Fix terminating pod autodiscover issue

CHANGELOG.next.asciidoc

@@ -147,6 +147,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Fix config reload metrics (`libbeat.config.module.start/stops/running`). {pull}19168[19168]
 - Fix metrics hints builder to avoid wrong container metadata usage when port is not exposed {pull}18979[18979]
 - Server-side TLS config now validates certificate and key are both specified {pull}19584[19584]
+- Fix terminating pod autodiscover issue. {pull}20084[20084]
 - Fix seccomp policy for calls to `chmod` and `chown`. {pull}20054[20054]
 
 *Auditbeat*

libbeat/autodiscover/providers/kubernetes/pod.go

@@ -146,6 +146,18 @@ func (p *pod) OnUpdate(obj interface{}) {
 		return
 	}
 
+	// here handle the case when a Pod is in `Terminating` phase.
+	// In this case the pod is neither `PodSucceeded` nor `PodFailed` and
+	// hence a stop/start sequence will take place. However we need to
+	// handle this as just a stop event with a cleanup timeout so as to
+	// to give time to any leftover log lines to be collected while the pod is
+	// in `Terminating` phase.
+	if pod.GetObjectMeta().GetDeletionTimestamp() != nil {
+		p.logger.Debugf("Watcher Pod update (being terminated): %+v", obj)
+		time.AfterFunc(p.config.CleanupTimeout, func() { p.emit(pod, "stop") })
+		return
+	}
+
 	p.logger.Debugf("Watcher Pod update: %+v", obj)
 	p.emit(pod, "stop")
 	p.emit(pod, "start")