From 903f351451c05141f00aa9f24bfb502bf3fc7d16 Mon Sep 17 00:00:00 2001
From: Johannes Rauh <johannes.rauh@icinga.com>
Date: Mon, 5 Aug 2024 12:16:54 +0200
Subject: [PATCH] Sync previous container logs

---
 pkg/schema/v1/container.go | 66 +++++++++++++++++++++++++++++++++-----
 1 file changed, 58 insertions(+), 8 deletions(-)

diff --git a/pkg/schema/v1/container.go b/pkg/schema/v1/container.go
index da199abf..605c1856 100644
--- a/pkg/schema/v1/container.go
+++ b/pkg/schema/v1/container.go
@@ -252,7 +252,50 @@ func (cl *ContainerLog) Upsert() interface{} {
 
 // syncContainerLogs fetches the logs from the kubernetes API for the given container and syncs to the database.
 func (cl *ContainerLog) syncContainerLogs(ctx context.Context, clientset *kubernetes.Clientset, db *database.Database) error {
-	logOptions := &kcorev1.PodLogOptions{Container: cl.ContainerName}
+	prevLogOptions := &kcorev1.PodLogOptions{
+		Container:  cl.ContainerName,
+		Previous:   true,
+		Timestamps: true,
+	}
+	if !cl.LastUpdate.Time().IsZero() {
+		sinceSeconds := int64(time.Since(cl.LastUpdate.Time()).Seconds())
+		prevLogOptions.SinceSeconds = &sinceSeconds
+		if cl.ContainerName == "tester" {
+			fmt.Println("SinceSeconds: ", sinceSeconds)
+		}
+	}
+	prevReq := clientset.CoreV1().Pods(cl.Namespace).GetLogs(cl.PodName, prevLogOptions)
+
+	prevBody, err := prevReq.Stream(ctx)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = prevBody.Close() }()
+
+	prevLogs, err := io.ReadAll(prevBody)
+	if err != nil {
+		return err
+	}
+
+	if len(prevLogs) > 0 {
+		cl.Logs = truncate(cl.Logs+string(prevLogs), MaxLogLength)
+
+		logLines := strings.Split(string(prevLogs), "\n")
+		lastLogLine := logLines[len(logLines)-1]
+		if lastLogLine == "" || lastLogLine == "\n" {
+			lastLogLine = logLines[len(logLines)-2]
+		}
+		if lastLogLine != "" {
+			ts := strings.Fields(lastLogLine)[0]
+			restartAtMessage := fmt.Sprintf("\nContainer %s restarted at %s\n\n", cl.ContainerName, ts)
+			cl.Logs = truncate(cl.Logs+restartAtMessage, MaxLogLength)
+		}
+	}
+
+	logOptions := &kcorev1.PodLogOptions{
+		Container:  cl.ContainerName,
+		Timestamps: true,
+	}
 	if !cl.LastUpdate.Time().IsZero() {
 		sinceSeconds := int64(time.Since(cl.LastUpdate.Time()).Seconds())
 		logOptions.SinceSeconds = &sinceSeconds
@@ -266,17 +309,24 @@ func (cl *ContainerLog) syncContainerLogs(ctx context.Context, clientset *kubern
 	defer func() { _ = body.Close() }()
 
 	logs, err := io.ReadAll(body)
-	if err != nil || len(logs) == 0 {
+	if err != nil {
 		return err
 	}
 
-	cl.LastUpdate = types.UnixMilli(time.Now())
-	cl.Logs = truncate(cl.Logs+string(logs), MaxLogLength)
-	entities := make(chan interface{}, 1)
-	entities <- cl
-	close(entities)
+	if len(logs) > 0 {
+		cl.Logs = truncate(cl.Logs+string(logs), MaxLogLength)
+	}
+
+	if len(logs) > 0 || len(prevLogs) > 0 {
+		cl.LastUpdate = types.UnixMilli(time.Now())
+		entities := make(chan interface{}, 1)
+		entities <- cl
+		close(entities)
+
+		return db.UpsertStreamed(ctx, entities)
+	}
 
-	return db.UpsertStreamed(ctx, entities)
+	return nil
 }
 
 func GetContainerState(container kcorev1.Container, status kcorev1.ContainerStatus) (IcingaState, string) {