## 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;probe backend_healthcheck { # 创建健康监测  .url = /health.html;  .window = 5;  .threshold = 2;  .interval = 3s;}backend web1 {	# 创建后端主机  .host = "static1.lnmmp.com";  .port = "80";  .probe = backend_healthcheck;}backend web2 {  .host = "static2.lnmmp.com";  .port = "80";  .probe = backend_healthcheck;}backend img1 {  .host = "img1.lnmmp.com";  .port = "80";  .probe = backend_healthcheck;}backend img2 {  .host = "img2.lnmmp.com";  .port = "80";  .probe = backend_healthcheck;}vcl_init {	# 创建后端主机组，即directors  new web_cluster = directors.random();  web_cluster.add_backend(web1);  web_cluster.add_backend(web2);  new img_cluster = directors.random();  img_cluster.add_backend(img1);  img_cluster.add_backend(img2);}acl purgers {	# 定义可访问来源IP    "127.0.0.1";    "192.168.0.0"/24;}sub vcl_recv {  if (req.request == "GET" && req.http.cookie) {	# 带cookie首部的GET请求也缓存    return(hash);}  if (req.url ~ "test.html") {	# test.html文件禁止缓存    return(pass);  }  if (req.request == "PURGE") {	# PURGE请求的处理    if (!client.ip ~ purgers) {      return(synth(405,"Method not allowed"));    }    return(hash);  }  if (req.http.X-Forward-For) {	# 为发往后端主机的请求添加X-Forward-For首部    set req.http.X-Forward-For = req.http.X-Forward-For + "," + client.ip;  } else {    set req.http.X-Forward-For = client.ip;  }  if (req.http.host ~ "(?i)^(www.)?lnmmp.com$") {	# 根据不同的访问域名，分发至不同的后端主机组    set req.http.host = "www.lnmmp.com";    set req.backend_hint = web_cluster.backend();    } elsif (req.http.host ~ "(?i)^images.lnmmp.com$") {      set req.backend_hint = img_cluster.backend();    }    return(hash);  }sub vcl_hit { # PURGE请求的处理  if (req.request == "PURGE") {      purge;    return(synth(200,"Purged"));  }}sub vcl_miss {	# PURGE请求的处理  if (req.request == "PURGE") {    purge;    return(synth(404,"Not in cache"));  }}sub vcl_pass {	# PURGE请求的处理  if (req.request == "PURGE") {    return(synth(502,"PURGE on a passed object"));  }}sub vcl_backend_response { # 自定义缓存文件的缓存时长，即TTL值  if (req.url ~ "\.(jpg|jpeg|gif|png)$") {    set beresp.ttl = 7200s;  }  if (req.url ~ "\.(html|css|js)$") {    set beresp.ttl = 1200s;  }  if (beresp.http.Set-Cookie) { # 定义带Set-Cookie首部的后端响应不缓存，直接返回给客户端    return(deliver);  }}sub vcl_deliver {  if (obj.hits > 0) {	# 为响应添加X-Cache首部，显示缓存是否命中    set resp.http.X-Cache = "HIT from " + server.ip;  } else {    set resp.http.X-Cache = "MISS";  }}