// treeFunc returns or accumulates keyPrefix dependencies.
func treeFunc(b *Brain, used, missing *dep.Set) func(string) ([]*dep.KeyPair, error) {
	return func(s string) ([]*dep.KeyPair, error) {
		result := []*dep.KeyPair{}

		if len(s) == 0 {
			return result, nil
		}

		d, err := dep.NewKVListQuery(s)
		if err != nil {
			return result, err
		}

		used.Add(d)

		// Only return non-empty top-level keys
		if value, ok := b.Recall(d); ok {
			for _, pair := range value.([]*dep.KeyPair) {
				parts := strings.Split(pair.Key, "/")
				if parts[len(parts)-1] != "" {
					result = append(result, pair)
				}
			}
			return result, nil
		}

		missing.Add(d)

		return result, nil
	}
}

// envFunc returns a function which checks the value of an environment variable.
// Invokers can specify their own environment, which takes precedences over any
// real environment variables
func envFunc(b *Brain, used, missing *dep.Set, overrides []string) func(string) (string, error) {
	return func(s string) (string, error) {
		var result string

		d, err := dep.NewEnvQuery(s)
		if err != nil {
			return result, err
		}

		used.Add(d)

		// Overrides lookup - we have to do this after adding the dependency,
		// otherwise dedupe sharing won't work.
		for _, e := range overrides {
			split := strings.SplitN(e, "=", 2)
			k, v := split[0], split[1]
			if k == s {
				return v, nil
			}
		}

		if value, ok := b.Recall(d); ok {
			return value.(string), nil
		}

		missing.Add(d)

		return result, nil
	}
}

// keyWithDefaultFunc returns or accumulates key dependencies that have a
// default value.
func keyWithDefaultFunc(b *Brain, used, missing *dep.Set) func(string, string) (string, error) {
	return func(s, def string) (string, error) {
		if len(s) == 0 {
			return def, nil
		}

		d, err := dep.NewKVGetQuery(s)
		if err != nil {
			return "", err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			if value == nil || value.(string) == "" {
				return def, nil
			}
			return value.(string), nil
		}

		missing.Add(d)

		return def, nil
	}
}

// secretsFunc returns or accumulates a list of secret dependencies from Vault.
func secretsFunc(b *Brain, used, missing *dep.Set) func(string) ([]string, error) {
	return func(s string) ([]string, error) {
		result := []string{}

		if len(s) == 0 {
			return result, nil
		}

		d, err := dep.NewVaultListQuery(s)
		if err != nil {
			return result, nil
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			result = value.([]string)
			return result, nil
		}

		missing.Add(d)

		return result, nil
	}
}

// keyFunc returns or accumulates key dependencies.
func keyFunc(b *Brain, used, missing *dep.Set) func(string) (string, error) {
	return func(s string) (string, error) {
		if len(s) == 0 {
			return "", nil
		}

		d, err := dep.NewKVGetQuery(s)
		if err != nil {
			return "", err
		}
		d.EnableBlocking()

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			if value == nil {
				return "", nil
			}
			return value.(string), nil
		}

		missing.Add(d)

		return "", nil
	}
}

// fileFunc returns or accumulates file dependencies.
func fileFunc(b *Brain, used, missing *dep.Set) func(string) (string, error) {
	return func(s string) (string, error) {
		if len(s) == 0 {
			return "", nil
		}

		d, err := dep.NewFileQuery(s)
		if err != nil {
			return "", err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			if value == nil {
				return "", nil
			}
			return value.(string), nil
		}

		missing.Add(d)

		return "", nil
	}
}

// nodeFunc returns or accumulates catalog node dependency.
func nodeFunc(b *Brain, used, missing *dep.Set) func(...string) (*dep.CatalogNode, error) {
	return func(s ...string) (*dep.CatalogNode, error) {

		d, err := dep.NewCatalogNodeQuery(strings.Join(s, ""))
		if err != nil {
			return nil, err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			return value.(*dep.CatalogNode), nil
		}

		missing.Add(d)

		return nil, nil
	}
}

// servicesFunc returns or accumulates catalog services dependencies.
func servicesFunc(b *Brain, used, missing *dep.Set) func(...string) ([]*dep.CatalogSnippet, error) {
	return func(s ...string) ([]*dep.CatalogSnippet, error) {
		result := []*dep.CatalogSnippet{}

		d, err := dep.NewCatalogServicesQuery(strings.Join(s, ""))
		if err != nil {
			return nil, err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			return value.([]*dep.CatalogSnippet), nil
		}

		missing.Add(d)

		return result, nil
	}
}

// datacentersFunc returns or accumulates datacenter dependencies.
func datacentersFunc(b *Brain, used, missing *dep.Set) func() ([]string, error) {
	return func() ([]string, error) {
		result := []string{}

