我想使用 Varnish 作为“智能”代理，它几乎可以工作。这个想法是一些请求应该通过 Varnish 传递，打到后端并返回，所有其他请求应该返回一个特定响应不包含结果的“synt”消息。
除了 Varnish 将 301 重定向返回到后端而不仅仅是来自实际后端的响应这一事实之外，这也是有效的。
后端和缓存不在同一主机上（在这种情况下甚至不在同一网络上）。
后端也在运行一个单独的 Varnish 实例，并且这个请求总是通过它传递。
// VCL.SHOW 0 1820 input
#
# 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;
### Here starts my part of the VCL
# Default backend definition. Set this to point to your content server.
backend default {
.host = "myhost.mydomain";
.port = "80";
}
sub vcl_recv {
# Happens before we check if we have this in cache already.
#
# Typically you clean up the request here, removing cookies you don't need,
# rewriting the request, etc.
if (req.url ~ "^\/cgi-bin\/wspd_cgi\.sh/apiFlightSearch.p\?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27")
{
return (hash);
}
return (synth(750));
}
sub vcl_synth {
if (resp.status == 750) {
# Set a status the client will understand
set resp.status = 200;
# Create our synthetic response
set resp.http.content-type = "text/xml";
synthetic("<flights xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'><status><status>No flights</status></status></flights>");
return(deliver);
}
}
sub vcl_backend_response {
# Happens after we have read the response headers from the backend.
#
# Here you clean the response headers, removing silly Set-Cookie headers
# and other mistakes your backend does.
set beresp.ttl = 10 s;
}
sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
}
### Here ends my part of the VCL. The rest I guess is built in.
// VCL.SHOW 1 5479 Builtin
/*-
* Copyright (c) 2006 Verdens Gang AS
* Copyright (c) 2006-2014 Varnish Software AS
* All rights reserved.
*
* Author: Poul-Henning Kamp <phk@phk.freebsd.dk>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* The built-in (previously called default) VCL code.
*
* NB! You do NOT need to copy & paste all of these functions into your
* own vcl code, if you do not provide a definition of one of these
* functions, the compiler will automatically fall back to the default
* code from this file.
*
* This code will be prefixed with a backend declaration built from the
* -b argument.
*/
vcl 4.0;
#######################################################################
# Client side
sub vcl_recv {
if (req.method == "PRI") {
/* We do not support SPDY or HTTP/2.0 */
return (synth(405));
}
if (req.method != "GET" &&
req.method != "HEAD" &&
req.method != "PUT" &&
req.method != "POST" &&
req.method != "TRACE" &&
req.method != "OPTIONS" &&
req.method != "DELETE") {
/* Non-RFC2616 or CONNECT which is weird. */
return (pipe);
}
if (req.method != "GET" && req.method != "HEAD") {
/* We only deal with GET and HEAD by default */
return (pass);
}
if (req.http.Authorization || req.http.Cookie) {
/* Not cacheable by default */
return (pass);
}
return (hash);
