[Loki] How to include label if not exist

[churtado-tech]

I am currently using Loki Mixin Dashboards and noticed that the current logs do not include a level label. I understand that this label is planned for future implementation in our apps, but in the meantime, I would like to suggest a temporary solution to improve dashboard functionality.

Problem:
• The Loki Mixin dashboards rely on the level label to categorize logs (e.g., info, warn, error), but currently, many logs do not have this label.
• This causes issues with filtering and visualizing logs effectively in the dashboards.
• Until the level label is officially included, users must manually handle missing levels, which disrupts dashboard usability.

Proposed Solution:
• Implement a default value of "info" for logs that do not have a level label.
• This could be achieved using a label_format transformation in Prometheus recording rules or by adjusting the dashboard queries to apply a default value when level is missing.
• This change would ensure that all logs are categorized properly and allow the dashboards to function as expected.

Expected Outcome:
• Logs without a level label will be treated as info, allowing dashboards to work consistently.
• Users will be able to filter logs based on level without missing uncategorized entries.
• Once the official implementation of level is completed, this workaround can be adjusted or removed accordingly.

How can achieve that?