Idiomatic error handling for app/e*.go (#9426)

4 files changed, 109 insertions, 98 deletions

diff --git a/app/elasticsearch.go b/app/elasticsearch.go
index c3b558bce..2e731f5d7 100644
--- a/app/elasticsearch.go
+++ b/app/elasticsearch.go
@@ -18,27 +18,28 @@ func (a *App) TestElasticsearch(cfg *model.Config) *model.AppError {
 		}
 	}
 
-	if esI := a.Elasticsearch; esI != nil {
-		if err := esI.TestConfig(cfg); err != nil {
-			return err
-		}
-	} else {
+	esI := a.Elasticsearch
+	if esI == nil {
 		err := model.NewAppError("TestElasticsearch", "ent.elasticsearch.test_config.license.error", nil, "", http.StatusNotImplemented)
 		return err
 	}
+	if err := esI.TestConfig(cfg); err != nil {
+		return err
+	}
 
 	return nil
 }
 
 func (a *App) PurgeElasticsearchIndexes() *model.AppError {
-	if esI := a.Elasticsearch; esI != nil {
-		if err := esI.PurgeIndexes(); err != nil {
-			return err
-		}
-	} else {
+	esI := a.Elasticsearch
+	if esI == nil {
 		err := model.NewAppError("PurgeElasticsearchIndexes", "ent.elasticsearch.test_config.license.error", nil, "", http.StatusNotImplemented)
 		return err
 	}
 
+	if err := esI.PurgeIndexes(); err != nil {
+		return err
+	}
+
 	return nil
 }
diff --git a/app/email.go b/app/email.go
index eefe83a81..143d4a052 100644
--- a/app/email.go
+++ b/app/email.go
@@ -291,6 +291,11 @@ func (a *App) SendInviteEmails(team *model.Team, senderName string, senderUserId
 		return
 	}
 	rateLimited, result, err := a.EmailRateLimiter.RateLimit(senderUserId, len(invites))
+	if err != nil {
+		a.Log.Error("Error rate limiting invite email.", mlog.String("user_id", senderUserId), mlog.String("team_id", team.Id), mlog.Err(err))
+		return
+	}
+
 	if rateLimited {
 		a.Log.Error("Invite emails rate limited.",
 			mlog.String("user_id", senderUserId),
@@ -298,9 +303,6 @@ func (a *App) SendInviteEmails(team *model.Team, senderName string, senderUserId
 			mlog.String("retry_after", result.RetryAfter.String()),
 			mlog.Err(err))
 		return
-	} else if err != nil {
-		a.Log.Error("Error rate limiting invite email.", mlog.String("user_id", senderUserId), mlog.String("team_id", team.Id), mlog.Err(err))
-		return
 	}
 
 	for _, invite := range invites {
diff --git a/app/email_batching.go b/app/email_batching.go
index aad1eb8cb..ceee47f32 100644
--- a/app/email_batching.go
+++ b/app/email_batching.go
@@ -139,21 +139,26 @@ func (job *EmailBatchingJob) checkPendingNotifications(now time.Time, handler fu
 			if inspectedTeamNames[notification.teamName] != "" {
 				continue
 			}
-			tchan := job.app.Srv.Store.Team().GetByName(notifications[0].teamName)
-			if result := <-tchan; result.Err != nil {
+
+			result := <-job.app.Srv.Store.Team().GetByName(notifications[0].teamName)
+			if result.Err != nil {
 				mlog.Error(fmt.Sprint("Unable to find Team id for notification", result.Err))
 				continue
-			} else if team, ok := result.Data.(*model.Team); ok {
+			}
+
+			if team, ok := result.Data.(*model.Team); ok {
 				inspectedTeamNames[notification.teamName] = team.Id
 			}
 
