From 0b78d228d21eff88344e1998ab0cc5e0030c9ad0 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Fri, 7 Jun 2019 23:17:57 +0300
Subject: [PATCH] app/vminsert: properly read trailing line without newline in
 the end

This fixes https://github.com/VictoriaMetrics/VictoriaMetrics/issues/60
---
 app/vminsert/common/lines_reader.go      | 8 ++++++++
 app/vminsert/common/lines_reader_test.go | 3 ---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/app/vminsert/common/lines_reader.go b/app/vminsert/common/lines_reader.go
index f2d7db3f7..4f28bf845 100644
--- a/app/vminsert/common/lines_reader.go
+++ b/app/vminsert/common/lines_reader.go
@@ -20,6 +20,7 @@ const defaultBlockSize = 64 * 1024
 //
 // Returns (dstBuf, tailBuf).
 func ReadLinesBlock(r io.Reader, dstBuf, tailBuf []byte) ([]byte, []byte, error) {
+	origDstBufLen := len(dstBuf)
 	if cap(dstBuf) < defaultBlockSize {
 		dstBuf = bytesutil.Resize(dstBuf, defaultBlockSize)
 	}
@@ -32,6 +33,13 @@ again:
 		if err == nil {
 			return dstBuf, tailBuf, fmt.Errorf("no forward progress made")
 		}
+		if err == io.EOF && len(dstBuf) > origDstBufLen {
+			// Missing newline in the end of stream. This is OK,
+			/// so suppress io.EOF for now. It will be returned during the next
+			// call to ReadLinesBlock.
+			// This fixes https://github.com/VictoriaMetrics/VictoriaMetrics/issues/60 .
+			return dstBuf, tailBuf, nil
+		}
 		return dstBuf, tailBuf, err
 	}
 	dstBuf = dstBuf[:len(dstBuf)+n]
diff --git a/app/vminsert/common/lines_reader_test.go b/app/vminsert/common/lines_reader_test.go
index 4f320e215..6c3d304c3 100644
--- a/app/vminsert/common/lines_reader_test.go
+++ b/app/vminsert/common/lines_reader_test.go
@@ -29,9 +29,6 @@ func TestReadLinesBlockFailure(t *testing.T) {
 	// empty string
 	f("")
 
-	// no newline in nonempty string
-	f("foobar")
-
 	// too long string
 	b := make([]byte, maxLineSize+1)
 	f(string(b))