private void addNewSlave()

in src/main/java/com/amazon/jenkins/ec2fleet/EC2FleetCloud.java [605:666]
46 lines of code
11 McCabe index (conditional complexity)

    private void addNewSlave(final AmazonEC2 ec2, final Instance instance, FleetStateStats stats) throws Exception {
        final String instanceId = instance.getInstanceId();

        // instance state check enabled and not running, skip adding
        if (addNodeOnlyIfRunning && InstanceStateName.Running != InstanceStateName.fromValue(instance.getState().getName()))
            return;

        final String address = privateIpUsed ? instance.getPrivateIpAddress() : instance.getPublicIpAddress();
        // Check if we have the address to use. Nodes don't get it immediately.
        if (address == null) {
            if (!privateIpUsed) {
                info("%s instance public IP address not assigned, it could take some time or" +
                        " Spot Request is not configured to assign public IPs", instance.getInstanceId());
            }
            return; // wait more time, probably IP address not yet assigned
        }

        // Generate a random FS root if one isn't specified
        final String effectiveFsRoot;
        if (StringUtils.isBlank(fsRoot)) {
            effectiveFsRoot = "/tmp/jenkins-" + UUID.randomUUID().toString().substring(0, 8);
        } else {
            effectiveFsRoot = fsRoot;
        }

        final Double instanceTypeWeight = stats.getInstanceTypeWeights().get(instance.getInstanceType());
        final int effectiveNumExecutors;
        if (scaleExecutorsByWeight && instanceTypeWeight != null) {
            effectiveNumExecutors = (int) Math.max(Math.round(numExecutors * instanceTypeWeight), 1);
        } else {
            effectiveNumExecutors = numExecutors;
        }

        final EC2FleetAutoResubmitComputerLauncher computerLauncher = new EC2FleetAutoResubmitComputerLauncher(
                computerConnector.launch(address, TaskListener.NULL));
        final Node.Mode nodeMode = restrictUsage ? Node.Mode.EXCLUSIVE : Node.Mode.NORMAL;
        final EC2FleetNode node = new EC2FleetNode(instanceId, "Fleet slave for " + instanceId,
                effectiveFsRoot, effectiveNumExecutors, nodeMode, labelString, new ArrayList<NodeProperty<?>>(),
                this, computerLauncher);

        // Initialize our retention strategy
        node.setRetentionStrategy(new IdleRetentionStrategy());

        final Jenkins jenkins = Jenkins.getInstance();
        // jenkins automatically remove old node with same name if any
        jenkins.addNode(node);

        final SettableFuture<Node> future;
        if (plannedNodesCache.isEmpty()) {
            future = SettableFuture.create();
        } else {
            final NodeProvisioner.PlannedNode plannedNode = plannedNodesCache.iterator().next();
            plannedNodesCache.remove(plannedNode);
            future = ((SettableFuture<Node>) plannedNode.future);
        }

        // use getters for timeout and interval as they provide default value
        // when user just install new version and did't recreate fleet
        EC2FleetOnlineChecker.start(node, future,
                TimeUnit.SECONDS.toMillis(getInitOnlineTimeoutSec()),
                TimeUnit.SECONDS.toMillis(getInitOnlineCheckIntervalSec()));
    }