 			// if the user has viewed any channels in this team since the notification was queued, delete
 			// all queued notifications
-			mchan := job.app.Srv.Store.Channel().GetMembersForUser(inspectedTeamNames[notification.teamName], userId)
-			if result := <-mchan; result.Err != nil {
+			result = <-job.app.Srv.Store.Channel().GetMembersForUser(inspectedTeamNames[notification.teamName], userId)
+			if result.Err != nil {
 				mlog.Error(fmt.Sprint("Unable to find ChannelMembers for user", result.Err))
 				continue
-			} else if channelMembers, ok := result.Data.(*model.ChannelMembers); ok {
+			}
+
+			if channelMembers, ok := result.Data.(*model.ChannelMembers); ok {
 				for _, channelMember := range *channelMembers {
 					if channelMember.LastViewedAt >= batchStartTime {
 						mlog.Debug(fmt.Sprintf("Deleted notifications for user %s", userId), mlog.String("user_id", userId))
@@ -194,38 +199,31 @@ func (job *EmailBatchingJob) checkPendingNotifications(now time.Time, handler fu
 }
 
 func (a *App) sendBatchedEmailNotification(userId string, notifications []*batchedNotification) {
-	uchan := a.Srv.Store.User().Get(userId)
-
-	var user *model.User
-	if result := <-uchan; result.Err != nil {
+	result := <-a.Srv.Store.User().Get(userId)
+	if result.Err != nil {
 		mlog.Warn("Unable to find recipient for batched email notification")
 		return
-	} else {
-		user = result.Data.(*model.User)
 	}
+	user := result.Data.(*model.User)
 
 	translateFunc := utils.GetUserTranslations(user.Locale)
 	displayNameFormat := *a.Config().TeamSettings.TeammateNameDisplay
 
 	var contents string
 	for _, notification := range notifications {
-		var sender *model.User
-		schan := a.Srv.Store.User().Get(notification.post.UserId)
-		if result := <-schan; result.Err != nil {
+		result := <-a.Srv.Store.User().Get(notification.post.UserId)
+		if result.Err != nil {
 			mlog.Warn("Unable to find sender of post for batched email notification")
 			continue
-		} else {
-			sender = result.Data.(*model.User)
 		}
+		sender := result.Data.(*model.User)
 
-		var channel *model.Channel
-		cchan := a.Srv.Store.Channel().Get(notification.post.ChannelId, true)
-		if result := <-cchan; result.Err != nil {
+		result = <-a.Srv.Store.Channel().Get(notification.post.ChannelId, true)
+		if result.Err != nil {
 			mlog.Warn("Unable to find channel of post for batched email notification")
 			continue
-		} else {
-			channel = result.Data.(*model.Channel)
 		}
+		channel := result.Data.(*model.Channel)
 
 		emailNotificationContentsType := model.EMAIL_NOTIFICATION_CONTENTS_FULL
 		if license := a.License(); license != nil && *license.Features.EmailNotificationContents {
diff --git a/app/emoji.go b/app/emoji.go
index 864dc31bf..c0eda18a1 100644
--- a/app/emoji.go
+++ b/app/emoji.go
@@ -49,29 +49,33 @@ func (a *App) CreateEmoji(sessionUserId string, emoji *model.Emoji, multiPartIma
 		return nil, model.NewAppError("createEmoji", "api.emoji.create.duplicate.app_error", nil, "", http.StatusBadRequest)
 	}
 
-	if imageData := multiPartImageData.File["image"]; len(imageData) == 0 {
+	imageData := multiPartImageData.File["image"]
+	if len(imageData) == 0 {
 		err := model.NewAppError("Context", "api.context.invalid_body_param.app_error", map[string]interface{}{"Name": "createEmoji"}, "", http.StatusBadRequest)
 		return nil, err
-	} else if err := a.UploadEmojiImage(emoji.Id, imageData[0]); err != nil {
+	}
+
+	if err := a.UploadEmojiImage(emoji.Id, imageData[0]); err != nil {
 		return nil, err
 	}
 
-	if result := <-a.Srv.Store.Emoji().Save(emoji); result.Err != nil {
+	result := <-a.Srv.Store.Emoji().Save(emoji)
+	if result.Err != nil {
 		return nil, result.Err
-	} else {
-		message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_EMOJI_ADDED, "", "", "", nil)
-		message.Add("emoji", emoji.ToJson())
-		a.Publish(message)
-		return result.Data.(*model.Emoji), nil
 	}
+
+	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_EMOJI_ADDED, "", "", "", nil)
+	message.Add("emoji", emoji.ToJson())
+	a.Publish(message)
+	return result.Data.(*model.Emoji), nil
 }
 
 func (a *App) GetEmojiList(page, perPage int, sort string) ([]*model.Emoji, *model.AppError) {
-	if result := <-a.Srv.Store.Emoji().GetList(page*perPage, perPage, sort); result.Err != nil {
+	result := <-a.Srv.Store.Emoji().GetList(page*perPage, perPage, sort)
+	if result.Err != nil {
 		return nil, result.Err
-	} else {
-		return result.Data.([]*model.Emoji), nil
 	}
+	return result.Data.([]*model.Emoji), nil
 }
 
 func (a *App) UploadEmojiImage(id string, imageData *multipart.FileHeader) *model.AppError {
@@ -85,41 +89,52 @@ func (a *App) UploadEmojiImage(id string, imageData *multipart.FileHeader) *mode
 	io.Copy(buf, file)
 
