Help debugging cacheability / ttl information?

Dag-Erling Smørgrav des at
Mon Feb 18 00:16:42 CET 2008

Denis Brækhus <denis at> writes:
> What I really am looking for is some help with how to best debug the
> setup with regards to TTLs and cacheability. I'd like to be able to
> inspect a specific cached objects TTL to see if my "set obj.ttl"
> overrides actually work or not. What is the best way to do that?

You should get a varnishlog entry for the TTL computation when an
object is retrieved from the backend, but there won't be a log entry
for VCL changing the TTL...

> On the client I use firebug, so all headers and responess are
> readily available on that end. The reason I don't think everything
> is as it should is that the Age header is very low most of the time.

Instead of Firebug, have you considered using the following:

while :; do
    wget -O/dev/null -S 2>&1 | \
        grep -i '^age:' ;
    sleep 5 ;

> For the record we are still at varnish 1.0.4 [...]

1.0.4 is almost a year old...  why not 1.1.2?  It has *much* better
support for examining and modifying HTTP headers.

Dag-Erling Smørgrav
Senior Software Developer
Linpro AS -

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