Use a custom type for our static CLI client (smaller change).

Before this change, we used the `fosite.DefaultOpenIDConnectClient{}` struct, which implements the  `fosite.Client` and `fosite.OpenIDConnectClient` interfaces. For a future change, we also need to implement some additional optional interfaces, so we can no longer use the provided default types. Instead, we now use a custom `clientregistry.Client{}` struct, which implements all the requisite interfaces and can be extended to handle the new functionality (in a future change).

There is also a new `clientregistry.StaticRegistry{}` struct, which implements the `fosite.ClientManager` and looks up our single static client. We could potentially extend this in the future with a registry backed by Kubernetes API, for example.

This should be 100% refactor, with no user-observable change.

Signed-off-by: Matt Moyer <moyerm@vmware.com>

internal/fositestorage/accesstoken/accesstoken.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package accesstoken
@@ -17,6 +17,7 @@ import (
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/crud"
 	"go.pinniped.dev/internal/fositestorage"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const (
@@ -108,7 +109,7 @@ func (a *accessTokenStorage) getSession(ctx context.Context, signature string) (
 func newValidEmptyAccessTokenSession() *session {
 	return &session{
 		Request: &fosite.Request{
-			Client:  &fosite.DefaultOpenIDConnectClient{},
+			Client:  &clientregistry.Client{},
 			Session: &openid.DefaultSession{},
 		},
 	}

internal/fositestorage/accesstoken/accesstoken_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package accesstoken
@@ -20,6 +20,8 @@ import (
 	"k8s.io/client-go/kubernetes/fake"
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	coretesting "k8s.io/client-go/testing"
+
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const namespace = "test-ns"
@@ -63,24 +65,25 @@ func TestAccessTokenStorage(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:            "pinny",
-				Secret:        nil,
-				RedirectURIs:  nil,
-				GrantTypes:    nil,
-				ResponseTypes: nil,
-				Scopes:        nil,
-				Audience:      nil,
-				Public:        true,
-			},
-			JSONWebKeysURI:                    "where",
-			JSONWebKeys:                       nil,
-			TokenEndpointAuthMethod:           "something",
-			RequestURIs:                       nil,
-			RequestObjectSigningAlgorithm:     "",
-			TokenEndpointAuthSigningAlgorithm: "",
-		},
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:            "pinny",
+					Secret:        nil,
+					RedirectURIs:  nil,
+					GrantTypes:    nil,
+					ResponseTypes: nil,
+					Scopes:        nil,
+					Audience:      nil,
+					Public:        true,
+				},
+				JSONWebKeysURI:                    "where",
+				JSONWebKeys:                       nil,
+				TokenEndpointAuthMethod:           "something",
+				RequestURIs:                       nil,
+				RequestObjectSigningAlgorithm:     "",
+				TokenEndpointAuthSigningAlgorithm: "",
+			}},
 		RequestedScope: nil,
 		GrantedScope:   nil,
 		Form:           url.Values{"key": []string{"val"}},
@@ -138,13 +141,15 @@ func TestAccessTokenStorageRevocation(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:     "pinny",
-				Public: true,
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:     "pinny",
+					Public: true,
+				},
+				JSONWebKeysURI:          "where",
+				TokenEndpointAuthMethod: "something",
 			},
-			JSONWebKeysURI:          "where",
-			TokenEndpointAuthMethod: "something",
 		},
 		Form: url.Values{"key": []string{"val"}},
 		Session: &openid.DefaultSession{
@@ -238,7 +243,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 
 	request := &fosite.Request{
 		Session: nil,
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreateAccessTokenSession(ctx, "signature-doesnt-matter", request)
 	require.EqualError(t, err, "requester's session must be of type openid.DefaultSession")
@@ -248,7 +253,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 		Client:  nil,
 	}
 	err = storage.CreateAccessTokenSession(ctx, "signature-doesnt-matter", request)
-	require.EqualError(t, err, "requester's client must be of type fosite.DefaultOpenIDConnectClient")
+	require.EqualError(t, err, "requester's client must be of type clientregistry.Client")
 }
 