		d, err := dep.NewCatalogDatacentersQuery()
		if err != nil {
			return result, err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			return value.([]string), nil
		}

		missing.Add(d)

		return result, nil
	}
}

// keyExistsFunc returns true if a key exists, false otherwise.
func keyExistsFunc(b *Brain, used, missing *dep.Set) func(string) (bool, error) {
	return func(s string) (bool, error) {
		if len(s) == 0 {
			return false, nil
		}

		d, err := dep.NewKVGetQuery(s)
		if err != nil {
			return false, err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			return value != nil, nil
		}

		missing.Add(d)

		return false, nil
	}
}

// serviceFunc returns or accumulates health service dependencies.
func serviceFunc(b *Brain, used, missing *dep.Set) func(...string) ([]*dep.HealthService, error) {
	return func(s ...string) ([]*dep.HealthService, error) {
		result := []*dep.HealthService{}

		if len(s) == 0 || s[0] == "" {
			return result, nil
		}

		d, err := dep.NewHealthServiceQuery(strings.Join(s, ""))
		if err != nil {
			return nil, err
		}

		used.Add(d)

		if value, ok := b.Recall(d); ok {
			return value.([]*dep.HealthService), nil
		}

		missing.Add(d)

		return result, nil
	}
}

// Run iterates over each template in this Runner and conditionally executes
// the template rendering and command execution.
//
// The template is rendered atomicly. If and only if the template render
// completes successfully, the optional commands will be executed, if given.
// Please note that all templates are rendered **and then** any commands are
// executed.
func (r *Runner) Run() error {
	log.Printf("[INFO] (runner) initiating run")

	var wouldRenderAny, renderedAny bool
	var commands []*config.TemplateConfig
	depsMap := make(map[string]dep.Dependency)

	for _, tmpl := range r.templates {
		log.Printf("[DEBUG] (runner) checking template %s", tmpl.ID())

		// Create the event
		event := &RenderEvent{
			Template:        tmpl,
			TemplateConfigs: r.templateConfigsFor(tmpl),
		}

		// Check if we are currently the leader instance
		isLeader := true
		if r.dedup != nil {
			isLeader = r.dedup.IsLeader(tmpl)
		}

		// If we are in once mode and this template was already rendered, move
		// onto the next one. We do not want to re-render the template if we are
		// in once mode, and we certainly do not want to re-run any commands.
		if r.once {
			r.renderEventsLock.RLock()
			_, rendered := r.renderEvents[tmpl.ID()]
			r.renderEventsLock.RUnlock()
			if rendered {
				log.Printf("[DEBUG] (runner) once mode and already rendered")
				continue
			}
		}

		// Attempt to render the template, returning any missing dependencies and
		// the rendered contents. If there are any missing dependencies, the
		// contents cannot be rendered or trusted!
		result, err := tmpl.Execute(&template.ExecuteInput{
			Brain: r.brain,
			Env:   r.childEnv(),
		})
		if err != nil {
			return errors.Wrap(err, tmpl.Source())
		}

		// Grab the list of used and missing dependencies.
		missing, used := result.Missing, result.Used

		// Add the dependency to the list of dependencies for this runner.
		for _, d := range used.List() {
			// If we've taken over leadership for a template, we may have data
			// that is cached, but not have the watcher. We must treat this as
			// missing so that we create the watcher and re-run the template.
			if isLeader && !r.watcher.Watching(d) {
				missing.Add(d)
			}
			if _, ok := depsMap[d.String()]; !ok {
				depsMap[d.String()] = d
			}
		}

		// Diff any missing dependencies the template reported with dependencies
		// the watcher is watching.
		unwatched := new(dep.Set)
		for _, d := range missing.List() {
			if !r.watcher.Watching(d) {
				unwatched.Add(d)
			}
		}

		// If there are unwatched dependencies, start the watcher and move onto the
		// next one.
		if l := unwatched.Len(); l > 0 {
			log.Printf("[DEBUG] (runner) was not watching %d dependencies", l)
			for _, d := range unwatched.List() {
				// If we are deduplicating, we must still handle non-sharable
				// dependencies, since those will be ignored.
				if isLeader || !d.CanShare() {
					r.watcher.Add(d)
				}
			}
			continue
		}

		// If the template is missing data for some dependencies then we are not
		// ready to render and need to move on to the next one.
		if l := missing.Len(); l > 0 {
			log.Printf("[DEBUG] (runner) missing data for %d dependencies", l)
			continue
		}

		// Trigger an update of the de-duplicaiton manager
//.........这里部分代码省略.........