adds the capability of adding new nodes after a deployment is started

docs/index.rst

@@ -31,5 +31,6 @@ called when a specific stack trace is present.
     pages/quickstart
     pages/deterministic
     pages/runseq
+    pages/newnode
     pages/jvmservice
     pages/docker

docs/pages/newnode.rst

@@ -0,0 +1,52 @@
+============================
+Adding New Nodes Dynamically
+============================
+
+It is possible to add new nodes dynamically after a defined deployment is started. New nodes can only be created out of
+pre-defined services and they can't include any internal events. In the following code, ``service1`` service is first created
+similar to the one in :doc:`quickstart`. Then, at line 31, a new node named ``n2`` is being created out of ``service1`` service.
+``Node.limitedBuilder`` method returns an instance of ``Node.LimitedBuilder`` which then can be further customized by chaining the proper
+method calls. This builder wouldn't allow the definition of internal events for the node. However, all the other node configurations
+are available.
+
+.. code-block:: java
+    :linenos:
+
+    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/bin/start.sh")
+                    .dockerImage("project/sampleTest:" + projectVersion)
+                    .dockerFileAddress("docker/Dockerfile", false)
+                    .serviceType(ServiceType.JAVA).and()
+                // Node Definitions
+                .withNode("n1", "service1").and()
+                .build();
+
+            FailifyRunner runner = FailifyRunner.run(deployment);
+        }
+
+        @AfterClass
+        public static void after() {
+            if (runner != null) {
+                runner.stop();
+            }
+        }
+
+        public void test1() throws RuntimeEngineException {
+            ..
+            runner.addNode(Node.limitedBuilder("n2", "s1"));
+            ..
+        }
+    }
+
+The current limitation of this capability is that if there is a network partition applied to the current deployment, the
+new node wouldn't be included in that network partition. Introduction of new network partitions will include the new node
+in generating blocking rules for iptables. This limitation will be removed in future releases.

failify/src/main/java/io/failify/FailifyRunner.java

@@ -25,6 +25,7 @@
 
 package io.failify;
 
+import io.failify.dsl.entities.Node;
 import io.failify.verification.DeploymentVerifier;
 import io.failify.verification.InternalReferencesVerifier;
 import io.failify.verification.RunSequenceVerifier;
@@ -194,6 +195,12 @@ public boolean isStopped() {
         }
         return runtimeEngine.isStopped();
     }
+
+    public void addNode(Node.LimitedBuilder limitedBuilder) throws WorkspaceException, RuntimeEngineException {
+        Node node = limitedBuilder.build();
+        NodeWorkspace nodeWorkspace = workspaceManager.createNodeWorkspace(node);
+        runtimeEngine.addNewNode(node, nodeWorkspace);
+    }
 }
 
 class FailifyShutdownHook extends Thread {

failify/src/main/java/io/failify/dsl/DeploymentEntity.java

@@ -50,6 +50,10 @@ public abstract static class BuilderBase<T extends DeploymentEntity, S extends B
         protected S parentBuilder;
 
         public BuilderBase(S parentBuilder, String name) {
+            if (name == null) {
+                throw new NullPointerException("A deployment entity name cannot be null");
+            }
+
             this.name = name;
             this.parentBuilder = parentBuilder;
         }