initial stab at delay between deleting pods, keel/forceDelay annotation

provider/kubernetes/force_update.go

@@ -2,6 +2,7 @@ package kubernetes
 
 import (
 	"fmt"
+	"time"
 
 	"k8s.io/api/extensions/v1beta1"
 	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -15,6 +16,7 @@ func (p *Provider) forceUpdate(deployment *v1beta1.Deployment) (err error) {
 
 	gracePeriod := types.ParsePodTerminationGracePeriod(deployment.Annotations)
 	selector := meta_v1.FormatLabelSelector(deployment.Spec.Selector)
+	podDeleteDelay := types.ParsePodDeleteDelay(deployment.Annotations)
 
 	// image tag didn't change, need to terminate pods
 	podList, err := p.implementer.Pods(deployment.Namespace, selector)
@@ -49,9 +51,9 @@ func (p *Provider) forceUpdate(deployment *v1beta1.Deployment) (err error) {
 				"namespace":  deployment.Namespace,
 				"deployment": deployment.Name,
 			}).Error("provider.kubernetes: got error while deleting a pod")
-			continue
 		}
 
+		time.Sleep(podDeleteDelay)
 	}
 
 	return nil

types/types.go

@@ -47,6 +47,10 @@ const KeelApprovalDeadlineLabel = "keel.sh/approvalDeadline"
 // KeelApprovalDeadlineDefault - default deadline in hours
 const KeelApprovalDeadlineDefault = 24
 
+// KeelPodDeleteDelay - optional delay betwen killing pods
+// during force deploy
+const KeelPodDeleteDelay = "keel.sh/forceDelay"
+
 // KeelPodTerminationGracePeriod - optional grace period during
 // pod termination
 const KeelPodTerminationGracePeriod = "keel.sh/gracePeriod"
@@ -206,6 +210,29 @@ func ParseEventNotificationChannels(annotations map[string]string) []string {
 	return channels
 }
 
+// ParsePodDeleteDelay - parses pod delete delay time in seconds
+// from a given map of annotations
+func ParsePodDeleteDelay(annotations map[string]string) int64 {
+	delay := int64(0)
+	if annotations == nil {
+		return delay
+	}
+	delayStr, ok := annotations[KeelPodDeleteDelay]
+	if ok {
+
+		g, err := strconv.Atoi(delayStr)
+		if err != nil {
+			return delay
+		}
+
+		if g > 0 && g < 600 {
+			return int64(g)
+		}
+	}
+
+	return delay
+}
+
 // ParsePodTerminationGracePeriod - parses pod termination time in seconds
 // from a given map of annotations
 func ParsePodTerminationGracePeriod(annotations map[string]string) int64 {