[MM-25647]: ability to permanently delete users (#14944)

Summary:
    Config option to allow permanent user deletion ServiceSettings.EnableAPIUserDeletion
    Expose permanent user deletion through API
    Local mode for delete user for use in mmctl

Ticket Link:
    Server part of https://mattermost.atlassian.net/browse/MM-25647

api4/user.go

@@ -1193,7 +1193,16 @@ func deleteUser(c *Context, w http.ResponseWriter, r *http.Request) {
 	}
 	auditRec.AddMeta("user", user)
 
-	if _, err = c.App.UpdateActive(user, false); err != nil {
+	if c.Params.Permanent {
+		if *c.App.Config().ServiceSettings.EnableAPIUserDeletion {
+			err = c.App.PermanentDeleteUser(user)
+		} else {
+			err = model.NewAppError("deleteUser", "api.user.delete_user.not_enabled.app_error", nil, "userId="+c.Params.UserId, http.StatusUnauthorized)
+		}
+	} else {
+		_, err = c.App.UpdateActive(user, false)
+	}
+	if err != nil {
 		c.Err = err
 		return
 	}

api4/user_local.go

@@ -19,6 +19,7 @@ func (api *API) InitUserLocal() {
 
 	api.BaseRoutes.User.Handle("", api.ApiLocal(getUser)).Methods("GET")
 	api.BaseRoutes.User.Handle("", api.ApiLocal(updateUser)).Methods("PUT")
+	api.BaseRoutes.User.Handle("", api.ApiLocal(localDeleteUser)).Methods("DELETE")
 	api.BaseRoutes.User.Handle("/roles", api.ApiLocal(updateUserRoles)).Methods("PUT")
 	api.BaseRoutes.User.Handle("/mfa", api.ApiLocal(updateUserMfa)).Methods("PUT")
 	api.BaseRoutes.User.Handle("/active", api.ApiLocal(updateUserActive)).Methods("PUT")
@@ -32,6 +33,38 @@ func (api *API) InitUserLocal() {
 	api.BaseRoutes.User.Handle("/tokens", api.ApiLocal(createUserAccessToken)).Methods("POST")
 }
 
+func localDeleteUser(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireUserId()
+	if c.Err != nil {
+		return
+	}
+
+	userId := c.Params.UserId
+
+	auditRec := c.MakeAuditRecord("localDeleteUser", audit.Fail)
+	defer c.LogAuditRec(auditRec)
+
+	user, err := c.App.GetUser(userId)
+	if err != nil {
+		c.Err = err
+		return
+	}
+	auditRec.AddMeta("user", user)
+
+	if c.Params.Permanent {
+		err = c.App.PermanentDeleteUser(user)
+	} else {
+		_, err = c.App.UpdateActive(user, false)
+	}
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	auditRec.Success()
+	ReturnStatusOK(w)
+}
+
 func localPermanentDeleteAllUsers(c *Context, w http.ResponseWriter, r *http.Request) {
 	auditRec := c.MakeAuditRecord("localPermanentDeleteAllUsers", audit.Fail)
 	defer c.LogAuditRec(auditRec)

api4/user_test.go

@@ -1857,34 +1857,32 @@ func TestDeleteUser(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()
 
-	user := th.BasicUser
 	th.LoginBasic()
-
-	testUser := th.SystemAdminUser
-	_, resp := th.Client.DeleteUser(testUser.Id)
+	_, resp := th.Client.DeleteUser(th.SystemAdminUser.Id)
 	CheckForbiddenStatus(t, resp)
 
 	th.Client.Logout()
-
-	_, resp = th.Client.DeleteUser(user.Id)
+	_, resp = th.Client.DeleteUser(th.BasicUser.Id)
 	CheckUnauthorizedStatus(t, resp)
 
-	th.Client.Login(testUser.Email, testUser.Password)
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		_, resp = c.DeleteUser(model.NewId())
+		CheckNotFoundStatus(t, resp)
 
-	user.Id = model.NewId()
-	_, resp = th.Client.DeleteUser(user.Id)
-	CheckNotFoundStatus(t, resp)
+		_, resp = c.DeleteUser("junk")
+		CheckBadRequestStatus(t, resp)
 
-	user.Id = "junk"
-	_, resp = th.Client.DeleteUser(user.Id)
-	CheckBadRequestStatus(t, resp)
-
-	_, resp = th.Client.DeleteUser(testUser.Id)
-	CheckNoError(t, resp)
+		userToDelete := th.CreateUser()
+		_, resp = c.DeleteUser(userToDelete.Id)
+		CheckNoError(t, resp)
+	})
 
 	selfDeleteUser := th.CreateUser()
-	th.Client.Login(selfDeleteUser.Email, selfDeleteUser.Password)
+	th.LoginBasic()
+	_, resp = th.Client.DeleteUser(selfDeleteUser.Id)
+	CheckForbiddenStatus(t, resp)
 
