AuthZ: GRPC client init and config options (#89161)

pkg/services/authz/README.md

@@ -1,3 +1,51 @@
 # Authorization
 
 This package contains the authorization server implementation.
+
+## Feature toggles
+
+The following feature toggles need to be activated:
+
+```ini
+[feature_toggles]
+authZGRPCServer = true
+grpcServer = true
+```
+
+## Configuration
+
+To configure the authorization server and client, use the "authorization" section of the configuration ini file.
+
+The `remote_address` setting, specifies the address where the authorization server is located (ex: `server.example.org:10000`). 
+
+The `mode` setting can be set to either `grpc` or `inproc`. When set to `grpc`, the client will connect to the specified address. When set to `inproc` the client will use inprocgrpc (relying on go channels) to wrap a local instantiation of the server. 
+
+The `listen` setting determines whether the authorization server should listen for incoming requests. When set to `true`, the authorization service will be registered to the Grafana GRPC server.
+
+The default configuration does not register the authorization service on the Grafana GRPC server and binds the client to it `inproc`:
+
+```ini
+[authorization]
+remote_address = ""
+listen = false
+mode = "inproc"
+```
+
+### Example
+
+Here is an example to connect the authorization client to a remote grpc server.
+
+```ini
+[authorization]
+remote_address = "server.example.org:10000"
+mode = "grpc"
+```
+
+Here is an example to register the authorization service on the Grafana GRPC server and connect the client to it through grpc
+
+```ini
+[authorization]
+remote_address = "localhost:10000"
+listen = true
+mode = "grpc"
+```

pkg/services/authz/client.go

@@ -1,10 +1,21 @@
 package authz
 
 import (
+	"context"
+
+	"github.com/fullstorydev/grpchan"
+	"github.com/fullstorydev/grpchan/inprocgrpc"
+	grpcAuth "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/auth"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+
+	authzv1 "github.com/grafana/authlib/authz/proto/v1"
+
 	"github.com/grafana/grafana/pkg/infra/tracing"
 	"github.com/grafana/grafana/pkg/services/accesscontrol"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/grpcserver"
+	grpcUtils "github.com/grafana/grafana/pkg/services/store/entity/grpc"
 	"github.com/grafana/grafana/pkg/setting"
 )
 
@@ -13,8 +24,10 @@ type Client interface {
 }
 
 type LegacyClient struct {
+	clientV1 authzv1.AuthzServiceClient
 }
 
+// ProvideAuthZClient provides an AuthZ client and creates the AuthZ service.
 func ProvideAuthZClient(
 	cfg *setting.Cfg, features featuremgmt.FeatureToggles, acSvc accesscontrol.Service,
 	grpcServer grpcserver.Provider, tracer tracing.Tracer,
@@ -23,11 +36,90 @@ func ProvideAuthZClient(
 		return nil, nil
 	}
 
-	_, err := newLegacyServer(acSvc, features, grpcServer, tracer)
+	authCfg, err := ReadCfg(cfg)
 	if err != nil {
 		return nil, err
 	}
 