 func TestCreateWithoutRequesterID(t *testing.T) {
@@ -257,7 +262,7 @@ func TestCreateWithoutRequesterID(t *testing.T) {
 	request := &fosite.Request{
 		ID:      "", // empty ID
 		Session: &openid.DefaultSession{},
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreateAccessTokenSession(ctx, "signature-doesnt-matter", request)
 	require.NoError(t, err)

internal/fositestorage/authorizationcode/authorizationcode.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package authorizationcode
@@ -18,6 +18,7 @@ import (
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/crud"
 	"go.pinniped.dev/internal/fositestorage"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const (
@@ -137,7 +138,7 @@ func (a *authorizeCodeStorage) getSession(ctx context.Context, signature string)
 func NewValidEmptyAuthorizeCodeSession() *AuthorizeCodeSession {
 	return &AuthorizeCodeSession{
 		Request: &fosite.Request{
-			Client:  &fosite.DefaultOpenIDConnectClient{},
+			Client:  &clientregistry.Client{},
 			Session: &openid.DefaultSession{},
 		},
 	}

internal/fositestorage/authorizationcode/authorizationcode_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package authorizationcode
@@ -33,6 +33,7 @@ import (
 	kubetesting "k8s.io/client-go/testing"
 
 	"go.pinniped.dev/internal/fositestorage"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const namespace = "test-ns"
@@ -92,23 +93,25 @@ func TestAuthorizationCodeStorage(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:            "pinny",
-				Secret:        nil,
-				RedirectURIs:  nil,
-				GrantTypes:    nil,
-				ResponseTypes: nil,
-				Scopes:        nil,
-				Audience:      nil,
-				Public:        true,
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:            "pinny",
+					Secret:        nil,
+					RedirectURIs:  nil,
+					GrantTypes:    nil,
+					ResponseTypes: nil,
+					Scopes:        nil,
+					Audience:      nil,
+					Public:        true,
+				},
+				JSONWebKeysURI:                    "where",
+				JSONWebKeys:                       nil,
+				TokenEndpointAuthMethod:           "something",
+				RequestURIs:                       nil,
+				RequestObjectSigningAlgorithm:     "",
+				TokenEndpointAuthSigningAlgorithm: "",
 			},
-			JSONWebKeysURI:                    "where",
-			JSONWebKeys:                       nil,
-			TokenEndpointAuthMethod:           "something",
-			RequestURIs:                       nil,
-			RequestObjectSigningAlgorithm:     "",
-			TokenEndpointAuthSigningAlgorithm: "",
 		},
 		RequestedScope: nil,
 		GrantedScope:   nil,
@@ -169,7 +172,7 @@ func TestInvalidateWhenConflictOnUpdateHappens(t *testing.T) {
 
 	request := &fosite.Request{
 		ID:      "some-request-id",
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 		Session: &openid.DefaultSession{},
 	}
 	err := storage.CreateAuthorizeCodeSession(ctx, "fancy-signature", request)
@@ -240,7 +243,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 
 	request := &fosite.Request{
 		Session: nil,
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreateAuthorizeCodeSession(ctx, "signature-doesnt-matter", request)
 	require.EqualError(t, err, "requester's session must be of type openid.DefaultSession")
@@ -250,7 +253,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 		Client:  nil,
 	}
 	err = storage.CreateAuthorizeCodeSession(ctx, "signature-doesnt-matter", request)
-	require.EqualError(t, err, "requester's client must be of type fosite.DefaultOpenIDConnectClient")
+	require.EqualError(t, err, "requester's client must be of type clientregistry.Client")
 }
 
 func makeTestSubject() (context.Context, *fake.Clientset, corev1client.SecretInterface, oauth2.AuthorizeCodeStorage) {
@@ -270,7 +273,7 @@ func TestFuzzAndJSONNewValidEmptyAuthorizeCodeSession(t *testing.T) {
 	require.Equal(t, validSession.Request, extractedRequest)
 
 	// checked above
-	defaultClient := validSession.Request.Client.(*fosite.DefaultOpenIDConnectClient)
+	defaultClient := validSession.Request.Client.(*clientregistry.Client)
 	defaultSession := validSession.Request.Session.(*openid.DefaultSession)
 
