CODEWITHSUNDEEP
varnishvarnish-vclsetcookie
Li1t
Li1t

Reputation: 622

Varnish HitPass debugging

I've noticed an issue on one of my sites whereby my content pages (which shouldn't set any cookies, should all be returning "Cache-Control: public" with a max-age set, and don't require authorization).

My issue is that somehow HitPass objects are making it into my cache, removing the caching from that page. I need to debug this, but am confused at exactly how best to do this particularly as I'm unable to replicate the issue.

I notice that varnish gives me an ID beside the HitPass in the varnish log. I assume this is the varnish ID for the request that generated the HitPass, and that searching back in a varnish log would tell me exactly what was wrong with the response?

Would it be better to just remove the SetCookie header from pages that I want to cache? The problem is that vcl_fetch is called even if a URL is passed... Is there any way to tell in vcl_fetch whether or not the current request has been passed by vcl_recv?

Upvotes: 1

Views: 956

Answers (1)

Clarence
Clarence

Reputation: 2964

SetCookie is indeed a reason why you get hit-for-pass objects in your cache. This is an important optimization for non-prepared sites. A hit-for-pass will let varnish go straight to the backend for each of these request instead of stall them and wait for the response of the previous one.

I'm not sure as to exactly what you are wanting to debug. If it's the set-cookie, you should probably either remove that from the backend or make your own rules on what ones to cache or what one's to ignore in your cache. If you still need the set-cookie and it has unique values, hit-for-pass is the way to do that best.

Upvotes: 0

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