-	// TODO differentiate run local from run remote grpc
+	var client *LegacyClient
-	return &LegacyClient{}, nil
+
+	// Register the server
+	server, err := newLegacyServer(acSvc, features, grpcServer, tracer, authCfg)
+	if err != nil {
+		return nil, err
+	}
+
+	switch authCfg.mode {
+	case ModeInProc:
+		client = newInProcLegacyClient(server)
+	case ModeGRPC:
+		client, err = newGrpcLegacyClient(authCfg.remoteAddress)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return client, err
+}
+
+// ProvideStandaloneAuthZClient provides a standalone AuthZ client, without registering the AuthZ service.
+// You need to provide a remote address in the configuration
+func ProvideStandaloneAuthZClient(
+	cfg *setting.Cfg, features featuremgmt.FeatureToggles, tracer tracing.Tracer,
+) (Client, error) {
+	if !features.IsEnabledGlobally(featuremgmt.FlagAuthZGRPCServer) {
+		return nil, nil
+	}
+
+	authCfg, err := ReadCfg(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return newGrpcLegacyClient(authCfg.remoteAddress)
+}
+
+func newInProcLegacyClient(server *legacyServer) *LegacyClient {
+	channel := &inprocgrpc.Channel{}
+
+	// TODO (gamab): change this once it's clear how to authenticate the client
+	// Choices are:
+	// - noAuth given it's in proc and we don't need the user
+	// - access_token verif only as it's consistent with when it's remote (we check the service is allowed to call the authz service)
+	// - access_token and id_token ? the id_token being only necessary when the user is trying to access the service straight away
+	// auth := grpcUtils.ProvideAuthenticator(cfg)
+	noAuth := func(ctx context.Context) (context.Context, error) {
+		return ctx, nil
+	}
+
+	channel.RegisterService(
+		grpchan.InterceptServer(
+			&authzv1.AuthzService_ServiceDesc,
+			grpcAuth.UnaryServerInterceptor(noAuth),
+			grpcAuth.StreamServerInterceptor(noAuth),
+		),
+		server,
+	)
+
+	conn := grpchan.InterceptClientConn(channel, grpcUtils.UnaryClientInterceptor, grpcUtils.StreamClientInterceptor)
+
+	client := authzv1.NewAuthzServiceClient(conn)
+
+	return &LegacyClient{
+		clientV1: client,
+	}
+}
+
+func newGrpcLegacyClient(address string) (*LegacyClient, error) {
+	// Create a connection to the gRPC server
+	conn, err := grpc.NewClient(address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		return nil, err
+	}
+
+	client := authzv1.NewAuthzServiceClient(conn)
+
+	return &LegacyClient{
+		clientV1: client,
+	}, nil
 }

pkg/services/authz/config.go

@@ -0,0 +1,43 @@
+package authz
+
+import (
+	"fmt"
+
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+type Mode string
+
+func (s Mode) IsValid() bool {
+	switch s {
+	case ModeGRPC, ModeInProc:
+		return true
+	}
+	return false
+}
+
+const (
+	ModeGRPC   Mode = "grpc"
+	ModeInProc Mode = "inproc"
+)
+
+type Cfg struct {
+	remoteAddress string
+	listen        bool
+	mode          Mode
+}
+
+func ReadCfg(cfg *setting.Cfg) (*Cfg, error) {
+	section := cfg.SectionWithEnvOverrides("authorization")
+
+	mode := Mode(section.Key("mode").MustString(string(ModeInProc)))
+	if !mode.IsValid() {
+		return nil, fmt.Errorf("authorization: invalid mode %q", mode)
+	}
+
+	return &Cfg{
+		remoteAddress: section.Key("remote_address").MustString(""),
+		listen:        section.Key("listen").MustBool(false),
+		mode:          mode,
+	}, nil
+}

pkg/services/authz/server.go

@@ -24,7 +24,7 @@ type legacyServer struct {
 
 func newLegacyServer(
 	acSvc accesscontrol.Service, features featuremgmt.FeatureToggles,
-	grpcServer grpcserver.Provider, tracer tracing.Tracer,
+	grpcServer grpcserver.Provider, tracer tracing.Tracer, cfg *Cfg,
 ) (*legacyServer, error) {
 	if !features.IsEnabledGlobally(featuremgmt.FlagAuthZGRPCServer) {
 		return nil, nil
@@ -36,7 +36,9 @@ func newLegacyServer(
 		tracer: tracer,
 	}
 
-	grpcServer.GetServer().RegisterService(&authzv1.AuthzService_ServiceDesc, s)
+	if cfg.listen {
+		grpcServer.GetServer().RegisterService(&authzv1.AuthzService_ServiceDesc, s)
+	}
 
 	return s, nil
 }