VMOD Varnish module utility
Function STRING hostname(PRIV_VCL) # Return hostname
Function STRING timestamp() # Return timestamp (%.9f)
Function REAL real(STRING, REAL) # Convert a string into a REAL (double)
Function IP ip(STRING, IP) # Convert a string into an IP
Function BOOL exists(STRING) # Test presence of a file
Add varnish hostname to HTTP headers sent to backend :
import utils;
sub vcl_pass {
set bereq.http.X-Varnish-Server = utils.hostname();
}
sub vcl_miss {
set bereq.http.X-Varnish-Server = utils.hostname();
}
Measure performance between VCL code or VMOD calls :
import utils;
sub vcl_recv {
std.log("t_prerecv:" + utils.timestamp());
(..) a lot of VCL or VMOD (..)
std.log("t_postrecv:" + utils.timestamp());
}
Do an action based on the presence of a file :
import utils;
sub vcl_recv {
if (std.tolower(req.url) == "/health_check") {
if (utils.exists("/etc/varnish/healthcheck_" + server.identity)) {
error 443 "Service not available";
}
else {
error 440 "OK";
}
}
}
sub vcl_error {
if (obj.status == 443) {
set obj.status = 503;
synthetic {"<body>0</body>"};
return (deliver);
}
else if (obj.status == 440) {
set obj.status = 200;
synthetic {"<body>1</body>"};
return (deliver);
}
}
This module is compatible and useful for Varnish 3.x only. Most of these functions have been integrated to Varnish 4. See the migration table below:
| Varnish 3.x libvmod-utils | Varnish 4.x |
|---|---|
utils.hostname() | server.hostname |
utils.timestamp("foobar") | std.timestamp("foobar") |
utils.real("42.1234", 0) | std.real("42.1234", 0) |
utils.ip(req.http.REMOTEADDRESS, client.ip) | std.ip(req.http.REMOTEADDRESS, client.ip) |
utils.exists("/etc/return_503") | std.file_exists("/etc/return_503") |
This document is licensed under BSD-2-Clause license. See LICENSE for details.
The code was opened by (c) Refinitiv (previously Thomson Reuters).