}
sub vcl_pipe {
# By default Connection: close is set on all piped requests, to stop
# connection reuse from sending future requests directly to the
# (potentially) wrong backend. If you do want this to happen, you can undo
# it here.
# unset bereq.http.connection;
return (pipe);
}
sub vcl_pass {
return (fetch);
}
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_purge {
return (synth(200, "Purged"));
}
sub vcl_hit {
if (obj.ttl >= 0s) {
// A pure unadultered hit, deliver it
return (deliver);
}
if (obj.ttl + obj.grace > 0s) {
// Object is in grace, deliver it
// Automatically triggers a background fetch
return (deliver);
}
// fetch & deliver once we get the result
return (fetch);
}
sub vcl_miss {
return (fetch);
}
sub vcl_deliver {
return (deliver);
}
/*
* We can come here "invisibly" with the following errors: 413, 417 & 503
*/
sub vcl_synth {
set resp.http.Content-Type = "text/html; charset=utf-8";
set resp.http.Retry-After = "5";
synthetic( {"<!DOCTYPE html>
<html>
<head>
<title>"} + resp.status + " " + resp.reason + {"</title>
</head>
<body>
<h1>Error "} + resp.status + " " + resp.reason + {"</h1>
<p>"} + resp.reason + {"</p>
<h3>Guru Meditation:</h3>
<p>XID: "} + req.xid + {"</p>
<hr>
<p>Varnish cache server</p>
</body>
</html>
"} );
return (deliver);
}
#######################################################################
# Backend Fetch
sub vcl_backend_fetch {
return (fetch);
}
sub vcl_backend_response {
if (beresp.ttl <= 0s ||
beresp.http.Set-Cookie ||
beresp.http.Surrogate-control ~ "no-store" ||
(!beresp.http.Surrogate-Control &&
beresp.http.Cache-Control ~ "no-cache|no-store|private") ||
beresp.http.Vary == "*") {
/*
* Mark as "Hit-For-Pass" for the next 2 minutes
*/
set beresp.ttl = 120s;
set beresp.uncacheable = true;
}
return (deliver);
}
sub vcl_backend_error {
set beresp.http.Content-Type = "text/html; charset=utf-8";
set beresp.http.Retry-After = "5";
synthetic( {"<!DOCTYPE html>
<html>
<head>
<title>"} + beresp.status + " " + beresp.reason + {"</title>
</head>
<body>
<h1>Error "} + beresp.status + " " + beresp.reason + {"</h1>
<p>"} + beresp.reason + {"</p>
<h3>Guru Meditation:</h3>
<p>XID: "} + bereq.xid + {"</p>
<hr>
<p>Varnish cache server</p>
</body>
</html>
"} );
return (deliver);
}
#######################################################################
# Housekeeping
sub vcl_init {
return (ok);
}
sub vcl_fini {
return (ok);
}
卷曲的输出：
$ curl "thisandthatip.compute.amazonaws.com/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0" -i
HTTP/1.1 301 Moved Permanently
Date: Wed, 15 Mar 2017 07:14:11 GMT
Server: Apache/2.2.15 (Red Hat)
Location: http://myserver.mydomain/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0
Content-Length: 514
Content-Type: text/html; charset=iso-8859-1
X-Varnish: 529144137
Via: 1.1 varnish-v4
X-Varnish: 98309 11
Age: 2
Via: 1.1 varnish-v4
Connection: keep-alive
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>301 Moved Permanently</title>
</head><body>
<h1>Moved Permanently</h1>
<p>The document has moved <a href="http://myserver.mydomain/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0">here</a>.</p>
<hr>
<address>Apache/2.2.15 (Red Hat) Server at thisandthatip.eu-central-1.compute.amazonaws.com Port 80</address>
</body></html>
后端apache访问日志
127.0.0.1 - - [15/Mar/2017:08:09:49 +0100] "GET /cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=arn&to=aok&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0 HTTP/1.1" 200 994 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36"
将请求从 AWS 实例发送到后端不会呈现 301 重定向：
$ curl "myserver.mydomain/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=arn&to=aok&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0" -i
HTTP/1.1 200 OK
Date: Wed, 15 Mar 2017 08:54:14 GMT
Server: Apache/2.2.15 (Red Hat)
Cache-Control: max-age=1
Expires: Wed, 15 Mar 2017 08:54:15 GMT
Content-Type: text/xml
X-Varnish: 527559784
Age: 0
Via: 1.1 varnish-v4
Transfer-Encoding: chunked
Connection: keep-alive
Accept-Ranges: bytes
... Response body here ...
