Having experimented with Fastly for a few weeks, not very long yet, here is an idea… A feature suggestion.
Right now, the “Check Cache” button seems very promising to assist with debugging.
It shows a status code (200 or 503), a response time, a cache server.
However, the information which I had hoped to see, and could perhaps be in a new button called “Debug Cache”, would instead show this information:
- the URL or file in question, such as “http://www.example.com/page1” or “http://www.example.com/page2”
- is this a cache HIT or a MISS? State that.
3a. If it’s a MISS, then what is the reason:
- Cookie header is set? (cookies prevent caching)
- Cache-Control=private? (private prevents caching)
- timed out, but will be cached for next time.
In other words, answer the question “Why was it a MISS?”
3b. On the other hand, if it’s a cache HIT, then in that case show:
- Time remaining in the cache
- Original TTL
- Any information about the source of the TTL information. Did the TTL originate from a Cache-Control header?
So, the “Debug Cache” button would show those data points. The file, the HIT/MISS status, the reason for the HIT/MISS, the time left in the cache. Nothing more. Each of those labeled in a user-friendly way, “Time left in cache”, etc.
Couldn’t that be helpful for administrators to debug, and understand, how the caching works? Anyway, to consider. Thanks.