// Handle processes deployment and either creates a deployer pod or responds
// to a terminal deployment status.
func (c *DeploymentController) Handle(deployment *kapi.ReplicationController) error {
	currentStatus := deployutil.DeploymentStatusFor(deployment)
	nextStatus := currentStatus

	switch currentStatus {
	case deployapi.DeploymentStatusNew:
		// If the deployment has been cancelled, don't create a deployer pod, and
		// transition to failed immediately.
		if deployutil.IsDeploymentCancelled(deployment) {
			nextStatus = deployapi.DeploymentStatusFailed
			break
		}

		// Generate a deployer pod spec.
		podTemplate, err := c.makeDeployerPod(deployment)
		if err != nil {
			return fatalError(fmt.Sprintf("couldn't make deployer pod for %s: %v", deployutil.LabelForDeployment(deployment), err))
		}

		// Create the deployer pod.
		deploymentPod, err := c.podClient.createPod(deployment.Namespace, podTemplate)
		if err == nil {
			deployment.Annotations[deployapi.DeploymentPodAnnotation] = deploymentPod.Name
			nextStatus = deployapi.DeploymentStatusPending
			glog.V(4).Infof("Created pod %s for deployment %s", deploymentPod.Name, deployutil.LabelForDeployment(deployment))
			break
		}

		// Retry on error.
		if !kerrors.IsAlreadyExists(err) {
			c.recorder.Eventf(deployment, "failedCreate", "Error creating deployer pod for %s: %v", deployutil.LabelForDeployment(deployment), err)
			return fmt.Errorf("couldn't create deployer pod for %s: %v", deployutil.LabelForDeployment(deployment), err)
		}

		// If the pod already exists, it's possible that a previous CreatePod
		// succeeded but the deployment state update failed and now we're re-
		// entering. Ensure that the pod is the one we created by verifying the
		// annotation on it, and throw a retryable error.
		existingPod, err := c.podClient.getPod(deployment.Namespace, deployutil.DeployerPodNameForDeployment(deployment.Name))
		if err != nil {
			c.recorder.Eventf(deployment, "failedCreate", "Error getting existing deployer pod for %s: %v", deployutil.LabelForDeployment(deployment), err)
			return fmt.Errorf("couldn't fetch existing deployer pod for %s: %v", deployutil.LabelForDeployment(deployment), err)
		}

		// Do a stronger check to validate that the existing deployer pod is
		// actually for this deployment, and if not, fail this deployment.
		//
		// TODO: Investigate checking the container image of the running pod and
		// comparing with the intended deployer pod image. If we do so, we'll need
		// to ensure that changes to 'unrelated' pods don't result in updates to
		// the deployment. So, the image check will have to be done in other areas
		// of the code as well.
		if deployutil.DeploymentNameFor(existingPod) != deployment.Name {
			nextStatus = deployapi.DeploymentStatusFailed
			deployment.Annotations[deployapi.DeploymentStatusReasonAnnotation] = deployapi.DeploymentFailedUnrelatedDeploymentExists
			c.recorder.Eventf(deployment, "failedCreate", "Error creating deployer pod for %s since another pod with the same name (%q) exists", deployutil.LabelForDeployment(deployment), existingPod.Name)
			glog.V(2).Infof("Couldn't create deployer pod for %s since an unrelated pod with the same name (%q) exists", deployutil.LabelForDeployment(deployment), existingPod.Name)
			break
		}

		// Update to pending relative to the existing validated deployer pod.
		deployment.Annotations[deployapi.DeploymentPodAnnotation] = existingPod.Name
		nextStatus = deployapi.DeploymentStatusPending
		glog.V(4).Infof("Detected existing deployer pod %s for deployment %s", existingPod.Name, deployutil.LabelForDeployment(deployment))
	case deployapi.DeploymentStatusPending, deployapi.DeploymentStatusRunning:
		// If the deployer pod has vanished, consider the deployment a failure.
		deployerPodName := deployutil.DeployerPodNameForDeployment(deployment.Name)
		if _, err := c.podClient.getPod(deployment.Namespace, deployerPodName); err != nil {
			if kerrors.IsNotFound(err) {
				nextStatus = deployapi.DeploymentStatusFailed
				deployment.Annotations[deployapi.DeploymentStatusAnnotation] = string(nextStatus)
				deployment.Annotations[deployapi.DeploymentStatusReasonAnnotation] = deployapi.DeploymentFailedDeployerPodNoLongerExists
				c.recorder.Eventf(deployment, "failed", "Deployer pod %q has gone missing", deployerPodName)
				glog.V(4).Infof("Failing deployment %q because its deployer pod %q disappeared", deployutil.LabelForDeployment(deployment), deployerPodName)
				break
			} else {
				// We'll try again later on resync. Continue to process cancellations.
				glog.V(2).Infof("Error getting deployer pod %s for deployment %s: %#v", deployerPodName, deployutil.LabelForDeployment(deployment), err)
			}
		}