 	// makes it easier to use a raw string

internal/fositestorage/fositestorage.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package fositestorage
@@ -8,11 +8,12 @@ import (
 	"github.com/ory/fosite/handler/openid"
 
 	"go.pinniped.dev/internal/constable"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const (
 	ErrInvalidRequestType     = constable.Error("requester must be of type fosite.Request")
-	ErrInvalidClientType      = constable.Error("requester's client must be of type fosite.DefaultOpenIDConnectClient")
+	ErrInvalidClientType      = constable.Error("requester's client must be of type clientregistry.Client")
 	ErrInvalidSessionType     = constable.Error("requester's session must be of type openid.DefaultSession")
 	StorageRequestIDLabelName = "storage.pinniped.dev/request-id" //nolint:gosec // this is not a credential
 )
@@ -22,7 +23,7 @@ func ValidateAndExtractAuthorizeRequest(requester fosite.Requester) (*fosite.Req
 	if !ok1 {
 		return nil, ErrInvalidRequestType
 	}
-	_, ok2 := request.Client.(*fosite.DefaultOpenIDConnectClient)
+	_, ok2 := request.Client.(*clientregistry.Client)
 	if !ok2 {
 		return nil, ErrInvalidClientType
 	}

internal/fositestorage/openidconnect/openidconnect.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package openidconnect
@@ -17,6 +17,7 @@ import (
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/crud"
 	"go.pinniped.dev/internal/fositestorage"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const (
@@ -110,7 +111,7 @@ func (a *openIDConnectRequestStorage) getSession(ctx context.Context, signature
 func newValidEmptyOIDCSession() *session {
 	return &session{
 		Request: &fosite.Request{
-			Client:  &fosite.DefaultOpenIDConnectClient{},
+			Client:  &clientregistry.Client{},
 			Session: &openid.DefaultSession{},
 		},
 	}

internal/fositestorage/openidconnect/openidconnect_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package openidconnect
@@ -20,6 +20,8 @@ import (
 	"k8s.io/client-go/kubernetes/fake"
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	coretesting "k8s.io/client-go/testing"
+
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const namespace = "test-ns"
@@ -62,23 +64,25 @@ func TestOpenIdConnectStorage(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:            "pinny",
-				Secret:        nil,
-				RedirectURIs:  nil,
-				GrantTypes:    nil,
-				ResponseTypes: nil,
-				Scopes:        nil,
-				Audience:      nil,
-				Public:        true,
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:            "pinny",
+					Secret:        nil,
+					RedirectURIs:  nil,
+					GrantTypes:    nil,
+					ResponseTypes: nil,
+					Scopes:        nil,
+					Audience:      nil,
+					Public:        true,
+				},
+				JSONWebKeysURI:                    "where",
+				JSONWebKeys:                       nil,
+				TokenEndpointAuthMethod:           "something",
+				RequestURIs:                       nil,
+				RequestObjectSigningAlgorithm:     "",
+				TokenEndpointAuthSigningAlgorithm: "",
 			},
-			JSONWebKeysURI:                    "where",
-			JSONWebKeys:                       nil,
-			TokenEndpointAuthMethod:           "something",
-			RequestURIs:                       nil,
-			RequestObjectSigningAlgorithm:     "",
-			TokenEndpointAuthSigningAlgorithm: "",
 		},
 		RequestedScope: nil,
 		GrantedScope:   nil,
@@ -176,7 +180,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 
 	request := &fosite.Request{
 		Session: nil,
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreateOpenIDConnectSession(ctx, "authcode.signature-doesnt-matter", request)
 	require.EqualError(t, err, "requester's session must be of type openid.DefaultSession")
@@ -186,7 +190,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 		Client:  nil,
 	}
 	err = storage.CreateOpenIDConnectSession(ctx, "authcode.signature-doesnt-matter", request)
-	require.EqualError(t, err, "requester's client must be of type fosite.DefaultOpenIDConnectClient")
+	require.EqualError(t, err, "requester's client must be of type clientregistry.Client")
 }
 
