CentOS 7.5 deploys Varnish cache server function

[root@varnish ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo 
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#
# This is an example VCL file for Varnish.
#
# It does not do anything by default, delegating control to the
# builtin VCL. The builtin VCL is called when there is no explicit
# return statement.
#
# See the VCL chapters in the Users Guide at https://www.varnish-cache.org/docs/
# and http://varnish-cache.org/trac/wiki/VCLExamples for more examples.

# Marker to tell the VCL compiler that this VCL has been adapted to the
# new 4.0 format.
vcl 4.0;
import directors;
import std;
# Default backend definition. Set this to point to your content server.
probe backend_healthcheck {
.url="/"; #Access the backend server root path.interval = 5s; #Request time interval.timeout = 1s; #Request timeout.window = 5; #Specify the number of polling times 5 times.threshold = 3; #If there are 3 failures, it means that the backend server is down}
backend web1 { #define the backend server.host = "192.168.20.4"; #IP or domain name of the host (i.e. the backend host) to be redirected.port = "80"; #specify the port number of the backend server.probe = backend_healthcheck; #Health check calls the content defined by backend_healthcheck}
backend web2 {
.host = "192.168.20.3";   
.port = "80";
.probe = backend_healthcheck;
}
acl purgers { #define access control list "127.0.0.1";
    "localhost";
    "192.168.20.0/24";
    !"192.168.20.4";
}
sub vcl_init { #Call vcl_init to initialize the subroutine and create the backend host group, i.e. directors
    new web_cluster = directors.round_robin(); #Use the new keyword to create a director object and use the round_robin algorithm web_cluster.add_backend(web1); #Add a backend server node web_cluster.add_backend(web2);
}
sub vcl_recv {
    set req.backend_hint = web_cluster.backend(); #Specify the backend node of the request web_cluster defined backend node if (req.method == "PURGE") { #Judge whether the client's request header is PURGE
        if (!client.ip ~ purgers) { #If yes, check whether the client's IP address is in the ACL access control list.
            return (synth(405, "Not Allowed.")); #If not, return a 405 status code to the client and return the defined page.
    }
    return (purge); #If it is defined by ACL, it will be handled by purge.
}
if (req.method != "GET" &&
    req.method != "HEAD" &&
    req.method != "PUT" &&
    req.method != "POST" &&
    req.method != "TRACE" &&
    req.method != "OPTIONS" &&
    req.method != "PATCH" &&
    req.method != "DELETE") { #Judge the client's request type return (pipe);
    }
if (req.method != "GET" && req.method != "HEAD") {
    return (pass); #If it is not GET or HEAD, pass it.
}
if (req.url ~ "\.(php|asp|aspx|jsp|do|ashx|shtml)($|\?)") {
    return (pass); #When the client accesses a file ending with .php, pass it to pass for processing.
}
if (req.http.Authorization) {
    return (pass); #When the page type requested by the client requires authentication, pass it to process}
if (req.http.Accept-Encoding) {
    if (req.url ~ "\.(bmp|png|gif|jpg|jpeg|ico|gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)$") {
    unset req.http.Accept-Encoding; #Cancel the compression type received by the client} elseif (req.http.Accept-Encoding ~ "gzip") {
        set req.http.Accept-Encoding = "gzip"; #If there is a gzip type, mark the gzip type.
    } elseif (req.http.Accept-Encoding ~ "deflate") {
        set req.http.Accept-Encoding = "deflate";
    } else {
    unset req.http.Accept-Encoding; #Other undefined pages also cancel the compression type received by the client.
    }
   }
if (req.url ~ "\.(css|js|html|htm|bmp|png|gif|jpg|jpeg|ico|gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)($|\?)") {
    unset req.http.cookie; #Cancel the client's cookie value.
    return (hash); #Forward the request to the hash subroutine, that is, check the local cache.
}
if (req.restarts == 0) { #Judge whether it is the first request from the client if (req.http.X-Forwarded-For) { #If it is the first request, set the client's IP address.
        set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
    } else {
    set req.http.X-Forwarded-For = client.ip;
    }
}
return (hash);
}
sub vcl_hash {
    hash_data(req.url); #View the page requested by the client and perform hashing
    if (req.http.host) {
        hash_data(req.http.host); #Set the client's host} else {
        hash_data(server.ip); #Set the server IP
    }
    return (lookup);
}
sub vcl_hit {
    if (req.method == "PURGE") { #If it is HIT and the client request type is PURGE, return the 200 status code and return the corresponding page.
        return (synth(200, "Purged."));
    }
    return (deliver);
}