单个请求的完整 varnishlog 输出
* << BeReq >> 98314
- Begin bereq 98313 fetch
- Timestamp Start: 1489568144.701450 0.000000 0.000000
- BereqMethod GET
- BereqURL /cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0
- BereqProtocol HTTP/1.1
- BereqHeader Host: thisandthatip.compute.amazonaws.com
- BereqHeader Upgrade-Insecure-Requests: 1
- BereqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36
- BereqHeader Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
- BereqHeader Accept-Language: sv-SE,sv;q=0.8,en-US;q=0.6,en;q=0.4
- BereqHeader X-Forwarded-For: ip.ip.ip.ip
- BereqHeader Accept-Encoding: gzip
- BereqHeader X-Varnish: 98314
- VCL_call BACKEND_FETCH
- VCL_return fetch
- BackendClose 17 default(ip.ip.ip.ip,,80) toolate
- BackendOpen 17 default(ip.ip.ip.ip,,80) 172.31.31.195 42868
- Backend 17 default default(ip.ip.ip.ip,,80)
- Timestamp Bereq: 1489568144.730329 0.028878 0.028878
- Timestamp Beresp: 1489568144.759773 0.058322 0.029444
- BerespProtocol HTTP/1.1
- BerespStatus 301
- BerespReason Moved Permanently
- BerespHeader Date: Wed, 15 Mar 2017 08:55:44 GMT
- BerespHeader Server: Apache/2.2.15 (Red Hat)
- BerespHeader Location: http://myserver.mydomain/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0
- BerespHeader Content-Length: 514
- BerespHeader Content-Type: text/html; charset=iso-8859-1
- BerespHeader X-Varnish: 526644873
- BerespHeader Age: 0
- BerespHeader Via: 1.1 varnish-v4
- BerespHeader Connection: keep-alive
- TTL RFC 120 -1 -1 1489568145 1489568145 1489568144 0 0
- VCL_call BACKEND_RESPONSE
- TTL VCL 10 10 0 1489568145
- VCL_return deliver
- Storage malloc s0
- ObjProtocol HTTP/1.1
- ObjStatus 301
- ObjReason Moved Permanently
- ObjHeader Date: Wed, 15 Mar 2017 08:55:44 GMT
- ObjHeader Server: Apache/2.2.15 (Red Hat)
- ObjHeader Location: http://myserver.mydomain/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0
- ObjHeader Content-Length: 514
- ObjHeader Content-Type: text/html; charset=iso-8859-1
- ObjHeader X-Varnish: 526644873
- ObjHeader Via: 1.1 varnish-v4
- Fetch_Body 3 length stream
- BackendReuse 17 default(ip.ip.ip.ip,,80)
- Timestamp BerespBody: 1489568144.759849 0.058398 0.000076
- Length 514
- BereqAcct 578 0 578 415 514 929
- End
* << Request >> 98313
- Begin req 98312 rxreq
- Timestamp Start: 1489568144.701372 0.000000 0.000000
- Timestamp Req: 1489568144.701372 0.000000 0.000000
- ReqStart ip.ip.ip.ip 63485
- ReqMethod GET
- ReqURL /cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0
- ReqProtocol HTTP/1.1
- ReqHeader Host: thisandthatip.compute.amazonaws.com
- ReqHeader Connection: keep-alive
- ReqHeader Upgrade-Insecure-Requests: 1
- ReqHeader User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36
- ReqHeader Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
- ReqHeader Accept-Encoding: gzip, deflate, sdch
- ReqHeader Accept-Language: sv-SE,sv;q=0.8,en-US;q=0.6,en;q=0.4
- ReqHeader X-Forwarded-For: ip.ip.ip.ip
- VCL_call RECV
- VCL_return hash
- ReqUnset Accept-Encoding: gzip, deflate, sdch
- ReqHeader Accept-Encoding: gzip
- VCL_call HASH
- VCL_return lookup
- Debug "XXXX MISS"
- VCL_call MISS
- VCL_return fetch
- Link bereq 98314 fetch
- Timestamp Fetch: 1489568144.759883 0.058511 0.058511
- RespProtocol HTTP/1.1
- RespStatus 301
- RespReason Moved Permanently
- RespHeader Date: Wed, 15 Mar 2017 08:55:44 GMT
- RespHeader Server: Apache/2.2.15 (Red Hat)
- RespHeader Location: http://myserver.mydomain/cgi-bin/wspd_cgi.sh/apiFlightSearch.p?from=ARN&to=AOK&date=2017-05-20&homedate=2017-05-27&adults=2&triptype=return&children=0&infants=0
- RespHeader Content-Length: 514
- RespHeader Content-Type: text/html; charset=iso-8859-1
- RespHeader X-Varnish: 526644873
- RespHeader Via: 1.1 varnish-v4
- RespHeader X-Varnish: 98313
- RespHeader Age: 0
- RespHeader Via: 1.1 varnish-v4
- VCL_call DELIVER
- VCL_return deliver
- Timestamp Process: 1489568144.759907 0.058535 0.000024
- Debug "RES_MODE 2"
- RespHeader Connection: keep-alive
- Timestamp Resp: 1489568144.759933 0.058561 0.000026
- Debug "XXX REF 2"
- ReqAcct 566 0 566 454 514 968
- End
在 AWS Amazon Linux 上运行的 Varnish 4.0.4。