 func TestAuthcodeHasNoDot(t *testing.T) {

internal/fositestorage/pkce/pkce.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package pkce
@@ -17,6 +17,7 @@ import (
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/crud"
 	"go.pinniped.dev/internal/fositestorage"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const (
@@ -94,7 +95,7 @@ func (a *pkceStorage) getSession(ctx context.Context, signature string) (*sessio
 func newValidEmptyPKCESession() *session {
 	return &session{
 		Request: &fosite.Request{
-			Client:  &fosite.DefaultOpenIDConnectClient{},
+			Client:  &clientregistry.Client{},
 			Session: &openid.DefaultSession{},
 		},
 	}

internal/fositestorage/pkce/pkce_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package pkce
@@ -21,6 +21,8 @@ import (
 	"k8s.io/client-go/kubernetes/fake"
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	coretesting "k8s.io/client-go/testing"
+
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const namespace = "test-ns"
@@ -63,23 +65,25 @@ func TestPKCEStorage(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:            "pinny",
-				Secret:        nil,
-				RedirectURIs:  nil,
-				GrantTypes:    nil,
-				ResponseTypes: nil,
-				Scopes:        nil,
-				Audience:      nil,
-				Public:        true,
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:            "pinny",
+					Secret:        nil,
+					RedirectURIs:  nil,
+					GrantTypes:    nil,
+					ResponseTypes: nil,
+					Scopes:        nil,
+					Audience:      nil,
+					Public:        true,
+				},
+				JSONWebKeysURI:                    "where",
+				JSONWebKeys:                       nil,
+				TokenEndpointAuthMethod:           "something",
+				RequestURIs:                       nil,
+				RequestObjectSigningAlgorithm:     "",
+				TokenEndpointAuthSigningAlgorithm: "",
 			},
-			JSONWebKeysURI:                    "where",
-			JSONWebKeys:                       nil,
-			TokenEndpointAuthMethod:           "something",
-			RequestURIs:                       nil,
-			RequestObjectSigningAlgorithm:     "",
-			TokenEndpointAuthSigningAlgorithm: "",
 		},
 		RequestedScope: nil,
 		GrantedScope:   nil,
@@ -183,7 +187,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 
 	request := &fosite.Request{
 		Session: nil,
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreatePKCERequestSession(ctx, "signature-doesnt-matter", request)
 	require.EqualError(t, err, "requester's session must be of type openid.DefaultSession")
@@ -193,7 +197,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 		Client:  nil,
 	}
 	err = storage.CreatePKCERequestSession(ctx, "signature-doesnt-matter", request)
-	require.EqualError(t, err, "requester's client must be of type fosite.DefaultOpenIDConnectClient")
+	require.EqualError(t, err, "requester's client must be of type clientregistry.Client")
 }
 
 func makeTestSubject() (context.Context, *fake.Clientset, corev1client.SecretInterface, pkce.PKCERequestStorage) {

internal/fositestorage/refreshtoken/refreshtoken.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package refreshtoken
@@ -17,6 +17,7 @@ import (
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/crud"
 	"go.pinniped.dev/internal/fositestorage"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const (
@@ -108,7 +109,7 @@ func (a *refreshTokenStorage) getSession(ctx context.Context, signature string)
 func newValidEmptyRefreshTokenSession() *session {
 	return &session{
 		Request: &fosite.Request{
-			Client:  &fosite.DefaultOpenIDConnectClient{},
+			Client:  &clientregistry.Client{},
 			Session: &openid.DefaultSession{},
 		},
 	}