		// If the deployment is cancelled, terminate any deployer/hook pods.
		// NOTE: Do not mark the deployment as Failed just yet.
		// The deployment will be marked as Failed by the deployer pod controller
		// when the deployer pod failure state is picked up
		// Also, it will scale down the failed deployment and scale back up
		// the last successful completed deployment
		if deployutil.IsDeploymentCancelled(deployment) {
			deployerPods, err := c.podClient.getDeployerPodsFor(deployment.Namespace, deployment.Name)
			if err != nil {
				return fmt.Errorf("couldn't fetch deployer pods for %s while trying to cancel deployment: %v", deployutil.LabelForDeployment(deployment), err)
			}
			glog.V(4).Infof("Cancelling %d deployer pods for deployment %s", len(deployerPods), deployutil.LabelForDeployment(deployment))
			zeroDelay := int64(1)
			for _, deployerPod := range deployerPods {
				// Set the ActiveDeadlineSeconds on the pod so it's terminated very soon.
				if deployerPod.Spec.ActiveDeadlineSeconds == nil || *deployerPod.Spec.ActiveDeadlineSeconds != zeroDelay {
					deployerPod.Spec.ActiveDeadlineSeconds = &zeroDelay
					if _, err := c.podClient.updatePod(deployerPod.Namespace, &deployerPod); err != nil {
						c.recorder.Eventf(deployment, "failedCancellation", "Error cancelling deployer pod %s for deployment %s: %v", deployerPod.Name, deployutil.LabelForDeployment(deployment), err)
						return fmt.Errorf("couldn't cancel deployer pod %s for deployment %s: %v", deployutil.LabelForDeployment(deployment), err)
					}
					glog.V(4).Infof("Cancelled deployer pod %s for deployment %s", deployerPod.Name, deployutil.LabelForDeployment(deployment))
				}
			}
			c.recorder.Eventf(deployment, "cancelled", "Cancelled deployment")
		}
	case deployapi.DeploymentStatusFailed:
		// Nothing to do in this terminal state.
		glog.V(4).Infof("Ignoring deployment %s (status %s)", deployutil.LabelForDeployment(deployment), currentStatus)
	case deployapi.DeploymentStatusComplete:
		// now list any pods in the namespace that have the specified label
		deployerPods, err := c.podClient.getDeployerPodsFor(deployment.Namespace, deployment.Name)
		if err != nil {
			return fmt.Errorf("couldn't fetch deployer pods for %s after successful completion: %v", deployutil.LabelForDeployment(deployment), err)
		}
		glog.V(4).Infof("Deleting %d deployer pods for deployment %s", len(deployerPods), deployutil.LabelForDeployment(deployment))
		cleanedAll := true
		for _, deployerPod := range deployerPods {
			if err := c.podClient.deletePod(deployerPod.Namespace, deployerPod.Name); err != nil {
				if !kerrors.IsNotFound(err) {
					// if the pod deletion failed, then log the error and continue
					// we will try to delete any remaining deployer pods and return an error later
					kutil.HandleError(fmt.Errorf("couldn't delete completed deployer pod %s/%s for deployment %s: %v", deployment.Namespace, deployerPod.Name, deployutil.LabelForDeployment(deployment), err))
					cleanedAll = false
				}
				// Already deleted
			} else {
				glog.V(4).Infof("Deleted completed deployer pod %s/%s for deployment %s", deployment.Namespace, deployerPod.Name, deployutil.LabelForDeployment(deployment))
			}
		}

		if !cleanedAll {
			return fmt.Errorf("couldn't clean up all deployer pods for %s", deployutil.LabelForDeployment(deployment))
		}
	}

