Audit log and server logs
MultiTaction Canvus Server keeps two kinds of records:
- The audit log records who did what: sign-ins, account and group changes, access tokens, and changes to canvases, folders and permissions. It is stored in the database.
- The server logs are text files with the server's operational messages: start-up, configuration, certificates, connections and errors.
Audit log
View the audit log
- Sign in to the web UI as an administrator.
- Open Admin > Audit log.
- Set the filters and click Apply filters:
- From and To: the date range. The page opens on the last 7 days.
- Target type: the kind of object the event concerns, for example
user,group,canvasorfolder. - Target ID: the ID of one object.
- Author ID: the user ID of the person who did it.
- Click Show details on an entry to see its details. Use Next page and First page to move through the results, 50 entries at a time.
Note
In Canvus Server releases before 26.10.3 the audit log page failed with "400 Bad Request" and showed no entries. Update the server if you see this.
Export the audit log
Click Export CSV to download the entries that match the current filters as a CSV file.
What each entry contains
| Field | Contents |
|---|---|
| When | Date and time of the event (stored in UTC, shown in your browser's time zone) |
| Author | User ID of the person who did it, and the IP address the request came from |
| Action | What happened |
| Target | Type and ID of the object it happened to: user, group, canvas, folder or server |
| Details | Extra information about the event, when there is any |
Which events are recorded
The audit log records these kinds of events:
- Sign-in, failed sign-in and sign-out
- Account changes: users created, registered, updated and deleted, email confirmations, password resets and forced password resets
- Groups created, updated and deleted, and members added or removed
- Access tokens created, updated and deleted
- Canvases and folders created, renamed, moved and deleted
- Permission changes, share-link permissions and canvas demo state
Retention
Canvus Server does not delete audit log entries automatically. They stay in the database until it is cleared, and they are included in server backups. Plan disk space and any retention policy of your own around this.
Developers can also read the audit log through the REST API, see Audit log.
Server logs
Where the log files are
| Deployment | Folder |
|---|---|
| Linux package | /var/lib/mt-canvus-server/logs/server/ |
| Windows MSI | %ProgramData%\MultiTaction\canvus\logs\server\ |
| Container | /canvus-data/logs/server/ on the host |
The folder is set by [system] log-path in mt-canvus-server.ini. If log-path is empty, the server writes no log files and prints its log to standard output only. See Log files.
On Windows, the installer also writes %ProgramData%\MultiTaction\canvus\logs\installer.log.
File names and disk space
Each time the server starts, it writes to a log file named after that day's date: mt-canvus-server-YYYY-MM-DD.log. The web dashboard writes into the same file, so one file covers both. A restart on the same day adds to the same file, and the file keeps growing for as long as the server runs, even past midnight. Canvus Server does not rotate, compress or delete log files. Check the size of the log folder from time to time, and delete or archive old files yourself, for example with a scheduled task or a logrotate rule.
Read logs in the web UI
From Canvus Server 26.10.5, administrators can read the log files in the browser:
- Open Admin > Server logs. The page lists the log files, newest first, with their size and when they were last written.
- Click Open to show a file as text in a new browser tab.
- Click Download to save a file as stored.
Only administrators can open the page or the files. The check is made on every request, so removing someone's administrator rights takes effect immediately. If file logging is off (log-path is empty), the page says so.
Read logs on the server
Linux package:
sudo ls -lt /var/lib/mt-canvus-server/logs/server/
sudo tail -f /var/lib/mt-canvus-server/logs/server/mt-canvus-server-*.log
Windows (PowerShell):
Get-ChildItem "$env:ProgramData\MultiTaction\canvus\logs\server" | Sort-Object LastWriteTime -Descending
Container:
sudo ls -lt /canvus-data/logs/server/
# Start-up messages from the container entrypoint
sudo podman logs --tail 100 canvus-combined
Database logs
| Deployment | Location |
|---|---|
| Linux package | /var/lib/canvus/postgres/log/ |
| Windows MSI | %ProgramData%\MultiTaction\canvus\postgres\log\. Service events are in the Windows Event Log; see Operating on Windows. |
| Container | sudo podman logs canvus-postgres |
The bundled PostgreSQL of the Linux package and the Windows MSI starts a new log file every day, or when the file reaches 100 MB.
Log lines to watch
- Certificate expiry. From Canvus Server 26.08.0, the server logs the certificate's subject, alternative names and expiry date at start-up. It logs a warning when the certificate expires within 30 days, and an error once it has expired.
- Certificate key problems. From Canvus Server 26.09.4, the server stops with
SSL certificate-key-file … contains no private keywhen the key file has no private key. - Conflicting settings.
Configuration option '…' has been superseded by '…' but now they have conflicting valuesmeans an old setting inmt-canvus-server.inidisagrees with its replacement. See Removed and renamed settings. - Email disabled.
Configuration option 'smtp/host' is empty, email sending is disabledmeans email is not configured. See Email (SMTP) setup.
From Canvus Server 26.11.0, a connection that opens and closes without sending anything, such as a certificate check, port scan or load-balancer health check, is no longer logged as an error.
More detail for troubleshooting
When MultiTaction support asks for more detail, start the server with one of these options:
--verbose: all debug messages.--verbose-modules <list>: debug messages from the named modules only (comma-separated).--print-thread-id: adds the thread ID to each line.