🔧 config: add log output file configuration and cleanup example files

.gitignore

@@ -20,3 +20,4 @@ go.work
 # Server runtime files
 server.log
 server.pid
+*.log

AGENTS.md

@@ -156,6 +156,7 @@ The server supports flexible configuration through environment variables with th
 | Port | `DLC_SERVER_PORT` | `8080` | Server listening port |
 | Shutdown Timeout | `DLC_SHUTDOWN_TIMEOUT` | `30s` | Graceful shutdown timeout |
 | JSON Logging | `DLC_LOGGING_JSON` | `false` | Enable JSON format logging |
+| Log Output | `DLC_LOGGING_OUTPUT` | `""` | Log output file path (empty for stderr) |
 
 **Usage Examples:**
 
@@ -176,6 +177,15 @@ export DLC_SHUTDOWN_TIMEOUT=45s
 # Enable JSON logging
 export DLC_LOGGING_JSON=true
 ./scripts/start-server.sh start
+
+# Log to file
+export DLC_LOGGING_OUTPUT="server.log"
+./scripts/start-server.sh start
+
+# Combined: JSON logging to file
+export DLC_LOGGING_JSON=true
+export DLC_LOGGING_OUTPUT="server.json.log"
+./scripts/start-server.sh start
 ```
 
 **Configuration File Support:**

cmd/server/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"os"
 
 	"DanceLessonsCoach/pkg/config"
 	"DanceLessonsCoach/pkg/server"
@@ -15,6 +16,9 @@ func main() {
 		log.Fatal().Err(err).Msg("Failed to load configuration")
 	}
 
+	// Setup log output based on configuration
+	setupLogOutput(cfg)
+
 	// Create readiness context to control readiness state
 	readyCtx, readyCancel := context.WithCancel(context.Background())
 	defer readyCancel()
@@ -25,3 +29,23 @@ func main() {
 		log.Fatal().Err(err).Msg("Server failed")
 	}
 }
+
+// setupLogOutput configures the log output based on configuration
+func setupLogOutput(cfg *config.Config) {
+	output := cfg.GetLogOutput()
+	if output == "" {
+		// Use stderr by default
+		return
+	}
+	
+	// Open the log file
+	file, err := os.OpenFile(output, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	if err != nil {
+		log.Error().Err(err).Str("output", output).Msg("Failed to open log file, using stderr")
+		return
+	}
+	
+	// Set the log output
+	log.Logger = log.Output(file)
+	log.Info().Str("output", output).Msg("Logging to file")
+}

config.example.yaml

@@ -1,66 +0,0 @@
-# DanceLessonsCoach Configuration Example
-# This file shows the available configuration options
-# You can use this as a template for your own configuration
-
-# Server configuration
-server:
-  # Host address to bind to (default: "0.0.0.0")
-  host: "0.0.0.0"
-  
-  # Port to listen on (default: 8080)
-  port: 8080
-
-# Shutdown configuration
-shutdown:
-  # Timeout duration for graceful shutdown (default: 30s)
-  # Format: number + unit (s, m, h)
-  timeout: 30s
-
-# Logging configuration
-logging:
-  # Enable JSON output for structured logging (default: false)
-  # When true, logs are output in JSON format instead of console format
-  json: false
-  
-  # Log level (default: "trace")
-  # Options: "trace", "debug", "info", "warn", "error", "fatal", "panic"
-  level: trace
-
-# Telemetry configuration (OpenTelemetry)
-telemetry:
-  # Enable OpenTelemetry tracing (default: false)
-  enabled: false
-  
-  # OTLP endpoint for trace export (default: "localhost:4317")
-  # Format: host:port
-  otlp_endpoint: "localhost:4317"
-  
-  # Service name for tracing (default: "DanceLessonsCoach")
-  service_name: "DanceLessonsCoach"
-  
-  # Use insecure connection (no TLS) (default: true)
-  insecure: true
-  
-  # Sampler configuration
-  sampler:
-    # Sampler type (default: "parentbased_always_on")
-    # Options: "always_on", "always_off", "traceidratio", "parentbased_always_on", "parentbased_always_off", "parentbased_traceidratio"
-    type: "parentbased_always_on"
-    
-    # Sampling ratio (0.0 to 1.0, default: 1.0)
-    # Only used with traceidratio and parentbased_traceidratio samplers
-    ratio: 1.0
-
-# Environment Variables
-# You can also configure via environment variables with DLC_ prefix:
-# DLC_SERVER_HOST=0.0.0.0
-# DLC_SERVER_PORT=8080
-# DLC_SHUTDOWN_TIMEOUT=30s
-# DLC_LOGGING_JSON=false
