From c8898990fb1f9cac4895074e936178385ce8201c Mon Sep 17 00:00:00 2001
From: Alexander Jung <alex@unikraft.io>
Date: Thu, 18 Apr 2024 16:07:34 +0200
Subject: [PATCH 1/2] refactor: Remove return error, consume multiple strings,
 no `\n`

This small refactor performs a number of actions simultaneously:

1. Removes the unnecessary `error` being returned from `Consume`
   which was ultimately never used by relevant consumers,
   resulting unnecessary error handling.
2. Updates the `Consume` prototype to accept multiple lines at
   once;
3. Employs the new-line at the consumer-level, since all other
   instances were always appending the newline itself.  This
   improves the code quality.
4. Subsequent to 3, appropraitely discard the the newline
   which has been retrieved via the `ReadBytes` from the
   `peekAndRed` of the internal log tail package.

Signed-off-by: Alexander Jung <alex@unikraft.io>
---
 internal/cli/kraft/cloud/instance/logs/logs.go |  5 +----
 internal/cli/kraft/logs/colorful_consumer.go   | 16 ++++++++--------
 internal/cli/kraft/logs/logs.go                |  9 ++-------
 internal/logtail/logtail.go                    |  2 +-
 4 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/internal/cli/kraft/cloud/instance/logs/logs.go b/internal/cli/kraft/cloud/instance/logs/logs.go
index 789c25766..093283afd 100644
--- a/internal/cli/kraft/cloud/instance/logs/logs.go
+++ b/internal/cli/kraft/cloud/instance/logs/logs.go
@@ -158,10 +158,7 @@ func Logs(ctx context.Context, opts *LogOptions, args ...string) error {
 					return
 				case line, ok := <-logChan:
 					if ok {
-						if err := consumer.Consume(fmt.Sprintf("%s\n", line)); err != nil {
-							errGroup = append(errGroup, err)
-							return
-						}
+						consumer.Consume(line)
 					}
 				}
 			}
diff --git a/internal/cli/kraft/logs/colorful_consumer.go b/internal/cli/kraft/logs/colorful_consumer.go
index eedbfc1aa..50695b223 100644
--- a/internal/cli/kraft/logs/colorful_consumer.go
+++ b/internal/cli/kraft/logs/colorful_consumer.go
@@ -13,7 +13,7 @@ import (
 )
 
 type LogConsumer interface {
-	Consume(line string) error
+	Consume(line ...string)
 }
 
 type ColorfulConsumer struct {
@@ -40,12 +40,12 @@ func NewColorfulConsumer(streams *iostreams.IOStreams, color bool, prefix string
 }
 
 // Consume implements logConsumer
-func (c *ColorfulConsumer) Consume(s string) error {
-	if c.prefix != "" {
-		s = fmt.Sprintf("%s | %s", c.color(c.prefix), s)
-	}
-
-	fmt.Fprint(c.streams.Out, s)
+func (c *ColorfulConsumer) Consume(strs ...string) {
+	for _, s := range strs {
+		if c.prefix != "" {
+			s = fmt.Sprintf("%s | %s", c.color(c.prefix), s)
+		}
 
-	return nil
+		fmt.Fprintf(c.streams.Out, "%s\n", s)
+	}
 }
diff --git a/internal/cli/kraft/logs/logs.go b/internal/cli/kraft/logs/logs.go
index 5dce5a322..17bf6d296 100644
--- a/internal/cli/kraft/logs/logs.go
+++ b/internal/cli/kraft/logs/logs.go
@@ -193,9 +193,7 @@ func (opts *LogOptions) Run(ctx context.Context, args []string) error {
 			} else {
 				scanner := bufio.NewScanner(fd)
 				for scanner.Scan() {
-					if err := consumer.Consume(scanner.Text() + "\n"); err != nil {
-						errGroup = append(errGroup, err)
-					}
+					consumer.Consume(scanner.Text())
 				}
 			}
 		}
@@ -285,10 +283,7 @@ loop:
 		// Wait on either channel
 		select {
 		case line := <-logs:
-			if err := consumer.Consume(line); err != nil {
-				log.G(ctx).Errorf("could not consume log line: %v", err)
-				return err
-			}
+			consumer.Consume(line)
 
 		case err := <-errs:
 			eof = true
diff --git a/internal/logtail/logtail.go b/internal/logtail/logtail.go
index f19999115..2a3973e5b 100644
--- a/internal/logtail/logtail.go
+++ b/internal/logtail/logtail.go
@@ -117,7 +117,7 @@ func peekAndRead(file *os.File, reader *bufio.Reader, logs *chan string, errs *c
 	}
 
 	if len(s) > discarded {
-		*logs <- string(s[discarded:])
+		*logs <- string(s[discarded : len(s)-1])
 	}
 
 	return false

From 9a1f49dc00ebe05c0a0665da87f56c79142a1e87 Mon Sep 17 00:00:00 2001
From: Alexander Jung <alex@unikraft.io>
Date: Thu, 18 Apr 2024 16:21:14 +0200
Subject: [PATCH 2/2] feat(logs): Add helpful troubleshoot message for fatal
 instances

Signed-off-by: Alexander Jung <alex@unikraft.io>
---
 .../cli/kraft/cloud/instance/logs/logs.go     | 29 ++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/internal/cli/kraft/cloud/instance/logs/logs.go b/internal/cli/kraft/cloud/instance/logs/logs.go
index 093283afd..87294ee3c 100644
--- a/internal/cli/kraft/cloud/instance/logs/logs.go
+++ b/internal/cli/kraft/cloud/instance/logs/logs.go
@@ -15,6 +15,7 @@ import (
 	"github.com/spf13/cobra"
 
 	kraftcloud "sdk.kraft.cloud"
+	kcinstances "sdk.kraft.cloud/instances"
 
 	"kraftkit.sh/cmdfactory"
 	"kraftkit.sh/config"
@@ -154,7 +155,33 @@ func Logs(ctx context.Context, opts *LogOptions, args ...string) error {
 				case <-ctx.Done():
 					return
 				case err := <-errChan:
-					errGroup = append(errGroup, err)
+					if err != nil {
+						errGroup = append(errGroup, err)
+					}
+
+					resp, err := opts.Client.Instances().WithMetro(opts.Metro).Get(ctx, instance)
+					if err != nil {
+						errGroup = append(errGroup, err)
+						return
+					}
+
+					inst, err := resp.FirstOrErr()
+					if err != nil {
+						errGroup = append(errGroup, err)
+					}
+
+					if inst.StopCodeReason() != kcinstances.StopCodeReasonOK {
+						message := []string{
+							"",
+							"It looks like the instance exited fatally.  To see more details about why, run:",
+							"",
+							fmt.Sprintf("\tkraft cloud instance get %s", inst.Name),
+							"",
+						}
+
+						consumer.Consume(message...)
+					}
+
 					return
 				case line, ok := <-logChan:
 					if ok {