vmod_std(3)

1VMOD(STD)                                                            VMOD(STD)
2
3
4

NAME

6       VMOD std - Varnish Standard Module
7

SYNOPSIS

9          import std [as name] [from "path"]
10
11          REAL random(REAL lo, REAL hi)
12
13          REAL round(REAL r)
14
15          VOID collect(HEADER hdr, STRING sep)
16
17          STRING querysort(STRING)
18
19          STRING toupper(STRING s)
20
21          STRING tolower(STRING s)
22
23          STRING strstr(STRING s1, STRING s2)
24
25          BOOL fnmatch(STRING pattern, STRING subject, BOOL pathname, BOOL noescape, BOOL period)
26
27          STRING fileread(STRING)
28
29          BOOL file_exists(STRING path)
30
31          BOOL healthy(BACKEND be)
32
33          INT port(IP ip)
34
35          DURATION duration([STRING s], [DURATION fallback], [REAL real], [INT integer])
36
37          BYTES bytes([STRING s], [BYTES fallback], [REAL real], [INT integer])
38
39          INT integer([STRING s], [INT fallback], [BOOL bool], [BYTES bytes], [DURATION duration], [REAL real], [TIME time])
40
41          IP ip(STRING s, [IP fallback], BOOL resolve, [STRING p])
42
43          REAL real([STRING s], [REAL fallback], [INT integer], [BOOL bool], [BYTES bytes], [DURATION duration], [TIME time])
44
45          TIME time([STRING s], [TIME fallback], [REAL real], [INT integer])
46
47          VOID log(STRING s)
48
49          VOID syslog(INT priority, STRING s)
50
51          VOID timestamp(STRING s)
52
53          BOOL syntax(REAL)
54
55          STRING getenv(STRING name)
56
57          BOOL cache_req_body(BYTES size)
58
59          VOID late_100_continue(BOOL late)
60
61          VOID set_ip_tos(INT tos)
62
63          VOID rollback(HTTP h)
64
65          INT real2integer(REAL r, INT fallback)
66
67          TIME real2time(REAL r, TIME fallback)
68
69          INT time2integer(TIME t, INT fallback)
70
71          REAL time2real(TIME t, REAL fallback)
72

DESCRIPTION

74       vmod_std contains basic functions which are part and parcel of Varnish,
75       but which for reasons of architecture fit better in a VMOD.
76

NUMERIC FUNCTIONS

78   REAL random(REAL lo, REAL hi)
79       Returns a random real number between lo and hi.
80
81       This function uses the "testable" random generator  in  varnishd  which
82       enables  determinstic  tests to be run (See m00002.vtc).  This function
83       should not be used for cryptographic applications.
84
85       Example:
86
87          set beresp.http.random-number = std.random(1, 100);
88
89   REAL round(REAL r)
90       Rounds the real r to the nearest integer, but round halfway cases  away
91       from zero (see round(3)).
92