internal/fositestorage/refreshtoken/refreshtoken_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package refreshtoken
@@ -20,6 +20,8 @@ import (
 	"k8s.io/client-go/kubernetes/fake"
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	coretesting "k8s.io/client-go/testing"
+
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const namespace = "test-ns"
@@ -62,23 +64,25 @@ func TestRefreshTokenStorage(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:            "pinny",
-				Secret:        nil,
-				RedirectURIs:  nil,
-				GrantTypes:    nil,
-				ResponseTypes: nil,
-				Scopes:        nil,
-				Audience:      nil,
-				Public:        true,
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:            "pinny",
+					Secret:        nil,
+					RedirectURIs:  nil,
+					GrantTypes:    nil,
+					ResponseTypes: nil,
+					Scopes:        nil,
+					Audience:      nil,
+					Public:        true,
+				},
+				JSONWebKeysURI:                    "where",
+				JSONWebKeys:                       nil,
+				TokenEndpointAuthMethod:           "something",
+				RequestURIs:                       nil,
+				RequestObjectSigningAlgorithm:     "",
+				TokenEndpointAuthSigningAlgorithm: "",
 			},
-			JSONWebKeysURI:                    "where",
-			JSONWebKeys:                       nil,
-			TokenEndpointAuthMethod:           "something",
-			RequestURIs:                       nil,
-			RequestObjectSigningAlgorithm:     "",
-			TokenEndpointAuthSigningAlgorithm: "",
 		},
 		RequestedScope: nil,
 		GrantedScope:   nil,
@@ -137,13 +141,15 @@ func TestRefreshTokenStorageRevocation(t *testing.T) {
 	request := &fosite.Request{
 		ID:          "abcd-1",
 		RequestedAt: time.Time{},
-		Client: &fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:     "pinny",
-				Public: true,
+		Client: &clientregistry.Client{
+			DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+				DefaultClient: &fosite.DefaultClient{
+					ID:     "pinny",
+					Public: true,
+				},
+				JSONWebKeysURI:          "where",
+				TokenEndpointAuthMethod: "something",
 			},
-			JSONWebKeysURI:          "where",
-			TokenEndpointAuthMethod: "something",
 		},
 		Form: url.Values{"key": []string{"val"}},
 		Session: &openid.DefaultSession{
@@ -237,7 +243,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 
 	request := &fosite.Request{
 		Session: nil,
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreateRefreshTokenSession(ctx, "signature-doesnt-matter", request)
 	require.EqualError(t, err, "requester's session must be of type openid.DefaultSession")
@@ -247,7 +253,7 @@ func TestCreateWithWrongRequesterDataTypes(t *testing.T) {
 		Client:  nil,
 	}
 	err = storage.CreateRefreshTokenSession(ctx, "signature-doesnt-matter", request)
-	require.EqualError(t, err, "requester's client must be of type fosite.DefaultOpenIDConnectClient")
+	require.EqualError(t, err, "requester's client must be of type clientregistry.Client")
 }
 
 func TestCreateWithoutRequesterID(t *testing.T) {
@@ -256,7 +262,7 @@ func TestCreateWithoutRequesterID(t *testing.T) {
 	request := &fosite.Request{
 		ID:      "", // empty ID
 		Session: &openid.DefaultSession{},
-		Client:  &fosite.DefaultOpenIDConnectClient{},
+		Client:  &clientregistry.Client{},
 	}
 	err := storage.CreateRefreshTokenSession(ctx, "signature-doesnt-matter", request)
 	require.NoError(t, err)