	if currentStatus != nextStatus {
		deployment.Annotations[deployapi.DeploymentStatusAnnotation] = string(nextStatus)
		if _, err := c.deploymentClient.updateDeployment(deployment.Namespace, deployment); err != nil {
			c.recorder.Eventf(deployment, "failedUpdate", "Error updating deployment %s status to %s", deployutil.LabelForDeployment(deployment), nextStatus)
			return fmt.Errorf("couldn't update deployment %s to status %s: %v", deployutil.LabelForDeployment(deployment), nextStatus, err)
		}
		glog.V(4).Infof("Updated deployment %s status from %s to %s", deployutil.LabelForDeployment(deployment), currentStatus, nextStatus)
	}
	return nil
}
// Handle syncs pod's status with any associated deployment.
func (c *DeployerPodController) Handle(pod *kapi.Pod) error {
	// Find the deployment associated with the deployer pod.
	deploymentName := deployutil.DeploymentNameFor(pod)
	if len(deploymentName) == 0 {
		return nil
	}
	// Reject updates to anything but the main deployer pod
	// TODO: Find a way to filter this on the watch side.
	if pod.Name != deployutil.DeployerPodNameForDeployment(deploymentName) {
		return nil
	}

	deployment, err := c.deploymentClient.getDeployment(pod.Namespace, deploymentName)
	// If the deployment for this pod has disappeared, we should clean up this
	// and any other deployer pods, then bail out.
	if err != nil {
		// Some retrieval error occured. Retry.
		if !kerrors.IsNotFound(err) {
			return fmt.Errorf("couldn't get deployment %s/%s which owns deployer pod %s/%s", pod.Namespace, deploymentName, pod.Name, pod.Namespace)
		}
		// Find all the deployer pods for the deployment (including this one).
		deployers, err := c.deployerPodsFor(pod.Namespace, deploymentName)
		if err != nil {
			// Retry.
			return fmt.Errorf("couldn't get deployer pods for %s: %v", deployutil.LabelForDeployment(deployment), err)
		}
		// Delete all deployers.
		for _, deployer := range deployers.Items {
			err := c.deletePod(deployer.Namespace, deployer.Name)
			if err != nil {
				if !kerrors.IsNotFound(err) {
					// TODO: Should this fire an event?
					glog.V(2).Infof("Couldn't delete orphaned deployer pod %s/%s: %v", deployer.Namespace, deployer.Name, err)
				}
			} else {
				// TODO: Should this fire an event?
				glog.V(2).Infof("Deleted orphaned deployer pod %s/%s", deployer.Namespace, deployer.Name)
			}
		}
		return nil
	}

	currentStatus := deployutil.DeploymentStatusFor(deployment)
	nextStatus := currentStatus

	switch pod.Status.Phase {
	case kapi.PodRunning:
		nextStatus = deployapi.DeploymentStatusRunning
	case kapi.PodSucceeded:
		// Detect failure based on the container state
		nextStatus = deployapi.DeploymentStatusComplete
		for _, info := range pod.Status.ContainerStatuses {
			if info.State.Termination != nil && info.State.Termination.ExitCode != 0 {
				nextStatus = deployapi.DeploymentStatusFailed
			}
		}
	case kapi.PodFailed:
		// if the deployment is already marked Failed, do not attempt clean up again
		if currentStatus != deployapi.DeploymentStatusFailed {
			// clean up will also update the deployment status to Failed
			// failure to clean up will result in retries and
			// the deployment will not be marked Failed
			// Note: this will prevent new deployments from being created for this config
			err := c.cleanupFailedDeployment(deployment)
			if err != nil {
				return transientError(fmt.Sprintf("couldn't clean up failed deployment: %v", err))
			}
		}
	}

	if currentStatus != nextStatus {
		deployment.Annotations[deployapi.DeploymentStatusAnnotation] = string(nextStatus)
		if _, err := c.deploymentClient.updateDeployment(deployment.Namespace, deployment); err != nil {
			if kerrors.IsNotFound(err) {
				return nil
			}
			return fmt.Errorf("couldn't update Deployment %s to status %s: %v", deployutil.LabelForDeployment(deployment), nextStatus, err)
		}
		glog.V(4).Infof("Updated Deployment %s status from %s to %s", deployutil.LabelForDeployment(deployment), currentStatus, nextStatus)
	}

	return nil
}