User-friendly error pages from Varnish
We are using Varnish at the front of Plone. In the case Plone goes down or serves an internal error we'd like to show a user-friendly static HTML page which some CSS styling + images. ("The server is being updated page")
How to开发者_JS百科 configure Varnish to do this?
Another simple way to do it is using the std vmod that comes with varnish. This is my preferred way to do it because I like having the error messages outside the configuration in case you want to have multiple responses for different status codes.
import std;
sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";
synthetic std.fileread("/path/to/file.html");
return (deliver);
}
You can customize the synthetic page being served on a vlc_error. The default.vcl configuration file already shows how to do this, by serving the famous "Guru Meditation" error page (ahh, those wonderful Amiga days).
An example customization:
sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";
synthetic {"
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>Sorry, server under maintainance - My Website"</title>
<style src="css/style.css"></style>
</head>
<body>
<h1>The server is being updated</h1>
<p>Please check back later. Meanwhile, here's a picture of a rabbit with a pancake on its head:</p>
<img src="img/wabbit.jpg" alt="awwwww!" />
</body>
</html>
"};
return (deliver);
}
There isn't much help for doing this with Varnish 4 at the moment.
Here is what I ended up with:
sub vcl_backend_error {
set beresp.http.Content-Type = "text/html; charset=utf-8";
synthetic(std.fileread("/var/www/errors/500.html"));
return (deliver);
}
For more info see the upgrading to 4.0 docs.
If you rather prefer to deliver an error page from a static file, you can override vcl_error() with a bit of C-code:
sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";
C{
#include <stdio.h>
#include <string.h>
FILE * pFile;
char content [100];
char page [10240];
char fname [50];
page[0] = '\0';
sprintf(fname, "/var/www/error/index.html", VRT_r_obj_status(sp));
pFile = fopen(fname, "r");
while (fgets(content, 100, pFile)) {
strcat(page, content);
}
fclose(pFile);
VRT_synth_page(sp, 0, page, "<!-- XID: ", VRT_r_req_xid(sp), " -->", vrt_magic_string_end);
return (deliver);
}C
}
加载中,请稍侯......
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