internal/oidc/clientregistry/clientregistry.go

@@ -0,0 +1,94 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package clientregistry defines Pinniped's OAuth2/OIDC clients.
+package clientregistry
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+	"github.com/ory/fosite"
+)
+
+// Client represents a Pinniped OAuth/OIDC client.
+type Client struct {
+	fosite.DefaultOpenIDConnectClient
+}
+
+// It implements both the base and OIDC client interfaces of Fosite.
+var (
+	_ fosite.Client              = (*Client)(nil)
+	_ fosite.OpenIDConnectClient = (*Client)(nil)
+)
+
+// StaticClientManager is a fosite.ClientManager with statically-defined clients.
+type StaticClientManager struct{}
+
+var _ fosite.ClientManager = (*StaticClientManager)(nil)
+
+// GetClient returns a static client specified by the given ID.
+//
+// It returns a fosite.ErrNotFound if an unknown client is specified.
+func (StaticClientManager) GetClient(_ context.Context, id string) (fosite.Client, error) {
+	switch id {
+	case "pinniped-cli":
+		return PinnipedCLI(), nil
+	default:
+		return nil, fosite.ErrNotFound.WithDescription("no such client")
+	}
+}
+
+// ClientAssertionJWTValid returns an error if the JTI is
+// known or the DB check failed and nil if the JTI is not known.
+//
+// This functionality is not supported by the StaticClientManager.
+func (StaticClientManager) ClientAssertionJWTValid(ctx context.Context, jti string) error {
+	return fmt.Errorf("not implemented")
+}
+
+// SetClientAssertionJWT marks a JTI as known for the given
+// expiry time. Before inserting the new JTI, it will clean
+// up any existing JTIs that have expired as those tokens can
+// not be replayed due to the expiry.
+//
+// This functionality is not supported by the StaticClientManager.
+func (StaticClientManager) SetClientAssertionJWT(ctx context.Context, jti string, exp time.Time) error {
+	return fmt.Errorf("not implemented")
+}
+
+// PinnipedCLI returns the static Client corresponding to the Pinniped CLI.
+func PinnipedCLI() *Client {
+	return &Client{
+		DefaultOpenIDConnectClient: fosite.DefaultOpenIDConnectClient{
+			DefaultClient: &fosite.DefaultClient{
+				ID:           "pinniped-cli",
+				Secret:       nil,
+				RedirectURIs: []string{"http://127.0.0.1/callback"},
+				GrantTypes: fosite.Arguments{
+					"authorization_code",
+					"refresh_token",
+					"urn:ietf:params:oauth:grant-type:token-exchange",
+				},
+				ResponseTypes: []string{"code"},
+				Scopes: fosite.Arguments{
+					oidc.ScopeOpenID,
+					oidc.ScopeOfflineAccess,
+					"profile",
+					"email",
+					"pinniped:request-audience",
+				},
+				Audience: nil,
+				Public:   true,
+			},
+			RequestURIs:                       nil,
+			JSONWebKeys:                       nil,
+			JSONWebKeysURI:                    "",
+			RequestObjectSigningAlgorithm:     "",
+			TokenEndpointAuthSigningAlgorithm: oidc.RS256,
+			TokenEndpointAuthMethod:           "none",
+		},
+	}
+}

internal/oidc/clientregistry/clientregistry_test.go

@@ -0,0 +1,95 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package clientregistry
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+	"github.com/ory/fosite"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStaticRegistry(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("unimplemented methods", func(t *testing.T) {
+		registry := StaticClientManager{}
+		require.EqualError(t, registry.ClientAssertionJWTValid(ctx, "some-token-id"), "not implemented")
+		require.EqualError(t, registry.SetClientAssertionJWT(ctx, "some-token-id", time.Now()), "not implemented")
+	})
+
+	t.Run("not found", func(t *testing.T) {
+		registry := StaticClientManager{}
+		got, err := registry.GetClient(ctx, "does-not-exist")
+		require.Error(t, err)
+		require.Nil(t, got)
+		rfcErr := fosite.ErrorToRFC6749Error(err)
+		require.NotNil(t, rfcErr)
+		require.Equal(t, rfcErr.CodeField, 404)
+		require.Equal(t, rfcErr.GetDescription(), "no such client")
+	})
+
+	t.Run("pinniped CLI", func(t *testing.T) {
+		registry := StaticClientManager{}
+		got, err := registry.GetClient(ctx, "pinniped-cli")
+		require.NoError(t, err)
+		require.NotNil(t, got)
+		require.IsType(t, &Client{}, got)
+	})
+}
+
+func TestPinnipedCLI(t *testing.T) {
+	c := PinnipedCLI()
+	require.Equal(t, "pinniped-cli", c.GetID())
+	require.Nil(t, c.GetHashedSecret())
+	require.Equal(t, []string{"http://127.0.0.1/callback"}, c.GetRedirectURIs())
+	require.Equal(t, fosite.Arguments{"authorization_code", "refresh_token", "urn:ietf:params:oauth:grant-type:token-exchange"}, c.GetGrantTypes())
+	require.Equal(t, fosite.Arguments{"code"}, c.GetResponseTypes())
+	require.Equal(t, fosite.Arguments{oidc.ScopeOpenID, oidc.ScopeOfflineAccess, "profile", "email", "pinniped:request-audience"}, c.GetScopes())
+	require.True(t, c.IsPublic())
+	require.Nil(t, c.GetAudience())
+	require.Nil(t, c.GetRequestURIs())
+	require.Nil(t, c.GetJSONWebKeys())
+	require.Equal(t, "", c.GetJSONWebKeysURI())
+	require.Equal(t, "", c.GetRequestObjectSigningAlgorithm())
+	require.Equal(t, "none", c.GetTokenEndpointAuthMethod())
+	require.Equal(t, "RS256", c.GetTokenEndpointAuthSigningAlgorithm())
+
+	marshaled, err := json.Marshal(c)
+	require.NoError(t, err)
+	require.JSONEq(t, `
+		{
+		  "id": "pinniped-cli",
+		  "redirect_uris": [
+			"http://127.0.0.1/callback"
+		  ],
+		  "grant_types": [
+			"authorization_code",
+			"refresh_token",
+			"urn:ietf:params:oauth:grant-type:token-exchange"
+		  ],
+		  "response_types": [
+			"code"
+		  ],
+		  "scopes": [
+			"openid",
+			"offline_access",
+			"profile",
+			"email",
+			"pinniped:request-audience"
+		  ],
+		  "audience": null,
+		  "public": true,
+		  "jwks_uri": "",
+		  "jwks": null,
+		  "token_endpoint_auth_method": "none",
+		  "request_uris": null,
+		  "request_object_signing_alg": "",
+		  "token_endpoint_auth_signing_alg": "RS256"
+		}`, string(marshaled))
+}

