Add configuration loading with defaults and environment variable support

server/pkg/config.go

@@ -0,0 +1,232 @@
+package llamactl
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Config represents the configuration for llamactl
+type Config struct {
+	Server    ServerConfig    `yaml:"server"`
+	Instances InstancesConfig `yaml:"instances"`
+}
+
+// ServerConfig contains HTTP server configuration
+type ServerConfig struct {
+	// Server host to bind to
+	Host string `yaml:"host"`
+
+	// Server port to bind to
+	Port int `yaml:"port"`
+}
+
+// InstancesConfig contains instance management configuration
+type InstancesConfig struct {
+	// Port range for instances (e.g., "8000-9000")
+	PortRange string `yaml:"port_range"`
+
+	// Directory where instance logs will be stored
+	LogDirectory string `yaml:"log_directory"`
+
+	// Maximum number of instances that can be created
+	MaxInstances int `yaml:"max_instances"`
+
+	// Path to llama-server executable
+	LlamaExecutable string `yaml:"llama_executable"`
+
+	// Default auto-restart setting for new instances
+	DefaultAutoRestart bool `yaml:"default_auto_restart"`
+
+	// Default max restarts for new instances
+	DefaultMaxRestarts int `yaml:"default_max_restarts"`
+
+	// Default restart delay for new instances
+	DefaultRestartDelay Duration `yaml:"default_restart_delay"`
+}
+
+// LoadConfig loads configuration with the following precedence:
+// 1. Hardcoded defaults
+// 2. Config file
+// 3. Environment variables
+func LoadConfig(configPath string) (Config, error) {
+	// 1. Start with defaults
+	cfg := Config{
+		Server: ServerConfig{
+			Host: "",
+			Port: 8080,
+		},
+		Instances: InstancesConfig{
+			PortRange:           "8000-9000",
+			LogDirectory:        "/tmp/llamactl",
+			MaxInstances:        10,
+			LlamaExecutable:     "llama-server",
+			DefaultAutoRestart:  false,
+			DefaultMaxRestarts:  3,
+			DefaultRestartDelay: Duration(5 * time.Second),
+		},
+	}
+
+	// 2. Load from config file
+	if err := loadConfigFile(&cfg, configPath); err != nil {
+		return cfg, err
+	}
+
+	// 3. Override with environment variables
+	loadEnvVars(&cfg)
+
+	return cfg, nil
+}
+
+// loadConfigFile attempts to load config from file with fallback locations
+func loadConfigFile(cfg *Config, configPath string) error {
+	var configLocations []string
+
+	// If specific config path provided, use only that
+	if configPath != "" {
+		configLocations = []string{configPath}
+	} else {
+		// Default config file locations (in order of precedence)
+		configLocations = getDefaultConfigLocations()
+	}
+
+	for _, path := range configLocations {
+		if data, err := os.ReadFile(path); err == nil {
+			if err := yaml.Unmarshal(data, cfg); err != nil {
+				return err
+			}
+			return nil
+		}
+	}
+
+	return nil
+}
+
+// loadEnvVars overrides config with environment variables
+func loadEnvVars(cfg *Config) {
+	// Server config
+	if host := os.Getenv("LLAMACTL_HOST"); host != "" {
+		cfg.Server.Host = host
+	}
+	if port := os.Getenv("LLAMACTL_PORT"); port != "" {
+		if p, err := strconv.Atoi(port); err == nil {
+			cfg.Server.Port = p
+		}
+	}
+
+	// Instance config
+	if portRange := os.Getenv("LLAMACTL_INSTANCE_PORT_RANGE"); portRange != "" {
+		cfg.Instances.PortRange = portRange
+	}
+	if logDir := os.Getenv("LLAMACTL_LOG_DIR"); logDir != "" {
+		cfg.Instances.LogDirectory = logDir
+	}
+	if maxInstances := os.Getenv("LLAMACTL_MAX_INSTANCES"); maxInstances != "" {