 	// make sure the file is an image and is within the required dimensions
-	if config, _, err := image.DecodeConfig(bytes.NewReader(buf.Bytes())); err != nil {
+	config, _, err := image.DecodeConfig(bytes.NewReader(buf.Bytes()))
+	if err != nil {
 		return model.NewAppError("uploadEmojiImage", "api.emoji.upload.image.app_error", nil, "", http.StatusBadRequest)
-	} else if config.Width > MaxEmojiOriginalWidth || config.Height > MaxEmojiOriginalHeight {
+	}
+
+	if config.Width > MaxEmojiOriginalWidth || config.Height > MaxEmojiOriginalHeight {
 		return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.too_large.app_error", map[string]interface{}{
 			"MaxWidth":  MaxEmojiOriginalWidth,
 			"MaxHeight": MaxEmojiOriginalHeight,
 		}, "", http.StatusBadRequest)
-	} else if config.Width > MaxEmojiWidth || config.Height > MaxEmojiHeight {
+	}
+
+	if config.Width > MaxEmojiWidth || config.Height > MaxEmojiHeight {
 		data := buf.Bytes()
 		newbuf := bytes.NewBuffer(nil)
-		if info, err := model.GetInfoForBytes(imageData.Filename, data); err != nil {
+		info, err := model.GetInfoForBytes(imageData.Filename, data)
+		if err != nil {
 			return err
-		} else if info.MimeType == "image/gif" {
-			if gif_data, err := gif.DecodeAll(bytes.NewReader(data)); err != nil {
+		}
+
+		if info.MimeType == "image/gif" {
+			gif_data, err := gif.DecodeAll(bytes.NewReader(data))
+			if err != nil {
 				return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.gif_decode_error", nil, "", http.StatusBadRequest)
-			} else {
-				resized_gif := resizeEmojiGif(gif_data)
-				if err := gif.EncodeAll(newbuf, resized_gif); err != nil {
-					return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.gif_encode_error", nil, "", http.StatusBadRequest)
-				}
-				if _, err := a.WriteFile(newbuf, getEmojiImagePath(id)); err != nil {
-					return err
-				}
+			}
+
+			resized_gif := resizeEmojiGif(gif_data)
+			if err := gif.EncodeAll(newbuf, resized_gif); err != nil {
+				return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.gif_encode_error", nil, "", http.StatusBadRequest)
+			}
+
+			if _, err := a.WriteFile(newbuf, getEmojiImagePath(id)); err != nil {
+				return err
 			}
 		} else {
-			if img, _, err := image.Decode(bytes.NewReader(data)); err != nil {
+			img, _, err := image.Decode(bytes.NewReader(data))
+			if err != nil {
 				return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.decode_error", nil, "", http.StatusBadRequest)
-			} else {
-				resized_image := resizeEmoji(img, config.Width, config.Height)
-				if err := png.Encode(newbuf, resized_image); err != nil {
-					return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.encode_error", nil, "", http.StatusBadRequest)
-				}
-				if _, err := a.WriteFile(newbuf, getEmojiImagePath(id)); err != nil {
-					return err
-				}
+			}
+
+			resized_image := resizeEmoji(img, config.Width, config.Height)
+			if err := png.Encode(newbuf, resized_image); err != nil {
+				return model.NewAppError("uploadEmojiImage", "api.emoji.upload.large_image.encode_error", nil, "", http.StatusBadRequest)
+			}
+			if _, err := a.WriteFile(newbuf, getEmojiImagePath(id)); err != nil {
+				return err
 			}
 		}
 	}
@@ -147,11 +162,11 @@ func (a *App) GetEmoji(emojiId string) (*model.Emoji, *model.AppError) {
 		return nil, model.NewAppError("GetEmoji", "api.emoji.storage.app_error", nil, "", http.StatusNotImplemented)
 	}
 
