Oh my. Is there any form of persistence, present or planned?
If there is - this means that there (eventually) will be a way to have logs from the edge servers. I'm just thinking about a worker that would collect the requests and responses data in some circular buffer, and try to push it to the origin server. Eventually, the data will get through, so no CDN-returned 52x ("web server is not responding" etc) errors would go unnoticed.
We won't offer writable storage at the edge in v1, but you could always make a background request to push these events back to some log service you maintain (on separate infrastructure from your main service to make simultaneous outages unlikely). Note that you can make background requests that happen after the main response has already returned (but still subject to the per-request CPU limits, etc.).
We're thinking about how to do writable storage, but it's tricky, since one thing we don't want is for developers to have to think about the fact that their code is running in hundreds of locations.
If there is - this means that there (eventually) will be a way to have logs from the edge servers. I'm just thinking about a worker that would collect the requests and responses data in some circular buffer, and try to push it to the origin server. Eventually, the data will get through, so no CDN-returned 52x ("web server is not responding" etc) errors would go unnoticed.