vtc man page

VTC — Varnish Test Case Syntax

Overview

This document describes the syntax used by Varnish Test Cases files (.vtc). A vtc file describe a scenario with different scripted HTTP-talking entities, and generally one or more Varnish instances to test.

Parsing

A vtc file will be read word after word, with very little tokenization, meaning a syntax error won't be detected until the test actually reach the relevant action in the test.

A parsing error will most of the time result in an assert being triggered. If this happens, please refer yourself to the related source file and line number. However, this guide should help you avoid the most common mistakes.

Words and strings

The parser splits words by detecting whitespace characters and a string is a word, or a series of words on the same line enclosed by double-quotes ("..."), or, for multi-line strings, enclosed in curly brackets ({...}).

Comments

The leading whitespaces of lines are ignored. Empty lines (or ones consisting only of whitespaces) are ignored too, as are the lines starting with "#" that are comments.

Lines and commands

Test files take at most one command per line, with the first word of the line being the command and the following ones being its arguments. To continue over to a new line without breaking the argument string, you can escape the newline character (n) with a backslash ().

Syntax

barrier

NOTE: this can be used from the top-level as well as from client and server specifications.

Barriers allows you to synchronize different threads to make sure events occur in the right order. It's even possible to use them in VCL.

First, it's necessary to declare the barrier:

barrier bNAME TYPE NUMBER [-cyclic]

With the arguments being:

bNAME

this is the name of the barrier, used to identify it when you'll create sync points. It must start with 'b'.

TYPE

it can be "cond" (mutex) or "sock" (socket) and sets internal behavior. If you don't need VCL synchronization, use cond.

NUMBER

number of sync point needed to go through the barrier.

-cyclic

if present, the barrier will reset itself and be ready for another round once gotten through.

Then, to add a sync point:

barrier bNAME sync

This will block the parent thread until the number of sync points for bNAME reaches the NUMBER given in the barrier declaration.

If you wish to synchronize the VCL, you need to declare a "sock" barrier. This will emit a macro definition named "bNAME_sock" that you can use in VCL (after importing the debug vmod):

debug.barrier_sync("${bNAME_sock}");

This function returns 0 if everything went well and is the equivalent of barrier bNAME sync at the VTC top-level.

client/server

Client and server threads are fake HTTP entities used to test your Varnish and VCL. They take any number of arguments, and the one that are not recognized, assuming they don't start with '-', are treated as specifications, laying out the actions to undertake:

client cNAME [...]
server sNAME [...]

Clients and server are identified by a string that's the first argument, clients' names start with 'c' and servers' names start with 's'.

As the client and server commands share a good deal of arguments and specification actions, they are grouped in this single section, specific items will be explicitly marked as such.

Arguments

-start

Start the thread in background, processing the last given specification.

-wait

Block until the thread finishes.

-run (client only)

Equivalent to "-start -wait".

repeat NUMBER

Instead of processing the specification only once, do it NUMBER times.

-break (server only)

Stop the server.

-listen STRING (server only)

Dictate the listening socket for the server. STRING is of the form "IP PORT".

-connect STRING (client only)

Indicate the server to connect to. STRING is also of the form "IP PORT".

-dispatch (server only, s0 only)

Normally, to keep things simple, server threads only handle one connection at a time, but the -dispatch switch allows to accept any number of connection and handle them following the given spec.

However, -dispatch is only allowed for the server name "s0".

-proxy1 STRING (client only)

Use the PROXY protocol version 1 for this connection. STRING is of the form "CLIENTIP:PORT SERVERIP:PORT".

-proxy2 STRING (client only)

Use the PROXY protocol version 2 for this connection. STRING is of the form "CLIENTIP:PORT SERVERIP:PORT".

Macros and automatic behaviour

To make things easier in the general case, clients will connect by default to the first Varnish server declared and the -vcl+backend switch of the varnish command will add all the declared servers as backends.

Be careful though, servers will by default listen to the 127.0.0.1 IP and will pick a random port, and publish 3 macros: sNAME_addr, sNAME_port and sNAME_sock, but only once they are started. For varnishtest to create the vcl with the correct values, the server must be started when you use -vcl+backend.