sub vcl_miss {
  if (req.method == "PURGE") {
        return (synth(404, "Purged.")); #If it is a miss, return 404
    }
    return (fetch);
}
sub vcl_deliver {
    if (obj.hits > 0) {
        set resp.http.CXK = "HIT-from-varnish"; #Set http header X-Cache = hit
        set resp.http.X-Cache-Hits = obj.hits; #Return the number of commands} else {
    set resp.http.X-Cache = "MISS";
    }
    unset resp.http.X-Powered-By; #Cancel displaying the web versionunset resp.http.Server; #Cancel displaying the Varnish serviceunset resp.http.X-Drupal-Cache; #Cancel displaying the cached frameworkunset resp.http.Via; #Cancel displaying the file content sourceunset resp.http.Link; #Cancel displaying the HTML hyperlink addressunset resp.http.X-Varnish; #Cancel displaying the Varnish ID
    set resp.http.xx_restarts_count = req.restarts; #Set the number of client requests set resp.http.xx_Age = resp.http.Age; #Show the length of cached files #set resp.http.hit_count = obj.hits; #Show the number of cache hits #unset resp.http.Age;
    return (deliver);
}
sub vcl_pass {
    return (fetch); #Cache the data returned by the backend server locally}
sub vcl_backend_response {
    set beresp.grace = 5m; #cache additional grace timeif (beresp.status == 499 || beresp.status == 404 || beresp.status == 502) {
        set beresp.uncacheable = true; #When the backend server responds with a status code of 449, etc., do not cache}
    if (bereq.url ~ "\.(php|jsp)(\?|$)") {
        set beresp.uncacheable = true; #When it is a PHP page, it is not cached} else {
        if (bereq.url ~ "\.(css|js|html|htm|bmp|png|gif|jpg|jpeg|ico)($|\?)") {
        set beresp.ttl = 15m; #When it ends with the above, cache for 15 minutes unset beresp.http.Set-Cookie;
        } elseif (bereq.url ~ "\.(gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)($|\?)") {
            set beresp.ttl = 30m; #cache for 30 minutes unset beresp.http.Set-Cookie;
        } else {
            set beresp.ttl = 10m; #Lifetime 10 minutes unset beresp.http.Set-Cookie;
        }
    }
    return (deliver);
}
sub vcl_purge {
    return (synth(200,"success"));
}
sub vcl_backend_error {
    if (beresp.status == 500 ||
        beresp.status == 501 ||
        beresp.status == 502 ||
        beresp.status == 503 ||
        beresp.status == 504) {
        return (retry); #If the status code is one of the above, re-request}
}
sub vcl_fini {
    return (ok);
}
#After editing, save and exit.
[root@varnish varnish]# varnishd -f /usr/local/var/varnish/example.vcl -s malloc,200M -a 0.0.0.0:80
#Start the Varnish service and listen to port 80 of all local IP addresses. -f specifies the vcl file and -s specifies the capacity for storing the cache. [root@varnish ~]# varnishlog #After Varnish is started, you can execute this command to view its log.