-	if result := <-a.Srv.Store.Emoji().Get(emojiId, false); result.Err != nil {
+	result := <-a.Srv.Store.Emoji().Get(emojiId, false)
+	if result.Err != nil {
 		return nil, result.Err
-	} else {
-		return result.Data.(*model.Emoji), nil
 	}
+	return result.Data.(*model.Emoji), nil
 }
 
 func (a *App) GetEmojiByName(emojiName string) (*model.Emoji, *model.AppError) {
@@ -163,32 +178,30 @@ func (a *App) GetEmojiByName(emojiName string) (*model.Emoji, *model.AppError) {
 		return nil, model.NewAppError("GetEmoji", "api.emoji.storage.app_error", nil, "", http.StatusNotImplemented)
 	}
 
-	if result := <-a.Srv.Store.Emoji().GetByName(emojiName); result.Err != nil {
+	result := <-a.Srv.Store.Emoji().GetByName(emojiName)
+	if result.Err != nil {
 		return nil, result.Err
-	} else {
-		return result.Data.(*model.Emoji), nil
 	}
+	return result.Data.(*model.Emoji), nil
 }
 
-func (a *App) GetEmojiImage(emojiId string) (imageByte []byte, imageType string, err *model.AppError) {
-	if result := <-a.Srv.Store.Emoji().Get(emojiId, true); result.Err != nil {
+func (a *App) GetEmojiImage(emojiId string) ([]byte, string, *model.AppError) {
+	result := <-a.Srv.Store.Emoji().Get(emojiId, true)
+	if result.Err != nil {
 		return nil, "", result.Err
-	} else {
-		var img []byte
-
-		if data, err := a.ReadFile(getEmojiImagePath(emojiId)); err != nil {
-			return nil, "", model.NewAppError("getEmojiImage", "api.emoji.get_image.read.app_error", nil, err.Error(), http.StatusNotFound)
-		} else {
-			img = data
-		}
+	}
 
-		_, imageType, err := image.DecodeConfig(bytes.NewReader(img))
-		if err != nil {
-			return nil, "", model.NewAppError("getEmojiImage", "api.emoji.get_image.decode.app_error", nil, err.Error(), http.StatusInternalServerError)
-		}
+	img, appErr := a.ReadFile(getEmojiImagePath(emojiId))
+	if appErr != nil {
+		return nil, "", model.NewAppError("getEmojiImage", "api.emoji.get_image.read.app_error", nil, appErr.Error(), http.StatusNotFound)
+	}
 
-		return img, imageType, nil
+	_, imageType, err := image.DecodeConfig(bytes.NewReader(img))
+	if err != nil {
+		return nil, "", model.NewAppError("getEmojiImage", "api.emoji.get_image.decode.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
+
+	return img, imageType, nil
 }
 
 func (a *App) SearchEmoji(name string, prefixOnly bool, limit int) ([]*model.Emoji, *model.AppError) {
@@ -196,11 +209,11 @@ func (a *App) SearchEmoji(name string, prefixOnly bool, limit int) ([]*model.Emo
 		return nil, model.NewAppError("SearchEmoji", "api.emoji.disabled.app_error", nil, "", http.StatusNotImplemented)
 	}
 
-	if result := <-a.Srv.Store.Emoji().Search(name, prefixOnly, limit); result.Err != nil {
+	result := <-a.Srv.Store.Emoji().Search(name, prefixOnly, limit)
+	if result.Err != nil {
 		return nil, result.Err
-	} else {
-		return result.Data.([]*model.Emoji), nil
 	}
+	return result.Data.([]*model.Emoji), nil
 }
 
 func resizeEmojiGif(gifImg *gif.GIF) *gif.GIF {
@@ -231,13 +244,10 @@ func resizeEmoji(img image.Image, width int, height int) image.Image {
 	emojiWidth := float64(width)
 	emojiHeight := float64(height)
 
-	var emoji image.Image
 	if emojiHeight <= MaxEmojiHeight && emojiWidth <= MaxEmojiWidth {
-		emoji = img
-	} else {
-		emoji = imaging.Fit(img, MaxEmojiWidth, MaxEmojiHeight, imaging.Lanczos)
+		return img
 	}
-	return emoji
+	return imaging.Fit(img, MaxEmojiWidth, MaxEmojiHeight, imaging.Lanczos)
 }
 
 func imageToPaletted(img image.Image) *image.Paletted {