internal/oidc/kube_storage.go

@@ -13,18 +13,17 @@ import (
 	fositepkce "github.com/ory/fosite/handler/pkce"
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 
-	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/fositestorage/accesstoken"
 	"go.pinniped.dev/internal/fositestorage/authorizationcode"
 	"go.pinniped.dev/internal/fositestorage/openidconnect"
 	"go.pinniped.dev/internal/fositestorage/pkce"
 	"go.pinniped.dev/internal/fositestorage/refreshtoken"
 	"go.pinniped.dev/internal/fositestoragei"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
-const errKubeStorageNotImplemented = constable.Error("KubeStorage does not implement this method. It should not have been called.")
-
 type KubeStorage struct {
+	clientManager            fosite.ClientManager
 	authorizationCodeStorage oauth2.AuthorizeCodeStorage
 	pkceStorage              fositepkce.PKCERequestStorage
 	oidcStorage              openid.OpenIDConnectRequestStorage
@@ -37,6 +36,7 @@ var _ fositestoragei.AllFositeStorage = &KubeStorage{}
 func NewKubeStorage(secrets corev1client.SecretInterface, timeoutsConfiguration TimeoutsConfiguration) *KubeStorage {
 	nowFunc := time.Now
 	return &KubeStorage{
+		clientManager:            &clientregistry.StaticClientManager{},
 		authorizationCodeStorage: authorizationcode.New(secrets, nowFunc, timeoutsConfiguration.AuthorizationCodeSessionStorageLifetime),
 		pkceStorage:              pkce.New(secrets, nowFunc, timeoutsConfiguration.PKCESessionStorageLifetime),
 		oidcStorage:              openidconnect.New(secrets, nowFunc, timeoutsConfiguration.OIDCSessionStorageLifetime),
@@ -183,26 +183,15 @@ func (k KubeStorage) RevokeRefreshToken(ctx context.Context, requestID string) e
 //
 // OAuth client definitions:
 //
-// For the time being, we only allow a single pre-defined client, so we do not need to interact with any underlying
-// storage mechanism to fetch them.
-//
 
-func (KubeStorage) GetClient(_ context.Context, id string) (fosite.Client, error) {
-	client := PinnipedCLIOIDCClient()
-	if client.ID == id {
-		return client, nil
-	}
-	return nil, fosite.ErrNotFound
+func (k KubeStorage) GetClient(ctx context.Context, id string) (fosite.Client, error) {
+	return k.clientManager.GetClient(ctx, id)
 }
 
-//
-// Unused interface methods.
-//
-
-func (KubeStorage) ClientAssertionJWTValid(_ context.Context, _ string) error {
-	return errKubeStorageNotImplemented
+func (k KubeStorage) ClientAssertionJWTValid(ctx context.Context, jti string) error {
+	return k.clientManager.ClientAssertionJWTValid(ctx, jti)
 }
 
-func (KubeStorage) SetClientAssertionJWT(_ context.Context, _ string, _ time.Time) error {
-	return errKubeStorageNotImplemented
+func (k KubeStorage) SetClientAssertionJWT(ctx context.Context, jti string, exp time.Time) error {
+	return k.clientManager.SetClientAssertionJWT(ctx, jti, exp)
 }

internal/oidc/nullstorage.go

@@ -5,17 +5,19 @@ package oidc
 
 import (
 	"context"
-	"time"
 
 	"github.com/ory/fosite"
 
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/fositestoragei"
+	"go.pinniped.dev/internal/oidc/clientregistry"
 )
 
 const errNullStorageNotImplemented = constable.Error("NullStorage does not implement this method. It should not have been called.")
 