[root@localhost ~]# curl -X "PURGE" 192.168.20.5 #Clear Varnish cache

vcl 4.0;
import directors;
import std;
probe backend_healthcheck {
.url="/"; 
.interval = 5s;
.timeout = 1s;
.window = 5; 
.threshold = 3; 
}
backend web1 { 
.host = "192.168.20.4"; 
.port = "80"; 
.probe = backend_healthcheck; 
}
backend web2 {
.host = "192.168.20.3";   
.port = "80";
.probe = backend_healthcheck;
}
acl purgers { 
    "127.0.0.1";
    "localhost";
    "192.168.20.0/24";
    !"192.168.20.4";
}
sub vcl_init { 
    new web_cluster = directors.round_robin();
    web_cluster.add_backend(web1); 
    web_cluster.add_backend(web2);
}
sub vcl_recv {
    set req.backend_hint = web_cluster.backend(); 
    if (req.method == "PURGE") { 
        if (!client.ip ~ purgers) {  
            return (synth(405, "Not Allowed.")); 
    }
    return (purge); 
}
if (req.method != "GET" &&
    req.method != "HEAD" &&
    req.method != "PUT" &&
    req.method != "POST" &&
    req.method != "TRACE" &&
    req.method != "OPTIONS" &&
    req.method != "PATCH" &&
    req.method != "DELETE") {  
        return (pipe);
    }
if (req.method != "GET" && req.method != "HEAD") {
    return (pass);
}
if (req.url ~ "\.(php|asp|aspx|jsp|do|ashx|shtml)($|\?)") {
    return (pass); 
}
if (req.http.Authorization) {
    return (pass); 
}
if (req.http.Accept-Encoding) {
    if (req.url ~ "\.(bmp|png|gif|jpg|jpeg|ico|gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)$") {
    unset req.http.Accept-Encoding; 
    } elseif (req.http.Accept-Encoding ~ "gzip") {
        set req.http.Accept-Encoding = "gzip"; 
    } elseif (req.http.Accept-Encoding ~ "deflate") {
        set req.http.Accept-Encoding = "deflate";
    } else {
    unset req.http.Accept-Encoding;
    }
   }
if (req.url ~ "\.(css|js|html|htm|bmp|png|gif|jpg|jpeg|ico|gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)($|\?)") {
    unset req.http.cookie; 
    return (hash);  
}
if (req.restarts == 0) { 
    if (req.http.X-Forwarded-For) {  
        set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
    } else {
    set req.http.X-Forwarded-For = client.ip;
    }
}
return (hash);
}
sub vcl_hash {
    hash_data(req.url); 
    if (req.http.host) {
        hash_data(req.http.host); 
    } else {
        hash_data(server.ip); 
    }
    return (lookup);
}
sub vcl_hit {
    if (req.method == "PURGE") { 
        return (synth(200, "Purged."));
    }
    return (deliver);
}

sub vcl_miss {
  if (req.method == "PURGE") {
        return (synth(404, "Purged."));
    }
    return (fetch);
}
sub vcl_deliver {
    if (obj.hits > 0) {
        set resp.http.CXK = "HIT-from-varnish";
        set resp.http.X-Cache-Hits = obj.hits; 
    } else {
    set resp.http.X-Cache = "MISS";
    }
    unset resp.http.X-Powered-By; 
    unset resp.http.Server;  
    unset resp.http.X-Drupal-Cache; 
    unset resp.http.Via; 
    unset resp.http.Link; 
    unset resp.http.X-Varnish; 
    set resp.http.xx_restarts_count = req.restarts; 
    set resp.http.xx_Age = resp.http.Age; 
    #set resp.http.hit_count = obj.hits; 
    #unset resp.http.Age;
    return (deliver);
}
sub vcl_pass {
    return (fetch); 
}
sub vcl_backend_response {
    set beresp.grace = 5m; 
    if (beresp.status == 499 || beresp.status == 404 || beresp.status == 502) {
        set beresp.uncacheable = true;
    }
    if (bereq.url ~ "\.(php|jsp)(\?|$)") {
        set beresp.uncacheable = true; 
    } else {
        if (bereq.url ~ "\.(css|js|html|htm|bmp|png|gif|jpg|jpeg|ico)($|\?)") {
        set beresp.ttl = 15m; 
        unset beresp.http.Set-Cookie;
        } elseif (bereq.url ~ "\.(gz|tgz|bz2|tbz|zip|rar|mp3|mp4|ogg|swf|flv)($|\?)") {
            set beresp.ttl = 30m;
            unset beresp.http.Set-Cookie;
        } else {
            set beresp.ttl = 10m;
            unset beresp.http.Set-Cookie;
        }
    }
    return (deliver);
}
sub vcl_purge {
    return (synth(200,"success"));
}
sub vcl_backend_error {
    if (beresp.status == 500 ||
        beresp.status == 501 ||
        beresp.status == 502 ||
        beresp.status == 503 ||
        beresp.status == 504) {
        return (retry); 
    }
}
sub vcl_fini {
    return (ok);
}

import directors;
probe backend_healthcheck {
    .url = "/";
    .timeout = 1s;
    .interval = 5s;
    .window = 5;
    .threshold = 3;
}
backend web1 {
    .host = "192.168.20.3";
    .port = "80";
    .probe = backend_healthcheck;
}
backend web2 {
    .host = "192.168.20.4";
    .port = "80";
    .probe = backend_healthcheck;
}
sub vcl_init {
    new web_cluster = directors.round_robin();
    web_cluster.add_backend(web1);
    web_cluster.add_backend(web2);
}
sub vcl_recv {
    set req.backend_hint = web_cluster.backend();
}