STRING FUNCTIONS

94   VOID collect(HEADER hdr, STRING sep=", )
95       Collapses  multiple hdr headers into one long header. The default sepa‐
96       rator sep is the standard comma separator to use when collapsing  head‐
97       ers, with an additional whitespace for pretty printing.
98
99       Care  should be taken when collapsing headers. In particular collapsing
100       Set-Cookie will lead to unexpected results on the browser side.
101
102       Examples:
103
104          std.collect(req.http.accept);
105          std.collect(req.http.cookie, "; ");
106
107   STRING querysort(STRING)
108       Sorts the query string for cache normalization purposes.
109
110       Example:
111
112          set req.url = std.querysort(req.url);
113
114   STRING toupper(STRING s)
115       Converts the string s to uppercase.
116
117       Example:
118
119          set beresp.http.scream = std.toupper("yes!");
120
121   STRING tolower(STRING s)
122       Converts the string s to lowercase.
123
124       Example:
125
126          set beresp.http.nice = std.tolower("VerY");
127
128   STRING strstr(STRING s1, STRING s2)
129       Returns a string beginning at the first occurrence of the string s2  in
130       the string s1, or an empty string if s2 is not found.
131
132       Note that the comparison is case sensitive.
133
134       Example:
135
136          if (std.strstr(req.url, req.http.restrict)) {
137                  ...
138          }
139
140       This  will check if the content of req.http.restrict occurs anywhere in
141       req.url.
142
143   BOOL fnmatch(STRING pattern, STRING subject, BOOL pathname, BOOL  noescape,
144       BOOL period)
145          BOOL fnmatch(
146             STRING pattern,
147             STRING subject,
148             BOOL pathname=1,
149             BOOL noescape=0,
150             BOOL period=0
151          )
152
153       Shell-style  pattern matching; returns true if subject matches pattern,
154       where pattern may contain wildcard characters such as * or ?.
155
156       The match is executed by the implementation of fnmatch(3) on your  sys‐
157       tem. The rules for pattern matching on most systems include the follow‐
158       ing:
159
160       · * matches any sequence of characters
161
162       · ? matches a single character
163
164       · a bracket expression such as [abc] or  [!0-9]  is  interpreted  as  a
165         character  class  according to the rules of basic regular expressions
166         (not pcre(3) regexen), except that !  is  used  for  character  class
167         negation instead of ^.
168
169       If pathname is true, then the forward slash character / is only matched
170       literally, and never matches *, ? or a bracket expression. Otherwise, /
171       may match one of those patterns.  By default, pathname is true.
172
173       If  noescape  is  true, then the backslash character \ is matched as an
174       ordinary character. Otherwise, \ is an escape  character,  and  matches
175       the character that follows it in the pattern. For example, \\ matches \
176       when noescape is true, and \\  when  false.  By  default,  noescape  is
177       false.
178
179       If  period is true, then a leading period character . only matches lit‐
180       erally, and never matches *, ? or a bracket  expression.  A  period  is
181       leading  if  it  is the first character in subject; if pathname is also
182       true, then a period that immediately follows a / is also leading (as in
183       /.).  By default, period is false.
184
185       std.fnmatch()  invokes  VCL failure and returns false if either of pat‐
186       tern or subject is NULL -- for example, if an unset  header  is  speci‐
187       fied.
188
189       Examples:
190
191          # Matches URLs such as /foo/bar and /foo/baz
192          if (std.fnmatch("/foo/\*", req.url)) { ... }
193
194          # Matches URLs such as /foo/bar/baz and /foo/baz/quux
195          if (std.fnmatch("/foo/\*/\*", bereq.url)) { ... }
196
197          # Matches /foo/bar/quux, but not /foo/bar/baz/quux
198          if (std.fnmatch("/foo/\*/quux", req.url)) { ... }
199
200          # Matches /foo/bar/quux and /foo/bar/baz/quux
201          if (std.fnmatch("/foo/\*/quux", req.url, pathname=false)) { ... }
202
203          # Matches /foo/bar, /foo/car and /foo/far
204          if (std.fnmatch("/foo/?ar", req.url)) { ... }
205
206          # Matches /foo/ followed by a non-digit
207          if (std.fnmatch("/foo/[!0-9]", req.url)) { ... }
208

FILE(SYSTEM) FUNCTIONS

210   STRING fileread(STRING)
211       Reads  a  file  and  returns  a  string with the content. The result is
212       cached indefinitely per filename.
213
214       Example:
215
216          synthetic("Response was served by " + std.fileread("/etc/hostname"));
217
218       Consider that the entire contents of the file appear in the string that
219       is  returned,  including newlines that may result in invalid headers if
220       std.fileread() is used to form a header. In that case, you may need  to
221       modify the string, for example with regsub() (see vcl(7)):
222
223          set beresp.http.served-by = regsub(std.fileread("/etc/hostname"), "\R$", "");
224
225   BOOL file_exists(STRING path)
226       Returns  true if path or the file pointed to by path exists, false oth‐
227       erwise.
228
229       Example:
230
231          if (std.file_exists("/etc/return_503")) {
232                  return (synth(503, "Varnish is in maintenance"));
233          }
234

TYPE INSPECTION FUNCTIONS

236   BOOL healthy(BACKEND be)
237       Returns true if the backend be is healthy.
238
239   INT port(IP ip)
240       Returns the port number of the IP address ip. Always returns  0  for  a
241       *.ip variable when the address is a Unix domain socket.
242

