From 02ab2b447a7af99503421b00ec77e8ee645bb3a2 Mon Sep 17 00:00:00 2001
From: Alex Van Boxel <alex@vanboxel.be>
Date: Thu, 15 Apr 2021 22:33:14 +0200
Subject: [PATCH] Add trace attributes to the log entry (#3018)

JSON log parsers are now able to extract the OpenTelemetry compliant
trace_id, span_id and trace_flags attributes and add them to the
correct attributes.
---
 internal/stanza/converter.go      | 19 +++++++++++++++++++
 internal/stanza/converter_test.go | 23 +++++++++++++++++++++++
 internal/stanza/register.go       |  1 +
 3 files changed, 43 insertions(+)

diff --git a/internal/stanza/converter.go b/internal/stanza/converter.go
index 74ae54963161..1f7498843abe 100644
--- a/internal/stanza/converter.go
+++ b/internal/stanza/converter.go
@@ -337,6 +337,25 @@ func convertInto(ent *entry.Entry, dest pdata.LogRecord) {
 	}
 
 	insertToAttributeVal(ent.Body, dest.Body())
+
+	if ent.TraceId != nil {
+		var buffer [16]byte
+		copy(buffer[0:16], ent.TraceId)
+		dest.SetTraceID(pdata.NewTraceID(buffer))
+	}
+	if ent.SpanId != nil {
+		var buffer [8]byte
+		copy(buffer[0:8], ent.SpanId)
+		dest.SetSpanID(pdata.NewSpanID(buffer))
+	}
+	if ent.TraceFlags != nil {
+		// The 8 least significant bits are the trace flags as defined in W3C Trace
+		// Context specification. Don't override the 24 reserved bits.
+		flags := dest.Flags()
+		flags = flags & 0xFFFFFF00
+		flags = flags | uint32(ent.TraceFlags[0])
+		dest.SetFlags(flags)
+	}
 }
 
 func insertToAttributeVal(value interface{}, dest pdata.AttributeValue) {
diff --git a/internal/stanza/converter_test.go b/internal/stanza/converter_test.go
index dae6c76fde4c..0e78518b05c9 100644
--- a/internal/stanza/converter_test.go
+++ b/internal/stanza/converter_test.go
@@ -551,3 +551,26 @@ func TestConvertSeverity(t *testing.T) {
 		})
 	}
 }
+
+func TestConvertTrace(t *testing.T) {
+	record := convertAndDrill(&entry.Entry{
+		TraceId: []byte{
+			0x48, 0x01, 0x40, 0xf3, 0xd7, 0x70, 0xa5, 0xae, 0x32, 0xf0, 0xa2, 0x2b, 0x6a, 0x81, 0x2c, 0xff,
+		},
+		SpanId: []byte{
+			0x32, 0xf0, 0xa2, 0x2b, 0x6a, 0x81, 0x2c, 0xff,
+		},
+		TraceFlags: []byte{
+			0x01,
+		}})
+
+	require.Equal(t, pdata.NewTraceID(
+		[16]byte{
+			0x48, 0x01, 0x40, 0xf3, 0xd7, 0x70, 0xa5, 0xae, 0x32, 0xf0, 0xa2, 0x2b, 0x6a, 0x81, 0x2c, 0xff,
+		}), record.TraceID())
+	require.Equal(t, pdata.NewSpanID(
+		[8]byte{
+			0x32, 0xf0, 0xa2, 0x2b, 0x6a, 0x81, 0x2c, 0xff,
+		}), record.SpanID())
+	require.Equal(t, uint32(0x01), record.Flags())
+}
diff --git a/internal/stanza/register.go b/internal/stanza/register.go
index d3c8145930c4..4754f35cf914 100644
--- a/internal/stanza/register.go
+++ b/internal/stanza/register.go
@@ -20,6 +20,7 @@ import (
 	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/parser/regex"
 	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/parser/severity"
 	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/parser/time"
+	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/parser/trace"
 	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/transformer/metadata"
 	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/transformer/restructure"
 	_ "github.com/open-telemetry/opentelemetry-log-collection/operator/builtin/transformer/router"