Any way to invoke code from VCL after a request has been serviced?

[Guillaume Quintard]

you can put anything in the priv field of the task, but the issue is that
you have to put that data in there, meaning a call to your vmod from the
vcl.

the VUT.dispatch_f function isn't to be called from a vmod, and I don't
think you need to.

Maybe it's time to take a step back, can you fill us in the whole workflow,
notably:
- what data do you inject, and how do you create it?
- what do you need to know about the req/resp/bereq/beresp?

I almost have the feeling that this could be solved through pure vcl+shell.

-- 
Guillaume Quintard

On Thu, May 11, 2017 at 5:33 PM, Ryan Burn <rnickb731 at gmail.com> wrote:

> From the free function, is there any way to get the status code or
> other properties of the request? I tried using VRT_r_obj_status with a
> stored reference to the context, but that doesn't seem to work since
> some of the request's resources have already been reclaimed:
>
> https://github.com/rnburn/varnish-opentracing/blob/
> master/opentracing/src/trace.cpp#L22
>
> Is there any other place something like the status would be stored?
>
>
> On Mon, May 8, 2017 at 11:13 AM, Reza Naghibi <reza at varnish-software.com>
> wrote:
> > Sorry, email misfire.
> >
> > You can do this in a VMOD via PRIV_TASK:
> >
> > https://varnish-cache.org/docs/trunk/reference/vmod.
> html#private-pointers
> >
> > It might make sense to track this stuff in some kind of struct, in which
> > case, put it into *priv and then register a *free callback. Otherwise,
> just
> > put a dummy value into the *priv. *free will get called after the
> request is
> > done and you can put your custom code in there.
> >
> > --
> > Reza Naghibi
> > Varnish Software
> >
> > On Mon, May 8, 2017 at 11:10 AM, Reza Naghibi <reza at varnish-software.com
> >
> > wrote:
> >>
> >> You can do this in a VMOD via PRIV_TASK:
> >>
> >>
> >> --
> >> Reza Naghibi
> >> Varnish Software
> >>
> >> On Fri, May 5, 2017 at 10:15 PM, Ryan Burn <rnickb731 at gmail.com> wrote:
> >>>
> >>> Hello,
> >>> From VCL, is it possible to execute code that runs after a request has
> >>> been processed?
> >>>
> >>> I'm looking into writing a module that enables Varnish for distributed
> >>> tracing using the OpenTracing project [opentracing.io]. This requires
> >>> invoking code at the beginning of a request to start a span and insert
> >>> tracing context into the request's headers and invoking code after a
> >>> request's been processed to finish the span and measure how long it
> >>> took to process.
> >>>
> >>> I recently did a similar project for nginx
> >>> [github.com/rnburn/nginx-opentracing]. Nginx provides an
> >>> NGX_HTTP_LOG_PHASE [www.nginxguts.com/2011/01/phases/] that allows you
> >>> to set up handlers run after requests are serviced. Can anything
> >>> equivalent be done using VCL?
> >>>
> >>> I image you could accomplish this by subscribing and regularly reading
> >>> from Varnish's shared memory log, but I'd much rather do it directly
> >>> if possible.
> >>>
> >>> Thanks, Ryan
> >>>
> >>> _______________________________________________
> >>> varnish-misc mailing list
> >>> varnish-misc at varnish-cache.org
> >>> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
> >>
> >>
> >
>
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