Specification

It's a string, either double-quoted "like this", but most of the time enclosed in curly brackets, allowing multilining. Write a command per line in it, empty line are ignored, and long line can be wrapped by using a backslash. For example:

client c1 {
    txreq -url /foo \
          -hdr "bar: baz"

    rxresp
} -run

accept (server)

Close the potential current connection, and accept a new one. Note that this new connection is H/1.

accept (server only)

Close the active connection (if any) and accept a new one.

barrier

Same as for the top-level barrier

chunked STRING

Send STRING as chunked encoding.

chunkedlen NUMBER

Do as chunked except that varnishtest will generate the string for you, with a length of NUMBER characters.

close (server)

Close the connection. Not that if operating in H/2 mode, no extra (GOAWAY) frame is sent, it's simply a TCP close.

close (server)

Close the connection. Not that if operating in H/2 mode, no extra (GOAWAY) frame is sent, it's simply a TCP close.

delay

Same as for the top-level delay.

delay

Same as for the top-level delay.

expect STRING1 OP STRING2

Test if "STRING1 OP STRING2" is true, and if not, fails the test. OP can be ==, <, <=, >, >= when STRING1 and STRING2 represent numbers in which case it's an order operator. If STRING1 and STRING2 are meant as strings OP is a matching operator, either == (exact match) or ~ (regex match).

varnishtet will first try to resolve STRING1 and STRING2 by looking if they have special meanings, in which case, the resolved value is use for the test. Note that this value can be a string representing a number, allowing for tests such as:

expect req.http.x-num > 2

Here's the list of recognized strings, most should be obvious as they either match VCL logic, or the txreq/txresp options:

  • remote.ip
  • remote.port
  • req.method
  • req.url
  • req.proto
  • resp.proto
  • resp.status
  • resp.reason
  • resp.chunklen
  • req.bodylen
  • req.body
  • resp.bodylen
  • resp.body
  • req.http.NAME
  • resp.http.NAME

expect_close (server)

Reads from the connection, expecting nothing to read but an EOF.

expect_close (server)

Reads from the connection, expecting nothing to read but an EOF.

fatal|non-fatal

Control whether a failure of this entity should stop the test.

loop NUMBER STRING

Process STRING as a specification, NUMBER times.

recv NUMBER

Read NUMBER bytes from the connection.

rxchunk

Receive an HTTP chunk

rxpri (server)

Receive a preface, and if it matches, sets the server to H/2, aborts otherwise.

rxreq (server only)

Receive and parse a request's headers and body.

rxreqbody (server only)

Receive a request's body.

rxreqhdrs

Receive and parse a request's headers (but not the body).

rxreqhdrs

Receive and parse a request's headers (but not the body).

rxresp [-no_obj] (client only)

Receive and parse a response's headers and body. If -no_obj is present, only get the headers.

rxrespbody

Receive a response's body.

send STRING

Push STRING on the connection.

send_n NUMBER STRING

Write STRING on the socket NUMBER times.

send_urgent STRING

Send string as TCP OOB urgent data. You will never need this.

sendhex STRING

Send bytes as described by STRING. STRING should consist of hex pairs possibly separated by whitespace or newlines. For example: "0F EE a5    3df2".

settings -dectbl INT

Force internal H/2 settings to certain values. Currently only support setting the decoding table size.

timeout NUMBER

Set the TCP timeout for this entity.

txpri (client)

Send an H/2 preface ("PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n") and set client to H/2.

txreq|txresp [...]

Send a minimal request or response, but overload it if necessary.

txreq is client-specific and txresp is server-specific.

The only thing different between a request and a response, apart from who can send them is that the first line (request line vs status line), so all the options are prety much the same.

-req STRING (txreq only)

What method to use (default: "GET").

-url STRING (txreq only)

What location to use (default "/").

-proto STRING

What protocol use in the status line. (default: "HTTP/1.1").

-status NUMBER (txresp only)

What status code to return (default 200).

-msg STRING (txresp only)

What message to put in the status line (default: "OK").

These three switches can appear in any order but must come before the following ones.

-nolen

Don't include a Content-Length header in the response.

-hdr STRING

Add STRING as a header, it must follow this format: "name: value". It can be called multiple times.

You can then use the arguments related to the body:

-body STRING

Input STRING as body.

-bodylen NUMBER

Generate and input a body that is NUMBER bytes-long.

-gziplevel NUMBER

Set the gzip level (call it before any of the other gzip switches).

