
                .applicationPath("config/n3.cfg", "/config.cfg".and()
            .build();

        FailifyRunner runner = FailifyRunner.run(deployment);
    }

    @AfterClass
    public static void after() {
        if (runner != null) {
            runner.stop();
        }
    }

    public void test1() throws RuntimeEngineException {
        ProjectClient client = ProjectClient.from(runner.runtime().ip("n1"),
            runner.runtime().portMapping("n1", 8765, PortType.TCP));
        ..
        runner.runtime().clockDrift("n1", 100);
        ..
        runner.runtime().networkPartition(NetPart.partitions("n1", "n2", "n3")
            .connect(1,3));
        ..
        runner.runtime().networkOperation("n2", NetOp.delay(100).jitter(10),
             NetOp.loss(10));
        ..
    }
}

Each Failify test case should start with defining a new Deployment object. A deployment definition consists of a a set of service and node definitions. A Service is a node template and defines the docker image for the node, the start bash command, required environment variables, common paths, etc. for a specific type of node. For additional info about available options for a service check ServiceBuilder’s JavaDoc.

Line 9-16 defines service1 service. Line 10 adds the zip file to the service at the /project address and also marks it as compressed so Failify decompresses it before adding it to the node (In Windows and Mac, you should make sure the local path you are using here is shared with the Docker VM). Line 11 defines the start command for the node, and in this case, it is using the start.sh bash file and it feeding it with -conf /config.cfg argument. This config file will be provided separately through node definitions later. Line 15 marks tcp port 8765 to be exposed for the service. This is specially important when using Failify in Windows and Mac as the only way to connect to the Docker containers in those platforms is through port forwarding. Line 16 concludes the service definition by marking it as a Java application. If the programming language in use is listed in ServiceType enum, make sure to mark your application with the right ServiceType.

Important

If your program runs on JVM and your programming language in use is not listed in the ServiceType enum, just choose ServiceType.Java as the service type.

Lines 18-23 defines two nodes named n1, n2 and n3 from service1 service and is adding a separate local config file to each of them which will be located at the same target address /config.cfg. Most of the service configuration can be overriden by nodes. For more information about available options for a node check Node Builder’s JavaDoc.

Line 26 starts the defined deployment and line 32 stops the deployment after all tests are executed.

Line 37-38 shows how the runner object can be used to get the ip address and port mappings for each node to be potentially used by a client. Line 40 shows a simple example of how Failify can manipulate the deployed environment by just a method call. In this case, a clock dirft of 100ms will be applied to node n1. Line 42 shows how a network partition can be defined and imposed. Here, each of the nodes will be in a separate partition and the first (n1) and third (n3) partition will be connected together. Line 45 shows an example of imposing network delay and loss on all the interfaces of a specific node. Here, a network delay from a uniform distribution with mean=100 and variance=10 will be applied on n2 and 10% of the packets will be lost. For more information about available runtime manipulation operations check LimitedRuntimeEngine’s JavaDoc.

Logger Configuration

Failify uses SLF4J for logging. As such, you can configure your logging tool of choice. A sample configuration with Logback can be like this:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="Console" class="ch.qos.logback.core.ConsoleAppender">
        <layout class="ch.qos.logback.classic.PatternLayout">
            <Pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</Pattern>
        </layout>
    </appender>

    <logger name="io.failify" level="DEBUG"/>

    <root level="ERROR">
        <appender-ref ref="Console" />
    </root>
</configuration>

Running the Test Case

Finally, to run the test cases, run the following bash command:

$  mvn clean verify