-type NullStorage struct{}
+type NullStorage struct {
+	clientregistry.StaticClientManager
+}
 
 var _ fositestoragei.AllFositeStorage = &NullStorage{}
 
@@ -86,19 +88,3 @@ func (NullStorage) GetAuthorizeCodeSession(_ context.Context, _ string, _ fosite
 func (NullStorage) InvalidateAuthorizeCodeSession(_ context.Context, _ string) (err error) {
 	return errNullStorageNotImplemented
 }
-
-func (NullStorage) GetClient(_ context.Context, id string) (fosite.Client, error) {
-	client := PinnipedCLIOIDCClient()
-	if client.ID == id {
-		return client, nil
-	}
-	return nil, fosite.ErrNotFound
-}
-
-func (NullStorage) ClientAssertionJWTValid(_ context.Context, _ string) error {
-	return errNullStorageNotImplemented
-}
-
-func (NullStorage) SetClientAssertionJWT(_ context.Context, _ string, _ time.Time) error {
-	return errNullStorageNotImplemented
-}

internal/oidc/nullstorage_test.go

@@ -1,37 +0,0 @@
-// Copyright 2020 the Pinniped contributors. All Rights Reserved.
-// SPDX-License-Identifier: Apache-2.0
-
-package oidc
-
-import (
-	"context"
-	"testing"
-
-	"github.com/ory/fosite"
-	"github.com/stretchr/testify/require"
-)
-
-func TestNullStorage_GetClient(t *testing.T) {
-	storage := NullStorage{}
-
-	client, err := storage.GetClient(context.Background(), "some-other-client")
-	require.Equal(t, fosite.ErrNotFound, err)
-	require.Zero(t, client)
-
-	client, err = storage.GetClient(context.Background(), "pinniped-cli")
-	require.NoError(t, err)
-	require.Equal(t,
-		&fosite.DefaultOpenIDConnectClient{
-			DefaultClient: &fosite.DefaultClient{
-				ID:            "pinniped-cli",
-				Public:        true,
-				RedirectURIs:  []string{"http://127.0.0.1/callback"},
-				ResponseTypes: []string{"code"},
-				GrantTypes:    []string{"authorization_code", "refresh_token", "urn:ietf:params:oauth:grant-type:token-exchange"},
-				Scopes:        []string{"openid", "offline_access", "profile", "email", "pinniped:request-audience"},
-			},
-			TokenEndpointAuthMethod: "none",
-		},
-		client,
-	)
-}

internal/oidc/oidc.go

@@ -98,20 +98,6 @@ type UpstreamStateParamData struct {
 	FormatVersion string              `json:"v"`
 }
 
-func PinnipedCLIOIDCClient() *fosite.DefaultOpenIDConnectClient {
-	return &fosite.DefaultOpenIDConnectClient{
-		DefaultClient: &fosite.DefaultClient{
-			ID:            "pinniped-cli",
-			Public:        true,
-			RedirectURIs:  []string{"http://127.0.0.1/callback"},
-			ResponseTypes: []string{"code"},
-			GrantTypes:    []string{"authorization_code", "refresh_token", "urn:ietf:params:oauth:grant-type:token-exchange"},
-			Scopes:        []string{coreosoidc.ScopeOpenID, coreosoidc.ScopeOfflineAccess, "profile", "email", "pinniped:request-audience"},
-		},
-		TokenEndpointAuthMethod: "none",
-	}
-}
-
 type TimeoutsConfiguration struct {
 	// The length of time that our state param that we encrypt and pass to the upstream OIDC IDP should be considered
 	// valid. If a state param generated by the authorize endpoint is sent to the callback endpoint after this much