Disabling CDN caching for active releases packages

[Etienne Champetier]

Le dim. 18 janv. 2026 à 19:15, Baptiste Jonglez
<baptiste at bitsofnetworks.org> a écrit :
>
> On 14-01-26, Etienne Champetier wrote:
> > Hi Baptiste,
> >
> > Le dim. 11 janv. 2026 à 18:33, Baptiste Jonglez
> > <baptiste at bitsofnetworks.org> a écrit :
> > >
> > > Hi,
> > >
> > > As discussed previously, I just disabled CDN caching for packages.
> >
> > Maybe that's already what you are doing, but instead of fully disabling caching,
> > can you always revalidate ? I think you just need to use
> > 'Cache-Control: no-cache' on the origin server
>
> We are not currently setting any cache header on the origin server.
>
> Just to understand, with your proposal, the CDN would check the origin
> server for each hit, but it would still serve from its cache if it detects
> that the file is up-to-date?

Yes, that's the goal

> Does it need other special headers, for instance to get the last update
> time for a file or even a checksum?

On the origin you need either Etag (best) of Last-Modified header,
then on varnish side you need to set a really small TTL (or even 0)
and tell it to keep stale objects
This blog post seems pretty good to me
https://info.varnish-software.com/blog/systematic-content-validation-with-varnish

>
> Baptiste