From 5d6ed236488e737be72a8f39488fe20ddb311811 Mon Sep 17 00:00:00 2001
From: Kyle McCullough <kylemcc@gmail.com>
Date: Wed, 17 Jun 2020 20:25:48 -0500
Subject: [PATCH] writer: preserve empty events

CloudWatch logs requires that events have a length > 0, so an empty
event is represented as a string containing a single null byte.

Previously, empty events were ignored. However, my use case cares about
formatting, so I've decided to "empty" events (i.e., lines that just
contain a newline character)
---
 writer/writer.go      |  2 +-
 writer/writer_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/writer/writer.go b/writer/writer.go
index 2519481..9af93f4 100644
--- a/writer/writer.go
+++ b/writer/writer.go
@@ -280,7 +280,7 @@ func (w *LogWriter) readLines() {
 
 func (w *LogWriter) appendEvent(text string) {
 	if text == "" {
-		return
+		text = "\u0000"
 	}
 
 	w.Lock()
diff --git a/writer/writer_test.go b/writer/writer_test.go
index 0858922..864f46e 100644
--- a/writer/writer_test.go
+++ b/writer/writer_test.go
@@ -123,6 +123,33 @@ func TestWriter(t *testing.T) {
 				},
 			},
 		},
+		{
+			"empty lines",
+			newTestInput([][]byte{
+				[]byte("test input\n"),
+				[]byte("\n"),
+				[]byte("more input\n"),
+				[]byte("\n"),
+			}),
+			Events{
+				{
+					Message:   aws.String("test input"),
+					Timestamp: aws.Int64(1),
+				},
+				{
+					Message:   aws.String("\u0000"),
+					Timestamp: aws.Int64(2),
+				},
+				{
+					Message:   aws.String("more input"),
+					Timestamp: aws.Int64(3),
+				},
+				{
+					Message:   aws.String("\u0000"),
+					Timestamp: aws.Int64(4),
+				},
+			},
+		},
 	}
 
 	for _, c := range cases {