Make OIDC username key configurable

Signed-off-by: Josh Winters <jwinters@pivotal.io>
Co-authored-by: Mark Huang <mhuang@pivotal.io>
Signed-off-by: Rui Yang <ruiya@vmware.com>

connector/oidc/oidc.go

@@ -55,6 +55,9 @@ type Config struct {
 	// Configurable key which contains the user name claim
 	UserNameKey string `json:"userNameKey"`
 
+	// Configurable key which contains the username claims
+	PreferredUsernameKey string `json:"preferredUsernameKey"` // defaults to "username"
+
 	// PromptType will be used fot the prompt parameter (when offline_access, by default prompt=consent)
 	PromptType string `json:"promptType"`
 }
@@ -143,6 +146,7 @@ func (c *Config) Open(id string, logger log.Logger) (conn connector.Connector, e
 		getUserInfo:               c.GetUserInfo,
 		userIDKey:                 c.UserIDKey,
 		userNameKey:               c.UserNameKey,
+		preferredUsernameKey:      c.PreferredUsernameKey,
 		promptType:                c.PromptType,
 	}, nil
 }
@@ -165,6 +169,7 @@ type oidcConnector struct {
 	getUserInfo               bool
 	userIDKey                 string
 	userNameKey               string
+	preferredUsernameKey      string
 	promptType                string
 }
 
@@ -296,6 +301,11 @@ func (c *oidcConnector) createIdentity(ctx context.Context, identity connector.I
 	}
 	hostedDomain, _ := claims["hd"].(string)
 
+	if c.preferredUsernameKey == "" {
+		c.preferredUsernameKey = "username"
+	}
+	username, _ := claims[c.preferredUsernameKey].(string)
+
 	if len(c.hostedDomains) > 0 {
 		found := false
 		for _, domain := range c.hostedDomains {
@@ -322,6 +332,7 @@ func (c *oidcConnector) createIdentity(ctx context.Context, identity connector.I
 	identity = connector.Identity{
 		UserID:            idToken.Subject,
 		Username:          name,
+		PreferredUsername: username,
 		Email:             email,
 		EmailVerified:     emailVerified,
 		ConnectorData:     connData,

connector/oidc/oidc_test.go

@@ -49,10 +49,12 @@ func TestHandleCallback(t *testing.T) {
 		name                      string
 		userIDKey                 string
 		userNameKey               string
+		preferredUsernameKey      string
 		insecureSkipEmailVerified bool
 		scopes                    []string
 		expectUserID              string
 		expectUserName            string
+		expectPreferredUsername   string
 		expectedEmailField        string
 		token                     map[string]interface{}
 	}{
@@ -108,6 +110,21 @@ func TestHandleCallback(t *testing.T) {
 				"email_verified": true,
 			},
 		},
+		{
+			name:                    "withPreferredUsernameKey",
+			preferredUsernameKey:    "preferred_username",
+			expectUserID:            "subvalue",
+			expectUserName:          "namevalue",
+			expectPreferredUsername: "usernamevalue",
+			expectedEmailField:      "emailvalue",
+			token: map[string]interface{}{
+				"sub":                "subvalue",
+				"name":               "namevalue",
+				"preferred_username": "usernamevalue",
+				"email":              "emailvalue",
+				"email_verified":     true,
+			},
+		},
 		{
 			name:                      "emptyEmailScope",
 			expectUserID:              "subvalue",
@@ -161,6 +178,7 @@ func TestHandleCallback(t *testing.T) {
 				RedirectURI:               fmt.Sprintf("%s/callback", serverURL),
 				UserIDKey:                 tc.userIDKey,
 				UserNameKey:               tc.userNameKey,
+				PreferredUsernameKey:      tc.preferredUsernameKey,
 				InsecureSkipEmailVerified: tc.insecureSkipEmailVerified,
 				BasicAuthUnsupported:      &basicAuth,
 			}
@@ -182,6 +200,7 @@ func TestHandleCallback(t *testing.T) {
 
 			expectEquals(t, identity.UserID, tc.expectUserID)
 			expectEquals(t, identity.Username, tc.expectUserName)
+			expectEquals(t, identity.PreferredUsername, tc.expectPreferredUsername)
 			expectEquals(t, identity.Email, tc.expectedEmailField)
 			expectEquals(t, identity.EmailVerified, true)
 		})