package configuration import ( "fmt" "os" "regexp" "strconv" "strings" "gopkg.in/BrianBland/yaml.v2" ) // Configuration is a versioned registry configuration, intended to be provided by a yaml file, and // optionally modified by environment variables type Configuration struct { // Version is the version which defines the format of the rest of the configuration Version Version `yaml:"version"` // Loglevel is the level at which registry operations are logged Loglevel Loglevel `yaml:"loglevel"` // Storage is the configuration for the registry's storage driver Storage Storage `yaml:"storage"` } // v_0_1_Configuration is a Version 0.1 Configuration struct // This is currently aliased to Configuration, as it is the current version type v_0_1_Configuration Configuration // Version is a major/minor version pair of the form Major.Minor // Major version upgrades indicate structure or type changes // Minor version upgrades should be strictly additive type Version string // MajorMinorVersion constructs a Version from its Major and Minor components func MajorMinorVersion(major, minor uint) Version { return Version(fmt.Sprintf("%d.%d", major, minor)) } func (version Version) major() (uint, error) { majorPart := strings.Split(string(version), ".")[0] major, err := strconv.ParseUint(majorPart, 10, 0) return uint(major), err } // Major returns the major version portion of a Version func (version Version) Major() uint { major, _ := version.major() return major } func (version Version) minor() (uint, error) { minorPart := strings.Split(string(version), ".")[1] minor, err := strconv.ParseUint(minorPart, 10, 0) return uint(minor), err } // Minor returns the minor version portion of a Version func (version Version) Minor() uint { minor, _ := version.minor() return minor } // UnmarshalYAML implements the yaml.Unmarshaler interface // Unmarshals a string of the form X.Y into a Version, validating that X and Y can represent uints func (version *Version) UnmarshalYAML(unmarshal func(interface{}) error) error { var versionString string err := unmarshal(&versionString) if err != nil { return err } newVersion := Version(versionString) if _, err := newVersion.major(); err != nil { return err } if _, err := newVersion.minor(); err != nil { return err } *version = newVersion return nil } // CurrentVersion is the most recent Version that can be parsed var CurrentVersion = MajorMinorVersion(0, 1) // Loglevel is the level at which operations are logged // This can be error, warn, info, or debug type Loglevel string // UnmarshalYAML implements the yaml.Umarshaler interface // Unmarshals a string into a Loglevel, lowercasing the string and validating that it represents a // valid loglevel func (loglevel *Loglevel) UnmarshalYAML(unmarshal func(interface{}) error) error { var loglevelString string err := unmarshal(&loglevelString) if err != nil { return err } loglevelString = strings.ToLower(loglevelString) switch loglevelString { case "error", "warn", "info", "debug": default: return fmt.Errorf("Invalid loglevel %s Must be one of [error, warn, info, debug]", loglevelString) } *loglevel = Loglevel(loglevelString) return nil } // Storage defines the configuration for registry object storage type Storage map[string]Parameters // Type returns the storage driver type, such as filesystem or s3 func (storage Storage) Type() string { // Return only key in this map for k := range storage { return k } return "" } // Parameters returns the Parameters map for a Storage configuration func (storage Storage) Parameters() Parameters { return storage[storage.Type()] } // setParameter changes the parameter at the provided key to the new value func (storage Storage) setParameter(key, value string) { storage[storage.Type()][key] = value } // UnmarshalYAML implements the yaml.Unmarshaler interface // Unmarshals a single item map into a Storage or a string into a Storage type with no parameters func (storage *Storage) UnmarshalYAML(unmarshal func(interface{}) error) error { var storageMap map[string]Parameters err := unmarshal(&storageMap) if err == nil { if len(storageMap) > 1 { types := make([]string, 0, len(storageMap)) for k := range storageMap { types = append(types, k) } return fmt.Errorf("Must provide exactly one storage type. Provided: %v", types) } *storage = storageMap return nil } var storageType string err = unmarshal(&storageType) if err == nil { *storage = Storage{storageType: Parameters{}} return nil } return err } // MarshalYAML implements the yaml.Marshaler interface func (storage Storage) MarshalYAML() (interface{}, error) { if storage.Parameters == nil { return storage.Type, nil } return map[string]Parameters(storage), nil } // Parameters defines a key-value parameters mapping type Parameters map[string]string // Parse parses an input configuration yaml document into a Configuration struct // This should generally be capable of handling old configuration format versions // // Environment variables may be used to override configuration parameters other than version, // following the scheme below: // Configuration.Abc may be replaced by the value of REGISTRY_ABC, // Configuration.Abc.Xyz may be replaced by the value of REGISTRY_ABC_XYZ, and so forth func Parse(in []byte) (*Configuration, error) { var untypedConfig struct { Version Version } var config *Configuration err := yaml.Unmarshal(in, &untypedConfig) if err != nil { return nil, err } if untypedConfig.Version == "" { return nil, fmt.Errorf("Please specify a configuration version. Current version is %s", CurrentVersion) } // Parse the remainder of the configuration depending on the provided version switch untypedConfig.Version { case "0.1": config, err = parseV_0_1_Registry(in) if err != nil { return nil, err } default: return nil, fmt.Errorf("Unsupported configuration version %s Current version is %s", untypedConfig.Version, CurrentVersion) } return config, nil } // parseV_0_1_Registry parses a registry Configuration for Version 0.1 func parseV_0_1_Registry(in []byte) (*Configuration, error) { envMap := getEnvMap() var config v_0_1_Configuration err := yaml.Unmarshal(in, &config) if err != nil { return nil, err } // Override config.Loglevel if environment variable is provided if loglevel, ok := envMap["REGISTRY_LOGLEVEL"]; ok { var newLoglevel Loglevel err := yaml.Unmarshal([]byte(loglevel), &newLoglevel) if err != nil { return nil, err } config.Loglevel = newLoglevel } // Override config.Storage if environment variable is provided if storageType, ok := envMap["REGISTRY_STORAGE"]; ok { if storageType != config.Storage.Type() { // Reset the storage parameters because we're using a different storage type config.Storage = Storage{storageType: Parameters{}} } } if config.Storage.Type() == "" { return nil, fmt.Errorf("Must provide exactly one storage type, optionally with parameters. Provided: %v", config.Storage) } // Override storage parameters with all environment variables of the format: // REGISTRY_STORAGE_<storage driver type>_<parameter name> storageParamsRegexp, err := regexp.Compile(fmt.Sprintf("^REGISTRY_STORAGE_%s_([A-Z0-9]+)$", strings.ToUpper(config.Storage.Type()))) if err != nil { return nil, err } for k, v := range envMap { if submatches := storageParamsRegexp.FindStringSubmatch(k); submatches != nil { config.Storage.setParameter(strings.ToLower(submatches[1]), v) } } return (*Configuration)(&config), nil } // getEnvMap reads the current environment variables and converts these into a key/value map // This is used to distinguish between empty strings returned by os.GetEnv(key) because of undefined // environment variables and explicitly empty ones func getEnvMap() map[string]string { envMap := make(map[string]string) for _, env := range os.Environ() { envParts := strings.SplitN(env, "=", 2) envMap[envParts[0]] = envParts[1] } return envMap }