Backups and Monitoring

If you host your own pretix instance, you also need to care about the availability of your service and the safety of your data yourself. This page gives you some information that you might need to do so properly.

Backups

There are essentially two things which you should create backups of:

Database
Your SQL database (MySQL or PostgreSQL). This is critical and you should absolutely always create automatic backups of your database. There are tons of tutorials on the internet on how to do this, and the exact process depends on the choice of your database. For MySQL, see mysqldump and for PostgreSQL, see the pg_dump tool. You probably want to create a cronjob that does the backups for you on a regular schedule.
Data directory
The data directory of your pretix configuration might contain some things that you should back up. If you did not specify a secret in your config file, back up the .secret text file in the data directory. If you lose your secret, all currently active user sessions, password reset links and similar things will be rendered invalid. Also, you probably want to backup the media subdirectory of the data directory which contains all user-uploaded and generated files. This includes files you could in theory regenerate (ticket downloads) but also files that you might be legally required to keep (invoice PDFs) or files that you would need to re-upload (event logos, product pictures, etc.). It is up to you if you create regular backups of this data, but we strongly advise you to do so. You can create backups e.g. using rsync. There is a lot of information on the internet on how to create backups of folders on a Linux machine.

There is no need to create backups of the redis database, if you use it. We only use it for non-critical, temporary or cached data.

Uptime monitoring

To monitor whether your pretix instance is running, you can issue a GET request to https://pretix.mydomain.com/healthcheck/. This endpoint tests if the connection to the database, to the configured cache and to redis (if used) is working correctly. If everything appears to work fine, an empty response with status code 200 is returned. If there is a problem, a status code in the 5xx range will be returned.

Performance monitoring

If you want to generate detailed performance statistics of your pretix installation, there is an endpoint at https://pretix.mydomain.com/metrics (no slash at the end) which returns a number of values in the text format understood by monitoring tools like Prometheus. This data is only collected and exposed if you enable it in the Metrics section of your pretix configuration. You can also configure basic auth credentials there to protect your statistics against unauthorized access. The data is temporarily collected in redis, so the performance impact of this feature depends on the connection to your redis database.

Currently, mostly response times of HTTP requests and background tasks are exposed.

If you want to go even further, you can set the profile option in the Django settings section to a value between 0 and 1. If you set it for example to 0.1, then 10% of your requests (randomly selected) will be run with cProfile activated. The profiling results will be saved to your data directory. As this might impact performance significantly and writes a lot of data to disk, we recommend to only enable it for a small number of requests – and only if you are really interested in the results.

Available metrics

The metrics available in pretix follow the standard metric types from the Prometheus world. Currently, the following metrics are exported:

pretix_view_requests_total
Counter. Counts requests to Django views, labeled with the resolved url_name, the used HTTP method and the status_code returned.
pretix_view_durations_seconds
Histogram. Measures duration of requests to Django views, labeled with the resolved url_name, the used HTTP method and the status_code returned.
pretix_task_runs_total
Counter. Counts executions of background tasks, labeled with the task_name and the status. The latter can be success, error or expected-error.
pretix_task_duration_seconds
Histogram. Measures duration of successful background task executions, labeled with the task_name.
pretix_model_instances
Gauge. Measures number of instances of a certain model within the database, labeled with the model name.