From 1b21a18f740f8d3562c047b46fe00ed1d8892a0a Mon Sep 17 00:00:00 2001
From: Ivan Pirlik <ivan.pirlik@deliveroo.co.uk>
Date: Tue, 9 Jan 2018 12:29:32 +0000
Subject: [PATCH] Add polling to pod watch

---
 cli/pipeline/watch.go | 70 ++++++++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 24 deletions(-)

diff --git a/cli/pipeline/watch.go b/cli/pipeline/watch.go
index dec6b86..58d736a 100644
--- a/cli/pipeline/watch.go
+++ b/cli/pipeline/watch.go
@@ -9,6 +9,7 @@ import (
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/kubernetes"
 	"log"
+	"time"
 )
 
 type WatchEventType string
@@ -21,6 +22,8 @@ const (
 	Failed    WatchEventType = "FAILED"
 )
 
+const watchPollInterval = 30 * time.Second
+
 type WatchEvent struct {
 	Type      WatchEventType
 	Pod       *v1.Pod
@@ -44,6 +47,33 @@ func Watch(ctx context.Context, c kubernetes.Interface, watchPod *v1.Pod) (<-cha
 
 	containers := make(map[string]bool)
 
+	parsePodStatus := func(pod *v1.Pod) {
+		if pod.Status.Phase == v1.PodSucceeded {
+			out <- WatchEvent{Completed, pod, "", ""}
+		} else if pod.Status.Phase == v1.PodFailed {
+			out <- WatchEvent{Failed, pod, "", ""}
+		} else {
+			for _, container := range pod.Status.ContainerStatuses {
+				if container.State.Running != nil {
+					_, present := containers[container.Name]
+					if !present {
+						out <- WatchEvent{Added, pod, container.Name, ""}
+						containers[container.Name] = true
+					}
+				} else if container.State.Terminated != nil {
+					_, present := containers[container.Name]
+					if present {
+						out <- WatchEvent{Removed, pod, container.Name, ""}
+						containers[container.Name] = false
+					}
+					if container.State.Terminated.ExitCode != 0 {
+						out <- WatchEvent{Failed, pod, container.Name, container.State.Terminated.Message}
+					}
+				}
+			}
+		}
+	}
+
 	go func() {
 		for {
 			select {
@@ -57,30 +87,7 @@ func Watch(ctx context.Context, c kubernetes.Interface, watchPod *v1.Pod) (<-cha
 
 				switch e.Type {
 				case watch.Added, watch.Modified:
-					if pod.Status.Phase == v1.PodSucceeded {
-						out <- WatchEvent{Completed, pod, "", ""}
-					} else if pod.Status.Phase == v1.PodFailed {
-						out <- WatchEvent{Failed, pod, "", ""}
-					} else {
-						for _, container := range pod.Status.ContainerStatuses {
-							if container.State.Running != nil {
-								_, present := containers[container.Name]
-								if !present {
-									out <- WatchEvent{Added, pod, container.Name, ""}
-									containers[container.Name] = true
-								}
-							} else if container.State.Terminated != nil {
-								_, present := containers[container.Name]
-								if present {
-									out <- WatchEvent{Removed, pod, container.Name, ""}
-									containers[container.Name] = false
-								}
-								if container.State.Terminated.ExitCode != 0 {
-									out <- WatchEvent{Failed, pod, container.Name, container.State.Terminated.Message}
-								}
-							}
-						}
-					}
+					parsePodStatus(pod)
 				case watch.Deleted:
 					out <- WatchEvent{Deleted, pod, "", ""}
 				case watch.Error:
@@ -94,6 +101,21 @@ func Watch(ctx context.Context, c kubernetes.Interface, watchPod *v1.Pod) (<-cha
 		}
 	}()
 
+	go func() {
+		for {
+			select {
+			case <-time.After(watchPollInterval):
+				pod, err := c.CoreV1().Pods(watchPod.Namespace).Get(watchPod.Name, metav1.GetOptions{})
+				if err != nil {
+					parsePodStatus(pod)
+				}
+			case <-ctx.Done():
+				return
+			}
+		}
+
+	}()
+
 	return out, nil
 }