+	th.Client.Login(selfDeleteUser.Email, selfDeleteUser.Password)
 	th.App.UpdateConfig(func(c *model.Config) {
 		*c.TeamSettings.EnableUserDeactivation = false
 	})
@@ -1898,6 +1896,46 @@ func TestDeleteUser(t *testing.T) {
 	CheckNoError(t, resp)
 }
 
+func TestPermanentDeleteUser(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+
+	enableAPIUserDeletion := *th.App.Config().ServiceSettings.EnableAPIUserDeletion
+	defer func() {
+		th.App.UpdateConfig(func(cfg *model.Config) { cfg.ServiceSettings.EnableAPIUserDeletion = &enableAPIUserDeletion })
+	}()
+
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableAPIUserDeletion = false })
+
+	userToDelete := th.CreateUser()
+
+	t.Run("Permanent deletion not available through API if EnableAPIUserDeletion is not set", func(t *testing.T) {
+		_, resp := th.SystemAdminClient.PermanentDeleteUser(userToDelete.Id)
+		CheckUnauthorizedStatus(t, resp)
+	})
+
+	t.Run("Permanent deletion available through local mode even if EnableAPIUserDeletion is not set", func(t *testing.T) {
+		ok, resp := th.LocalClient.PermanentDeleteUser(userToDelete.Id)
+		CheckNoError(t, resp)
+		assert.True(t, ok)
+	})
+
+	th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ServiceSettings.EnableAPIUserDeletion = true })
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		userToDelete = th.CreateUser()
+		ok, resp := c.PermanentDeleteUser(userToDelete.Id)
+		CheckNoError(t, resp)
+		assert.True(t, ok)
+
+		_, err := th.App.GetTeam(userToDelete.Id)
+		assert.NotNil(t, err)
+
+		ok, resp = c.PermanentDeleteUser("junk")
+		CheckBadRequestStatus(t, resp)
+		require.False(t, ok, "should have returned false")
+	}, "Permanent deletion with EnableAPIUserDeletion set")
+}
+
 func TestPermanentDeleteAllUsers(t *testing.T) {
 	th := Setup(t).InitBasic()
 	defer th.TearDown()

i18n/en.json

@@ -2622,6 +2622,10 @@
     "id": "api.user.delete_team.not_enabled.app_error",
     "translation": "Permanent team deletion feature is not enabled. Please contact your System Administrator."
   },
+  {
+    "id": "api.user.delete_user.not_enabled.app_error",
+    "translation": "Permanent user deletion feature is not enabled. Please contact your System Administrator."
+  },
   {
     "id": "api.user.demote_user_to_guest.already_guest.app_error",
     "translation": "Unable to convert the user to guest because is already a guest."

model/client4.go

@@ -1240,6 +1240,16 @@ func (c *Client4) DeleteUser(userId string) (bool, *Response) {
 	return CheckStatusOK(r), BuildResponse(r)
 }
 
+// PermanentDeleteUser deletes a user in the system based on the provided user id string.
+func (c *Client4) PermanentDeleteUser(userId string) (bool, *Response) {
+	r, err := c.DoApiDelete(c.GetUserRoute(userId) + "?permanent=" + c.boolString(true))
+	if err != nil {
+		return false, BuildErrorResponse(r, err)
+	}
+	defer closeBody(r)
+	return CheckStatusOK(r), BuildResponse(r)
+}
+
 // ConvertUserToBot converts a user to a bot user.
 func (c *Client4) ConvertUserToBot(userId string) (*Bot, *Response) {
 	r, err := c.DoApiPost(c.GetUserRoute(userId)+"/convert_to_bot", "")

model/config.go

@@ -327,6 +327,7 @@ type ServiceSettings struct {
 	DEPRECATED_DO_NOT_USE_ImageProxyURL               *string `json:"ImageProxyURL" mapstructure:"ImageProxyURL"`         // This field is deprecated and must not be used.
 	DEPRECATED_DO_NOT_USE_ImageProxyOptions           *string `json:"ImageProxyOptions" mapstructure:"ImageProxyOptions"` // This field is deprecated and must not be used.
 	EnableAPITeamDeletion                             *bool
+	EnableAPIUserDeletion                             *bool
 	ExperimentalEnableHardenedMode                    *bool
 	DisableLegacyMFA                                  *bool `restricted:"true"`
 	ExperimentalStrictCSRFEnforcement                 *bool `restricted:"true"`
@@ -699,6 +700,10 @@ func (s *ServiceSettings) SetDefaults(isUpdate bool) {
 		s.EnableAPITeamDeletion = NewBool(false)
 	}
 
+	if s.EnableAPIUserDeletion == nil {
+		s.EnableAPIUserDeletion = NewBool(false)
+	}
+
 	if s.ExperimentalEnableHardenedMode == nil {
 		s.ExperimentalEnableHardenedMode = NewBool(false)
 	}