Chore: Check errors from Close calls (#29562)

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/api/dashboard.go

@@ -15,7 +15,6 @@ import (
 	"github.com/grafana/grafana/pkg/bus"
 	"github.com/grafana/grafana/pkg/components/dashdiffs"
 	"github.com/grafana/grafana/pkg/components/simplejson"
-	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/infra/metrics"
 	"github.com/grafana/grafana/pkg/plugins"
 	"github.com/grafana/grafana/pkg/services/guardian"
@@ -334,7 +333,7 @@ func (hs *HTTPServer) GetHomeDashboard(c *models.ReqContext) Response {
 			dashRedirect := dtos.DashboardRedirect{RedirectUri: url}
 			return JSON(200, &dashRedirect)
 		}
-		log.Warnf("Failed to get slug from database, %s", err.Error())
+		hs.log.Warn("Failed to get slug from database", "err", err)
 	}
 
 	filePath := hs.Cfg.DefaultHomeDashboardPath
@@ -346,7 +345,11 @@ func (hs *HTTPServer) GetHomeDashboard(c *models.ReqContext) Response {
 	if err != nil {
 		return Error(500, "Failed to load home dashboard", err)
 	}
-	defer file.Close()
+	defer func() {
+		if err := file.Close(); err != nil {
+			hs.log.Warn("Failed to close dashboard file", "path", filePath, "err", err)
+		}
+	}()
 
 	dash := dtos.DashboardFullWithMeta{}
 	dash.Meta.IsHome = true

pkg/cmd/grafana-server/main.go

@@ -116,7 +116,11 @@ func executeServer(configFile, homePath, pidFile, packaging string, traceDiagnos
 		if err != nil {
 			panic(err)
 		}
-		defer f.Close()
+		defer func() {
+			if err := f.Close(); err != nil {
+				log.Error("Failed to write trace diagnostics", "path", traceDiagnostics.file, "err", err)
+			}
+		}()
 
 		if err := trace.Start(f); err != nil {
 			panic(err)

pkg/components/imguploader/azureblobuploader.go

@@ -49,7 +49,11 @@ func (az *AzureBlobUploader) Upload(ctx context.Context, imageDiskPath string) (
 	if err != nil {
 		return "", err
 	}
-	defer file.Close()
+	defer func() {
+		if err := file.Close(); err != nil {
+			az.log.Warn("Failed to close file", "path", imageDiskPath, "err", err)
+		}
+	}()
 
 	randomFileName, err := util.GetRandomString(30)
 	if err != nil {

pkg/components/imguploader/gcs/gcsuploader.go

@@ -153,7 +153,11 @@ func (u *Uploader) uploadFile(
 	if err != nil {
 		return err
 	}
-	defer fileReader.Close()
+	defer func() {
+		if err := fileReader.Close(); err != nil {
+			u.log.Warn("Failed to close file", "err", err, "path", imageDiskPath)
+		}
+	}()
 
 	// Set public access if not generating a signed URL
 	pubAcc := !u.enableSignedURLs

pkg/components/imguploader/s3uploader.go

@@ -80,12 +80,17 @@ func (u *S3Uploader) Upload(ctx context.Context, imageDiskPath string) (string,
 	if err != nil {
 		return "", err
 	}
-	defer file.Close()
+	defer func() {
+		if err := file.Close(); err != nil {
+			u.log.Warn("Failed to close file", "path", imageDiskPath, "err", err)
+		}
+	}()
 
 	sess, err = session.NewSession(cfg)
 	if err != nil {
 		return "", err
 	}
+
 	uploader := s3manager.NewUploader(sess)
 	result, err := uploader.UploadWithContext(ctx, &s3manager.UploadInput{
 		Bucket:      aws.String(u.bucket),

pkg/infra/log/log.go

@@ -80,6 +80,10 @@ func Warnf(format string, v ...interface{}) {
 	Root.Warn(message)
 }
 
+func Error(msg string, args ...interface{}) {
+	Root.Error(msg, args...)
+}
+
 func Errorf(skip int, format string, v ...interface{}) {
 	Root.Error(fmt.Sprintf(format, v...))
 }

pkg/plugins/dashboards.go

@@ -91,7 +91,6 @@ func GetPluginDashboards(orgId int64, pluginId string) ([]*PluginDashboardInfoDT
 
 func loadPluginDashboard(pluginId, path string) (*models.Dashboard, error) {
 	plugin, exists := Plugins[pluginId]
-
 	if !exists {
 		return nil, PluginNotFoundError{pluginId}
 	}
@@ -102,7 +101,11 @@ func loadPluginDashboard(pluginId, path string) (*models.Dashboard, error) {
 		return nil, err
 	}
 
