Skip to content

Troubleshooting

This section lists some common pitfalls that you might encounter when setting up or using this activity archiving driver.

A job timeouts prior to the configured timeout value

Check your timeout settings. Be aware that there is a configurable job timeout within the Moodle plugin settings (local_archiving | job_timeout_min) as well as one within the archive worker service (MOODLE_ARCHIVER_REQUEST_TIMEOUT_SEC).

Warning

Since the shortest timeout always takes precedence, make sure to adjust both timeout settings as required.

The archive worker service cannot access the Moodle instance

If the archive worker service can not access your Moodle instance, you should check the following:

  1. Ensure that the archive worker service is able to resolve the hostname of your Moodle instance.
    • You can test this by running nslookup yourmoodle.tld on the machine that runs the archive worker service.
    • If the lookup fails, check the DNS settings on the machine that runs the archive worker service.
  2. Ensure that the archive worker service is able to reach the machine that runs your Moodle instance.
    • You can test this by running ping yourmoodle.tld on the machine that runs the archive worker service.
    • If the ping fails, check the network and firewall settings on both machines.
  3. Ensure that the archive worker service is able to retrieve a basic web page from your Moodle instance.
    • You can test this by running curl -v https://yourmoodle.tld on the machine that runs the archive worker service.
    • If the curl command fails, check the firewall settings on both machines.

Proxy Servers

If your archive worker requires a proxy server to access your Moodle instance, you can find information on how to configure it here: Worker Service > Proxy Servers

Access to Moodle webservice functions fails

If you get an error message that access to one or more webservice functions is denied, you should check the following:

  1. Ensure that your archive worker service is able to connect to your Moodle instance.
  2. Ensure that webservices and the REST protocol are enabled globally.

Upload of created archives fail

If the archive worker is able to create the archive but fails to upload it back to your Moodle instance, you should check the following things:

  1. Ensure that your Moodle is configured to file uploads. $CFG->maxbytes should be set to the same value as PHP upload_max_filesize (see below).
  2. Ensure you have configured PHP to accept file uploads. The upload_max_filesize and post_max_size settings in your php.ini should be set to a value that matches $CFG->maxbytes from your Moodle settings.
  3. If you are using an ingress webserver and PHP-FPM via FastCGI, ensure that the fastcgi_send_timeout and fastcgi_read_timeout settings are long enough to allow the upload of the largest archive file that you expect. Nginx usually signals this problem by returning a '504 Gateway Time-out' after 60 seconds (default).
  4. Ensure that your antivirus plugin is capable of handling large files. When using ClamAV you can control maximum file sizes by setting MaxFileSize, MaxScanSize, and StreamMaxLength (when using a TCP socket) inside clamd.conf.

Chunked file uploads

The worker service automatically detects the maximum file upload size that is configured in your Moodle instance and uses chunked file uploads to transfer the archive back to Moodle whenever necessary. This allows you to keep the max file upload size to a reasonable value while still being able to create large archives.

Text is not rendered correctly

If the text inside the generated PDF files is not rendered correctly, e.g., when only rectangles are displayed instead of characters, please make sure that an extended set of base fonts is available on your server.

If you are running Ubuntu or Debian, you can ensure this by installing the fonts-noto package via your package manager.

If you are using the official Docker image, please open a bug report instead.

Readiness probe fails (MathJax, GeoGebra, ...)

Some question types contain content that is rendered asynchronously by JavaScript after the page has already been loaded (e.g., MathJax, GeoGebra, ...). Therefore, the archive worker service contains a readiness probe that determines whether all dynamic content has been rendered and delays PDF generation until everything is ready.

If your activity contains such dynamically rendered content and your archive jobs fail after a short time, you should check the logs of your archive worker for messages like Ready signal not received or similar.

At this point you can try increasing the number of seconds the archive worker waits before considering the check to have failed via MOODLE_ARCHIVER_WAIT_FOR_READY_SIGNAL_TIMEOUT_SEC. If desired, you can also make the archive worker simply continue after the timeout is reached and generating the PDF as is by setting MOODLE_ARCHIVER_CONTINUE_AFTER_READY_SIGNAL_TIMEOUT=True.

If you believe that the readiness probe failure is caused by a bug, please do not hesitate to open a bug report.