Support CONTAINER_LOG_PATH.

Signed-off-by: Josh Baird <[email protected]>

Author: joshuabaird

cmd/fluent-manager/main.go

@@ -230,10 +230,20 @@ func main() {
 		}
 	}
 
-	if envs, err := godotenv.Read("/fluent-operator/fluent-bit.env"); err == nil {
+	// CONTAINER_ROOT_DIR is the location that Fluent Bit looks for container logs on nodes
+	// Falls back to legacy file-based configuration for backward compatibility
+	if envLogPath := os.Getenv("CONTAINER_LOG_PATH"); envLogPath != "" {
+		logPath = envLogPath
+	} else if envs, err := godotenv.Read("/fluent-operator/fluent-bit.env"); err == nil {
 		logPath = envs["CONTAINER_ROOT_DIR"] + "/containers"
 	}
 
+	// If neither the env var or file based config is available, fall back to the
+	// default path for containerd/CRI-O
+	if logPath == "" {
+		logPath = "/var/log/containers"
+	}
+
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrlOpts)
 	if err != nil {
 		setupLog.Error(err, "unable to start manager")

cmd/fluent-manager/main_test.go

@@ -0,0 +1,184 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/joho/godotenv"
+)
+
+// TestContainerLogPathResolution tests the container log path resolution logic
+// that will be added to main.go
+func TestContainerLogPathResolution(t *testing.T) {
+	tests := []struct {
+		name           string
+		envVar         string
+		fileContent    string
+		expectedPath   string
+		setupFile      bool
+	}{
+		{
+			name:         "prefer environment variable over file",
+			envVar:       "/custom/containers",
+			fileContent:  "CONTAINER_ROOT_DIR=/var/log",
+			expectedPath: "/custom/containers",
+			setupFile:    true,
+		},
+		{
+			name:         "fallback to file when env var not set",
+			envVar:       "",
+			fileContent:  "CONTAINER_ROOT_DIR=/var/log",
+			expectedPath: "/var/log/containers",
+			setupFile:    true,
+		},
+		{
+			name:         "fallback to file for docker path",
+			envVar:       "",
+			fileContent:  "CONTAINER_ROOT_DIR=/var/lib/docker",
+			expectedPath: "/var/lib/docker/containers",
+			setupFile:    true,
+		},
+		{
+			name:         "use default when neither env var nor file present",
+			envVar:       "",
+			fileContent:  "",
+			expectedPath: "/var/log/containers",
+			setupFile:    false,
+		},
+		{
+			name:         "env var takes precedence even with docker in file",
+			envVar:       "/override/containers",
+			fileContent:  "CONTAINER_ROOT_DIR=/var/lib/docker",
+			expectedPath: "/override/containers",
+			setupFile:    true,
+		},
+		{
+			name:         "handle empty env var (should fallback)",
+			envVar:       "",
+			fileContent:  "CONTAINER_ROOT_DIR=/var/log",
+			expectedPath: "/var/log/containers",
+			setupFile:    true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Create temporary directory for test file
+			tmpDir := t.TempDir()
+			testFile := filepath.Join(tmpDir, "fluent-bit.env")
+
+			// Setup environment variable
+			if tt.envVar != "" {
+				os.Setenv("CONTAINER_LOG_PATH", tt.envVar)
+				defer os.Unsetenv("CONTAINER_LOG_PATH")
+			} else {
+				os.Unsetenv("CONTAINER_LOG_PATH")
+			}
+
+			// Setup file if needed
+			if tt.setupFile && tt.fileContent != "" {
+				err := os.WriteFile(testFile, []byte(tt.fileContent), 0644)
+				if err != nil {
+					t.Fatalf("failed to create test file: %v", err)
+				}
+			}
+
+			// Execute the resolution logic (mimics what will be in main.go)
+			var logPath string
+
+			// Prefer environment variable for container log path (modern approach)
+			// Fall back to file-based configuration for backward compatibility
+			if envLogPath := os.Getenv("CONTAINER_LOG_PATH"); envLogPath != "" {
+				logPath = envLogPath
+			} else if tt.setupFile {
+				if envs, err := godotenv.Read(testFile); err == nil {
+					logPath = envs["CONTAINER_ROOT_DIR"] + "/containers"
+				}
+			}
+
+			// Final fallback to safe default for containerd/CRI-O
+			if logPath == "" {
+				logPath = "/var/log/containers"
+			}
+
+			// Verify result
+			if logPath != tt.expectedPath {
+				t.Errorf("expected logPath to be %q, got %q", tt.expectedPath, logPath)
+			}
+		})
+	}
+}
+
+// TestContainerLogPathEnvVarPrecedence specifically tests that env var always wins
+func TestContainerLogPathEnvVarPrecedence(t *testing.T) {
+	tmpDir := t.TempDir()
+	testFile := filepath.Join(tmpDir, "fluent-bit.env")
+
+	// Create file with one path
+	err := os.WriteFile(testFile, []byte("CONTAINER_ROOT_DIR=/var/lib/docker"), 0644)
+	if err != nil {
+		t.Fatalf("failed to create test file: %v", err)
+	}
+
+	// Set env var with different path
+	envPath := "/env/var/wins"
+	os.Setenv("CONTAINER_LOG_PATH", envPath)
+	defer os.Unsetenv("CONTAINER_LOG_PATH")
+
+	// Execute resolution logic
+	var logPath string
+	if envLogPath := os.Getenv("CONTAINER_LOG_PATH"); envLogPath != "" {
+		logPath = envLogPath
+	} else if envs, err := godotenv.Read(testFile); err == nil {
+		logPath = envs["CONTAINER_ROOT_DIR"] + "/containers"
+	}
+	if logPath == "" {
+		logPath = "/var/log/containers"
+	}
+
+	// Env var should win
+	if logPath != envPath {
+		t.Errorf("environment variable should take precedence: expected %q, got %q", envPath, logPath)
+	}
+}
+
+// TestContainerLogPathFilePathsAppendContainers verifies /containers is appended
+func TestContainerLogPathFilePathsAppendContainers(t *testing.T) {
+	tmpDir := t.TempDir()
+	testFile := filepath.Join(tmpDir, "fluent-bit.env")
+
+	// Unset env var
+	os.Unsetenv("CONTAINER_LOG_PATH")
+
+	tests := []struct {
+		rootDir      string
+		expectedPath string
+	}{
+		{"/var/log", "/var/log/containers"},
+		{"/var/lib/docker", "/var/lib/docker/containers"},
+		{"/custom/path", "/custom/path/containers"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.rootDir, func(t *testing.T) {
+			// Write test file
+			content := "CONTAINER_ROOT_DIR=" + tt.rootDir
+			err := os.WriteFile(testFile, []byte(content), 0644)
+			if err != nil {
+				t.Fatalf("failed to create test file: %v", err)
+			}
+
+			// Execute resolution logic
+			var logPath string
+			if envs, err := godotenv.Read(testFile); err == nil {
+				logPath = envs["CONTAINER_ROOT_DIR"] + "/containers"
+			}
+
+			if logPath != tt.expectedPath {
+				t.Errorf("expected %q, got %q", tt.expectedPath, logPath)
+			}
+		})
+	}
+}
+