-# DLC_LOGGING_LEVEL=trace
-# DLC_TELEMETRY_ENABLED=true
-# DLC_TELEMETRY_OTLP_ENDPOINT="jaeger:4317"
-# DLC_TELEMETRY_SERVICE_NAME="DanceLessonsCoach"
-# DLC_TELEMETRY_INSECURE=true
-# DLC_TELEMETRY_SAMPLER_TYPE="parentbased_always_on"
-# DLC_TELEMETRY_SAMPLER_RATIO=1.0

config.json_test.yaml

@@ -1,7 +0,0 @@
-server:
-  host: "0.0.0.0"
-  port: 8080
-shutdown:
-  timeout: 5s
-logging:
-  json: true

config.yaml

@@ -1,5 +1,58 @@
+# DanceLessonsCoach Configuration
+# This file serves as both the default configuration and documentation
+# All available options are shown with their default values
+
+# Server configuration
 server:
+  # Host address to bind to (default: "0.0.0.0")
   host: "0.0.0.0"
+  
+  # Port to listen on (default: 8080)
   port: 8080
+
+# Shutdown configuration
 shutdown:
-  timeout: 5s
+  # Timeout duration for graceful shutdown (default: 30s)
+  # Format: number + unit (s, m, h)
+  timeout: 30s
+
+# Logging configuration
+logging:
+  # Enable JSON output for structured logging (default: false)
+  # When true, logs are output in JSON format instead of console format
+  json: false
+  
+  # Log level (default: "trace")
+  # Options: "trace", "debug", "info", "warn", "error", "fatal", "panic"
+  level: trace
+  
+  # Log output file path (default: "" for stderr)
+  # If empty, logs will be written to stderr
+  # If specified, logs will be written to the specified file
+  # Example: "server.log" or "/var/log/dance-lessons-coach.log"
+  output: ""
+
+# Telemetry configuration (OpenTelemetry)
+telemetry:
+  # Enable OpenTelemetry tracing (default: false)
+  enabled: false
+  
+  # OTLP endpoint for trace export (default: "localhost:4317")
+  # Format: host:port
+  otlp_endpoint: "localhost:4317"
+  
+  # Service name for tracing (default: "DanceLessonsCoach")
+  service_name: "DanceLessonsCoach"
+  
+  # Use insecure connection (no TLS) (default: true)
+  insecure: true
+  
+  # Sampler configuration
+  sampler:
+    # Sampler type (default: "parentbased_always_on")
+    # Options: "always_on", "always_off", "traceidratio", "parentbased_always_on", "parentbased_always_off", "parentbased_traceidratio"
+    type: "parentbased_always_on"
+    
+    # Sampling ratio (0.0 to 1.0, default: 1.0)
+    # Only used with traceidratio and parentbased_traceidratio samplers
+    ratio: 1.0

pkg/config/config.go

@@ -34,6 +34,7 @@ type ShutdownConfig struct {
 type LoggingConfig struct {
 	JSON    bool   `mapstructure:"json"`
 	Level   string `mapstructure:"level"`
+	Output  string `mapstructure:"output"`
 }
 
 // TelemetryConfig holds OpenTelemetry-related configuration
@@ -67,6 +68,7 @@ func LoadConfig() (*Config, error) {
 	v.SetDefault("shutdown.timeout", 30*time.Second)
 	v.SetDefault("logging.json", false)
 	v.SetDefault("logging.level", "trace")
+	v.SetDefault("logging.output", "")
 
 	// Telemetry defaults
 	v.SetDefault("telemetry.enabled", false)
@@ -106,6 +108,7 @@ func LoadConfig() (*Config, error) {
 	v.BindEnv("shutdown.timeout", "DLC_SHUTDOWN_TIMEOUT")
 	v.BindEnv("logging.json", "DLC_LOGGING_JSON")
 	v.BindEnv("logging.level", "DLC_LOGGING_LEVEL")
+	v.BindEnv("logging.output", "DLC_LOGGING_OUTPUT")
 
 	// Telemetry environment variables
 	v.BindEnv("telemetry.enabled", "DLC_TELEMETRY_ENABLED")
@@ -139,6 +142,7 @@ func LoadConfig() (*Config, error) {
 		Dur("shutdown_timeout", config.Shutdown.Timeout).
 		Bool("logging_json", config.Logging.JSON).
 		Str("logging_level", config.Logging.Level).
+		Str("logging_output", config.Logging.Output).
 		Bool("telemetry_enabled", config.Telemetry.Enabled).
 		Str("telemetry_service", config.Telemetry.ServiceName).
 		Msg("Configuration loaded")
@@ -186,6 +190,11 @@ func (c *Config) GetLogLevel() string {
 	return c.Logging.Level
 }
 
+// GetLogOutput returns the log output path
+func (c *Config) GetLogOutput() string {
+	return c.Logging.Output
+}
+
 // SetupLogging configures zerolog based on the configuration
 func (c *Config) SetupLogging() {
 	// Parse log level