-	defer reader.Close()
+	defer func() {
+		if err := reader.Close(); err != nil {
+			plog.Warn("Failed to close file", "path", dashboardFilePath, "err", err)
+		}
+	}()
 
 	data, err := simplejson.NewFromReader(reader)
 	if err != nil {

pkg/plugins/manifest.go

@@ -113,7 +113,11 @@ func getPluginSignatureState(log log.Logger, plugin *PluginBase) PluginSignature
 		if err != nil {
 			return PluginSignatureModified
 		}
-		defer f.Close()
+		defer func() {
+			if err := f.Close(); err != nil {
+				log.Warn("Failed to close plugin file", "path", fp, "err", err)
+			}
+		}()
 
 		h := sha256.New()
 		if _, err := io.Copy(h, f); err != nil {

pkg/plugins/plugins.go

@@ -273,7 +273,11 @@ func (pm *PluginManager) scan(pluginDir string, requireSigned bool) error {
 		if err != nil {
 			return err
 		}
-		defer reader.Close()
+		defer func() {
+			if err := reader.Close(); err != nil {
+				scanner.log.Warn("Failed to close JSON file", "path", jsonFPath, "err", err)
+			}
+		}()
 
 		jsonParser := json.NewDecoder(reader)
 
@@ -343,7 +347,11 @@ func (s *PluginScanner) loadPlugin(pluginJSONFilePath string) error {
 	if err != nil {
 		return err
 	}
-	defer reader.Close()
+	defer func() {
+		if err := reader.Close(); err != nil {
+			s.log.Warn("Failed to close JSON file", "path", pluginJSONFilePath, "err", err)
+		}
+	}()
 
 	jsonParser := json.NewDecoder(reader)
 	pluginCommon := PluginBase{}

pkg/services/alerting/notifiers/discord.go

@@ -2,6 +2,7 @@ package notifiers
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"mime/multipart"
 	"os"
@@ -168,12 +169,20 @@ func (dn *DiscordNotifier) embedImage(cmd *models.SendWebhookSync, imagePath str
 			return err
 		}
 	}
-
+	defer func() {
-	defer f.Close()
+		if err := f.Close(); err != nil {
+			dn.log.Warn("Failed to close file", "path", imagePath, "err", err)
+		}
+	}()
 
 	var b bytes.Buffer
 	w := multipart.NewWriter(&b)
-
+	defer func() {
+		if err := w.Close(); err != nil {
+			// Should be OK since we already close it on non-error path
+			dn.log.Warn("Failed to close multipart writer", "err", err)
+		}
+	}()
 	fw, err := w.CreateFormField("payload_json")
 	if err != nil {
 		return err
@@ -192,7 +201,9 @@ func (dn *DiscordNotifier) embedImage(cmd *models.SendWebhookSync, imagePath str
 		return err
 	}
 
-	w.Close()
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("failed to close multipart writer: %w", err)
+	}
 
 	cmd.Body = b.String()
 	cmd.ContentType = w.FormDataContentType()

pkg/services/alerting/notifiers/pushover.go

@@ -292,7 +292,11 @@ func (pn *PushoverNotifier) genPushoverBody(evalContext *alerting.EvalContext, m
 		if err != nil {
 			return nil, b, err
 		}
-		defer f.Close()
+		defer func() {
+			if err := f.Close(); err != nil {
+				pn.log.Warn("Failed to close file", "path", evalContext.ImageOnDiskPath, "err", err)
+			}
+		}()
 
 		fw, err := w.CreateFormFile("attachment", evalContext.ImageOnDiskPath)
 		if err != nil {

pkg/services/alerting/notifiers/slack.go

@@ -321,7 +321,7 @@ func (sn *SlackNotifier) Notify(evalContext *alerting.EvalContext) error {
 		return err
 	}
 	if sn.Token != "" && sn.UploadImage {
-		err = slackFileUpload(evalContext, sn.log, "https://slack.com/api/files.upload", sn.Recipient, sn.Token)
+		err = sn.slackFileUpload(evalContext, sn.log, "https://slack.com/api/files.upload", sn.Recipient, sn.Token)
 		if err != nil {
 			return err
 		}
@@ -329,12 +329,12 @@ func (sn *SlackNotifier) Notify(evalContext *alerting.EvalContext) error {
 	return nil
 }
 