+		if m, err := strconv.Atoi(maxInstances); err == nil {
+			cfg.Instances.MaxInstances = m
+		}
+	}
+	if llamaExec := os.Getenv("LLAMACTL_LLAMA_EXECUTABLE"); llamaExec != "" {
+		cfg.Instances.LlamaExecutable = llamaExec
+	}
+	if autoRestart := os.Getenv("LLAMACTL_DEFAULT_AUTO_RESTART"); autoRestart != "" {
+		if b, err := strconv.ParseBool(autoRestart); err == nil {
+			cfg.Instances.DefaultAutoRestart = b
+		}
+	}
+	if maxRestarts := os.Getenv("LLAMACTL_DEFAULT_MAX_RESTARTS"); maxRestarts != "" {
+		if m, err := strconv.Atoi(maxRestarts); err == nil {
+			cfg.Instances.DefaultMaxRestarts = m
+		}
+	}
+	if restartDelay := os.Getenv("LLAMACTL_DEFAULT_RESTART_DELAY"); restartDelay != "" {
+		if d, err := parseDelaySeconds(restartDelay); err == nil {
+			cfg.Instances.DefaultRestartDelay = Duration(d)
+		}
+	}
+}
+
+// parseDelaySeconds parses a string as seconds and returns a time.Duration
+// Accepts both plain numbers (seconds) and duration strings like "5s", "30s"
+func parseDelaySeconds(s string) (time.Duration, error) {
+	// If it contains letters, try parsing as duration
+	if strings.ContainsAny(s, "smh") {
+		return time.ParseDuration(s)
+	}
+
+	// Otherwise parse as seconds
+	seconds, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return time.Duration(seconds * float64(time.Second)), nil
+}
+
+// getDefaultConfigLocations returns platform-specific config file locations
+func getDefaultConfigLocations() []string {
+	var locations []string
+
+	// Current directory (cross-platform)
+	locations = append(locations,
+		"./llamactl.yaml",
+		"./config.yaml",
+	)
+
+	homeDir, _ := os.UserHomeDir()
+
+	switch runtime.GOOS {
+	case "windows":
+		// Windows: Use APPDATA and ProgramData
+		if appData := os.Getenv("APPDATA"); appData != "" {
+			locations = append(locations, filepath.Join(appData, "llamactl", "config.yaml"))
+		}
+		if programData := os.Getenv("PROGRAMDATA"); programData != "" {
+			locations = append(locations, filepath.Join(programData, "llamactl", "config.yaml"))
+		}
+		// Fallback to user home
+		if homeDir != "" {
+			locations = append(locations, filepath.Join(homeDir, "llamactl", "config.yaml"))
+		}
+
+	case "darwin":
+		// macOS: Use proper Application Support directories
+		if homeDir != "" {
+			locations = append(locations,
+				filepath.Join(homeDir, "Library", "Application Support", "llamactl", "config.yaml"),
+				filepath.Join(homeDir, ".config", "llamactl", "config.yaml"), // XDG fallback
+			)
+		}
+		locations = append(locations, "/Library/Application Support/llamactl/config.yaml")
+		locations = append(locations, "/etc/llamactl/config.yaml") // Unix fallback
+
+	default:
+		// User config: $XDG_CONFIG_HOME/llamactl/config.yaml or ~/.config/llamactl/config.yaml
+		configHome := os.Getenv("XDG_CONFIG_HOME")
+		if configHome == "" && homeDir != "" {
+			configHome = filepath.Join(homeDir, ".config")
+		}
+		if configHome != "" {
+			locations = append(locations, filepath.Join(configHome, "llamactl", "config.yaml"))
+		}
+
+		// System config: /etc/llamactl/config.yaml
+		locations = append(locations, "/etc/llamactl/config.yaml")
+
+		// Additional system locations
+		if xdgConfigDirs := os.Getenv("XDG_CONFIG_DIRS"); xdgConfigDirs != "" {
+			for _, dir := range strings.Split(xdgConfigDirs, ":") {
+				if dir != "" {
+					locations = append(locations, filepath.Join(dir, "llamactl", "config.yaml"))
+				}
+			}
+		}
+	}
+
+	return locations
+}