[exporter/loki] fix issue with log message quotation (#12116)

* wrap double quotes to log entry line

* use strconv.Quote for wrapping quotation marks

* Add test case for quotation marks in loki exporter

* add changelog

* fix additional double quote in the beginning of the attribute

exporter/lokiexporter/exporter.go

@@ -298,7 +298,8 @@ func (l *lokiExporter) convertLogBodyToEntry(lr plog.LogRecord, res pcommon.Reso
 		if _, found := l.config.Labels.Attributes[k]; !found {
 			b.WriteString(k)
 			b.WriteString("=")
-			b.WriteString(v.AsString())
+			// encapsulate with double quotes. See https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/11827
+			b.WriteString(strconv.Quote(v.AsString()))
 			b.WriteRune(' ')
 		}
 		return true

exporter/lokiexporter/exporter_test.go

@@ -298,13 +298,14 @@ func TestExporter_logDataToLoki(t *testing.T) {
 		lr.Body().SetStringVal("log message")
 		lr.Attributes().InsertString(conventions.AttributeContainerName, "mycontainer")
 		lr.Attributes().InsertString("severity", "info")
-		lr.Attributes().InsertString("random.attribute", "random")
+		lr.Attributes().InsertString("random.attribute", "random attribute")
 		lr.SetTimestamp(ts)
 
 		pr, numDroppedLogs := exp.logDataToLoki(logs)
 		require.Equal(t, 0, numDroppedLogs)
 		require.NotNil(t, pr)
 		require.Len(t, pr.Streams, 1)
+		require.Contains(t, pr.Streams[0].Entries[0].Line, fmt.Sprintf("%q", "random attribute"))
 	})
 
 	t.Run("with multiple logs and same attributes", func(t *testing.T) {

unreleased/fix-loki-quote-issue.yaml

@@ -0,0 +1,15 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: 'bug_fix'
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: lokiexporter
+
+# A brief description of the change
+note: Wrap quotes around log message
+
+# One or more tracking issues related to the change
+issues: [11827]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# subtext: