VMOD_STD(3)VMOD_STD(3)NAMEvmod_std - Varnish Standard Module
SYNOPSIS
import std [from "path"] ;
DESCRIPTION
Vmod_std contains basic functions which are part and parcel of Varnish,
but which for reasons of architecture fit better in a VMOD.
One particular class of functions in vmod_std is the conversions func‐
tions which all have the form:
TYPE type(STRING, TYPE)
These functions attempt to convert STRING to the TYPE, and if that
fails, they return the second argument, which must have the given TYPE.
CONTENTS
· VOID collect(HEADER)
· DURATION duration(STRING, DURATION)
· STRING fileread(PRIV_CALL, STRING)
· BOOL healthy(BACKEND)
· INT integer(STRING, INT)
· IP ip(STRING, IP)
· VOID log(STRING_LIST)
· INT port(IP)
· REAL random(REAL, REAL)
· VOID set_ip_tos(INT)
· VOID syslog(INT, STRING_LIST)
· VOID timestamp(STRING)
· STRING tolower(STRING_LIST)
· STRING toupper(STRING_LIST)
STRING toupper(STRING_LIST)
Prototype
STRING toupper(STRING_LIST)
Description
Converts the string s to upper case.
Example
set beresp.http.x-scream = std.toupper("yes!");
STRING tolower(STRING_LIST)
Prototype
STRING tolower(STRING_LIST)
Description
Converts the string s to lower case.
Example
set beresp.http.x-nice = std.tolower("VerY");
VOID set_ip_tos(INT)
Prototype
VOID set_ip_tos(INT)
Description
Sets the Type-of-Service flag for the current session. Please
note that the TOS flag is not removed by the end of the request
so probably want to set it on every request should you utilize
it.
Example
if (req.url ~ ^/slow/) {
std.set_ip_tos(0x0);
}
REAL random(REAL, REAL)
Prototype
REAL random(REAL, REAL)
Description
Returns a random REAL number between a and b.
Example
set beresp.http.x-random-number = std.random(1, 100);
VOID log(STRING_LIST)
Prototype
VOID log(STRING_LIST)
Description
Logs string to the shared memory log, using VSL tag SLT_VCL_Log.
Example
std.log("Something fishy is going on with the vhost " +
req.host);
VOID syslog(INT, STRING_LIST)
Prototype
VOID syslog(INT, STRING_LIST)
Description
Logs string to syslog marked with priority. See your system's
syslog.h file for the legal values of priority.
Example
std.syslog(8 + 1, "Something is wrong");
STRING fileread(PRIV_CALL, STRING)
Prototype
STRING fileread(PRIV_CALL, STRING)
Description
Reads a file and returns a string with the content. Please note
that it is not recommended to send variables to this function
the caching in the function doesn't take this into account.
Also, files are not re-read.
Example
set beresp.http.x-served-by = std.fileread("/etc/hostname");
VOID collect(HEADER)
Prototype
VOID collect(HEADER)
Description
Collapses the header, joining the headers into one.
Example
std.collect(req.http.cookie); This will collapse several Cookie:
headers into one, long cookie header.
DURATION duration(STRING, DURATION)
Prototype
DURATION duration(STRING, DURATION)
Description
Converts the string s to seconds. s must be quantified with ms
(milliseconds), s (seconds), m (minutes), h (hours), d (days) or
w (weeks) units. If s fails to parse, fallback will be returned.
Example
set beresp.ttl = std.duration("1w", 3600s);
INT integer(STRING, INT)
Prototype
INT integer(STRING, INT)
Description
Converts the string s to an integer. If s fails to parse, fall‐
back will be returned.
Example
if (std.integer(beresp.http.x-foo, 0) > 5) { ... }
IP ip(STRING, IP)
Prototype
IP ip(STRING, IP)
Description
Converts string s to the first IP number returned by the system
library function getaddrinfo(3). If conversion fails, fallback
will be returned.
Example
if (std.ip(req.http.X-forwarded-for, "0.0.0.0") ~ my_acl) { ...
}
BOOL healthy(BACKEND)
Prototype
BOOL healthy(BACKEND)
Description
Returns true if the backend is healthy.
INT port(IP)
Prototype
INT port(IP)
Description
Returns the port number of an IP address.
VOID timestamp(STRING)
Prototype
VOID timestamp(STRING)
Description
Introduces a timestamp in the log with the current time. Uses
the argument as the timespamp label. This is useful to time the
execution of lengthy VCL procedures, and makes the timestamps
inserted automatically by Varnish more accurate.
Example
std.timestamp("curl-request");
SEE ALSO
· vcl(7)
· varnishd(1)HISTORY
The Varnish standard module was released along with Varnish Cache 3.0.
This manual page was written by Per Buer with help from Martin Blix
Grydeland.
COPYRIGHT
This document is licensed under the same licence as Varnish itself. See
LICENCE for details.
VMOD_STD(3)
