Varnish for PHP developers (LaraconEU 2016)

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VARNISH FOR PHP DEVELOPERS

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WHAT'S THIS TALK ABOUT?

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HI, I'M MATTIAS GENIAR!

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WHAT IS VARNISH?

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IMPORTANT VARNISH VERSIONS

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WHY USE VARNISH?

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REMINDER: HTTP HEADERS

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REQUEST HEADERS

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GET / HTTP/1.1 Accept: */* Accept-Encoding: gzip, deflate Host: ma.ttias.be User-Agent: Chrome/52 Cookie: laravel_session=eyJpdiI6...

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RESPONSE HEADERS HTTP/1.1 200 OK Cache-Control: private, max-age=0 Content-Encoding: gzip Content-Length: 9944 Content-Type: text/html; charset=UTF-8 Server: Apache Date: Tue, 23 Aug 2016 14:15:50 GMT

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HOW VARNISH WORKS

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VARNISH CONFIGURATION LANGUAGE $ cat /etc/varnish/default.vcl vcl 4.0; sub vcl_recv { } sub vcl_backend_response { } sub vcl_backend_fetch { } sub vcl_deliver { }

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MANIPULATING THE CLIENT REQUEST sub vcl_recv { # Only cache GET or HEAD requests. if (req.method != "GET" && req.method != "HEAD") { return (pass); } # Remove any Google Analytics based cookies set req.http.Cookie = regsuball(req.http.Cookie, "__utm.=[^;]+(; )?", ""); set req.http.Cookie = regsuball(req.http.Cookie, "_ga=[^;]+(; )?", ""); ... }

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MANIPULATING THE CLIENT REQUEST sub vcl_recv { if (req.http.host ~ "^(www\.)?domain\.tld$" || req.http.host ~ "test"){ set req.backend = specific_backend; return (pass); } }

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MANIPULATING THE CLIENT REQUEST sub vcl_recv { if (req.url ~ "^[^?]*\.(css|gif|gz|ico|jpeg|jpg|js|png|xml)(\?.*)?$") { unset req.http.Cookie; return (lookup); } }

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MANIPULATING THE RESPONSE sub vcl_backend_response { if (bereq.url ~ "^[^?]*\.(css|gif|gz|ico|jpeg|jpg|js|png|xml)(\?.*)?$") { unset bereq.http.Set-Cookie; # Case insensitive headers return (deliver); } }

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MANIPULATING THE RESPONSE sub vcl_backend_response { # Don't cache 50x responses if (beresp.status == 500 || beresp.status == 502 || beresp.status == 503) { return (abandon); } # Allow stale content, in case the backend goes down. # make Varnish keep all objects for 2 hours beyond their TTL set beresp.grace = 2h; }

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MANIPULATING THE DELIVERY sub vcl_deliver { if (obj.hits > 0) { set resp.http.X-Cache = "HIT"; } else { set resp.http.X-Cache = "MISS"; } set resp.http.X-Cache-Hits = obj.hits; unset resp.http.X-Powered-By; unset resp.http.Server; }

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CHALLENGE: VISUALISING CHANGES

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EXAMPLE +

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DETERMINING HASH KEYS sub vcl_hash { hash_data(req.url); // ie: /blog/your-clickbait-title hash_data(req.http.host); // ie: ma.ttias.be hash_data(req.http.Cookie); // ie: language=nl }

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CHALLENGE: URLS sub vcl_recv { # Sort all query arguments set req.url = std.querysort(req.url); // ie: "?lang=nl&p=5" == "?p=5&lang=nl" # Remove GA tags: domain.tld?utm_source=email&utm_medium=buffer&... set req.url = regsuball(req.url, "(utm_source|utm_medium|...)=(...)", ""); }

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CHALLENGE: COOKIES sub vcl_hash { // ... hash_data(req.http.Cookie); // ie: language=nl }

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CHALLENGE: COOKIES import cookie; sub vcl_recv { # Use libvmod-cookie, parse the "Cookie:" header from the client cookie.parse(req.http.cookie); # Filter all except these cookies from it cookie.filter_except("laravel_session,custom_cookie"); # Set the "Cookie:" header back to the parsed/filtered value set req.http.cookie = cookie.get_string(); }

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CHALLENGE: HOST sub vcl_recv { # domain.tld vs www.domain.tld, force www subdomain if (req.http.host == "domain.tld") { return (synth(720, "http://www.domain.tld")); } } sub vcl_synth { if (resp.status == 720) { set resp.http.Location = resp.reason; set resp.status = 301; return (deliver); } }

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CACHING API REQUESTS sub vcl_hash { hash_data(req.url); // ie: /api/companies/5/products hash_data(req.http.host); // ie: ma.ttias.be if (req.http.Authorization) { hash_data(req.http.Authorization); // ie: Bearer Access-Token } if (req.http.X-Custom-Header) { hash_data(req.http.X-Custom-Header); // ie: app specific } }

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FLUSHING THE CACHE

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PURGE REQUEST acl purge { "localhost"; "192.168.55.0"/24; } sub vcl_recv { # allow PURGE from localhost and 192.168.55... if (req.method == "PURGE") { if (!client.ip ~ purge) { return(synth(405,"Not allowed.")); } return (purge); } } $ curl -X PURGE -H "Host: domain.tld" http://31.193.180.217/blog/page1

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BAN REQUEST $ varnishadm \ -S /etc/varnish/secret \ "ban req.http.host ~ (www.)?domain.tld" $ varnishadm \ -S /etc/varnish/secret \ -T 31.193.180.217:6082 \ "ban req.http.host ~ www.domain.tld && req.url ~ .css" $ cat /etc/varnish/secret yb9exW6O57c77b9T9lHxkLAShsJ-QbXAdB7CMlGegGK1Q5ViJ5NTwRW

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EDGE SIDE INCLUDES

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TTL: HOW LONG TO CACHE? header("Cache-Control: public, max-age=900"); sub vcl_backend_response { if (bereq.url ~ "/blog/post-on-hackernews") { set beresp.ttl = 600s; return (deliver); } }

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GRACE MODE sub vcl_backend_response { # All objects get a 10 minute cache lifetime set beresp.ttl = 10m; # But just in case, keep objects in cache for an extra 20 min # Can be served to clients while fetching new content # Total time object can be in the cache: 10min + 20min = 30min set beresp.grace = 20m; }