-gzipresidual NUMBER

Add extra gzip bits. You should never need it.

-gzipbody STRING

Zip STRING and send it as body.

-gziplen NUMBER

Combine -body and -gzipbody: create a body of length NUMBER, zip it and send as body.

stream

H/2 introduces the concept of streams, and these come with their own specification, and as it's quite big, have bee move to their own chapter.

err_shell

This is very similar to the the shell command, except it takes a first string as argument before the command:

err_shell "foo" "echo foo"

err_shell expect the shell command to fail AND stdout to match the string, failing the test case otherwise.

feature

Test that the required feature(s) for a test are available, and skip the test otherwise. feature takes any number of arguments from this list:

SO_RCVTIMEO_WORKS

The SO_RCVTIMEO socket option is working

64bit

The environment is 64 bits

!OSX

The environment is not OSX

dns

DNS lookups are working

topbuild

varnishtest has been started with '-i'

root

varnishtest has been invoked by the root user

user_varnish

The varnish user is present

user_vcache

The vcache user is present

group_varnish

The varnish group is present

cmd <command-line>

A command line that should execute with a zero exit status

logexpect

Reads the VSL and looks for records matching a given specification. It will process records trying to match the first pattern, and when done, will continue processing, trying to match the following pattern. If a pattern isn't matched, the test will fail.

logexpect threads are declared this way:

logexpect lNAME -v <id> [-g <grouping>] [-d 0|1] [-q query] \
        [vsl arguments] {
                expect <skip> <vxid> <tag> <regex>
                expect <skip> <vxid> <tag> <regex>
                ...
        } [-start|-wait]

And once declared, you can start them, or wait on them:

logexpect lNAME <-start|-wait>

With:

lNAME

Name the logexpect thread, it must start with 'l'.

-v id

Specify the varnish instance to use (most of the time, id=v1).

-g <session|request|vxid|raw

Decide how records are grouped, see -g in man varnishlog for more information.

-d <0|1>

Start processing log records at the head of the log instead of the tail.

-q query

Filter records using a query expression, see man vsl-query for more information.

-start

Start the logexpect thread in the background.

-wait

Wait for the logexpect thread to finish

VSL arguments (similar to the varnishlog options):

-b|-c

Process only backend/client records.

-C

Use caseless regex

-i <taglist>

Include tags

-I <[taglist:]regex>

Include by regex

-T <seconds>

Transaction end timeout

And the arguments of the specifications lines are:

skip: [uint|*]

Max number of record to skip

vxid: [uint|*|=]

vxid to match

tag: [tagname|*|=]

Tag to match against

regex:

regular expression to match against (optional) ('*' is anything, '=' is the value of the last matched record)

shell

Pass the string given as argument to a shell. If you have multiple commands to run, you can use curly barces to describe a multi-lines script, eg:

shell {
        echo begin
        cat /etc/fstab
        echo end
}

The vtc will fail if the return code of the shell is not 0.

stream

(note: this section is at the top-level for easier navigation, but it's part of the client/server specification)

Streams map roughly to a request in H/2, a request is sent on stream N, the response too, then the stream is discarded. The main exception is the first stream, 0, that serves as coordinator.

Stream syntax follow the client/server one:

stream ID [SPEC] [ACTION]

ID is the H/2 stream number, while SPEC describes what will be done in that stream.

Note that, when parsing a stream action, if the entity isn't operating in H/2 mode, these spec is ran before:

txpri/rxpri # client/server
stream 0 {
    txsettings
    rxsettings
    txsettings -ack
    rxsettings
    expect settings.ack == true
} -run

And H/2 mode is then activated before parsing the specification.

Actions

-start

Run the specification in a thread, giving back control immediately.

-wait

Wait for the started thread to finish running the spec.

-run

equivalent to calling -start then -wait.

Specification

The specification of a stream follows the exact same rules as one for a client or a server.

txreq, txresp, txcont, txpush

These four commands are about sending headers. txreq,  txresp will send HEADER frames, txcont will send CONTINUATION frames, and txpush PUSH frames. The only difference between txreq and txresp are the default headers set by each of them.

-noadd

Do not add default headers. Useful to avoid duplicates when sending default headers using -hdr, -idxHdr and -litIdxHdr.

