Nginx error log settings to write each error only once

I am not aware of any way to do this. While it would be possible to disable error logs completely I don’t know of any native way to filter them like this. I can also see this causing potential issues. If you were able to set this up, while you would no longer be flooded with error messages, how would you know an error that occurred previously was fixed if your web server stopped reporting it after it occurred once? How would you know if an issue in your logs was a one-off instance or endemic and affecting all your users? There are solutions for log analysis (feeding your logs into another system to process them) or rotation (to prevent ending up with massive log files to dig through) that might be a better fit.