From 5da7a21119fa9a930a201c890b593929220cb285 Mon Sep 17 00:00:00 2001
From: henrygd <hank@henrygd.me>
Date: Thu, 8 Jan 2026 13:57:56 -0500
Subject: [PATCH] agent: fix container logs decoding for raw streams (#1535)

---
 agent/docker.go      |  9 +++++++--
 agent/docker_test.go | 17 ++++++++++++++---
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/agent/docker.go b/agent/docker.go
index 3b83ed59..44558b24 100644
--- a/agent/docker.go
+++ b/agent/docker.go
@@ -694,7 +694,8 @@ func (dm *dockerManager) getLogs(ctx context.Context, containerID string) (strin
 	}
 
 	var builder strings.Builder
-	if err := decodeDockerLogStream(resp.Body, &builder); err != nil {
+	multiplexed := resp.Header.Get("Content-Type") == "application/vnd.docker.multiplexed-stream"
+	if err := decodeDockerLogStream(resp.Body, &builder, multiplexed); err != nil {
 		return "", err
 	}
 
@@ -706,7 +707,11 @@ func (dm *dockerManager) getLogs(ctx context.Context, containerID string) (strin
 	return logs, nil
 }
 
-func decodeDockerLogStream(reader io.Reader, builder *strings.Builder) error {
+func decodeDockerLogStream(reader io.Reader, builder *strings.Builder, multiplexed bool) error {
+	if !multiplexed {
+		_, err := io.Copy(builder, io.LimitReader(reader, maxTotalLogSize))
+		return err
+	}
 	const headerSize = 8
 	var header [headerSize]byte
 	totalBytesRead := 0
diff --git a/agent/docker_test.go b/agent/docker_test.go
index 601e6b39..972ae56f 100644
--- a/agent/docker_test.go
+++ b/agent/docker_test.go
@@ -950,6 +950,7 @@ func TestDecodeDockerLogStream(t *testing.T) {
 		input       []byte
 		expected    string
 		expectError bool
+		multiplexed bool
 	}{
 		{
 			name: "simple log entry",
@@ -960,6 +961,7 @@ func TestDecodeDockerLogStream(t *testing.T) {
 			},
 			expected:    "Hello World",
 			expectError: false,
+			multiplexed: true,
 		},
 		{
 			name: "multiple frames",
@@ -973,6 +975,7 @@ func TestDecodeDockerLogStream(t *testing.T) {
 			},
 			expected:    "HelloWorld",
 			expectError: false,
+			multiplexed: true,
 		},
 		{
 			name: "zero length frame",
@@ -985,12 +988,20 @@ func TestDecodeDockerLogStream(t *testing.T) {
 			},
 			expected:    "Hello",
 			expectError: false,
+			multiplexed: true,
 		},
 		{
 			name:        "empty input",
 			input:       []byte{},
 			expected:    "",
 			expectError: false,
+			multiplexed: true,
+		},
+		{
+			name:        "raw stream (not multiplexed)",
+			input:       []byte("raw log content"),
+			expected:    "raw log content",
+			multiplexed: false,
 		},
 	}
 
@@ -998,7 +1009,7 @@ func TestDecodeDockerLogStream(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			reader := bytes.NewReader(tt.input)
 			var builder strings.Builder
-			err := decodeDockerLogStream(reader, &builder)
+			err := decodeDockerLogStream(reader, &builder, tt.multiplexed)
 
 			if tt.expectError {
 				assert.Error(t, err)
@@ -1022,7 +1033,7 @@ func TestDecodeDockerLogStreamMemoryProtection(t *testing.T) {
 
 		reader := bytes.NewReader(input)
 		var builder strings.Builder
-		err := decodeDockerLogStream(reader, &builder)
+		err := decodeDockerLogStream(reader, &builder, true)
 
 		assert.Error(t, err)
 		assert.Contains(t, err.Error(), "log frame size")
@@ -1056,7 +1067,7 @@ func TestDecodeDockerLogStreamMemoryProtection(t *testing.T) {
 
 		reader := bytes.NewReader(input)
 		var builder strings.Builder
-		err := decodeDockerLogStream(reader, &builder)
+		err := decodeDockerLogStream(reader, &builder, true)
 
 		// Should complete without error (graceful truncation)
 		assert.NoError(t, err)