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Asked: 2014-06-10 02:45:03 +0800 CST

varnishncsa not logging custom headers

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I'm using Varnish 3.0.2 on a Debian Wheezy system. I'd like to be able to set custom headers and have their contents appear in the request logs. However, although I know the headers are being set and passed to the back end, their contents don't seem to be visible to varnishncsa.

In my vcl_recv I have

set req.http.X-my-header = "blahblah";

and, for testing, this is my custom format string for varnishncsa:

'%{X-my-header}i'

I should see blahblah in the log for each request. However, all I get is -. It seems that my header isn't being passed through to varnishncsa.

How can I include my custom headers in my logs?

varnish

2 Answers

  1. I just ran into this issue and this was the top result when searching for it, so I'll post my solution/workaround here for future reference :)

    varnishncsa can log values set by std.log("key:value") in VCL 1. I used this to log my custom header. Using your example, add this in your vcl_recv:

    set req.http.X-my-header = "blahblah";
std.log("X-my-header:" + req.http.X-my-header);

    Then use the following somewhere in your logformat string for varnishncsa (mind the x in stead of the i after the header name):

    %{VCL_Log:X-my-header}x
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  2. I think there's a bug in Varnish Book when it comes to explaining how to log headers. Try this:

    varnishncsa -F '<%{age}o> <%{x-cache}o> %U %s'
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