Auth (#1147)

Implement the Auth interface, with JWT and service implementations.

* Update Auth Interface

* Define Auth Service Implementation

* Support Service Auth

* Add Auth Service Proto

* Remove erronious files

* Implement Auth Service Package

* Update Auth Interface

* Update Auth Interface. Add Validate, remove Add/Remove roles

* Make Revoke interface more explicit

* Refactor serializing and deserializing service accounts

* Fix srv name & update interface to be more explicit

* Require jwt public key for auth

* Rename Variables (Resource.ID => Resource.Name & ServiceAccount => Account)

* Implement JWT Auth Package

* Remove parent, add ID

* Update auth imports to v2. Add String() to auth interface

auth/service/service.go

@@ -0,0 +1,128 @@
+package service
+
+import (
+	"context"
+	"time"
+
+	"github.com/micro/go-micro/client"
+	"github.com/micro/go-micro/v2/auth"
+	pb "github.com/micro/go-micro/v2/auth/service/proto"
+)
+
+// NewAuth returns a new instance of the Auth service
+func NewAuth(opts ...auth.Option) auth.Auth {
+	svc := new(svc)
+	svc.Init(opts...)
+	return svc
+}
+
+// svc is the service implementation of the Auth interface
+type svc struct {
+	options auth.Options
+	auth    pb.AuthService
+}
+
+func (s *svc) String() string {
+	return "service"
+}
+
+func (s *svc) Init(opts ...auth.Option) error {
+	for _, o := range opts {
+		o(&s.options)
+	}
+
+	dc := client.DefaultClient
+	s.auth = pb.NewAuthService("go.micro.auth", dc)
+
+	return nil
+}
+
+// Generate a new auth account
+func (s *svc) Generate(id string, opts ...auth.GenerateOption) (*auth.Account, error) {
+	// construct the request
+	options := auth.NewGenerateOptions(opts...)
+	sa := &auth.Account{
+		Id:       id,
+		Roles:    options.Roles,
+		Metadata: options.Metadata,
+	}
+	req := &pb.GenerateRequest{Account: serializeAccount(sa)}
+
+	// execute the request
+	resp, err := s.auth.Generate(context.Background(), req)
+	if err != nil {
+		return nil, err
+	}
+
+	// format the response
+	return deserializeAccount(resp.Account), nil
+}
+
+// Revoke an authorization account
+func (s *svc) Revoke(token string) error {
+	// contruct the request
+	req := &pb.RevokeRequest{Token: token}
+
+	// execute the request
+	_, err := s.auth.Revoke(context.Background(), req)
+	return err
+}
+
+// Validate an account token
+func (s *svc) Validate(token string) (*auth.Account, error) {
+	resp, err := s.auth.Validate(context.Background(), &pb.ValidateRequest{Token: token})
+	if err != nil {
+		return nil, err
+	}
+
+	return deserializeAccount(resp.Account), nil
+}
+
+func serializeAccount(sa *auth.Account) *pb.Account {
+	roles := make([]*pb.Role, len(sa.Roles))
+	for i, r := range sa.Roles {
+		roles[i] = &pb.Role{
+			Name: r.Name,
+		}
+
+		if r.Resource != nil {
+			roles[i].Resource = &pb.Resource{
+				Name: r.Resource.Name,
+				Type: r.Resource.Type,
+			}
+		}
+	}
+
+	return &pb.Account{
+		Id:       sa.Id,
+		Roles:    roles,
+		Metadata: sa.Metadata,
+	}
+}
+
+func deserializeAccount(a *pb.Account) *auth.Account {
+	// format the response
+	sa := &auth.Account{
+		Id:       a.Id,
+		Token:    a.Token,
+		Created:  time.Unix(a.Created, 0),
+		Expiry:   time.Unix(a.Expiry, 0),
+		Metadata: a.Metadata,
+	}
+
+	sa.Roles = make([]*auth.Role, len(a.Roles))
+	for i, r := range a.Roles {
+		sa.Roles[i] = &auth.Role{
+			Name: r.Name,
+		}
+
+		if r.Resource != nil {
+			sa.Roles[i].Resource = &auth.Resource{
+				Name: r.Resource.Name,
+				Type: r.Resource.Type,
+			}
+		}
+	}
+
+	return sa
+}