Golang Config.UnknownAttrs方法代碼示例

func (p manualProvider) Prepare(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	if _, ok := cfg.UnknownAttrs()["storage-auth-key"]; !ok {
		uuid, err := utils.NewUUID()
		if err != nil {
			return nil, err
		}
		cfg, err = cfg.Apply(map[string]interface{}{
			"storage-auth-key": uuid.String(),
		})
		if err != nil {
			return nil, err
		}
	}
	if use, ok := cfg.UnknownAttrs()["use-sshstorage"].(bool); ok && !use {
		return nil, fmt.Errorf("use-sshstorage must not be specified")
	}
	envConfig, err := p.validate(cfg, nil)
	if err != nil {
		return nil, err
	}
	if err := ensureBootstrapUbuntuUser(ctx, envConfig); err != nil {
		return nil, err
	}
	return p.open(envConfig)
}

func prepareConfig(cfg *config.Config) (*config.Config, error) {
	// Turn an incomplete config into a valid one, if possible.
	attrs := cfg.UnknownAttrs()

	if _, ok := attrs["control-dir"]; !ok {
		uuid, err := utils.NewUUID()
		if err != nil {
			return nil, err
		}
		attrs["control-dir"] = fmt.Sprintf("%x", uuid.Raw())
	}
	return cfg.Apply(attrs)
}

func (p maasEnvironProvider) Prepare(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	attrs := cfg.UnknownAttrs()
	oldName, found := attrs["maas-agent-name"]
	if found && oldName != "" {
		return nil, errAgentNameAlreadySet
	}
	uuid, err := utils.NewUUID()
	if err != nil {
		return nil, err
	}
	attrs["maas-agent-name"] = uuid.String()
	cfg, err = cfg.Apply(attrs)
	if err != nil {
		return nil, err
	}
	return p.Open(cfg)
}

// Open implements environs.EnvironProvider.Open.
func (environProvider) Open(cfg *config.Config) (environs.Environ, error) {
	logger.Infof("opening environment %q", cfg.Name())
	if _, ok := cfg.AgentVersion(); !ok {
		newCfg, err := cfg.Apply(map[string]interface{}{
			"agent-version": version.Current.Number.String(),
		})
		if err != nil {
			return nil, err
		}
		cfg = newCfg
	}
	// Set the "namespace" attribute. We do this here, and not in Prepare,
	// for backwards compatibility: older versions did not store the namespace
	// in config.
	if namespace, _ := cfg.UnknownAttrs()["namespace"].(string); namespace == "" {
		username := os.Getenv("USER")
		if username == "" {
			u, err := userCurrent()
			if err != nil {
				return nil, fmt.Errorf("failed to determine username for namespace: %v", err)
			}
			username = u.Username
		}
		var err error
		namespace = fmt.Sprintf("%s-%s", username, cfg.Name())
		cfg, err = cfg.Apply(map[string]interface{}{"namespace": namespace})
		if err != nil {
			return nil, fmt.Errorf("failed to create namespace: %v", err)
		}
	}
	// Do the initial validation on the config.
	localConfig, err := providerInstance.newConfig(cfg)
	if err != nil {
		return nil, err
	}
	if err := VerifyPrerequisites(localConfig.container()); err != nil {
		return nil, fmt.Errorf("failed verification of local provider prerequisites: %v", err)
	}
	environ := &localEnviron{name: cfg.Name()}
	if err := environ.SetConfig(cfg); err != nil {
		return nil, fmt.Errorf("failure setting config: %v", err)
	}
	return environ, nil
}

func (prov maasEnvironProvider) Validate(cfg, oldCfg *config.Config) (*config.Config, error) {
	// Validate base configuration change before validating MAAS specifics.
	err := config.Validate(cfg, oldCfg)
	if err != nil {
		return nil, err
	}

	validated, err := cfg.ValidateUnknownAttrs(configFields, configDefaults)
	if err != nil {
		return nil, err
	}
	if oldCfg != nil {
		oldAttrs := oldCfg.UnknownAttrs()
		validMaasAgentName := false
		if oldName, ok := oldAttrs["maas-agent-name"]; !ok || oldName == nil {
			// If maas-agent-name was nil (because the config was
			// generated pre-1.16.2 the only correct value for it is ""
			// See bug #1256179
			validMaasAgentName = (validated["maas-agent-name"] == "")
		} else {
			validMaasAgentName = (validated["maas-agent-name"] == oldName)
		}
		if !validMaasAgentName {
			return nil, fmt.Errorf("cannot change maas-agent-name")
		}
	}
	envCfg := new(maasEnvironConfig)
	envCfg.Config = cfg
	envCfg.attrs = validated
	server := envCfg.maasServer()
	serverURL, err := url.Parse(server)
	if err != nil || serverURL.Scheme == "" || serverURL.Host == "" {
		return nil, fmt.Errorf("malformed maas-server URL '%v': %s", server, err)
	}
	oauth := envCfg.maasOAuth()
	if strings.Count(oauth, ":") != 2 {
		return nil, errMalformedMaasOAuth
	}
	return cfg.Apply(envCfg.attrs)
}