TYPE CONVERSION FUNCTIONS

244       These functions all have the same form:
245
246          TYPE type([arguments], [fallback TYPE])
247
248       Precisely  one  of the arguments must be provided (besides the optional
249       fallback), and it will be converted to TYPE.
250
251       If conversion fails, fallback will be returned and if no  fallback  was
252       specified, the VCL will be failed.
253
254   DURATION  duration([STRING s], [DURATION fallback], [REAL real], [INT inte‐
255       ger])
256          DURATION duration(
257             [STRING s],
258             [DURATION fallback],
259             [REAL real],
260             [INT integer]
261          )
262
263       Returns a DURATION from a STRING, REAL or INT argument.
264
265       For a STRING s argument, s must be quantified by ms  (milliseconds),  s
266       (seconds),  m (minutes), h (hours),``d`` (days), w (weeks) or y (years)
267       units.
268
269       real and integer arguments are taken as seconds.
270
271       If the conversion of an s argument fails, fallback will be returned  if
272       provided, or a VCL failure will be triggered.
273
274       Conversions from real and integer arguments never fail.
275
276       Only  one  of  the  s,  real or integer arguments may be given or a VCL
277       failure will be triggered.
278
279       Examples::
280              set beresp.ttl = std.duration("1w",  3600s);  set  beresp.ttl  =
281              std.duration(real=1.5);   set  beresp.ttl  =  std.duration(inte‐
282              ger=10);
283
284   BYTES bytes([STRING s], [BYTES fallback], [REAL real], [INT integer])
285          BYTES bytes(
286             [STRING s],
287             [BYTES fallback],
288             [REAL real],
289             [INT integer]
290          )
291
292       Returns BYTES from a STRING, REAL or INT argument.
293
294       A STRING s argument can be quantified with a multiplier  (k  (kilo),  m
295       (mega), g (giga), t (tera) or p (peta)).
296
297       real and integer arguments are taken as bytes.
298
299       If  the conversion of an s argument fails, fallback will be returned if
300       provided, or a VCL failure will be triggered.
301
302       Other conversions may fail if the  argument  can  not  be  represented,
303       because it is negative, too small or too large. Again, fallback will be
304       returned if provided, or a VCL failure will be triggered.
305
306       real arguments will be rounded down.
307
308       Only one of the s, real or integer arguments may  be  given  or  a  VCL
309       failure will be triggered.
310
311       Example::
312              std.cache_req_body(std.bytes(something.somewhere,         10K));
313              std.cache_req_body(std.bytes(integer=10*1024));
314              std.cache_req_body(std.bytes(real=10.0*1024));
315
316   INT  integer([STRING s], [INT fallback], [BOOL bool], [BYTES bytes], [DURA‐
317       TION duration], [REAL real], [TIME time])
318          INT integer(
319             [STRING s],
320             [INT fallback],
321             [BOOL bool],
322             [BYTES bytes],
323             [DURATION duration],
324             [REAL real],
325             [TIME time]
326          )
327
328       Returns an INT from a STRING, BOOL or other quantity.
329
330       If the conversion of an s argument fails, fallback will be returned  if
331       provided, or a VCL failure will be triggered.
332
333       A  bool  argument  will be returned as 0 for false and 1 for true. This
334       conversion will never fail.
335
336       For a bytes argument, the number of bytes will be returned.  This  con‐
337       version will never fail.
338
339       A  duration  argument will be rounded down to the number of seconds and
340       returned.
341
342       A real argument will be rounded down and returned.
343
344       For a time argument,  the  number  of  seconds  since  the  UNIX  epoch
345       (1970-01-01 00:00:00 UTC) will be returned.
346
347       duration, real and time conversions may fail if the argument can not be
348       represented because it is too small or too large. If so, fallback  will
