feat: add main entry point and stdout sink for Docker build

- Create cmd/logcorrelator/main.go as the application entry point
  - Loads configuration from YAML file
  - Initializes Unix socket sources, file/ClickHouse/stdout sinks
  - Sets up correlation service and orchestrator
  - Handles graceful shutdown on SIGINT/SIGTERM
  - Supports -version flag to print version

- Add internal/adapters/outbound/stdout/sink.go
  - Implements CorrelatedLogSink interface for stdout output
  - Writes JSON lines to standard output

- Fix .gitignore to use /logcorrelator instead of logcorrelator
  - Prevents cmd/logcorrelator directory from being ignored

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

cmd/logcorrelator/main.go

@@ -0,0 +1,143 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/logcorrelator/logcorrelator/internal/adapters/inbound/unixsocket"
+	"github.com/logcorrelator/logcorrelator/internal/adapters/outbound/clickhouse"
+	"github.com/logcorrelator/logcorrelator/internal/adapters/outbound/file"
+	"github.com/logcorrelator/logcorrelator/internal/adapters/outbound/multi"
+	"github.com/logcorrelator/logcorrelator/internal/adapters/outbound/stdout"
+	"github.com/logcorrelator/logcorrelator/internal/app"
+	"github.com/logcorrelator/logcorrelator/internal/config"
+	"github.com/logcorrelator/logcorrelator/internal/domain"
+	"github.com/logcorrelator/logcorrelator/internal/observability"
+	"github.com/logcorrelator/logcorrelator/internal/ports"
+)
+
+var Version = "dev"
+
+func main() {
+	configPath := flag.String("config", "config.yml", "path to configuration file")
+	version := flag.Bool("version", false, "print version and exit")
+	flag.Parse()
+
+	if *version {
+		fmt.Println(Version)
+		os.Exit(0)
+	}
+
+	// Load configuration
+	cfg, err := config.Load(*configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error loading configuration: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Initialize logger
+	logger := observability.NewLogger(cfg.Service.Name)
+
+	logger.Info(fmt.Sprintf("Starting logcorrelator version %s", Version))
+
+	// Create sources
+	sources := make([]ports.EventSource, 0, len(cfg.Inputs.UnixSockets))
+	for _, inputCfg := range cfg.Inputs.UnixSockets {
+		source := unixsocket.NewUnixSocketSource(unixsocket.Config{
+			Name:       inputCfg.Name,
+			Path:       inputCfg.Path,
+			SourceType: inputCfg.SourceType,
+		})
+		sources = append(sources, source)
+		logger.Info(fmt.Sprintf("Configured input source: name=%s, path=%s", inputCfg.Name, inputCfg.Path))
+	}
+
+	// Create sinks
+	sinks := make([]ports.CorrelatedLogSink, 0)
+
+	if cfg.Outputs.File.Enabled {
+		fileSink, err := file.NewFileSink(file.Config{
+			Path: cfg.Outputs.File.Path,
+		})
+		if err != nil {
+			logger.Error("Failed to create file sink", err)
+			os.Exit(1)
+		}
+		sinks = append(sinks, fileSink)
+		logger.Info(fmt.Sprintf("Configured file sink: path=%s", cfg.Outputs.File.Path))
+	}
+
+	if cfg.Outputs.ClickHouse.Enabled {
+		clickHouseSink, err := clickhouse.NewClickHouseSink(clickhouse.Config{
+			DSN:             cfg.Outputs.ClickHouse.DSN,
+			Table:           cfg.Outputs.ClickHouse.Table,
+			BatchSize:       cfg.Outputs.ClickHouse.BatchSize,
+			FlushIntervalMs: cfg.Outputs.ClickHouse.FlushIntervalMs,
+			MaxBufferSize:   cfg.Outputs.ClickHouse.MaxBufferSize,
+			DropOnOverflow:  cfg.Outputs.ClickHouse.DropOnOverflow,
+			AsyncInsert:     cfg.Outputs.ClickHouse.AsyncInsert,
+			TimeoutMs:       cfg.Outputs.ClickHouse.TimeoutMs,
+		})
+		if err != nil {
+			logger.Error("Failed to create ClickHouse sink", err)
+			os.Exit(1)
+		}
+		sinks = append(sinks, clickHouseSink)
+		logger.Info(fmt.Sprintf("Configured ClickHouse sink: table=%s", cfg.Outputs.ClickHouse.Table))
+	}
+
+	if cfg.Outputs.Stdout.Enabled {
+		stdoutSink := stdout.NewStdoutSink(stdout.Config{
+			Enabled: cfg.Outputs.Stdout.Enabled,
+		})
+		sinks = append(sinks, stdoutSink)
+		logger.Info("Configured stdout sink")
+	}
+
+	// Create multi-sink wrapper
+	multiSink := multi.NewMultiSink(sinks...)
+
+	// Create correlation service
+	correlationSvc := domain.NewCorrelationService(domain.CorrelationConfig{
+		TimeWindow:       cfg.Correlation.GetTimeWindow(),
+		ApacheAlwaysEmit: cfg.Correlation.OrphanPolicy.ApacheAlwaysEmit,
+		NetworkEmit:      cfg.Correlation.OrphanPolicy.NetworkEmit,
+		MaxBufferSize:    domain.DefaultMaxBufferSize,
+	}, &domain.RealTimeProvider{})
+
+	logger.Info(fmt.Sprintf("Correlation service initialized: time_window=%s, apache_always_emit=%v, network_emit=%v",
+		cfg.Correlation.GetTimeWindow().String(),
+		cfg.Correlation.OrphanPolicy.ApacheAlwaysEmit,
+		cfg.Correlation.OrphanPolicy.NetworkEmit))
+
+	// Create orchestrator
+	orchestrator := app.NewOrchestrator(app.OrchestratorConfig{
+		Sources: sources,
+		Sink:    multiSink,
+	}, correlationSvc)
+
+	// Start the application
+	if err := orchestrator.Start(); err != nil {
+		logger.Error("Failed to start orchestrator", err)
+		os.Exit(1)
+	}
+
+	logger.Info("logcorrelator started successfully")
+
+	// Wait for shutdown signal
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+	sig := <-sigChan
+
+	logger.Info(fmt.Sprintf("Shutdown signal received: %v", sig))
+
+	// Graceful shutdown
+	if err := orchestrator.Stop(); err != nil {
+		logger.Error("Error during shutdown", err)
+	}
+
+	logger.Info("logcorrelator stopped")
+}