How to set up Downstream Caches?

[Christian Bieser]

Hi there! 

I am just trying to climb through in the instructions for configuring Downstream Caches <https://developers.google.com/speed/pagespeed/module/downstream-caching>. However, I do not see any common thread among the ports in the manual. Port 80 is assigned twice and there is no demonstrable link between nginx and varnish. 

My nginx listens on port 80 and serves content from varnish via port 8380 and varnish listens on port 8380 to serve content from the origin.

--- nginx.conf (truncated) ---

http {

  upstream varnish{

    server 127.0.0.1:8380

  }

  server {

    listen 80;

    server_name localhost;

    #pagespeed config removed for example

    location / {

      proxy_pass http://varnish;

      proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;

      proxy_redirect off;

      proxy_buffering off;

      proxy_set_header Host $host;

      proxy_set_header X-Real-IP $remote_addr;

      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

    }

  }

}

---

--- varnish: run.sh ---

exec 2>&1

exec varnishd -F -s malloc,512M -u nobody -g nobody -p cli_timeout=30 \

  -f /etc/varnish/default.vcl -T 127.0.0.1:2000 \

  -a 0.0.0.0:8380

---

--- varnish: backend.vcl ---

backend origin {

    .host = "originhost";

    .port = "80";

    .first_byte_timeout = 300s; # How long to wait before we receive a first byte from our backend?

    .connect_timeout = 5s; # How long to wait for a backend connection?

    .between_bytes_timeout = 2s; # How long to wait between bytes received from our backend?

}

---

How can all be brought together as Downstream Cache? 

Thanks and regards 

Christian

[Joshua Marantz]

Did you try setting up a block like this (from the doc):

pagespeed DownstreamCachePurgeLocationPrefix http://localhost:80;


pagespeed DownstreamCachePurgeMethod PURGE;


pagespeed DownstreamCacheRewrittenPercentageThreshold 95;

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[Christian Bieser]

According to the docs i have to write:

---

pagespeed DownstreamCachePurgeLocationPrefix http://localhost:8380;

pagespeed DownstreamCachePurgeMethod PURGE;

pagespeed DownstreamCacheRewrittenPercentageThreshold 95;

---

Am I wrong?

[Joshua Marantz]

Yes, that looks good.

--

[Christian Bieser]

Well, and what about the other parts in the doc? That's certainly not everything? 

For example, Configuring Varnish servers: run and backend default. Varnish is listening on port 80, nginx (Pagespeed​​) on 8080. Port 8080 is not mentioned above in the doc. Instead nginx is listening already on port 80...

[Jeff Kaufman]

It sounds like you're running nginx in front of varnish. Your structure is:

[origin] -> [varnish] -> [nginx] -> [user]

The downstream caching docs are for people who have things set up as:

[origin] -> [nginx] -> [varnish] -> [user]

In your setup, with no cache between nginx and the user, you don't
need to configure downstream caching at all.

[Christian Bieser]

In the meantime, I finally understood that Google has described in the docs two types of downstream caches. I had the perceived differently. 

It works now. Just not on SLES (Segmentation fault in PSOL) ...

[Jeff Kaufman]

If you could a start a new thread with the details of your segfault on
SUSE I'd be happy to look at it.

[Christian Bieser]

Take a look at this <https://groups.google.com/forum/#!topic/ngx-pagespeed-discuss/zqYG8xbrNHY>

Thank you!