mirror of
https://gitlab.com/pulsechaincom/prysm-pulse.git
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96 lines
3.1 KiB
Go
96 lines
3.1 KiB
Go
package shared
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import (
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"fmt"
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"reflect"
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"github.com/sirupsen/logrus"
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)
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var log = logrus.WithField("prefix", "registry")
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// Service is a struct that can be registered into a ServiceRegistry for
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// easy dependency management.
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type Service interface {
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// Start spawns any goroutines required by the service.
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Start()
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// Stop terminates all goroutines belonging to the service,
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// blocking until they are all terminated.
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Stop() error
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// Returns error if the service is not considered healthy.
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Status() error
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}
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// ServiceRegistry provides a useful pattern for managing services.
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// It allows for ease of dependency management and ensures services
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// dependent on others use the same references in memory.
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type ServiceRegistry struct {
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services map[reflect.Type]Service // map of types to services.
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serviceTypes []reflect.Type // keep an ordered slice of registered service types.
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}
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// NewServiceRegistry starts a registry instance for convenience
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func NewServiceRegistry() *ServiceRegistry {
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return &ServiceRegistry{
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services: make(map[reflect.Type]Service),
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}
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}
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// StartAll initialized each service in order of registration.
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func (s *ServiceRegistry) StartAll() {
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log.Infof("Starting %d services: %v", len(s.serviceTypes), s.serviceTypes)
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for _, kind := range s.serviceTypes {
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log.Debugf("Starting service type %v", kind)
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go s.services[kind].Start()
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}
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}
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// StopAll ends every service in reverse order of registration, logging a
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// panic if any of them fail to stop.
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func (s *ServiceRegistry) StopAll() {
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for i := len(s.serviceTypes) - 1; i >= 0; i-- {
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kind := s.serviceTypes[i]
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service := s.services[kind]
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if err := service.Stop(); err != nil {
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log.Panicf("Could not stop the following service: %v, %v", kind, err)
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}
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}
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}
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// Statuses returns a map of Service type -> error. The map will be populated
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// with the results of each service.Status() method call.
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func (s *ServiceRegistry) Statuses() map[reflect.Type]error {
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m := make(map[reflect.Type]error)
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for _, kind := range s.serviceTypes {
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m[kind] = s.services[kind].Status()
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}
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return m
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}
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// RegisterService appends a service constructor function to the service
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// registry.
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func (s *ServiceRegistry) RegisterService(service Service) error {
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kind := reflect.TypeOf(service)
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if _, exists := s.services[kind]; exists {
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return fmt.Errorf("service already exists: %v", kind)
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}
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s.services[kind] = service
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s.serviceTypes = append(s.serviceTypes, kind)
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return nil
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}
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// FetchService takes in a struct pointer and sets the value of that pointer
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// to a service currently stored in the service registry. This ensures the input argument is
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// set to the right pointer that refers to the originally registered service.
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func (s *ServiceRegistry) FetchService(service interface{}) error {
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if reflect.TypeOf(service).Kind() != reflect.Ptr {
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return fmt.Errorf("input must be of pointer type, received value type instead: %T", service)
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}
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element := reflect.ValueOf(service).Elem()
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if running, ok := s.services[element.Type()]; ok {
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element.Set(reflect.ValueOf(running))
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return nil
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}
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return fmt.Errorf("unknown service: %T", service)
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}
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