349       be returned if provided, or a VCL failure will be triggered.
350
351       Only one of the s, bool, bytes, duration, real or time arguments may be
352       given or a VCL failure will be triggered.
353
354       Examples:
355
356          if (std.integer(req.http.foo, 0) > 5) {
357                  ...
358          }
359
360          set resp.http.answer = std.integer(real=126.42/3);
361
362   IP ip(STRING s, [IP fallback], BOOL resolve=1, [STRING p])
363       Converts the string s to the first IP number  returned  by  the  system
364       library  function getaddrinfo(3). If conversion fails, fallback will be
365       returned or VCL failure will happen.
366
367       The IP address includes a port number that can be found with std.port()
368       that  defaults  to 80. The default port can be set to a different value
369       with the p argument. It will be overriden if  s  contains  both  an  IP
370       address and a port number or service name.
371
372       When  s  contains  both,  the  syntax is either address:port or address
373       port. If the address is a numerical IPv6 address it  must  be  enclosed
374       between brackets, for example [::1] 80 or [::1]:http.  The fallback may
375       also contain both an address and a port, but its default port is always
376       80.
377
378       If  resolve is false, getaddrinfo(3) is called using AI_NUMERICHOST and
379       AI_NUMERICSERV to avoid  network  lookups  depending  on  the  system's
380       getaddrinfo(3)  or  nsswitch  configuration.  This makes "numerical" IP
381       strings and services cheaper to convert.
382
383       Example:
384
385          if (std.ip(req.http.X-forwarded-for, "0.0.0.0") ~ my_acl) {
386                  ...
387          }
388
389   REAL real([STRING s], [REAL fallback], [INT integer], [BOOL  bool],  [BYTES
390       bytes], [DURATION duration], [TIME time])
391          REAL real(
392             [STRING s],
393             [REAL fallback],
394             [INT integer],
395             [BOOL bool],
396             [BYTES bytes],
397             [DURATION duration],
398             [TIME time]
399          )
400
401       Returns a REAL from a STRING, BOOL or other quantity.
402
403       If  the conversion of an s argument fails, fallback will be returned if
404       provided, or a VCL failure will be triggered.
405
406       A bool argument will be returned as 0.0 for false and 1.0 for true.
407
408       For a bytes argument, the number of bytes will be returned.
409
410       For a duration argument, the number of seconds will be returned.
411
412       An integer argument will be returned as a REAL.
413
414       For a time argument,  the  number  of  seconds  since  the  UNIX  epoch
415       (1970-01-01 00:00:00 UTC) will be returned.
416
417       None of these conversions other than s will fail.
418
419       Only one of the s, integer, bool, bytes, duration or time arguments may
420       be given or a VCL failure will be triggered.
421
422       Example:
423
424          if (std.real(req.http.foo, 0.0) > 5.5) {
425                  ...
426          }
427
428   TIME time([STRING s], [TIME fallback], [REAL real], [INT integer])
429          TIME time([STRING s], [TIME fallback], [REAL real], [INT integer])
430
431       Returns a TIME from a STRING, REAL or INT argument.
432
433       For a STRING s argument, the following formats are supported:
434
435          "Sun, 06 Nov 1994 08:49:37 GMT"
436          "Sunday, 06-Nov-94 08:49:37 GMT"
437          "Sun Nov  6 08:49:37 1994"
438          "1994-11-06T08:49:37"
439          "784111777.00"
440          "784111777"
441
442       real and integer arguments are taken as seconds since the epoch.
443
444       If the conversion of an s argument fails or a negative real or  integer
445       argument  is  given,  fallback  will  be returned if provided, or a VCL
446       failure will be triggered.
447
448       Examples:
449
450          if (std.time(resp.http.last-modified, now) < now - 1w) {
451                  ...
452          }
453
454          if (std.time(int=2147483647) < now - 1w) {
455                  ...
456          }
457