-status INT (txresp)

Set the :status pseudo-header.

-url STRING (txreq, txpush)

Set the :path pseudo-header.

-req STRING (txreq, txpush)

Set the :method pseudo-header.

-scheme STRING (txreq, txpush)

Set the :scheme pseudo-header.

-hdr STRING1 STRING2

Insert a header, STRING1 being the name, and STRING2 the value.

-idxHdr INT

Insert an indexed header, using INT as index.

-litIdxHdr inc|not|never INT huf|plain STRING

Insert an literal, indexed header. The first argument specify if the header should be added to the table, shouldn't, or mustn't be compressed if/when retransmitted.

INT is the idex of the header name to use.

The third argument informs about the Huffman encoding: yes (huf) or no (plain).

The last term is the literal value of the header.

-litHdr inc|not|never huf|plain STRING1 huf|plain STRING2

Insert a literal header, with the same first argument as -litIdxHdr.

The second and third terms tell what the name of the header is and if it should be Huffman-encoded, while the last two do the same regarding the value.

-body STRING (txreq, txresp)

Specify a body, effectively putting STRING into a DATA frame after the HEADER frame is sent.

-bodylen INT (txreq, txresp)

Do the same thing as -body but generate an string of INT length for you.

-nostrend (txreq, txresp)

Don't set the END_STREAM flag automatically, making the peer expect a body after the headers.

-nohdrend

Don't set the END_HEADERS flag automatically, making the peer expect more HEADER frames.

-dep INT (txreq, txresp)

Tell the peer that this content depends on the stream with the INT id.

-ex (txreq, txresp)

Make the dependency exclusive (-dep is still needed).

-weight (txreq, txresp)

Set the weight for the dependency.

-promised INT (txpush)

The id of the promised stream.

-pad STRING / -padlen INT (txreq, txresp, txpush)

Add string as padding to the frame, either the one you provided with -pad, or one that is generated for you, of length INT is -padlen case.

txdata

By default, data frames are empty. The receiving end will know the whole body has been delivered thanks to the END_STREAM flag set in the last DATA frame, and txdata automatically set it.

-data STRING

Data to be embedded into the frame.

-datalen INT

Generate and INT-bytes long string to be sent in the frame.

-pad STRING / -padlen INT

Add string as padding to the frame, either the one you provided with -pad, or one that is generated for you, of length INT is -padlen case.

-nostrend

Don't set the END_STREAM flag, allowing to send more data on this stream.

rxreq, rxresp

These are two convenience functions to receive headers and body of an incoming request or response. The only difference is that rxreq can only be by a server, and rxresp by a client.

rxpush

This works like rxhdrs, expecting a PUSH frame and then zero or more CONTINUATION frames.

-all

Keep waiting for CONTINUATION frames until END_HEADERS flag is seen.

-some INT

Retrieve INT - 1 CONTINUATION frames after the PUSH frame.

rxhdrs

rxhdrs will expect one HEADER frame, then, depending on the arguments, zero or more CONTINUATION frame.

-all

Keep waiting for CONTINUATION frames until END_HEADERS flag is seen.

-some INT

Retrieve INT - 1 CONTINUATION frames after the HEADER frame.

rxdata

Receiving data is done using the rxdata keywords and will retrieve one DATA frame, if you wish to receive more, you can use these two convenience arguments:

-all

keep waiting for DATA frame until one sets the END_STREAM flag

-some INT

retrieve INT DATA frames.

delay

Take a float as argument and sleep for that number of seconds.

Receive a frame, any frame.

sendhex

Push bytes directly on the wire. sendhex takes exactly one argument: a string describing the bytes, in hex notation, will possible whitespaces between them. Here's an example:

sendhex "00 00 08 00 0900       8d"

rxgoaway

Receive a GOAWAY frame

rxgoaway

Possible options include:

-err STRING|INT

set the error code to eplain the termination. The second argument can be a integer or the string version of the error code as found in rfc7540#7.

-laststream INT

the id of the "highest-numbered stream identifier for which the sender of the GOAWAY frame might have taken some action on or might yet take action on".

-debug

specify the debug data, if any to append to the frame.

rxping

Receive a PING frame

txping

Send PING frame.

-data STRING

specify the payload of the frame, with STRING being an 8-char string.

