Split large package into subpackages

pkg/instance/logging.go

@@ -0,0 +1,118 @@
+package instance
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+)
+
+type InstanceLogger struct {
+	name        string
+	logDir      string
+	logFile     *os.File
+	logFilePath string
+}
+
+func NewInstanceLogger(name string, logDir string) *InstanceLogger {
+	return &InstanceLogger{
+		name:   name,
+		logDir: logDir,
+	}
+}
+
+// Create creates and opens the log files for stdout and stderr
+func (i *InstanceLogger) Create() error {
+	if i.logDir == "" {
+		return fmt.Errorf("logDir is empty for instance %s", i.name)
+	}
+
+	// Set up instance logs
+	logPath := i.logDir + "/" + i.name + ".log"
+
+	i.logFilePath = logPath
+	if err := os.MkdirAll(i.logDir, 0755); err != nil {
+		return fmt.Errorf("failed to create log directory: %w", err)
+	}
+
+	logFile, err := os.OpenFile(logPath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to create stdout log file: %w", err)
+	}
+
+	i.logFile = logFile
+
+	// Write a startup marker to both files
+	timestamp := time.Now().Format("2006-01-02 15:04:05")
+	fmt.Fprintf(i.logFile, "\n=== Instance %s started at %s ===\n", i.name, timestamp)
+
+	return nil
+}
+
+// GetLogs retrieves the last n lines of logs from the instance
+func (i *Instance) GetLogs(num_lines int) (string, error) {
+	i.mu.RLock()
+	logFileName := i.logger.logFilePath
+	i.mu.RUnlock()
+
+	if logFileName == "" {
+		return "", fmt.Errorf("log file not created for instance %s", i.Name)
+	}
+
+	file, err := os.Open(logFileName)
+	if err != nil {
+		return "", fmt.Errorf("failed to open log file: %w", err)
+	}
+	defer file.Close()
+
+	if num_lines <= 0 {
+		content, err := io.ReadAll(file)
+		if err != nil {
+			return "", fmt.Errorf("failed to read log file: %w", err)
+		}
+		return string(content), nil
+	}
+
+	var lines []string
+	scanner := bufio.NewScanner(file)
+
+	// Read all lines into a slice
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		return "", fmt.Errorf("error reading file: %w", err)
+	}
+
+	// Return the last N lines
+	start := max(len(lines)-num_lines, 0)
+
+	return strings.Join(lines[start:], "\n"), nil
+}
+
+// closeLogFile closes the log files
+func (i *InstanceLogger) Close() {
+	if i.logFile != nil {
+		timestamp := time.Now().Format("2006-01-02 15:04:05")
+		fmt.Fprintf(i.logFile, "=== Instance %s stopped at %s ===\n\n", i.name, timestamp)
+		i.logFile.Close()
+		i.logFile = nil
+	}
+}
+
+// readOutput reads from the given reader and writes lines to the log file
+func (i *InstanceLogger) readOutput(reader io.ReadCloser) {
+	defer reader.Close()
+
+	scanner := bufio.NewScanner(reader)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if i.logFile != nil {
+			fmt.Fprintln(i.logFile, line)
+			i.logFile.Sync() // Ensure data is written to disk
+		}
+	}
+}