Während der Programmausführung kommt es immer zu Ereignissen und Zuständen, die für die Fehlersuche und die Programmanalyse interessant sind.

• Admin: richtet das Programm ein und kümmert sich um dessen Betrieb, vorrangiges Interesse an der Lauffähigkeit
• Entwickler: entwickelt das Programm
• Support-Mitarbeiter/Nutzer: arbeitet mit dem Programm und interessiert sich für dessen Funktionsfähigkeit, korrekte Arbeitsweise

Critical

• Target: Service Admin
• Reason: events rendering the service unusable and manual action from the Admin is required
• Example:
  • invalid config setting
  • access to database prohibited, i. e. login failure
  • bind to listening socket failed

Error

• Target: Service Admin
• Reason: Bad events, where no fallback or auto-recovery is possible and manual action from the Admin is required
• Example:
  • unhandled exception
  • database connection failed (due to network outage), but possibly the next request might succeed

Warn

• Target: Service Admin
• Reason: Bad events, where fallback or auto-recovery exists, but the admin should care about, because they should not happen too often
• Example:
  • database query failed due to lock contention and a rerun of the query happens
  • connection to remote system failed, user has to start a new run (i. e. user interaction required)

Notice

• Target: Service Admin
• Reason: Interesting actions which are helpful for reporting and examination of user error reports; syslog says »normal, but significant, condition«
• Example:
  • login/logout of users
  • new entities (account, business unit, invoice, chat room)
  • broken user requests
  • connection to remote system failed, (automatic) retry in the next cycle (i. e. no user interaction required)

Info

• Target: Developer, Reporting system, someone who analyses problems
• Reason: informational message
• Example:
  • request … handled within … seconds
  • save attachment to file …
  • connecting to …
  • federation_transaction_transmission_loop TimeoutError('',)
  • federation_transaction_transmission_loop HttpResponseException("403: b'Forbidden'",)

Debug

• Target: Developer
• Reason: messages showing some interesting behaviour what the service is doing, but mostly useful for developers.
• Example:
  • Lock acquired/released
  • Value of variables on some points
  • Number of written bytes

Trace

• Target: Developer
• Reason: Verbose message printing the state of a variable or a point in the code. Only interesting during development.