Better handling of big log files to avoid crash of the viewer

Steps to reproduce

1. Set loglevel to in config/config.php to 0 ('loglevel' => 0).
2. Execute many actions which will trigger a log message to get written.
3. Open the log viewer when the logfile has more than 60000 entires.

Expected behaviour

The log viewer displays the log.

If the log is too big to be displayed, truncate to the newest n entries (where n is a value which can be handled by the frontend - for example 1000 or 5000) or paginate the log.

Actual behaviour

The log viewer crashes, so the page will get blank. It's not clear when exactly this happens. I have seen this with a logfile which counts about 62000 entries, but I believe the actual limit is lower and also depends on what browser and runtime environment you use.

Server configuration

Operating system: Ubuntu 20.04

Web server: Apache 2.4.41-4ubuntu3.10

Database: MariaDB 10.5.15

PHP version: 7.4

Nextcloud version: 24.0.0

Where did you install Nextcloud from: nextcloud.com

List of activated apps:

Enabled:
  - accessibility: 1.10.0
  - activity: 2.16.0
  - admin_audit: 1.14.0
  - apporder: 0.15.0
  - bookmarks: 10.3.1
  - calendar: 3.3.0
  - circles: 24.0.0
  - cloud_federation_api: 1.7.0
  - comments: 1.14.0
  - contacts: 4.1.0
  - contactsinteraction: 1.5.0
  - dashboard: 7.4.0
  - dav: 1.22.0
  - deck: 1.7.0
  - drawio: 1.0.2
  - external: 4.0.0
  - federatedfilesharing: 1.14.0
  - federation: 1.14.0
  - files: 1.19.0
  - files_fulltextsearch: 24.0.0
  - files_fulltextsearch_tesseract: 24.0.0
  - files_pdfviewer: 2.5.0
  - files_rightclick: 1.3.0
  - files_sharing: 1.16.2
  - files_trashbin: 1.14.0
  - files_versions: 1.17.0
  - files_videoplayer: 1.13.0
  - firstrunwizard: 2.13.0
  - forms: 2.5.0
  - fulltextsearch: 24.0.0
  - fulltextsearch_elasticsearch: 24.0.0
  - gpxpod: 4.3.0
  - keeweb: 0.6.9
  - logreader: 2.9.0
  - lookup_server_connector: 1.12.0
  - nextcloud_announcements: 1.13.0
  - notes: 4.3.1
  - notifications: 2.12.0
  - oauth2: 1.12.0
  - onlyoffice: 7.3.4
  - password_policy: 1.14.0
  - phonetrack: 0.7.0
  - photos: 1.6.0
  - polls: 3.6.1
  - privacy: 1.8.0
  - provisioning_api: 1.14.0
  - quota_warning: 1.14.0
  - serverinfo: 1.14.0
  - settings: 1.6.0
  - sharebymail: 1.14.0
  - spreed: 14.0.1
  - support: 1.7.0
  - survey_client: 1.12.0
  - systemtags: 1.14.0
  - tasks: 0.14.4
  - text: 3.5.1
  - theming: 1.15.0
  - theming_customcss: 1.11.0
  - twofactor_backupcodes: 1.13.0
  - updatenotification: 1.14.0
  - user_status: 1.4.0
  - viewer: 1.8.0
  - workflowengine: 2.6.0
Disabled:
  - encryption: 2.2.0
  - files_external: 1.15.0
  - recommendations: 0.4.0
  - user_ldap
  - weather_status: 1.3.0

Nextcloud configuration:

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "nextcloud.0x0c.de"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "skeletondirectory": "",
        "overwrite.cli.url": "https:\/\/nextcloud.0x0c.de",
        "dbtype": "mysql",
        "version": "24.0.0.12",
        "installed": true,
        "htaccess.RewriteBase": "\/",
        "maintenance": false,
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "knowledgebaseenabled": false,
        "theme": "",
        "simpleSignUpLink.shown": false,
        "loglevel": 2,
        "log_authfailip": true,
        "mysql.utf8mb4": true,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "sendmail",
        "mail_smtpauthtype": "LOGIN",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "updater.release.channel": "stable",
        "trashbin_retention_obligation": "auto, 30",
        "app_install_overwrite": [
            "apporder",
            "deck",
            "keeweb",
            "appointments",
            "drawio",
            "bookmarks",
            "spreed"
        ],
        "has_rebuilt_cache": true,
        "onlyoffice": {
            "verify_peer_off": true
        },
        "default_language": "de",
        "default_phone_region": "DE",
        "check_data_directory_permissions": false,
        "log_rotate_size": 52428800
    }
}

Client configuration

Browser:
Vivaldi 5.2.2623.46 (Stable channel) (64-Bit)

Operating system:
Windows 10

Logs

Nextcloud log (data/owncloud.log)

(not relevant)

Browser log

react-dom.production.min.js:216 Error: Minified React error #188; visit https://reactjs.org/docs/error-decoder.html?invariant=188 for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
    at t.findDOMNode (react-dom.production.min.js:289:284)
    at t.transition (CSSTransitionGroupChild.js:129:30)
    at t.r.componentWillEnter (CSSTransitionGroupChild.js:97:15)
    at t.s.performEnter (TransitionGroup.js:83:19)
    at TransitionGroup.js:192:21
    at Array.forEach (<anonymous>)
    at t.componentDidUpdate (TransitionGroup.js:191:17)
    at co (react-dom.production.min.js:219:502)
    at xl (react-dom.production.min.js:259:160)
    at t.unstable_runWithPriority (scheduler.production.min.js:18:343)

Uncaught (in promise) Error: Minified React error #188; visit https://reactjs.org/docs/error-decoder.html?invariant=188 for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
    at t.findDOMNode (react-dom.production.min.js:289:284)
    at t.transition (CSSTransitionGroupChild.js:129:30)
    at t.r.componentWillEnter (CSSTransitionGroupChild.js:97:15)
    at t.s.performEnter (TransitionGroup.js:83:19)
    at TransitionGroup.js:192:21
    at Array.forEach (<anonymous>)
    at t.componentDidUpdate (TransitionGroup.js:191:17)
    at co (react-dom.production.min.js:219:502)
    at xl (react-dom.production.min.js:259:160)
    at t.unstable_runWithPriority (scheduler.production.min.js:18:343)

Start with the log viewer entry point and reproduce the crash using a logfile with more than 60,000 entries. Inspect the browser console for the reported React error and determine whether the viewer should limit entries or paginate them; done means large logs display without blanking the page.