-ack

set the ACK flag.

rxprio

Receive a PRIORITY frame

txprio

Send a PRIORITY frame

-stream INT

indicate the id of the stream the sender stream depends on.

-ex

the dependency should be made exclusive (only this streams depends on the parent stream).

-weight INT

an 8-bits integer is used to balance priority between streams depending on the same streams.

rxrst

Receive a RST_STREAM frame

txrst

Send a RST_STREAM frame. By default, txrst will send a 0 error code (NO_ERROR).

-err STRING|INT

Sets the error code to be sent. The argument can be an integer or a string describing the error, such as NO_ERROR, or CANCEL (see rfc7540#11.4 for more strings).

rxsettings

Receive a SETTINGS frame

txsettings

SETTINGS frames must be acknowledge, arguments are as follow (most of them are from  rfc7540#6.5.2):

-hdrtbl INT

headers table size

-push BOOL

whether push frames are accepted or not

-maxstreams INT

maximum concurrent streams allowed

-winsize INT

sender's initial window size

-framesize INT

largest frame size authorized

-hdrsize INT

maximum size of the header list authorized

-ack

set the ack bit

rxwinup

Receive a WINDOW_UPDATE frame

txwinup

Transmit a WINDOW_UPDATE frame, increasing the amount of credit of the connection (from stream 0) or of the stream (any other stream).

-size INT

give INT credits to the peer.

expect

expect in stream works as it does in client or server, except that the elements compared will be different.

Most of these elements will be frame specific, meaning that the last frame received on that stream must of the correct type.

Here the list of keywords you can look at.

varnish

Define and interact with varnish instances.

To define a Varnish server, you'll use this syntax:

varnish vNAME [-arg STRING] [-vcl STRING] [-vcl+backend STRING]
        [-errvcl STRING STRING] [-jail STRING] [-proto PROXY]

The first varnish vNAME invocation will start the varnishd master process in the background, waiting for the -start switch to actually start the child.

With:

vNAME

Identify the Varnish server with a string, it must starts with 'v'.

-arg STRING

Pass an argument to varnishd, for example "-h simple_list".

-vcl STRING

Specify the VCL to load on this Varnish instance. You'll probably want to use multi-lines strings for this ({...}).

-vcl+backend STRING

Do the exact same thing as -vcl, but adds the definition block of known backends (ie. already defined).

-errvcl STRING1 STRING2

Load STRING2 as VCL, expecting it to fail, and Varnish to send an error string matching STRING2

-jail STRING

Look at man varnishd (-j) for more information.

-proto PROXY

Have Varnish use the proxy protocol. Note that PROXY here is the actual string.

You can decide to start the Varnish instance and/or wait for several events:

varnish vNAME [-start] [-wait] [-wait-running] [-wait-stopped]
-start

Start the child process.

-stop

Stop the child process.

-syntax

Set the VCL syntax level (default: 4.0)

-wait

Wait for that instance to terminate.

-wait-running

Wait for the Varnish child process to be started.

-wait-stopped

Wait for the Varnish child process to stop.

-cleanup

Once Varnish is stopped, clean everything after it. This is only used in one test and you should never need it.

Once Varnish is started, you can talk to it (as you would through varnishadm) with these additional switches:

varnish vNAME [-cli STRING] [-cliok STRING] [-clierr STRING]
              [-expect STRING OP NUMBER]
-cli STRING|-cliok STRING|-clierr STATUS STRING

All three of these will send STRING to the CLI, the only difference is what they expect the return code to be. -cli doesn't expect anything, -cliok expects 200 and -clierr expects STATUS

-expect STRING OP NUMBER

Look into the VSM and make sure the counter identified by STRING has a correct value. OP can be ==, >, >=, <, <=. For example:

varnish v1 -expect SMA.s1.g_space > 1000000
-vsc PATTERN

Dump VSC counters matching PATTERN.  The PATTERN is a 'glob' style pattern (ie: fnmatch(3)) as used in shell filename expansion. To see all counters use pattern "*", to see all counters about requests use "req".

varnishtest

This should be the first command in your vtc as it will identify the test case with a short yet descriptive sentence. It takes exactly one argument, a string, eg:

varnishtest "Check that varnishtest is actually a valid command"

It will also print that string in the log.

History

This document has been written by Guillaume Quintard.

See Also

Referenced By

varnishtest(1).