at-container-registry/pkg/labeler/config.go

// Package labeler implements the ATCR labeler service, an ATProto-compatible
// content moderation service for issuing takedown labels on container registry content.
package labeler

import (
	"fmt"
	"net/url"
	"strings"

	"github.com/spf13/viper"

	"atcr.io/pkg/config"
)

// Config represents the labeler service configuration.
// It reuses the appview config YAML structure, reading from the "labeler" section.
type Config struct {
	Version    string                  `yaml:"version" comment:"Configuration format version."`
	LogLevel   string                  `yaml:"log_level" comment:"Log level: debug, info, warn, error."`
	Labeler    LabelerConfig           `yaml:"labeler" comment:"Labeler service settings."`
	Server     AppviewServerConfig     `yaml:"server" comment:"AppView server settings (shared config)."`
	LogShipper config.LogShipperConfig `yaml:"log_shipper" comment:"Remote log shipping settings."`
}

// LabelerConfig defines labeler-specific settings.
type LabelerConfig struct {
	// Enable the labeler service.
	Enabled bool `yaml:"enabled" comment:"Enable the labeler service."`

	// Listen address for the labeler HTTP server.
	Addr string `yaml:"addr" comment:"Listen address for labeler (e.g., :5002)."`

	// DID of the labeler admin. Only this DID can log into the admin panel.
	OwnerDID string `yaml:"owner_did" comment:"DID of the labeler admin. Only this DID can log into the admin panel."`

	// Path to labeler SQLite database.
	DBPath string `yaml:"db_path" comment:"Path to labeler SQLite database."`
}

// AppviewServerConfig is a subset of the appview ServerConfig that the labeler needs.
type AppviewServerConfig struct {
	BaseURL         string `yaml:"base_url"`
	ClientName      string `yaml:"client_name"`
	ClientShortName string `yaml:"client_short_name"`
	TestMode        bool   `yaml:"test_mode"`
}

// PublicURL returns the labeler's public URL derived from the appview base URL.
// If appview is https://atcr.io, labeler is https://labeler.atcr.io.
func (c *Config) PublicURL() string {
	u, err := url.Parse(c.Server.BaseURL)
	if err != nil {
		return ""
	}
	u.Host = "labeler." + u.Host
	return u.String()
}

// DID returns the labeler's did:web identity derived from its public URL.
func (c *Config) DID() string {
	u, err := url.Parse(c.PublicURL())
	if err != nil {
		return ""
	}
	host := u.Hostname()
	if port := u.Port(); port != "" {
		host += "%3A" + port
	}
	return "did:web:" + host
}

func setDefaults(v *viper.Viper) {
	v.SetDefault("version", "0.1")
	v.SetDefault("log_level", "info")

	// Labeler defaults
	v.SetDefault("labeler.enabled", false)
	v.SetDefault("labeler.addr", ":5002")
	v.SetDefault("labeler.owner_did", "")
	v.SetDefault("labeler.db_path", "/var/lib/atcr-labeler/labeler.db")

	// Server defaults (read from shared appview config)
	v.SetDefault("server.base_url", "")
	v.SetDefault("server.client_name", "AT Container Registry")
	v.SetDefault("server.client_short_name", "ATCR")
	v.SetDefault("server.test_mode", false)
}

// LoadConfig loads the labeler configuration from the appview config YAML.
func LoadConfig(yamlPath string) (*Config, error) {
	v := config.NewViper("LABELER", yamlPath)
	setDefaults(v)

	cfg := &Config{}
	if err := v.Unmarshal(cfg, config.UnmarshalOption()); err != nil {
		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
	}

	// Also try ATCR_ prefix for shared server config
	atcrV := config.NewViper("ATCR", yamlPath)
	if baseURL := atcrV.GetString("server.base_url"); baseURL != "" && cfg.Server.BaseURL == "" {
		cfg.Server.BaseURL = baseURL
	}
	if clientName := atcrV.GetString("server.client_name"); clientName != "" && cfg.Server.ClientName == "" {
		cfg.Server.ClientName = clientName
	}
	if clientShortName := atcrV.GetString("server.client_short_name"); clientShortName != "" && cfg.Server.ClientShortName == "" {
		cfg.Server.ClientShortName = clientShortName
	}
	if atcrV.GetBool("server.test_mode") {
		cfg.Server.TestMode = true
	}

	// Validation
	if cfg.Server.BaseURL == "" {
		return nil, fmt.Errorf("server.base_url is required")
	}
	if cfg.Labeler.OwnerDID == "" {
		return nil, fmt.Errorf("labeler.owner_did is required")
	}
	if !strings.HasPrefix(cfg.Labeler.OwnerDID, "did:") {
		return nil, fmt.Errorf("labeler.owner_did must be a DID (got %q)", cfg.Labeler.OwnerDID)
	}

	return cfg, nil
}

// ExampleYAML generates an example labeler configuration file.
func ExampleYAML() ([]byte, error) {
	cfg := &Config{
		Version:  "0.1",
		LogLevel: "info",
		Server: AppviewServerConfig{
			BaseURL:         "https://atcr.io",
			ClientName:      "AT Container Registry",
			ClientShortName: "ATCR",
		},
		Labeler: LabelerConfig{
			Enabled:  true,
			Addr:     ":5002",
			OwnerDID: "did:plc:your-did-here",
			DBPath:   "/var/lib/atcr-labeler/labeler.db",
		},
	}
	return config.MarshalCommentedYAML("ATCR Labeler Configuration", cfg)
}