LOGGING FUNCTIONS

459   VOID log(STRING s)
460       Logs  the  string  s  to  the  shared  memory  log,  using  vsl(7)  tag
461       SLT_VCL_Log.
462
463       Example:
464
465          std.log("Something fishy is going on with the vhost " + req.http.host);
466
467   VOID syslog(INT priority, STRING s)
468       Logs the string s to syslog tagged with priority. priority is formed by
469       ORing the facility and level values. See your  system's  syslog.h  file
470       for possible values.
471
472       Notice:  Unlike  VCL and other functions in the std vmod, this function
473       will not fail VCL processing for workspace overflows:  For  an  out  of
474       workspace condition, the std.syslog() function has no effect.
475
476       Example:
477
478          std.syslog(9, "Something is wrong");
479
480       This will send a message to syslog using LOG_USER | LOG_ALERT.
481
482   VOID timestamp(STRING s)
483       Introduces  a  timestamp  in  the  log with the current time, using the
484       string s as the label. This is useful to time the execution of  lengthy
485       VCL procedures, and makes the timestamps inserted automatically by Var‐
486       nish more accurate.
487
488       Example:
489
490          std.timestamp("curl-request");
491

CONTROL AND INFORMATION FUNCTIONS

493   BOOL syntax(REAL)
494       Returns true if VCL version is at least REAL.
495
496   STRING getenv(STRING name)
497       Return environment variable name or the empty string. See getenv(3).
498
499       Example:
500
501          set req.http.My-Env = std.getenv("MY_ENV");
502
503   BOOL cache_req_body(BYTES size)
504       Caches the request body if it is smaller than size.   Returns  true  if
505       the body was cached, false otherwise.
506
507       Normally  the  request  body  can only be sent once. Caching it enables
508       retrying backend requests with a request body, as usually the case with
509       POST and PUT.
510
511       Example:
512
513          if (std.cache_req_body(1KB)) {
514                  ...
515          }
516
517   VOID late_100_continue(BOOL late)
518       Controls  when varnish reacts to an Expect: 100-continue client request
519       header.
520
521       Varnish always generates a 100 Continue response if  requested  by  the
522       client  trough the Expect: 100-continue header when waiting for request
523       body data.
524
525       But, by default, the 100 Continue response is already generated immedi‐
526       ately  after  vcl_recv returns to reduce latencies under the assumption
527       that the request body will be read eventually.
528
529       Calling std.late_100_continue(true) in vcl_recv will cause the 100 Con‐
530       tinue  response  to only be sent when needed. This may cause additional
531       latencies for processing request bodies, but is the correct behavior by
532       strict interpretation of RFC7231.
533
534       This  function  has  no  effect  outside  vcl_recv  and  after  calling
535       std.cache_req_body() or any other function consuming the request body.
536
537       Example:
538
539          vcl_recv {
540                  std.late_100_continue(true);
541
542                  if (req.method == "POST") {
543                          std.late_100_continue(false);
544                          return (pass);
545                  }
546                  ...
547           }
548
549   VOID set_ip_tos(INT tos)
550       Sets the IP type-of-service (TOS) field for the current session to tos.
551       Silently ignored if the listen address is a Unix domain socket.
552
553       Please note that the TOS field is not removed by the end of the request
554       so probably want to set it on every request should you utilize it.
555
556       Example:
557
558          if (req.url ~ "^/slow/") {
559                  std.set_ip_tos(0);
560          }
561
562   VOID rollback(HTTP h)
563       Restores the h HTTP headers to their original state.
564
565       Example:
566
567          std.rollback(bereq);
568

DEPRECATED FUNCTIONS

570   INT real2integer(REAL r, INT fallback)
571       DEPRECATED: This function will be removed in a future version  of  var‐
572       nish,  use std.integer() with a real argument and the std.round() func‐
573       tion instead, for example:
574
575          std.integer(real=std.round(...), fallback=...)
576
577       Rounds the real r to the nearest integer, but round halfway cases  away
578       from  zero  (see  round(3)).  If  conversion  fails,  fallback  will be
579       returned.
580
581       Examples:
582
583          set req.http.integer = std.real2integer(1140618699.00, 0);
584          set req.http.posone = real2integer( 0.5, 0);    # =  1.0
585          set req.http.negone = real2integer(-0.5, 0);    # = -1.0
586
587   TIME real2time(REAL r, TIME fallback)
588       DEPRECATED: This function will be removed in a future version  of  var‐
589       nish,  use std.time() with a real argument and the std.round() function
590       instead, for example:
591
592          std.time(real=std.round(...), fallback=...)
593
594       Rounds the real r to the nearest integer (see  std.real2integer())  and
595       returns  the  corresponding  time  when interpreted as a unix epoch. If
596       conversion fails, fallback will be returned.
597
598       Example:
599
600          set req.http.time = std.real2time(1140618699.00, now);
601
602   INT time2integer(TIME t, INT fallback)
603       DEPRECATED: This function will be removed in a future version  of  var‐
604       nish, use std.integer() with a time argument instead, for example:
605
606          std.integer(time=..., fallback=...)
607
608       Converts the time t to a integer. If conversion fails, fallback will be
609       returned.
610
611       Example:
612
613          set req.http.int = std.time2integer(now, 0);
614
615   REAL time2real(TIME t, REAL fallback)
616       DEPRECATED: This function will be removed in a future version  of  var‐
617       nish, use std.real() with a time argument instead, for example:
618
619          std.real(time=..., fallback=...)
620
621       Converts  the  time  t to a real. If conversion fails, fallback will be
622       returned.
623
624       Example:
625
626          set req.http.real = std.time2real(now, 1.0);
627

COPYRIGHT

636          Copyright (c) 2010-2017 Varnish Software AS
637          All rights reserved.
638
639          Author: Poul-Henning Kamp <phk@FreeBSD.org>
640
641          Redistribution and use in source and binary forms, with or without
642          modification, are permitted provided that the following conditions
643          are met:
644          1. Redistributions of source code must retain the above copyright
645             notice, this list of conditions and the following disclaimer.
646          2. Redistributions in binary form must reproduce the above copyright
647             notice, this list of conditions and the following disclaimer in the
648             documentation and/or other materials provided with the distribution.
649
650          THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
651          ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
652          IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
653          ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
654          FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
655          DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
656          OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
657          HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
658          LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
659          OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
660          SUCH DAMAGE.
661
662
663
664
665                                       3                             VMOD(STD)