MM-57013 Added download button for downloading logs from server logs page in system console (#26389)

* added download system logs

* download all logs

* download all logs check-lint fix

* check lint fix

* download logs api

* download logs api working

* download logs working with error log

* linting issues and code cleanup

* CI check fix

* documented the api and logs from file with error handling

* test and final changes done

* final changes done

* Fix order of server-side translations

* Fix incorrect indentation of logs.yaml

---------

Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>

server/channels/api4/system.go

@@ -50,6 +50,7 @@ func (api *API) InitSystem() {
 	api.BaseRoutes.APIRoot.Handle("/caches/invalidate", api.APISessionRequired(invalidateCaches)).Methods("POST")
 
 	api.BaseRoutes.APIRoot.Handle("/logs", api.APISessionRequired(getLogs)).Methods("GET")
+	api.BaseRoutes.APIRoot.Handle("/logs/download", api.APISessionRequired(downloadLogs)).Methods("GET")
 	api.BaseRoutes.APIRoot.Handle("/logs/query", api.APISessionRequired(queryLogs)).Methods("POST")
 	api.BaseRoutes.APIRoot.Handle("/logs", api.APIHandler(postLog)).Methods("POST")
 
@@ -414,6 +415,36 @@ func getLogs(c *Context, w http.ResponseWriter, r *http.Request) {
 	w.Write([]byte(model.ArrayToJSON(lines)))
 }
 
+func downloadLogs(c *Context, w http.ResponseWriter, r *http.Request) {
+	auditRec := c.MakeAuditRecord("downloadLogs", audit.Fail)
+	defer c.LogAuditRec(auditRec)
+	if *c.App.Config().ExperimentalSettings.RestrictSystemAdmin {
+		c.Err = model.NewAppError("downloadLogs", "api.restricted_system_admin", nil, "", http.StatusForbidden)
+		return
+	}
+	if !c.App.SessionHasPermissionTo(*c.AppContext.Session(), model.PermissionGetLogs) {
+		c.SetPermissionError(model.PermissionGetLogs)
+		return
+	}
+
+	fileData, err := c.App.GetMattermostLog(c.AppContext)
+	if err != nil {
+		c.Err = model.NewAppError("downloadLogs", "api.system.logs.download_bytes_buffer.app_error", nil, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	reader := bytes.NewReader(fileData.Body)
+	web.WriteFileResponse("mattermost.log",
+		"text/plain",
+		int64(len(fileData.Body)),
+		time.Now(),
+		*c.App.Config().ServiceSettings.WebserverMode,
+		reader,
+		true,
+		w,
+		r)
+}
+
 func postLog(c *Context, w http.ResponseWriter, r *http.Request) {
 	forceToDebug := false
 

server/channels/api4/system_test.go

@@ -402,6 +402,46 @@ func TestGetLogs(t *testing.T) {
 	CheckUnauthorizedStatus(t, resp)
 }
 
+func TestDownloadLogs(t *testing.T) {
+	th := Setup(t)
+	defer th.TearDown()
+
+	for i := 0; i < 20; i++ {
+		th.TestLogger.Info(strconv.Itoa(i))
+	}
+	err := th.TestLogger.Flush()
+	require.NoError(t, err, "failed to flush log")
+
+	t.Run("Download Logs as system admin", func(t *testing.T) {
+		resData, resp, err2 := th.SystemAdminClient.DownloadLogs(context.Background())
+		require.NoError(t, err2)
+
+		require.Equal(t, "text/plain", resp.Header.Get("Content-Type"))
+		require.Contains(t, resp.Header.Get("Content-Disposition"), "attachment;filename=\"mattermost.log\"")
+
+		bodyString := string(resData)
+		for i := 0; i < 20; i++ {
+			assert.Contains(t, bodyString, fmt.Sprintf(`"msg":"%d"`, i))
+		}
+	})
+
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.ExperimentalSettings.RestrictSystemAdmin = true })
+		_, resp, err2 := th.Client.DownloadLogs(context.Background())
+		require.Error(t, err2)
+		CheckForbiddenStatus(t, resp)
+	})
+
+	_, resp, err := th.Client.DownloadLogs(context.Background())
+	require.Error(t, err)
+	CheckForbiddenStatus(t, resp)
+
+	th.Client.Logout(context.Background())
+	_, resp, err = th.Client.DownloadLogs(context.Background())
+	require.Error(t, err)
+	CheckUnauthorizedStatus(t, resp)
+}
+
 func TestPostLog(t *testing.T) {
 	th := Setup(t)
 	defer th.TearDown()