-func slackFileUpload(evalContext *alerting.EvalContext, log log.Logger, url string, recipient string, token string) error {
+func (sn *SlackNotifier) slackFileUpload(evalContext *alerting.EvalContext, log log.Logger, url string, recipient string, token string) error {
 	if evalContext.ImageOnDiskPath == "" {
 		evalContext.ImageOnDiskPath = filepath.Join(setting.HomePath, "public/img/mixed_styles.png")
 	}
 	log.Info("Uploading to slack via file.upload API")
-	headers, uploadBody, err := generateSlackBody(evalContext.ImageOnDiskPath, token, recipient)
+	headers, uploadBody, err := sn.generateSlackBody(evalContext.ImageOnDiskPath, token, recipient)
 	if err != nil {
 		return err
 	}
@@ -346,37 +346,47 @@ func slackFileUpload(evalContext *alerting.EvalContext, log log.Logger, url stri
 	return nil
 }
 
-func generateSlackBody(file string, token string, recipient string) (map[string]string, bytes.Buffer, error) {
+func (sn *SlackNotifier) generateSlackBody(path string, token string, recipient string) (map[string]string, bytes.Buffer, error) {
 	// Slack requires all POSTs to files.upload to present
 	// an "application/x-www-form-urlencoded" encoded querystring
 	// See https://api.slack.com/methods/files.upload
 	var b bytes.Buffer
 	w := multipart.NewWriter(&b)
+	defer func() {
+		if err := w.Close(); err != nil {
+			// Shouldn't matter since we already close w explicitly on the non-error path
+			sn.log.Warn("Failed to close multipart writer", "err", err)
+		}
+	}()
+
 	// Add the generated image file
-	f, err := os.Open(file)
+	f, err := os.Open(path)
 	if err != nil {
 		return nil, b, err
 	}
-	defer f.Close()
+	defer func() {
-	fw, err := w.CreateFormFile("file", file)
+		if err := f.Close(); err != nil {
+			sn.log.Warn("Failed to close file", "path", path, "err", err)
+		}
+	}()
+	fw, err := w.CreateFormFile("file", path)
 	if err != nil {
 		return nil, b, err
 	}
-	_, err = io.Copy(fw, f)
+	if _, err := io.Copy(fw, f); err != nil {
-	if err != nil {
 		return nil, b, err
 	}
 	// Add the authorization token
-	err = w.WriteField("token", token)
+	if err := w.WriteField("token", token); err != nil {
-	if err != nil {
 		return nil, b, err
 	}
 	// Add the channel(s) to POST to
-	err = w.WriteField("channels", recipient)
+	if err := w.WriteField("channels", recipient); err != nil {
-	if err != nil {
 		return nil, b, err
 	}
-	w.Close()
+	if err := w.Close(); err != nil {
+		return nil, b, fmt.Errorf("failed to close multipart writer: %w", err)
+	}
 	headers := map[string]string{
 		"Content-Type":  w.FormDataContentType(),
 		"Authorization": "auth_token=\"" + token + "\"",

pkg/services/provisioning/dashboards/file_reader.go

@@ -347,7 +347,11 @@ func (fr *FileReader) readDashboardFromFile(path string, lastModified time.Time,
 	if err != nil {
 		return nil, err
 	}
-	defer reader.Close()
+	defer func() {
+		if err := reader.Close(); err != nil {
+			fr.log.Warn("Failed to close file", "path", path, "err", err)
+		}
+	}()
 
 	all, err := ioutil.ReadAll(reader)
 	if err != nil {

pkg/services/rendering/http_mode.go

@@ -96,7 +96,12 @@ func (rs *RenderingService) renderViaHttp(ctx context.Context, renderKey string,
 	if err != nil {
 		return nil, err
 	}
-	defer out.Close()
+	defer func() {
+		if err := out.Close(); err != nil {
+			// We already close the file explicitly in the non-error path, so shouldn't be a problem
+			rs.log.Warn("Failed to close file", "path", filePath, "err", err)
+		}
+	}()
 	_, err = io.Copy(out, resp.Body)
 	if err != nil {
 		// check that we didn't timeout while receiving the response.
@@ -107,6 +112,9 @@ func (rs *RenderingService) renderViaHttp(ctx context.Context, renderKey string,
 		rs.log.Error("Remote rendering request failed", "error", err)
 		return nil, fmt.Errorf("remote rendering request failed: %w", err)
 	}
+	if err := out.Close(); err != nil {
+		return nil, fmt.Errorf("failed to write to %q: %w", filePath, err)
+	}
 
 	return &RenderResult{FilePath: filePath}, err
 }